Techniques of cultivating one-year-old and large seedlings by cutting of Photinia rugosa

Red leaf heather can also be called flame red, millennium red, red Robin, red lips, acid leaf heather, acid leaf tree, mainly distributed in southeast Asia and eastern and temperate regions of North America, now planted in many places in China, flowering 5-7 months, fruit maturity 9-10 months, mainly used for gardens to do hedges or do street trees.

Cultivation of 1-year-old red-leaf Photinia seedlings

1.1 nursery site selection and site preparation

Choose convenient drainage and irrigation, loose texture, moist and fertile, the previous crop for rice sandy soil as nursery land, taboo in poor drainage, poor air permeability of low land planting.

1.2 cutting time

The cutting time in Jiangxi is from May to June, that is, when the new shoots of Photinia chinensis mother tree changed from red to green, it healed quickly and was easy to take root. The nursery should be broken up and fine, and the basic fertilizer should be applied before soil preparation (40kg of compound fertilizer per 667m2, withered cake 50kg). The soil preparation can be broken and turned into the soil by tractor or diesel rotary tiller. Make a bed (1m wide and 30cm high) 20 days before cutting. after the bed is finished, spray the bed surface and path ditch with 70kg per 667m2500g and 0.5% potassium permanganate solution to reduce weed breeding and soil disinfection. After the seedbed is finished, cover it with plastic desert and set aside.

1.3 Mother Tree selection

Choose the variety you like, the mother tree is 10 to 15 years old, at the same time, the mother tree is required to develop normally, grow healthily and free from diseases and insect pests.

1.4 Branch selection

Choose the sturdy branches in the middle and upper part of the crown, which are full of life and are most likely to breed new plants.

1.5 Branch cutting

Choose to prune on rainy days or when there is dew in the morning. immediately after pruning, wrap it in a cool place with a wet cloth to prevent moisture loss. The 6~10cm is left in the branch, the thick 0.3cm is about, the upper end of the branch is cut flat, the lower part is cut into an oblique shape, the section should be smooth and smooth, the upper end of the branch retains 0.5 leaves, and the rest is cut off. The base of the cut panicle should be soaked in the mixed solution of fresh yellow mud and ABT rooting powder 200mg/L for 1 hour or 2 hours, which is beneficial to promote new roots and survival rate.

1.6 Cuttage

When cutting, cuttings should pay attention to moisturizing, and then insert the cuttings into the hole with a bamboo stick, the depth of which is about 1/2 of the length of the spike, then press the soil to the center of the spike with two hands, and then spray the cuttings with methyl topiramate or carbendazim solution. After that, it is necessary to build a frame with bamboo or wood strips immediately, cover it with a shading net and make a shading shed with a sunshade net. The height of the shed requires 80~100cm off the bed surface, and the shading net should be covered with double layers of three stitches or two needles. At the same time, it is necessary to cover the cuttings with shade along with watering, so as to avoid the water loss of cuttings themselves.

1.7 Post-cutting management

1.7.1 humidity and temperature control: according to Rain Water's condition after cutting, the soil can be watered once a day according to the dry and wet condition of the soil to keep the soil moist. The most suitable temperature for cutting is 25 degrees. When the temperature exceeds 35 degrees, the cuttings are easy to dry and wither, so it is necessary to build a sunshade net to control the temperature and increase the humidity in the shed.

1.7.2 Light control: Photinia przewalskii cutting for about 30 days, the base begins to merge and grow new roots, and then gradually remove the sunshade net, all to be removed after October, in order to speed up Lignification and enhance wind and cold resistance.

1.8 fertilization

Topdressing 2-3 times from August to September can be applied thinly with human feces and urine, generally 1 tablespoon of human feces and urine with 1 bucket of water, or with compound fertilizer 0.2kg mixed with water 50kg, fully dissolved and stirred.

2 cultivation of large seedlings

2.1 nursery site selection, soil preparation, application of basic fertilizer, bed making

Transplant the new shoots before and after the Beginning of Spring. The seedlings should be raised with a hoe or tooth rake, and the seedlings should be collected and bundled according to first-class seedlings and second-class seedlings. When planting, primary seedlings and secondary seedlings are planted separately, which is conducive to the uniform growth of seedlings, small differentiation, and promote the growth of more and denser lateral fibrous roots. The branches and leaves should be pruned properly according to the growth of the tree. When planting, it can be planted straight, relaxed and tight, and the planting depth is suitable, which is generally deeper than that of seedlings in the rhizosphere of 3~5cm. Water the roots thoroughly after planting.

2.2 Management after colonization

Ploughing and loosening soil with a small hoe combined with weeding after planting. Fertilizing with rotten thin human feces and urine can be applied 4 times before June in the first half of the year and 2 times after September in the second half of the year. At the same time, it can also be applied with compound fertilizer hole, 30 ~ 40g per hole and covered with soil after fertilization. Pruning and topping are carried out according to the growth of the plant, mainly to promote lateral branches and make the tree plump.

2.3 after 3 ~ 4 years of cultivation, the seedling height can reach 1.5 × 2m, which can be transplant with soil again, trim the branches and leaves properly, or determine the cultivation period according to the demand of the market.

Market value and market potential of Photinia rugosa

Photinia rubra may be one of the most well-known seedling varieties on the market at present. Under the vigorous publicity and promotion of several large production enterprises headed by Zhejiang Senhe seed Industry Co., Ltd., it is soon a household name in the seedling industry. However, as there are still many uncertain factors in the market, many operators hold a hesitant attitude towards it. The reporter conducted a market survey on this issue for reference for seedling workers.

Red leaf Photinia comes out in front of the trend

Photinia rugosa was gradually known by people only last year. In the eyes of many people, it seems to be "born rich": it became popular as soon as it entered the country. In fact, like many other seedling varieties, the "good day" of Photinia rubra is also waiting for it.

Nanjing Wanhe Photinia seedlings Farm began to plant red-leaf Photinia on a small scale eight years ago, and it is one of the earliest production units in China. Ji Guoping, general manager of the nursery, said that the red-leaf Photinia in Nanjing was originally introduced from Japan by a local scientific research unit. when he saw it, he felt very beautiful and planted some in the nursery. In the first few years, Wanhe did not push Photinia mandshurica very much, but only carried out a small amount of propagation each year. It was not until two years ago that Wanhe consciously expanded the reproduction of seedlings when some enterprises advertised Photinia rugosa on the market.

Jiangsu spark lawn joint development company introduced a batch of Photinia rugosa from Europe in 1999 and began to supply seedlings to the market in bulk in the past two years. Wang Fuyin, general manager of the company, said that this is on the one hand because it takes two years to observe and test the introduction of new varieties, and on the other hand, because colored-leaf trees have only become hot in recent years, there was little demand in the past.

After Nanjing Wanhe and Xinghuo Lawn, Senhe seed Industry, Shanghai Luya Landscape Engineering Co., Ltd., Zhejiang Yuyao Ruan Yi seed Industry Co., Ltd. have also introduced and propagated Photinia rubra. The common view of these introduction units is that Photinia is concerned by everyone, which is closely related to the current situation of landscaping construction in our country.

At present, the urban greening in our country is mainly green, and the color is relatively monotonous. In order to change this situation, many cities put forward the slogan of "beautification and beautification". Zheng Yongping, chairman of Senhe seed Industry Co., Ltd., said that China's greening construction has changed from simply building green to beautifying the city, and the proportion of colored leaf trees in the city will gradually increase, which is expected to reach 15-20%. If calculated according to the annual increase of 20, 000 hectares of urban green space in the country, the demand for colored leaf seedlings is 4000 hectares, the number is very large. Moreover, at this stage, the share of colored-leaf seedlings in the market is still very small, the number of native trees is not large, and most of the shrub varieties imported from abroad are in the stage of propagation. These objective conditions determine that excellent colored-leaf tree species have a huge market prospect.

Rare red-leaf tree species

There are hundreds of colorful leaf trees in the world, why do people stare at a red leaf heather?

Ji Guoping said that when the staff of the Nanjing Garden Bureau went to Japan to inspect, they did not look at the cherry blossoms, the national flower of Japan, but brought back the red-leaf heather. Zheng Yongping and Tian Di, general manager of Luya Company, also said that the first thing I saw when I went abroad was Photinia rugosa. At present, among the red-leaf shrub varieties, no other particularly good varieties have been found except Photinia rubra. The field has been doing greening projects for many years, and he expounds the four advantages of Photinia rugosa from the point of view of users. The first is the good landscape effect. Photinia rugosa is an evergreen color tree species. In East China, its red leaf period is as long as 8 to 9 months in a year, and its color is bright and lasting, which is very rare in evergreen color leaf trees. Second, it does not have high requirements for reproductive technology, and it is relatively easy to popularize. Third, Photinia rubra is widely used in greening. It grows fast and is resistant to pruning. It can be used to make color blocks and hedges, and it can also be cultivated into single-pole and spherical crown trees, which can not only form a landscape independently, but also play a role in embellishment. Fourth, Photinia przewalskii has strong adaptability, low temperature tolerance, barren soil resistance, certain saline-alkali tolerance and drought tolerance, likes strong light and strong shade tolerance, and is suitable for growth.

Zheng Yongping said that before deciding what kind of seedlings to make, Senhe inspected more than 8000 varieties at home and abroad, and finally selected 212. after three years of determination, it was found that the comprehensive performance of Photinia rubra was particularly outstanding among these varieties. He said that Photinia rugosa has been developed in New Zealand for 40 years and has been used in Europe, America and Japan for more than 20 years. It is a popular mature tree species and is known as the "king of red-leaf hedges", which is also an important reason why Senhe chose Photinia rugosa in the first place.

From the feedback of the greening project market, Photinia chinensis has been recognized by many units, and Tangshan Gardens Company also advertises in the newspaper to buy Photinia tomentosa.

It is difficult to reach a final conclusion on the key issues

Now, the slightly larger nursery all know the red leaf Photinia, but few dare to introduce a large number of species, and most people are still in a state of "holding money for purchase". There are two main issues that people are concerned about: how many seedlings are there now? How much is its demand?

The propagation rate of Photinia rubra is very fast, and an one-year-old female seedling can generally propagate 30 to 40 plants a year. If we continue to propagate with these seedlings, there will be more than 1000 plants two years later, and the increase is astonishing. Therefore, it is of great reference value to find out the current base number of Photinia rubra. It is difficult to count this number accurately because many seedling companies use it as a trade secret. Others exaggerate the quantity at will in order to publicize the need, so there is a lot of false information. According to Zheng Yongping and Tian Di, the current number of red-leaf Photinia seedlings is about 10 million to 20 million, and the finished seedling is about 1 million. There may be a deviation between these two figures, but it is a fact that the number of red-leaf Photinia seedlings and finished seedlings is small. First of all, there are not many enterprises producing Photinia on a large scale at present. The introduction sites of enterprises in Shandong, Henan and other places are basically the same, concentrated in Nanjing, Hangzhou, Jurong, Shanghai and other nurseries where Photinia rubra was introduced earlier. Shenyang, Dalian, Anshan and other enterprises producing red-leaf Photinia tissue culture seedlings are basically sold to Jiangsu and Zhejiang. Secondly, the price of Photinia chinensis seedlings is high, and a seedling of more than 10 centimeters sells for 3 or 5 yuan, which limits the introduction of nurseries that lack financial strength. Now the nursery introduction is becoming more and more cautious, for this new variety of Photinia rubra, generally only try to buy a hundred and eighty plants. Finally, the first few units to do Photinia rubra are unwilling to sell more than one-year-old seedlings, but mostly stay for propagation of mother plants, from which we can also see that the number of mother plants is limited. As for engineering seedlings, the current shortage situation in the market is very obvious, which can be seen from the price of up to 10 yuan per one-year-old seedling and the use of units to advertise for seedlings.

Red leaf Berberis and Carthamus tinctorius are the main tree species to make hedges and color blocks in urban greening, with a large amount of more than 1 billion trees every year. When promoting red-leaf Photinia, manufacturers like to compare it with red-leaf Berberis and Carthamus tinctorius, and say that red-leaf Photinia will replace the latter in the near future. Their reason is that the leaves of red leaf Berberis and Carthamus tinctorius are low leathery, the color is dark purplish red, and red leaf Berberis is deciduous in winter, and it is only suitable for planting in acidic soil, which can not be comparable to Photinia rubra in ornamental effect and adaptability.

However, for this comparison, some people in the industry think that it is inappropriate. Liu Yalong admitted that Photinia rubra is a good variety and has great potential in Jiangsu and Zhejiang provinces. At the same time, he said that it is best to compare seedlings of the same genus and species, and Berberis Berberis is something that has been pushed away and has been widely accepted by the units in use. at high latitudes, its cold tolerance is not as good as that of Photinia rubra. Liu Yalong said: "what kind of seedlings are used in the greening project mainly depends on two points: the landscape effect and the price. Now the cutting seedlings of Berberis amurensis are about 10 cents per plant, and the engineering seedlings are only more than one yuan. Compared with the red leaf Photinia, the price advantage is obvious." Hou Boxin, an expert in safflower research and associate researcher of Hunan Academy of Forestry Sciences, also stressed the price advantage of Carthamus tinctorius. Its engineering seedlings cost less than one yuan per plant, and its flowers are very beautiful, which is inferior to Photinia rugosa. Hou Boxin has now selected a cold-tolerant variety of Carthamus tinctorius, and is preparing to take it to Beijing for trial planting.

The northern boundary of introduction is not clear.

To determine the market size of a seedling variety, in addition to its own traits, the appropriate planting range is also very important. So how wide is the planting range of Photinia chinensis in China? A common saying is that it can be planted in areas east of Xi'an and south of Beijing, but reporters heard different voices in the survey.

On the seedling variety display page on the website of Beijing Linda Forestry Science and Technology Co., Ltd., red leaf Photinia ranked first, but the company's Qiao transfer manager told reporters positively, "Red leaf Photinia is not good in Beijing, and the cost of overwintering is too high." He said they tried it two years ago and found that they needed to build a small arched shed to survive the winter, but now they basically don't do it.

The Forest Bioengineering Company of Northeast normal University began to make tissue culture seedlings of Photinia rubra in 2001, and it has been planted in Beijing, Dalian, Shandong and Henan. According to Zhang Yifei of the company, Photinia rubrum is quite frozen in winter in Beijing and Dalian, and the open field is not more winter. Some areas of Shandong are similar to Beijing, and now their tissue culture seedlings are mainly sold to Jiangsu and Zhejiang.

Zhu Shaoyuan, general manager of Huamu Farm in Changyi City, Shandong Province, said: "Photinia is widely planted in Hokkaido, Japan, and Shandong should also be able to grow it in terms of latitude. However, according to the experiments in recent years, it is possible to survive the winter in the south of Jinan, but not in Weifang, Dezhou and other northern Shandong areas. if you want to push it out in Shandong, you need to slowly lead it one stop at a time, first from Nanjing to Henan, and then from Henan to Shandong."

The winter temperature in Henan is higher than that in Shandong, and the domestic Photinia glauca and Photinia chinensis grow very well there. Liu Yalong of Wanchunyuan Forest Greening Co., Ltd., Lushan County, Henan Province, which began experimenting with growing red-leaf photinia four years ago, said that the overall performance of red-leaf photinia in Henan is OK, and its tender shoots are very beautiful, but there are also some problems. He found that the red-leaf Photinia introduced from different units varied greatly in characters. The variety he first introduced from the Zhongshan Botanical Garden in Nanjing was very hardy, while the variety introduced from an enterprise in Shanghai last year had dry shoots in winter. "at that time, the impact was not great," Liu Yalong said. "you can simply buckle it with a small arch shed. But when the film was uncovered this year, it was found that there were aphids harming the tender shoots." It can be seen that in Hebei, Shandong, Shaanxi, Shanxi and other areas, the introduction of Photinia should be particularly cautious.

The introduction of varieties is a complex issue, and the differences between planting techniques and varieties may also lead to different conclusions from different units. Considering the situation in various places, it is safe to say that Photinia rubra is planted to the south of the Yellow River at present.

Opportunity and risk coexist

The overwhelming advertising of Photinia chinensis is easy to remind people of the fast-growing poplar in the past, and some people think that this way of promotion is open to question.

Zhu Shaoyuan said that seedling varieties are not consumer goods, as long as they are branded. Seedlings are living organisms, and there are many factors affecting their growth. The best way to promote them is to plant a piece for everyone to see. Publicity alone is not enough. Zhang Qi, general manager of the giant company, believes that Photinia rugosa has a good color and new varieties, and many people are interested in it, but it is not clear to what extent it can be applied in the end. "it is unknown that there may be problems or may be smooth in the process of using the new varieties," he said. Generally speaking, it takes at least 5 years for a variety to be tested before it can be safely used. A few days ago, red-leaf heather can only say that it is probably possible, but it has yet to be tested by nature. "

Senhe seed industry is full of confidence in Photinia chinensis. In order to let more greening engineering units know about Photinia rubra, the enterprise has also carried out a "double 100 demonstration project". Zheng Yongping said: "at present, there are very few units with pure varieties and technical strength. with the increase of reproduction and the increasing popularity of technology, there is a lot of room for price reduction of red-leaf Photinia engineering seedlings, which can reach the level of red-leaf Berberis and safflower." He predicts that Photinia rubra will be a more profitable species in five to eight years. At present, the key is to push Photinia chinensis to the engineering market as soon as possible, and then pull the seedling market.

Driven by interests, many people are eager to try, but the market situation of Photinia rubra is not clear, and its rapid breeding speed makes them hesitant.

As the saying goes, opportunity always favors the foresight, but a hidden sentence is not said: risk is the twin brother of opportunity, and the two go hand in hand.

In the current situation that the market information about Photinia is incomplete, the decision-making has a certain nature of game. Whether it is suitable for the development of Photinia rubra needs to be decided by each nursery according to its own actual situation.

Vegetative Propagation of seedlings-Greenwood Cuttage

Vegetative Propagation of seedlings-Greenwood Cuttage

Vegetative reproduction is a method of raising seedlings by using the vegetative organs of plants, such as branches, roots, stems, leaves, etc., under suitable conditions. Vegetative reproduction is also called asexual reproduction without the participation of sexual cells. The seedlings cultivated by the method of vegetative propagation are called vegetative or asexual seedlings.

Vegetative reproduction is a method of raising seedlings by making use of the regeneration ability and meristematic ability of plant cells and the affinity of grafted growth with another plant. Regeneration ability refers to the ability of plant vegetative organs (roots, stems, leaves) to differentiate into other parts that they did not have, such as growing new leaves and roots with stem or branch cuttings, growing new branches and leaves with root cuttings, and growing new roots and stems with leaf cuttings. Meristematic ability means that some plants can grow some special abnormal organs specially for vegetative reproduction, such as bulbs, bulbs, stolons and so on.

V vegetative reproduction has the following characteristics:

v① It can maintain the excellent characters of female parent. Because vegetative reproduction is not produced by the combination of hermaphroditic cells, but by somatic cells directly divided by meristem, all genetic information of parents can be reproduced, and the excellent characters and inherent phenotypic characteristics of the original female parent can be maintained, without the phenomenon of character separation like seed reproduction. thus achieving the purpose of preserving and propagating fine varieties.

v② The seedlings of vegetative propagation generally grow fast and can bloom and bear fruit early. Because vegetative reproduction of new plants is based on the continuation of the original stage of development of the female parent, unlike seed reproduction seedlings, ontogeny restarts.

v③ Some garden plants do not bear fruit or bear less or do not produce effective seeds, they can be cultivated through vegetative propagation to improve the effectiveness of production seedlings and reproductive coefficient. Such as double-petalled peach, stone fruit and so on.

v④ Some garden plants with special shapes need to be propagated and produced through vegetative propagation methods, such as tree (shaped) rose, dragon claw locust, etc. Moreover, the rejuvenation of ancient and famous trees in gardens also needs to promote tissue proliferation or restore their growth potential through grafting (high grafting or bridging).

v ④ The method is simple and economical. Because some garden plant seeds have deep dormancy, it is more cumbersome and difficult to reproduce with seeds, and it is easier, simpler and more economical to reproduce with nutrition.

v It can be seen from the above that vegetative propagation plays a very important role in garden seedling, plant modeling and rejuvenation of ancient and famous trees. However, vegetative propagation also has its shortcomings, such as vegetative propagation seedlings have no obvious taproot roots, not as developed as the roots of seedlings (except grafted seedlings), poor resistance, and short life. For some tree species, multiple generations of repeated vegetative reproduction is easy to cause degradation, resulting in weak seedling growth, such as Chinese fir.

V vegetative propagation in the cultivation of garden seedlings commonly used methods are: cuttage propagation, grafting propagation, plant propagation, buried propagation, layering propagation.

Section 1---

v Cutting propagation is the use of isolated plant vegetative organs such as roots, stems (branches), leaves and other parts, under certain conditions inserted into soil, sand or other substrates, the use of plant regeneration ability, through artificial cultivation to develop into a complete new plant propagation method. After cutting for direct cuttage part called cuttings, with cuttage propagation of seedlings called cuttings.

Cuttage propagation method is simple, the material is sufficient, can carry out a large number of seedlings and multi-season seedlings, has become one of the main propagation methods of trees, especially non-bearing or rare fruit garden trees. Cuttage seedling, like other vegetative propagation, has the characteristics of rapid seedling growth, old stage development and good traits of female parent. However, due to cuttings from the mother, must be given suitable temperature, humidity and other environmental conditions to survive, for some higher requirements of tree species, but also need to adopt necessary measures such as shade, spray, set up plastic shed and other measures to succeed. Therefore, cuttage propagation requires fine management and more labor.

1. Principle of cuttage survival

(i) Rooting types of cuttings

V plant cuttings take root, because there is no fixed position, so called adventitious root. The key to survival of cuttings is the formation of adventitious roots, which originate from cell groups of some meristems. The origin of these meristems varies greatly with plant species. The adventitious roots can be divided into two types according to the position of adventitious roots formation: one type is skin rooting type, that is, skin rooting is the main type, and many adventitious roots are sent out from the skin holes and nodes (buds) of the cuttings. The other is callus rooting type, that is, callus rooting mainly, from the base callus (or healing tissue), or from the callus adjacent to the stem node issued a lot of adventitious roots. The rooting mechanism of these two rooting types is different, so the rooting difficulty is different. But there are also many tree species whose rooting is in the middle state, that is, comprehensive rooting type, the difference between the number of callus rooting and bark rooting is small, such as poplar, grape, oleander, Ligustrum lucidum, Heather and so on.

v1. Cuttings belonging to this type all have root primordia or root primordia located at the intersection of the widest pith ray and cambium. This is due to cambium cell division, outward differentiation into obtuse conical root primordia, invasion of phloem, leading to dermatomes. During the outward development of root primitive, the pith ray connected with root primitive also gradually thickened, passed through xylem to pith, and obtained nutrients from pith cells. This kind of bark rooting is rapid, rooting area is wide, and there is no connection with healing tissue. Generally speaking, this bark rooting type belongs to easy rooting tree species.

V2. Callus rooting type This rooting type of cuttings, the formation of adventitious roots through callus differentiation to complete. First, parenchyma cells with translucent and obvious nuclei formed on the surface of the incision under the cutting, that is, primary callus. The primary callus cells continued to differentiate and gradually formed xylem, phloem and cambium, which were related to the corresponding tissues of cuttings. At last, the callus fully healed, and roots differentiated from the callus under suitable temperature and humidity conditions. Because this kind of rooting takes a long time and grows slowly, most of the rooting sites are callus rooting for all the species that are difficult to survive and take root slowly.

v In addition, after the cuttings survive, the first bud (or the second bud) germinates from the upper part and grows into a new stem. When the base of the new stem is buried by the matrix, adventitious roots often grow. This root is called a new stem root. Such as poplar, willow, platanus, incense, pomegranate flowers, etc. can promote new stem rooting to increase the number of roots and improve the yield and quality of seedlings.

callus rooting type

picture 2

adventitious root location

v In the study of cuttage rooting theory, many scholars have done a lot of work, from different angles put forward a lot of opinions, and used to guide cuttage practice, and achieved certain results. These views are summarized as follows:

v1. Auxin view that plant cuttings rooting, healing tissue formation are controlled and regulated by auxin, cytokinin and abscisic acid also have a certain relationship. The auxin synthesized by the branches themselves can promote the formation of roots, which is mainly synthesized in the tender buds and leaves of the branches, and then moves to the base to participate in the formation of roots. Production practice proved that people use plant tender technology for cuttage propagation, its endogenous auxin content is high, cell differentiation ability is strong, cuttage is easy to survive. Grape cuttings do not have latent root primordia. When grape cuttings are cut with leaves, their roots are very developed. If the buds and leaves are removed in advance, the rooting ability will be significantly affected or not rooted at all. This indicates that there is an important substance affecting the rooting of cuttings, that is, the leaves and buds of plants can synthesize natural auxin and other effective substances for rooting, and transport them downward to the base of cuttings through phloem. This indicates that there is a polar transport from top to base. It also showed that the base of cuttings was the most active place to promote root formation.

Among auxins, auxin a, auxin b, and indoleacetic acid (IAA) have been found. These results provide a basis for human to utilize endogenous auxin and synthetic exogenous auxin to promote adventitious root formation at the base of cuttings. At present, IBA, IAA, NAA, NAD, ABT, HL-43 and so on are used in the production. These auxins can improve the rooting rate and shorten the rooting time. In addition, many experiments and production practices have also confirmed that auxin is not the only substance that promotes rooting of cuttings, but must be assisted by another special substance produced in buds and leaves to cause adventitious roots. This substance is a rooting auxiliary factor.

Growth inhibitor A growth inhibitor is a substance in plants that inhibits rooting. A lot of researches confirmed that the content of inhibitor in old trees was higher in life cycle, and the content was highest in dormant period of tree growth cycle. Therefore, in production practice, we can take corresponding measures, such as running water elution, low temperature treatment, dark treatment, etc., to eliminate or reduce inhibitors, in order to facilitate rooting.

v3. The survival of nutrient cuttings is related to the contents of nutrients, especially carbon and nitrogen, and their relative ratios. Generally speaking, C/N ratio is high, that is to say, the carbohydrate content in plants is high and the relative nitrogen compound content is low, which is beneficial to the induction of adventitious roots in cuttings. Low nitrogen can increase the number of roots, while nitrogen deficiency can inhibit rooting. Full nutrition of cuttings can not only promote the formation of root primordia, but also promote the growth of aboveground parts. Practice has proved that carbohydrate and nitrogen supplementation can promote rooting. Generally, the rooting rate can be improved by soaking the cuttings in sugar solution or spraying nitrogen such as urea on the cuttings. But exogenous carbohydrate supplement, easy to cause incision decay.

v4. Plant development Due to the effects of chronological, ontogenetic and physiological senescence, the ability of plant cuttings to take root decreases with the age of the mother tree. According to this characteristic, for some rare, precious tree species or difficult to reproduce tree species, in order to make it physiologically "rejuvenate" can take the following effective ways.

v (1) hedgerow harvesting is to cut the mother tree to be harvested, not to make it grow upward, but to sprout many new branches.

v (2) Continuous cuttage propagation 2~3 times, the rooting ability of new branches increased sharply, and the rooting rate increased by 40%~50%.

v (3) Continuous grafting propagation with young rootstock means grafting scion collected from old mother tree to young rootstock, repeatedly grafting for 2~3 times to make it "rejuvenate", and then collecting branches or needle bundles for cuttage.

v (4) Using basal budding shoots as cuttings, i.e. sawing old trunks, so that new budding shoots can be produced in the juvenile area for cutting.

v5. Anatomical structure of stem

The difficulty of rooting of cuttings is closely related to the anatomical structure of stem. Rooting is difficult if there is a ring of sclerenchyma composed of one, two or more layers of fibrous cells in the cortex of the cuttings; rooting is easier if there is no or discontinuous sclerenchyma in the cortex. Therefore, cutting seedlings can be taken to cut the cortex method, destroy its circular sclerenchyma and promote rooting. For example, Hubei Forestry Institute will cut olive cuttings longitudinally and improve the survival rate of cuttings.

2. Factors affecting rooting of cuttings

v The formation of adventitious roots of cuttings is a complex physiological process. Whether cuttings can take root and survive after cutting is closely related to both internal factors and external environmental factors.

(1) Internal factors affecting rooting of cuttings

1. Biological characteristics of tree species Different tree species have different biological characteristics, so their rooting ability is different. According to the difficulty of rooting cuttings can be divided into:

v (1) tree species easy to root, such as willow, poplar, black poplar, metasequoia, fir, cedar, buxus microphylla, amorpha, forsythia, rose, spring jasmine, honeysuckle, ivy, euonymus, southern sky bamboo, red leaf tiller, buxus, silver wood, grape, fig and pomegranate;

v (2) easier to root tree species such as Platycladus orientalis, Cypress obtusa, Arhat cypress, Podocarpus sinensis, Robinia pseudoacacia, Sophora japonica, Camellia sinensis, Cherry, Wild Rose, Rhododendron, Sorbaria chinensis, Fraxinus chinensis, Platanus acanthopanax, Elderberry, Ligustrum lucidum, Actinidia chinensis, etc.;

v (3) The tree species difficult to root, such as Pinus pseudoacacia, Sabina chinensis, Pinus japonica, Chinese parasol tree, Melia azedarach, Ailanthus altissima, Qianzi, Milan, Begonia, Jujube tree, etc.;

v (4) Very difficult to root tree species such as black pine, masson pine, red pine, camphor tree, chestnut, walnut, oak, Liriodendron chinense, persimmon, elm, maple and so on.

V different tree species rooting difficulty, but relatively speaking, with the deepening of scientific research, some difficult to root trees may become easy to cut trees, and in production to be promoted and applied. Therefore, in the cuttage seedlings, we should pay attention to the reference has been confirmed information, there is no information on the varieties, to carry out trial insertion, so as not to take detours. In cutting propagation, as long as attention is paid to improving the method, it is possible to improve the survival rate. Such as red pine, black pine, etc., which are generally considered to be difficult to cut, the rooting rate can reach more than 80% through the cultivation of budding strips and hormone treatment under the technical conditions of automatic spray cutting in full light. Generally belong to cutting easy rose varieties, there are many excellent strains rooting is very difficult, such as in the cutting period after autumn with leaves cutting, in the heat preservation and spray moisture conditions, rooting rate can reach more than 95%. This shows that many difficult to root trees or flowers, in the case of continuous progress in science and technology, according to the genetic characteristics of parents, take corresponding measures, is a good way to find roots.

v2. The age of cuttings includes two meanings: one is the age of the mother tree of the picked branches; the other is the age of the picked branches themselves.

v (1) The rooting ability of cuttings decreases with the age of mother tree. Generally, the older the mother tree is, the more difficult it is for the cuttings to take root, while the younger the mother tree is, the easier it is for the cuttings to take root. Because of the strong and weak metabolism of trees, it is weakened with the aging of development stages, and its vitality and adaptability are gradually reduced. On the contrary, the young branches of young mother trees have strong ability of life activity of cortical meristem, and the survival rate of cuttings collected is high. Therefore, in the selection should be collected from young mother trees, especially for many difficult to root species, should choose 1~2 years old seedlings on the branches, cutting effect is the best. For example, Qianjiang Forestry Research Institute of Hubei Province conducted cutting experiments on annual branches of Metasequoia glyptostroboides with different mother tree ages. The rooting rate of cuttings was 92% for 1 year old, 66% for 2 years old, 61% for 3 years old, 42% for 4 years old and 34% for 5 years old. The rooting rate of cuttings decreased with the increase of mother tree age. The reasons for the decrease of rooting ability of cuttings with the increase of age of mother trees are that besides the decline of vitality, the substances necessary for rooting decrease, and the substances hindering rooting increase, such as rooting hindering substances or tannins found in the cuttings of red pine, black pine, cypress, larch and Cryptomeria. With the increase of age, the nutritional conditions of mother trees may be worse, especially in the cutting nursery, due to repeated cutting, soil fertility failure, insufficient nutrition in the branches of the mother tree, will also affect the rooting ability of cuttings.

v (2) Cuttings age has significant effect on rooting, generally the regeneration ability of the current year shoots is the strongest, this is because the high endogenous auxin content and strong cell differentiation ability of the shoots promote the formation of adventitious roots. The regeneration ability of annual branches is also strong, but the specific age varies with tree species. For example, poplars have a high survival rate of 1-year-old branches and a low survival rate of 2-year-old branches. Even if they survive, the growth of seedlings is poor. 1-year-old branches of Metasequoia and Cryptomeria are better, and the base can also have a 2-year-old branch segment, while the rooting rate of 2 - 3-year-old branch segments of Lohanopsis is higher.

v3. The position and development of branches Some tree species have low rooting rate of branches on the crown, but high rooting rate of roots and stem base germination strips. Because the annual sprouts at the root neck of the mother tree have the youngest development stage and strong regeneration ability, and because the growth position of the sprouts is close to the root system, they get more nutrients and have higher plasticity, which is easy to survive after cutting. Although the rooting rate of germinated shoots was high, the sources were few. Therefore, it is ideal to use the branches of the cutting nursery for cutting. If there is no cutting nursery, the seedlings of cutting seedlings, root seedlings and cutting seedlings can be used, and the later two are better.

V. The branches of conifer mother tree have strong rooting power, and the lateral branches, especially those with multiple branches, have weak rooting power. If the branches are collected from the crown, it is better to collect the branches from the lower part of the crown with weak light. In production practice, some tree species with a part of 2-year-old branches, that is, the use of "heel cutting method" or "horseshoe cutting method" can often improve the survival rate.

Branches of hardwood cuttings must be fully developed, robust, fully lignified, and free of pests and diseases.

v4. The root primordia quantity and stored nutrient quantity of different parts of the same branch are different, and the rooting rate, survival rate and seedling growth quantity of cuttings are obviously different. But which part is good, but also consider the root type of the plant, the maturity of the branch and so on. Generally speaking, evergreen trees in the upper branches better. This is mainly because the middle and upper branches grow healthily, metabolism is vigorous, nutrition is sufficient, and the photosynthesis of new branches in the middle and upper parts is also strong, which is beneficial to rooting. Hardwood cuttings of deciduous tree species are better in the middle and lower branches. Because the middle and lower branches developed fully and stored more nutrients, it provided favorable factors for rooting. If deciduous tree species softwood cuttings, then the upper branches are better. Because of the tender branches, the highest endogenous auxin content in the upper part, and cell differentiation ability, beneficial to rooting, such as Populus tomentosa cuttings, the best tip.

v5. The thickness and length of cuttings have certain influence on survival rate and seedling growth. For most tree species, long cuttings have more root primordia and stored more nutrients, which is beneficial to rooting. The length of cuttings should be determined according to the rooting speed of tree species and soil moisture conditions. Generally, the cuttings of hard branches of deciduous trees are 10~25cm, and those of evergreen trees are 10~35cm. With the improvement of cuttage technology, cuttage gradually to the direction of short cuttings development, some even a bud a leaf cuttage, such as tea, grape using 3~5cm short branch cuttage, the effect is very good.

v For cuttings of different thickness, coarse cuttings contained more nutrients, which was beneficial to rooting. The suitable thickness of cuttings varies with tree species, most of which are 0.3~1cm in diameter for conifer species and 0.5~2cm for broadleaf species.

In production practice, proper length and thickness of cuttings should be adopted according to needs and possibilities, branches should be reasonably utilized, and the principle of short thick branches and long thin branches should be mastered.

v6. The leaves and buds of the cuttings are the basis for the formation of stems and stems. Bud and leaf can supply the necessary nutrients, growth hormones and vitamins for rooting, which is beneficial to rooting. Especially for softwood cuttings and coniferous species, evergreen species cuttings are more important. The number of leaves left for cutting is generally determined according to the specific situation. Generally, 2~4 leaves are left. If there is a spray device, regular moisture can be kept, and more leaves can be left to accelerate rooting.

V in addition, branches or cuttings collected from mother trees are significantly less resistant to drying and bacterial infection, so when cutting propagation, attention must be paid to maintaining the moisture of cuttings themselves. In production, the lower end of cuttings can be soaked in water, which can not only increase the moisture of cuttings, but also reduce the substances that inhibit rooting.

(2) external factors affecting the rooting of cuttings

The main external factors affecting the rooting of cuttings are temperature, humidity, ventilation, light, substrate and so on. The factors influence and restrict each other, so it is necessary to make various environmental factors meet the requirements of cutting rooting organically in order to improve the rooting rate and cultivate high-quality seedlings.

V1. the suitable temperature for rooting of cuttings varies from tree species to tree species. The optimum temperature for rooting of most tree species is 15-25 ℃, and the most suitable temperature is 20 ℃. However, many tree species have their lowest rooting temperature, such as poplar and willow begin to take root at about 7 ℃. The general rule is that the temperature is lower for early germination such as poplar and willow, and higher temperature for late germination and evergreen tree species such as sweet-scented osmanthus, gardenia and coral trees. In addition, the most suitable cutting temperature for plants in different climatic zones is also different, such as MaLisch H in the United States thinks that temperate plants are about 20 ℃, and tropical plants are about 23 ℃. Soviet scholars believe that temperate plants are between 20 and 25 ℃, while tropical plants are between 25 and 30 ℃.

V the requirements of soil temperature for cuttings rooting of different tree species are also different. Generally, when the soil temperature is 3-5 ℃ higher than the air temperature, it is very beneficial to rooting. This is beneficial to the formation of adventitious roots but not suitable for bud germination, and concentrate nutrients on bud germination and growth after adventitious root formation. In production, horse dung or electric hot line can be used as heating materials to increase ground temperature, and the heat energy of sunlight can be used to invert and promote roots to improve the survival rate of cuttings.

V temperature is more important for tender wood cuttings, and less than 30 ℃ is beneficial to rooting and promoting the utilization of substances in branches, so it is beneficial to rooting. But when the temperature is higher than 30 ℃, the cuttage will fail. Generally, spraying can be used to reduce the temperature of cuttings. The best period for cuttage activity is also the period when bacteria are rampant, so special attention should be paid to cuttings.

V2. Humidity in the process of rooting of cuttings, the relative humidity of the air, the humidity of the soil and the water content of the cuttings themselves are the key to the survival of cuttings, especially the tender wood cuttings, we should pay special attention to maintain the appropriate humidity.

V (1) the relative humidity of the air has a great influence on the needles and broad-leaved tree species which are difficult to take root. The air relative humidity required for cuttings is generally about 90%. Hardwood cutting can be slightly lower, but the relative humidity of tender wood cutting air must be controlled above 90%, so that the transpiration intensity of branches is the lowest. In production, water spraying and interval control spray can be used to improve the relative humidity of the air, so that the cuttings are easy to take root.

V (2) soil moisture cuttings are most likely to lose water balance, so suitable moisture is required for soil cutting. The soil humidity depends on the cutting substrate, cutting materials and management technology. According to the cutting experiment of Populus tomentosa, the water content in the cutting soil is generally 20%-25%. When the water content is less than 20%, the rooting and survival of cuttings are affected. It has been reported that from cuttage to callus production and rooting, the requirements of soil water content in different stages are different, usually the former is the highest, and the latter decreases in turn. Especially after completely rooting, the water supply should be gradually reduced to restrain the vigorous growth of the aboveground part of cuttings, increase the Lignification degree of new shoots, and better adapt to the field environment after transplantation.

V3. Oxygen is needed for cuttings to take root under ventilated conditions. Japanese Fujii grapes were tested in soil with different oxygen concentrations (Table 5-1). It can be seen from Table 5-1 that the rooting rate of cuttings is proportional to the oxygen content in the soil. Therefore, when cutting, the cuttage substrate should be loose and breathable. Especially for the tree species with more oxygen demand, we should choose the loose and breathable cutting substrate and shallow cutting at the same time. If the substrate is loam, the soil must be loosened in time after each irrigation, otherwise the survival rate will be reduced.

Picture 6

V4. Light can promote the rooting of cuttings, which is indispensable for evergreen trees and tender wood cuttings. However, in the process of cutting, strong light will make the cuttings dry or burn and reduce the survival rate. In practical work, measures such as cooling by spraying water or proper shading can be taken to maintain the water balance of cuttings. When cutting in summer, the best method is to apply full light automatic intermittent spraying, which not only ensures the water supply but also does not affect the light.

V5. No matter what kind of substrate is used in cutting substrate, it is beneficial to rooting as long as it can meet the requirements of substrate moisture and aeration conditions for cuttings. The cutting substrates used at present have the following three states:

V (1) the most commonly used substrates in solid-state production are river sand, vermiculite, perlite, slag, peat soil, carbonized rice husk, peanut shell, moss, foam and so on. The aeration and drainage properties of these substrates are good. However, after repeated use, the particles are often broken and the powder composition increases, so the new matrix should be replaced regularly.

V (2) liquid cuttings are inserted into water or nutrient solution to make them root and survive, which is called liquid cuttage. Liquid cuttings are often used for tree species that are easy to root. Due to the nutrient solution as the substrate, cuttings are easy to rot, so they should be used with caution in general.

V (3) the air is in a state of water vapor fog, and the cuttings are suspended in the fog to make it take root and survive, which is called fog insertion or air insertion. The fog cuttings can make full use of the space as long as the temperature and air relative humidity are well controlled, the cuttings take root quickly and the seedling raising period is shortened. However, as the cuttings take root under the conditions of high temperature and high humidity, seedling refining has become one of the important links in the survival of fog cuttings.

The selection of v substrate should be based on the requirements of tree species and the most suitable substrate should be selected. When cutting in the open field, it is actually impossible to replace the cutting soil in a large area, so the sandy loam with good drainage is usually selected.

3. Techniques for promoting rooting of cuttings

V1. Auxin and rooting promoter treatment

V (1) the commonly used auxins in growth hormone treatment are naphthylacetic acid (NAA), indoleacetic acid (IAA), indolebutyric acid (IBA), 2mem4murD and so on. The method of use is to first dissolve auxin with a small amount of alcohol, and then configure it into a solution of different concentrations. Soak the lower end of cuttings in low concentration (such as 50~200mg/L) solution for 6 hours, and high concentration (such as 500~10000mg/L) for rapid treatment (a few seconds to one minute); second, mix the dissolved auxin with talc powder or charcoal powder evenly, dry and make powder, then dip the lower end of cuttings with wet cuttings; or dilute the powder into a paste and dip it with the lower end of cuttings; or make it muddy and enclose the lower end of cuttings. The treatment time and solution concentration varied with different tree species and cuttings. In general, the concentration of rooting is higher, and the concentration of easier rooting is lower. The concentration of hard branches is higher than that of twigs.

V (2) at present, the widely used rooting promoters are "ABT rooting powder" series developed by Wang Tao of Forestry Research Institute of Chinese Academy of Forestry Sciences, broad-spectrum "plant rooting agent HL-43" developed by Forestry Department of Huazhong Agricultural University, "Genbao" developed by Forestry Department of Shanxi Agricultural University and won the National Science and Technology Invention Award, and "3A series rooting powder" developed by Kunming Garden Institute. All of them can improve the rooting rate of many kinds of trees, such as ginkgo, sweet-scented osmanthus, chestnut, red maple, cherry blossom, plum, larch, etc., the rooting rate can reach more than 90%, and the root system is developed, and the number of absorbed roots increases.

V2. Elution treatment generally includes warm water treatment, running water treatment, alcohol treatment and so on. Elution treatment can not only reduce the content of inhibitory substances in branches, but also increase the content of water in branches.

V (1) the lower end of cuttings was immersed in lukewarm water of 30-35 ℃ for several hours or more, the specific time varied with different tree species. Some coniferous branches, such as pine, larch and spruce, are soaked for 2 hours and play the role of degreasing, which is beneficial to incision healing and rooting.

V (2) Water elution treatment put the cuttings into flowing water and soak for several hours, and the specific time varies with different tree species. Most of them are within 24 hours, some can be up to 72 hours, and some are even longer.

V (3) Alcohol elution treatment can also effectively reduce the inhibitory substances in cuttings and greatly increase the rooting rate. Generally use a concentration of 1%-3%, or a mixture of 1% alcohol and 1% ether for about 6 hours, such as rhododendrons.

V3. Cutting cuttings treated with vitamins, sugars and other nitrogen for nutritional treatment is also one of the measures to promote rooting. For example, the cuttings of cedar, cypress, metasequoia and other tree species were treated with 5%-10% sucrose solution for 12-24 hours, which had a significant effect on promoting rooting. If sugars and plant auxin are used together, the effect is better. Spraying urea on the leaves of softwood cuttings is also a kind of nutritional treatment.

V4. Some chemicals can also effectively promote the rooting of cuttings. Such as acetic acid, phosphoric acid, potassium permanganate, manganese sulfate, magnesium sulfate and so on. For example, soaking cuttings such as Euonymus and cloves with 0.1% acetic acid solution in production can significantly promote rooting. Soaking cuttings with 0.05%-0.1% potassium permanganate solution for 12 hours can not only promote rooting, but also inhibit the development of bacteria and play the role of disinfection.

V6. Warming treatment in spring, because the air temperature is higher than the ground temperature, when cutting in the open field, it is easy to sprout and spread leaves before taking root, so as to reduce the survival rate of cutting. For this reason, measures such as laying an electric hot line in the slotting bed (that is, the electric heating bed method) or putting raw horse dung in the slotting bed (that is, brewing heat to promote rooting) can be adopted to increase the ground temperature and promote rooting.

V7. Inverted root stimulation usually takes place at the end of winter and the beginning of spring. Taking advantage of the characteristic that the surface temperature in spring is higher than that in the pit, the cuttings are placed upside down in the pit, the pores are filled with sand, and the pit surface is covered with 2cm sand, so that the temperature at the base of the inverted cuttings is higher than that at the top of the cuttings, which creates favorable conditions for the formation of the root primordium of callus at the base of cuttings, thus promoting rooting, but attention should be paid to water control.

V8. Before the growing season, the yellowing treatment is covered with black plastic bags to make the branches of cuttings grow in the dark and form tender tissue. After the branches and leaves grow to a certain extent, they are cut off for cutting, which can create more favorable conditions for rooting.

V9. Mechanical treatment in the tree growing season, the base of the branch will be peeled, scratched or tied with wire, hemp rope or nylon rope, to prevent the upper part of the branch carbohydrate and auxin downward transport, make it store nutrients, to the dormant period and then cut the branch from the base for cutting, can significantly promote rooting.

Picture 7

IV. Cutting period, selection and cutting of cuttings

(1) cutting period

V generally speaking, plant cutting propagation can be carried out all the year round. The suitable cutting period varies with the species and characteristics of plants, the methods of cutting and so on.

V1. Spring cutting is suitable for most plants. Spring cutting is the use of the previous year's dormant branches directly or after low-temperature storage in winter for cutting, also known as hardwood cutting. The rooting inhibitory substances in the branches have been transformed and are rich in nutrients, but under the same conditions, it is easy to cause metabolic disorders in the branches due to the uncoordinated development of aboveground and underground parts. Therefore, it is appropriate to cut early in spring, and to create conditions, first break the dormancy of the lower part of the branch, maintain the upper dormancy, and then germinate and grow after the adventitious root is formed. Therefore, the key to the technology of cutting seedlings in this season is to take measures to improve the ground temperature. The methods used in spring cutting production are field cuttage and plastic shed cuttage.

V2. Summer cutting is the use of vigorous growth of twigs or semi-lignified branches for cutting, also known as softwood cuttings. Coniferous trees generally use semi-lignified branches, while broad-leaved trees use twigs in the period of vigorous growth. Summer cuttings are in the vigorous growth period, the ability of cell division is strong, the function of metabolism is exuberant, and the content of endogenous auxin in branches is high, all these factors are beneficial to rooting. However, due to the high temperature and tender branches in summer, it is easy to cause transpiration and death of branches. Therefore, the key technology of summer seedling cultivation is to improve the relative humidity of the air, reduce the transpiration intensity of cuttings, improve the survival rate of detached branches and leaves, and then improve the rooting survival rate. The cutting methods used in summer often include plastic shed cutting under shade shed and full-light automatic intermittent spray cutting.

V3. Autumn cutting is the use of fully developed, nutrient-rich branches that have stopped growing but have not entered the dormant period. The content of inhibitory substances in the branches did not reach the peak, which could promote the early formation of callus and be beneficial to rooting. Autumn insertion should be early to facilitate complete material transformation and safe overwintering. Therefore, the key to the technology of cutting seedlings in this season is to take measures to improve the ground temperature. The method of cutting in autumn is commonly used to raise seedlings in plastic sheds, and sunny border cuttings can also be used in the north.

V4. Winter cuttage is a hotbed cuttage using dormant branches that break dormancy. In the north, it should be carried out in a plastic shed or greenhouse, and an electric hot line should be laid on the substrate to increase the temperature of the cutting substrate. In the south, it can be cut directly in the nursery.

V different regions can choose different periods for different tree species. The cutting of deciduous trees can be carried out in both spring and autumn. However, it is more common in spring, and cutting in spring should be carried out as early as possible before bud germination. In the north, it can be carried out when the soil begins to thaw, usually from mid-late March to mid-late April. Autumn planting is suitable for planting with picking before soil freezing, and autumn planting is widely used in the warm areas of southern China. In the dry and cold areas of the north or less snowy areas in winter, cuttings are easy to be air-dried and frozen in autumn, so the cuttings should be covered with soil after cuttings, and then removed when sprouting in spring. In order to solve the difficulties of cutting in autumn and reduce the overwintering work, cuttings can be stored until the coming spring for cutting, which is very safe. The cutting of deciduous trees in the growing period is mostly carried out in the stable period after the end of the first period of growth in summer. Production practice has proved that in many areas, many tree species can be cut in four seasons. Such as rose, wild rose, pomegranate, gardenia, hypericum and pine and cypress can be cut in Hangzhou for four seasons.

V the cuttings of southern evergreen trees are mostly carried out in the Meiyu season. In general, the roots of evergreen trees need a higher temperature, so the cuttings of evergreen trees should be cut at the end of the first stage and before the beginning of the second stage. At this time, it is the plum rain season from May to July in the south, with more Rain Water and high humidity, the cuttings are not easy to wither and are easy to survive.

V cuttings can be divided into dormant period and growing period according to different periods. The former is hardwood cuttings and the latter is soft (tender) cuttings.

V1. Selection and cutting of hardwood cuttings

V (1) cutting time of cuttings the nutrients stored in cuttings are the main energy source for hardwood cuttings to take root and shoot. The time of cutting is different, and the amount of stored nutrients is also different, so we should choose the period when the branches contain the most nutrients. In this period, the sap flows slowly and the growth stops completely, that is, the deciduous tree species are cut after falling leaves in autumn or when they begin to fall leaves to sprouting in the next spring.

V (2) according to the principle of cuttage survival, 1-2-year-old branches or sprouting shoots with full development and full Lignification on excellent young mother trees should be selected, and robust, pest-free and sturdy branches with many nutrients should be selected.

V (3) if the cuttings are not cut immediately after the cuttings are collected in the north, the cuttings will be stored for Laichun cutting. there are two methods: burying in the open field and indoor storage. Buried strip in the open ground is to choose high dry, well-drained and leeward-facing places to dig ditches, the ditch depth is generally 50~6Ocm (according to the local climate, but the depth must be below the permafrost), tie up the branches in bundles every 50 to 100, stand at the bottom of the ditch, bury them with wet sand, and erect grass in the middle to facilitate ventilation. It should be checked once or twice a month to maintain suitable temperature and humidity conditions to ensure a safe winter. After burying, the skin of the branches softened and the internal storage substances began to transform, which laid a good foundation for the rooting of cuttings in spring. In indoor storage, the branches are also buried in wet sand, pay attention to indoor ventilation and maintain a proper temperature, the number of accumulation layers should not be too high, more than 2 or 3 layers is appropriate, too high will cause high temperature, causing branches to rot. If there are few spikes in the south, they need to be stored and can be put in the refrigerator storeroom. In garden practice, the branches cut off during shaping and pruning can also be selected for storage.

The cutting of v (4) cuttings is generally long cuttings with long 15~20cm, which ensures that there are 2 or 3 fully developed buds on the cuttings, and the length of single bud cuttings is 3~5cm. When shearing, the upper incision is about the apical bud 1cm, and the position of the lower incision varies according to the plant species. Generally, there are many parenchyma cells near the node, the cells divide quickly, the nutrition is rich, and it is easy to form callus and root, so the incision under the cuttings should be close to the node. The lower incision has several cutting methods, such as flat cutting, oblique cutting, double-sided cutting, heel cutting and so on (see figure 5-1). Generally, the rooting of the flat cut is uniformly distributed in a ring, which is convenient for mechanized cutting, and the flat incision should be used for the tree species with rooting type and fast rooting; the contact area between the oblique incision and the cuttings matrix is large, which can form callus with larger area, which is beneficial to absorb water and nutrients and improve the survival rate, but the roots are mostly born at one end of the oblique mouth, which is easy to form partial roots, and it is also more laborious to cut ears. The contact area between double-sided cutting and soil insertion is larger, and it is widely used in plants where it is difficult to take root. The heel-shaped incision is usually used when there are 2-3-year-old branches at the lower end of the cuttings, often used in conifers.

Picture 8

Figure 5-1 cut shape and rooting under cuttings

1. Flat cut 2. Oblique cut 3. Double-sided cut 4. Lower incision flat cut rooting evenly 5. Lower incision oblique cutting root to one side

V2. Selection and cutting of twig cuttings

V (1) the cutting time of softwood cuttings is cutting along with picking. It is best to choose from the young mother tree with strong growth, and the twig that begins to Lignification is the best, which contains sufficient nutrients, strong vitality and easy to heal and take root. However, branches that are too young or too woody are not suitable to be used. Twigs should be picked before sunrise in the morning or on rainy days, not in sunny, windy or hot days.

V (2) selection of shoot cuttings in general coniferous trees such as pine, cypress, juniper, etc., it is better to cut the semi-lignified branches in the middle and upper part at the end of summer. Practical experience has proved that the rooting of the middle and upper branches is better than that of the basal branches. Conifers do not have strict requirements for moisture, but attention should be paid to keeping moisture in their branches. For softwood cuttings of deciduous broad-leaved trees and evergreen broad-leaved trees, young branches are generally cut in the peak period of height growth, and for large-leaf plants, it is appropriate to pick strips when the leaves are not unfolded into large leaves. Spray water in time after picking strips and pay attention to moisturizing. For tender wood cuttings, the pretreatment before cutting is very important. Plants with high tannin and difficult to root can be yellowed, girdled and bundled before the growing season.

V (3) after the cuttings of the twigs were collected, they were cut in the shade and leeward. Generally, the cuttings are long 10~15cm with 2-3 buds. The number of leaves retained on the cuttings can be determined according to plant species and cutting methods. The lower incision is cut into a flat or small oblique mouth to reduce the decay of the incision.

5. Types and methods of cutting

V in plant cutting propagation, according to the different materials used for propagation, it can be divided into branch cutting, root cutting, leaf cutting, bud cutting, fruit cutting and so on. The classification is shown in figure 5-2.

Picture 9

(1) Branch cuttings

V-branch cutting is the most commonly used cutting method in garden trees. According to the maturity of branches and cutting season, branches can be divided into dormant branch cutting and growing branch cutting. All kinds of branches are divided according to the shape and length of the materials used.

V1. Dormant branch cuttage is the use of dormant branches as cuttings for cutting, because the dormant branches have been lignified, also known as hardwood cuttings. It is usually divided into long spike cuttings and single bud cuttings. Long ear cuttings are cuttings with more than two buds, and single bud cuttings are cuttings with branches of one bud. Because the branches are short, they are also called short spikes.

V (1) long spike cuttings usually have common cuttings, heel-shaped cuttings, hammer-shaped cuttings, etc. (see figure 5-3).

V ① common cuttage is the most widely used in the cutting propagation of woody plants, and most tree species can use this method. Either cutter cuttings or field cuttings can be used, such as flat cropping or ridge cropping. The general length of cuttings is 10~20cm, 2-3 buds are retained on the cuttings, and the cuttings are inserted into the soil or substrate at a depth of 2 to 3 of the length of the cuttings. The cuttings with short cuttings should be cut straight, which not only avoids oblique cuttings causing partial root, but also facilitates seedling emergence.

V ② heel-shaped cuttings have a part of biennial branches at the base of cuttings, which are similar to heel feet. This kind of cuttings have concentrated nutrients in the lower part and are easy to root, but waste branches, that is, each branch can only take one cuttage, which is suitable for pine, cypress, sweet-scented osmanthus and other tree species that are difficult to survive.

③ mallet is a kind of heel-shaped insert, the base with more old branches than the heel-shaped insert, generally long 2~4cm, both ends oblique cut into a hammer-shaped.

Picture 10

Figure 5-3 cutting and hardwood cuttings

1. Heel insert 2, 3. Mallet insert

V in addition to the above three cutting methods, in order to improve the rooting and survival rate, several cutting methods are formed by taking various measures on the basis of ordinary cutting:

V cut and cut the lower part of the cuttings from the middle, sandwiched with pebbles, etc. The method of man-made trauma was used to stimulate the formation of wound healing tissue and expand the rooting area of cuttings. This method is mostly used for tree species that are difficult to root and take root with callus, such as sweet-scented osmanthus, camellia, plum blossom and so on.

V soil ball insertion wraps the base of cuttings in a heavier soil ball, and then inserts the cuttings with soil balls into the soil, using soil balls to maintain high moisture. This method is mostly used for evergreen trees and conifers, such as cedar, bamboo and cypress and so on.

V sarcoma insertion method is in the growing season before the branches are cut, ring peeling and other methods to cause the formation of sarcoma at the base of the cuttings with callus protuberance, increase nutritional storage, and then cut for cutting. This method has many procedures and wastes branches. However, it is beneficial to the reproduction of tree species with difficulty in rooting, so it is mostly used for the reproduction of precious tree species.

V-long stem cuttage and ready-to-use long branch cuttings generally use 50cm long, or 1 to 2 m long perennial branches as cuttings, which are mostly used for tree species that are easy to root. By using this method, large seedlings with trunk can be obtained in a short period of time, or directly inserted in the place where they want to be planted to reduce transplantation.

V drifting cuttage this method uses water as the substrate for cutting, that is, cuttings are cut in water and taken out and planted in time after rooting. The root inserted with water is brittle and easy to break if it is too long.

V (2) single bud cuttings (short spike cuttings) are cut with branches with only one bud, selecting short branches, generally insufficient 10cm, saving materials, but less nutrients in the cuttings, and easy to lose water, therefore, oblique cutting of the lower incision, expanding the water absorption area and healing surface of the branch incision is beneficial to rooting, and water spraying is needed to maintain higher air relative humidity and temperature, so that the cuttings can take root and survive in a short time. This method is mostly used for cutting propagation of evergreen tree species. Cutting Baiyang tea with this method, the branches 2.5cm about, rooting in 2-3 months, the survival rate can reach 90%, and the survival rate of sweet-scented osmanthus cuttings is 70%-80%.

V tidy up the cutter before cutting dormant branches. Open-field cutting should be meticulous soil preparation, apply sufficient basic fertilizer, so that the soil loose, sufficient water. Soil disinfection should be carried out if necessary. The cutting density can be determined according to the growth rate of tree species, seedling specifications, soil conditions and the machines used. General plant spacing 10~50cm, row spacing 30~80cm. In the greenhouse and breeding room, generally close insertion, cuttings rooting and sprouting, and then transplant. There are two kinds of cuttings: direct cuttage and oblique cutting. in general, direct cuttage is mostly used. The cutting angle of oblique cutting should not exceed 45o. The insertion depth should depend on the tree species and environment. The cuttings of deciduous tree species are all inserted into the ground, showing a bud or flat with the ground. Cutting in the open field can make the buds slightly dewy in the warm and humid areas of the south. In the greenhouse and breeding room, the cutting substrate is generally exposed at the upper end of the cuttings. The insertion depth of evergreen tree species should be 1 × 10 ~ 2 of the length of cuttings.

2. Growing branch cuttings in the growing season, using vigorous young twigs or semi-lignified branches as cuttings, tender branches have many parenchyma cells, strong cell vitality and strong meristem ability. and the tender branches have high water content, many soluble nutrients, strong enzyme activity and new leaves can produce some photosynthetic products, which are favorable internal causes for rooting, and many tree species are suitable to use young wood cuttings. The length of cuttings is generally shorter than that of hardwood cuttings, most of them have 1-4 internodes, about 5~20cm, some leaves are retained, and the larger leaves are cut off by half. The lower incision is located under the leaf and axillary bud to facilitate rooting, and the cut can be flat or oblique. The cuttings are then cut on the soil (see figure 5-4).

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Fig. 5-4 Common tender wood cutting methods

During the growing branch cutting period, in the south, spring, summer and autumn can be carried out, while in the north, it is mainly carried out in summer, and the specific cutting time is carried out in the morning and evening. The cuttings are mostly cut on the cuttage bed with loose ventilation and good moisturizing effect, the cutting depth is about 3cm, and the density of the leaves of the two cuttings should not overlap each other in order to maintain sufficient photosynthesis. The cutting angle is generally straight cutting. The cuttage depth is generally the length of the cuttings of 1 beat, 2 cuttings, 1 arrow, 3 cuttings, if the environmental conditions can be manually controlled, the shallower the cutting depth, the better, it can be about 0.5cm, not toppling. Growing branch cuttings require high air humidity in order to avoid a large amount of water transpiration in the plant body. Now full light automatic interval spray cutting equipment, small plastic shed cuttings in the shade shed, and other methods can also be used (see figure 5-5). To ensure appropriate air humidity. This kind of cuttings have a high density on the cutting bed, and most of them are transplanted to the nursery for production immediately after rooting.

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Fig. 5-5 softwood cutting method

1. Cuttage in plastic shed 2. Large pots and dense cuttings 3. Dark bottle water cutting

(2) Root insertion

V for some tree species with difficulty in rooting, root cuttings can be used for asexual propagation in order to maintain the good characters of their female parents.

V1. generally, strong young trees or 1 ~ 2-year-old seedlings with strong growth should be selected as the mother trees for root picking, and the age of roots and ears should be one year old. If you pick roots from a single tree, you should not pick too many roots at one time, otherwise it will affect the growth of the mother tree. Don't hurt the root bark when picking the root. Root picking is generally carried out during the dormant period of trees and is buried in time after harvest. In the south, it is best to pick roots in early spring and then cut them.

V2. The cutting of root spike can be cut into different specifications according to different tree species. Generally, the length of root and ear is 15~20cm, and the thickness of big head is 0.5~2cm. In order to distinguish the upper and lower ends of the root ear, the upper end can be cut into a flat mouth and the lower end into an oblique mouth. In addition, some tree species such as Toona sinensis, Robinia pseudoacacia and paulownia can also use thin and short root segments, long 3~5cm and coarse 0.2~0.5cm.

V3. Before cutting, the soil will be carefully leveled and filled with enough bottom water. Insert the long 15~20cm or so root cuttings vertically or obliquely into the soil, pay attention to the upper and lower ends of the roots, and do not insert them backwards. It is best not to irrigate before sprouting and rooting after planting, so as to avoid the decrease of ground temperature and the rot of roots and ears caused by too much water. The short root segments of some tree species can also be raised by sowing.

(3) Leaf cutting

V the leaves are used to propagate and cultivate new plants because the leaves have the ability of regeneration and callus. The aboveground parts of leaf cuttings of most woody plants are developed from bud primordia. Therefore, leaf cuttings should carry bud primordia and protect them from injury, otherwise they cannot form aboveground parts. The underground part (root) is the root primordium induced by the callus and develops into root. The leaf cuttings of woody plants are mainly planted with coniferous bundles of water (whole-leaf cutting of herbaceous flowers and foliage herbs, leaf insertion refer to relevant florology textbooks), such as Pinus elliottii, loblolly pine, Masson pine and other full-light spray seedlings of Pinus elliottii, Pinus elliottii and Pinus massoniana studied by the Forestry Institute of Jingzhou, Hubei Province, and used in production; the needle bundle seedlings of Pinus elliottii and Pinus koraiensis were cultivated successively by water insertion in Rushan County, Shandong Province and Yantai Forestry Institute. The procedure of needle bundle seedling raising is as follows:

V1. The leaves were collected in autumn and winter, and the sturdy needle bundles of strong biennial seedlings or young branches were selected as propagation materials.

V2. The needle bundles were treated with the harvested needle bundles, washed, and then stored in sterilized pure sand (the buried depth of the leaf bundles was 2 ℃ 3). The leaf bundles were watered thoroughly and kept moist frequently, and the temperature was controlled between 0: 10 mol / L for about a month. Sand storage plays a role in degreasing. For the leaf bundle after sand storage, the base of the leaf bundle can be cut off below the growth point with a fast blade (do not hurt the growth point), resulting in a fresh wound, which is conducive to healing and rooting. The leaf bundles after cutting base were treated with hormone.

V3. Water insertion is actually not inserted in water, but in a certain nutrient solution. The basic formula of the nutrient solution is 50~70mg/L borate, ammonium nitrate 20mg/L, vitamin B120 mg/L, and other drugs such as vitamin B6 can be added according to different tree species. The nutrient solution can be treated with well water and the pH value is below 7. The needle bundles treated by cutting base and hormone are inserted into the hydroponic nutrient solution and fixed. The temperature is controlled between 10 ℃ and 28 ℃, the air relative humidity is about 80%, and the accumulated temperature is about 1000 ℃. Generally, the leaf bundle should be washed, the hydroponic container should be cleaned, and the nutrient solution should be replaced once in a week or so.

V4. Transplant when the leaf bundle root grows to 1~2cm, it can be transplanted and inoculated with mycorrhiza. When transplanting, use a small shovel to open the hole, insert the bundle with roots and leaves, bury the roots in depth, gently compact, and always keep the soil moist. At the initial stage of transplantation, the sun is too strong around noon, so it should be shaded properly. The most important problem after transplantation is to promote the germination, germination and stem growth of the growing point. Leaf bundle germination is closely related to the quality of leaf bundle. The leaves are strong, heavy and easy to sprout. In addition, mycorrhizal inoculation can promote germination. Sometimes in order to promote germination, gibberellin can also be sprayed.

The management of v-leaf bundle seedlings after sprouting, sprouting and stalking is the same as the general seedling raising method.

V post-cutting management is also very important. Generally, water should be irrigated immediately after cutting. after that, attention should be paid to keep the humidity of soil and air, and do a good job of preserving soil moisture and loosening soil. If there are flower buds on the cuttings, they should be removed as soon as possible. When the aboveground leaves have spread before rooting, part of the leaves should be removed, and when the new seedlings reach 15~30cm, a strong erect branch should be left, the rest should be erased, and grass mulching can be carried out between the rows if necessary, so as to maintain moisture and prevent Rain Water from splashing soil on the tender leaves. Hardwood cuttings for tree species that are not easy to take root for a long time should pay attention to shading when necessary, and open-field cuttings of twigs should also build a shade to cool down, shading and cooling after 10:00 to 4 p.m., while spraying water every day to maintain humidity. When the cuttings are sealed in the plastic shed, the times of irrigation can be reduced, once or twice a week, but the temperature and humidity in the shed should be adjusted in time. After the cuttings survive, the cuttings should go through the stage of seedling refining and gradually adapt to the external environment and then move to the nursery. When cutting in a greenhouse or hotbed, after taking root and spreading leaves, it is necessary to gradually open the window to circulate the air, so as to gradually adapt to the external environment, and then move to the nursery.

V in areas with high air temperature and plenty of sunshine, full-light intermittent spray cutting bed can be used for cutting.

7. New techniques of cutting seedlings

(1) full-light automatic spraying technology

V1. The origin of full-light automatic spray cutting in the process of rooting for a long time, whether the cuttings can take root or not, the most important thing is to keep the branches without losing water. If the branch loses moisture, there is no hope of taking root. The various measures taken in the process of cutting are to maintain the moisture of the branches, to create water for the branches separated from the mother plant, and to obtain the water needed to supplement the life activities of the branches, as well as other nutrition and environmental conditions suitable for rooting.

As early as 1941, Lenis, Cardell and Fisher in the United States reported that the application of spray technology could keep the branches from losing moisture and promote the rooting effect of cuttings. Hess and Schneider have proposed the application of clock control spray device. Lanheng and Peterson invented sunlight control. Praton proposed the air wetting method. In the 1960s, the intermittent spraying device controlled by electronic leaves was invented by Cornison University in the United States, and it was proved that its effect and economic benefit were better than the former three, which made the spray device enter the stage of production and application. This new technology was reported and quoted in China in 1977. in China, in the early 1980s, Tan Yong of Nanjing Forestry University first reported the development of "electronic leaf" intermittent spraying device and its successful application in seedling breeding. Hunan Forestry Institute and other units have successively developed improved "electronic leaves" and "electronic seedlings", and Beijing Bureau of Gardens and Beijing Botanical Garden of the Chinese Academy of Sciences have also successfully developed intermittent spraying devices for "electronic leaves". In 1983, Xu Chuansen of Jilin Railway Branch developed a sensor based on the principle of dry and wet bulb hygrometer and a full set of spraying devices, which were widely used in many seedling breeding units all over the country. In 1987, the water evaporation controller of 2P-204 automatic intermittent spraying device was developed by the Science and Technology Information Center of the Ministry of Forestry and popularized to the whole country. In only more than ten years, all-light fog has been inserted into many seedling units all over the country. In 1995, the Chinese Academy of Forestry Sciences launched a rotary all-light fog insertion device, which greatly increased the control area of the seedling bed and produced good seedling effect and economic benefits.

V2. All-optical automatic spraying device

V (1) the humidity automatic control instrument receives and amplifies the signal input from the electronic leaf or sensor, and controls whether the relay is turned off and synchronized with the solenoid valve, so as to control whether it is sprayed or not. There are signal amplifying circuit and relay in the humidity automatic control instrument.

V (2) Electronic leaves and humidity sensors are devices that generate signals. The electronic leaf is the two poles of the low-voltage power supply installed on an insulating board, and the two poles are connected to the humidity self-control instrument through wires to form a closed circuit in parallel. The humidity sensor uses the change of the temperature difference between the dry and wet bulbs to generate a signal and input the humidity automatic control instrument to control the spray.

V (3) the solenoid valve is the solenoid valve switch that controls the water. When the solenoid valve receives the electrical signal of the humidity self-control instrument, the solenoid valve opens the sprinkler to spray water. When there is no electric signal, the solenoid valve closes and does not spray water.

V (4) the pressure requirement of all-optical automatic spray for high pressure water source is 1.5~3Kg/cm, and the amount of water supply should match that of the sprinkler, and the water supply is uninterrupted. Less than the pressure and flow of this water, the ejected water can not be atomized, there must be sufficient pressure and flow. The all-optical automatic spraying device is shown in figure 5-6.

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Figure 5-6 all-optical automatic spraying device diagram

1. Electronic leaf 2. Solenoid valve 3. Humidity automatic control instrument 4. Sprinkler 5. Cutting bed

V3. Whether the sprinkler can be sprayed or not depends first of all on the electrical signal input by the electronic leaf or humidity sensor. There are two electrodes on the electronic leaf and the humidity sensor. When there is water on the electronic leaf, the closed circuit of the electronic leaf or humidity sensor is turned on, the induction signal is input, and the weak electrical signal is amplified step by step through the wireless circuit signal. The amplified electrical signal is first input to a small relay, and then a small relay drives a large relay. When the large relay is electrified, the suction solenoid valve switch is turned off. When the water film on the electronic leaf evaporates dry, the induction circuit is turned off and there is no induction signal input to small and large relays. Large relay has no electricity, can not suck off the solenoid valve switch, solenoid valve switch in the opening and closing state, solenoid valve open, sprinkler water. When the water fog reaches a certain degree, the electronic leaf closing circuit is turned on, the induction signal is input, and after the above signal is amplified, the relay linkage and suction solenoid valve switch are closed. Work like this over and over again.

V 4. All-light automatic spray cutting precautions the substrate of full-light automatic spray cutting must be loose ventilation, good drainage, prevent the branches from rotting due to stagnant water in the bed, but keep the cutter moist.

V full light automatic spray cutting cuttings, generally speaking, the more leaves the cuttings have, the longer the cuttings are, the higher the rooting rate will be. After the larger cuttings survive, the seedlings grow strong, the cuttings are too long, the cuttings are wasted and uneconomical to use. Therefore, it is generally appropriate to 15cm around. On the contrary, the leaves of branches are few and short, the survival rate is low, the quality of seedlings is poor, and the survival rate of transplanting is low. The leaves and twigs inserted into the substrate at the bottom of the cuttings should be cut off.

If the full light automatic spray cutting is treated with rooting hormone, it can promote the rooting of cuttings, especially the tree species which are difficult to take root can improve the rooting rate, take root ahead of time and increase the amount of roots. Automatic spray cutting is easy to cause nutrient dissolution in the branches, due to frequent leaching, so that the hormones in the branches are also dissolved. The use of hormone treatment can increase branch nutrients and take root ahead of time, so it is more important to use spray cuttage plus hormone treatment.

(2) the technique of promoting root and seedling in matrix electric hotbed.

V electric hotbed seedling raising technology is designed to make use of the temperature difference effect of plant rooting to create the optimum temperature for plant callus and rooting. Using electric heating line to increase the ground temperature of seedling bed and promote the rooting of cuttings is a modern method of raising seedlings. Because of its electric heating, the target temperature can be controlled manually by plant growth simulation computer, and the temperature can be kept stable, which is beneficial to the rooting of cuttings. It has been widely used in ornamental tree cutting, forest tree cutting, fruit tree cutting, vegetable seedling and so on. First, choose a relatively dry flat ground indoors or in the greenhouse, use brick as a seedbed with a width of 1.5m, and cover the bottom with a layer of yellow sand or perlite. A square wood strip of 7cm × 7cm is placed at both ends and in the middle of the bed, and then a small iron nail is nailed every 6 cm, and the depth is the length of the small iron nail. the electric heating wire is wound back between the small iron nails, and the two ends of the electric heating wire are drawn out of the hotbed and connected to the seedling controller. Then add wet sand or perlite on the electric heating line, arrange the base of cuttings downward in the hotbed, and then fill with wet sand (or perlite) between cuttings to cover the top of cuttings. A temperature sensor should be inserted into the nursery bed and the temperature sensing head should be close to the base of the cuttings to correctly measure the temperature of the hair root. After electrification, the electric heating line begins to heat up. When the temperature rises to 28 ℃, the seedling controller can automatically adjust and work to stabilize the temperature of the hotbed in the range of 28 ℃.

V hotbed open the spray system 2 times three times a day to increase humidity, so that there is enough humidity at the base of the cuttings in the seedbed. If the seedbed is too dry, the cuttage cortex will not root; if there is too much water, it will cause cortical rot. In general, when plant cuttings are kept in the seedbed for about 10 to 15 days, the callus at the base of the cuttings is enlarged, the root is white, and the young root protuberances about 1mm grow, which can be moved into the field nursery and planted at this time. Transplanting too early and too late will affect the survival rate of cuttings. When transplanting, the seedbed should be built into a high border with a width of 1.3m and unlimited length, which can be determined by the topography. First, dig the cuttage ditch perpendicular to the border surface, the depth is 15 cm, pour enough bottom water in the ditch, cut the cuttings at the interval of 10 cm, put it vertically on one side of the ditch, then use fine soil to compact the cuttings with soil, and the top bud is exposed on the border surface. After planting, the border surface should be covered with grass to keep warm and moisturizing. After all the transplants are finished, the beds should be watered with fixed roots at one time.

V this technique is especially suitable for the branches of deciduous trees and shrubs in winter, which are bundled or tightly inserted in the seedling bed after branch treatment to adjust the optimal base temperature of the branches, so as to enhance the respiration of the injured cells in the wound and accelerate the enzymatic reaction. callus or root primordium is produced as soon as possible. Such as poplar, metasequoia, mulberry, pomegranate, peach, plum, grape, ginkgo, kiwifruit and other plants can use the bald hard branches after deciduous leaves to promote roots and seedlings. It has the characteristics of small area and high density (1m2 can discharge 5000-10000 cuttings).

(3) the technology of fog insertion (air humidification, heating and breeding)

V to raise seedlings in the cold winter season, it is necessary to turn on the air heating system. The heat source for heating is air heating hotline or oil-fired steam hot air stove. After the heat source is installed, it is connected with the plant growth simulation computer to realize automatic control, so that the air temperature can reach the optimum. In addition, the fog insertion (or air insertion) technology used in plant rapid propagation provides a stable growth and rooting temperature for the closed fog chamber.

V1. The characteristics of fog insertion are carried out in the greenhouse or plastic shed, and the semi-lignified branches of the year are fixed upright on the rack. By spraying and heating, the cuttings are kept in high humidity, suitable temperature and certain light conditions, and the cuttings heal and take root. Because the cuttings are in a more suitable temperature, humidity and certain light environment than the soil, the cuttings heal and take root quickly, the seedling rate is high, and the seedling raising time is short. for example, 80% of jujube is rooting in 5 days by fog insertion, and pearl plum can take root 10 days after it is inserted in soil. if the soil is inserted, it will take more than a month. The fog cutting method saves land and can make full use of the ground and space for multi-layer cutting. The utility model has the advantages of simple operation, easy management, no need to dig seedlings and other operations, and the root system has no loss and high survival rate. It is not limited by external environmental conditions, and uses plant growth simulation computer to automatically adjust temperature and humidity, so it is suitable for industrial production of seedlings.

V2. Facilities and methods of fog insertion

V (1) the fog insertion room (or air insertion chamber) is generally a greenhouse or plastic shed, and spraying devices and cutting fixtures should be installed in the room.

V (2) slotting machine in order to make full use of indoor space, a brick bed is built on the ground, generally 1-1.5 m wide and 20-25 cm deep, and the length depends on the length of greenhouse or shed, the bottom of the bed is covered with gravel or slag 3-5 cm thick to facilitate water seepage, and the above bed is covered with sand or vermiculite 15-20 cm thick as the matrix, and a trail is left between and around the two beds, and a ditch with a depth of 10 cm is dug on one side to facilitate drainage.

V (3) the cuttage fixing frame is provided with a layered cutting fixing frame on the cutter. One is to make a bracket with parallel arrangement of No. 8 lead wire at a height of 2 / 3 cm from the bed surface, with a row spacing of 8 / 10 cm. Each lead wire is bent into a "U" shaped hole with a plant spacing of 6 / 8 cm, so that the cutter is vertically stuck in the hole. The other is a layered fixed frame in the air, which is mostly made of triangular iron. Plastic plates are placed on the frame, and equidistant "U"-shaped holes are engraved on both sides of the board. The insert is vertically fixed in the hole, and a movable baffle is arranged next to the hole to prevent the insert from falling off.

(4) spray heating equipment in order to ensure a suitable and stable environment for spike rooting in the air plug chamber, artificial spray pipes should be installed above the scaffolding, spray nozzles should be installed according to the spray distance, preferably fog, indoor relative humidity should be controlled above 90% by plant growth simulation computer, temperature should be kept at 25: 30 ℃, and light intensity should be controlled at 600~800Lx.

V3. Management of fog cutting propagation

V (1) pre-insertion disinfection because the air chamber has been in high humidity and suitable temperature, which is beneficial to the growth and reproduction of bacteria. Therefore, attention must be paid to disinfection at any time, and the air plug room should be thoroughly disinfected before insertion. Usually, 0.4%-0.5% potassium permanganate solution is sprayed, and every 10 days or so after insertion, Bordeaux solution of 100% Bordeaux is sprayed to prevent the occurrence of fungi. In case of fungal infection, 800 times bacilli can be sprayed to prevent spread, and in serious cases, it can be unplugged and destroyed.

V (2) to control the temperature, humidity and light environment of the air cuttings, it is necessary to make it stable and suitable, such as a sudden power outage, in order to prevent the cuttings from wilting and causing sprouting and drying up, artificial water spraying should be done in time. In the summer high temperature season, the indoor temperature often exceeds 30 ℃. It is necessary to spray water in time to cool down, temporarily open the window for ventilation and adjust the temperature. In winter, use sunlight to increase temperature during the day, heat preservation with hot line at night, or heating with fire channel, hot air stove and so on.

V (3) timely check the rooting of cuttings. When the new root grows to 2 / 3 cm, it can be transplanted or put on the pot in time. Before transplanting, it is necessary to go through proper seedling training, usually in a shade shed or general greenhouse, and then move to the open field after growing steadily.