Five techniques of grafting new varieties of plants in gardens

Grafting of garden trees is a common method of artificial propagation of plants in horticulture, which makes use of the ability of two different plants to connect the branches or buds of one kind of plant to the stem or root of another plant and make them heal together to form an independent new individual. It can maintain the excellent characteristics of varieties, enhance the resistance and adaptability of scion varieties, change the plant type and the age of early flowering.

In the process of grafting, we should pay attention to the following five points:

1. Affinity between rootstock and scion

The so-called affinity refers to the healing ability of rootstock and scion after grafting. The affinity is determined by the genetic relationship, physiology, morphological structure and genetic characteristics of plants, as well as the influence of inclusions. For example, if grafted peaches are used as rootstocks, both of them have strong affinity and are easy to survive after grafting, but if different families of Robinia pseudoacacia are selected as rootstocks, if they are not compatible, grafting will not survive.

2. Selection of rootstocks and scions

The following conditions should be paid attention to in the selection of rootstocks:

The main results are as follows: (1) Middle-aged or young trees with developed root system and strong growth, which have good adaptability to climate, soil and other environmental conditions in the cultivated area.

(2) No diseases and insect pests, and good resistance to drought and flood, low temperature, air pollution and so on.

(3) the source is abundant, easy to reproduce, and can meet the special needs in application, such as Arbor, dwarfing, thornless and so on. In addition, scions should also be selected for vigorous growth, free from diseases and insect pests, and one-year-old or current-year-old semi-lignified branches should be the best. If the scion is too old, the healing survival is poor or difficult to survive.

3. Scions should be grafted with cutting.

The scion should not be cut for too long to prevent dehydration and dryness and affect the survival rate. For example, the five-needle pine scion cut from a distance in winter should be temporarily placed indoors, but pay attention to moisturizing storage. Peach bud grafting should be paid more attention to with cutting because the leaf bud is smaller. Grafting should choose no wind and shade place to prevent the sun and rain, causing the scion to lose water and dry up, affecting survival.

4. Grafting time:

It is better to choose the grafting time when the scion and the rootstock are in the budding or growing period, too early and too late, and the healing condition is not good. The grafting time of fruit peach and five-needle pine can also be carried out in July when the plant growth is slow.

5. Formation layer alignment:

Plant stem is composed of surface layer, cortex, phloem, xylem and pith. Among them, the cambium is the key to the healing of grafting, and the grafting is easy to survive if the cambium is aligned and closely combined between the rootstock and the scion. Especially for plants with thick rootstocks and thin scions, more attention should be paid to cambium alignment.

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A complete Collection of Plant grafting knowledge

A complete Collection of Plant grafting knowledge

First, the significance and function of grafting: in production practice, various grafting methods of cash crops such as fruit trees, vegetables, flowers and so on have been widely used. In recent years, the techniques of stem tip grafting, in vitro stem segment grafting, test tube plantlet grafting, callus grafting, cell grafting and model plant Arabidopsis thaliana grafting have been paid more and more attention. botanists' studies on the cytology, physiology and biochemistry of grafted body development, the interaction mechanism between scion and rootstock and the mechanism of grafting compatibility will bring new scientific research achievements to our life.

The significance of grafting: grafting means that people purposefully make use of the ability of two kinds of plants to connect the branches or buds of one plant to the stems (branches) or roots of another plant, so that they can heal and grow together. a method of reproduction to form an independent plant. In the process of production practice, there are many examples of the improvement of economic value by grafting: for example, ordinary metasequoia is worth one yuan; after being cultivated into Metasequoia glyptostroboides by means of grafting, the economic value is increased by more than 20 times; the ordinary large-leaf privet tree is worth a few cents; and by means of grafting, after it is cultivated into a colored leaf frame tree, its economic value is nearly a hundred times. Thus it can be seen that grafting is of great significance to the improvement of varieties and the improvement of economic value. Grafting is of great significance to the reproduction of some fruit trees that do not produce seeds, such as persimmon and citrus varieties. Grafting can not only maintain the excellent characters of scion varieties, but also make use of the favorable characteristics of rootstocks to achieve early fruiting, enhance cold resistance, drought resistance, disease and insect pest resistance, and economically utilize breeding materials and increase the number of seedlings. It is often used in the reproduction of fruit trees, trees and flowers; it is also used in raising seedlings of melons and vegetables. There are two types of grafting: branch grafting and bud grafting. The former is suitable for spring and autumn, especially the survival rate is higher in spring, and the latter is suitable for summer. The branch or bud for grafting is called scion or bud; the plant that bears scion or bud (root plant, root segment or branch segment) is called rootstock. Those who use branches as scions are called branch grafting, and those who use buds as scions are called bud grafting. The seedlings obtained by grafting are called grafted seedlings. The difference between grafted seedlings and other vegetative propagation seedlings is with the help of the roots of another plant, so grafted seedlings are "other root seedlings". 02. The history of grafting: grafting originated in nature. In nature, we can often see the phenomenon of natural grafting, that is, the branches of trees grow staggered, and because of the wind and rain, the branches are injured by friction with each other, and the injured surfaces naturally heal together. the formation of what people often call "Lianli tree" or "Lianli branch"; the roots of two trees grow close to each other, and they will also produce "Lianli root" for a long time. This kind of connection phenomenon, that is, the natural connection, and it is further found that the plants that form connected branches or roots generally grow vigorously. People get inspiration from the "connecting branches". After artificially cutting the epidermis of the two branches of the tree, they lean against each other, resulting in grafting. It can be seen that grafting is the first rely on grafting, and then developed into a variety of other grafting methods. China is the first country in the world to apply the technology of grafting (branch grafting). For the earliest records of grafting, see Shangshu Yugong: "tangerine exceeds Huaibei and becomes trifoliate orange". It is inferred that the orange was grafted on the trifoliate orange and moved to Huaibei, where the developed orange could not tolerate cold and froze to death, the hardy orange germinated again, and the orange became trifoliate again. Generally speaking, the grafting technology in China has a history of 3000 years, which is speculated on this basis. The grafting technology is clearly recorded in our country, which can be found in the Book of Shengsheng written by Li Sheng in the first century BC, in which there is a detailed account of the production of ladles by grafting. By the 5th century AD, the grafting technology in China had developed to a considerable level. In the Northern Wei Dynasty, Jia sixie had grafting methods of pears and persimmons in Qi Min Yao Shu, and mulberry trees were grafted in Chen Funong Shu of the Southern Song Dynasty. Ouyangxiu grafted peony in Luoyang Peony Story; since then, the grafting methods in Wang Zhennong Shu, Qunfang Spectrum and Flower Mirror have been very detailed, and many techniques have been used until now. 03, the function of grafting: grafting propagation is a very important method in garden plant seedling production. It not only has the advantages of general vegetative reproduction, but also has other functions that vegetative reproduction can not play:-- 01) maintain the excellent characteristics of plant quality and improve the ornamental value: the scions used for grafting and propagation of garden plants, all come from the mother plant with good quality; hereditary stability, in landscaping and beautification, the ornamental effect is better than that of seed propagation. Grafting can preserve the excellent characters of plants, which has been widely used in the production of fruit trees. For a long time, most fruit trees have been propagated by grafting. Although it is affected by the rootstock in different degrees after grafting, it can basically maintain the good characters of the female parent.

02) increase resistance and adaptability: most of the rootstocks used for grafting are wild species, semi-wild species and native species. This kind of rootstock has strong adaptability and can grow and develop normally under poor natural conditions. Once they are used as rootstocks, they can make the grafted varieties adapt to the adverse environment, improve the resistance of grafted seedlings, expand the cultivation range, and improve the ability of cold resistance, drought resistance, saline-alkali resistance and pest resistance with the physiological effects of rootstocks on scions. For example, sour jujube is resistant to drought and barren, and using it as rootstock to graft jujube increases the ability of jujube to adapt to barren mountains; maple poplar is resistant to water and moisture, and grafting walnut expands the cultivation range of walnut on water wetlands; Populus tomentosa is vulnerable to freezing damage in Hohhot, Inner Mongolia, so it is difficult to plant locally, and grafting with local small leaf poplar as rootstock can safely survive the winter. Grafting persimmon on Jun Qian seed can improve cold resistance. Apple grafted on begonia can resist cotton aphid; green peach grows vigorously on mountain peach and is easy to form tall plants; grafted on Shouxing peach to form dwarf plants; citrus virus-free stem tips are grafted on aseptic virus-free rootstocks and virus-free citrus clones can be cultured. 03) early flowering and fruiting: grafting can make the ornamental flowers, fruits and fruit trees blossom and bear fruit earlier, and make the timber tree species mature ahead of time. Grafting promotes ornamental trees and fruit trees to blossom and bear fruit earlier, mainly because scions are collected from mature trees that have entered the flowering and fruiting stage. once such scions are grafted, they will blossom and bear fruit soon once they heal and resume growth. For example:-- propagating Chinese chestnut with seeds will not bear fruit until 15 years later, with an average yield of 1~1.5kg per plant. On the other hand, the grafted chestnut can blossom and bear fruit in the second year, and the plant yield can reach more than 5kg after 4 years, citrus seedlings need 10-15 years to bear fruit, grafted seedlings can bear fruit in 4-6 years, apple seedlings can bear fruit in 6-8 years, grafted seedlings only 4-5 years. In the aspect of wood tree species, through grafting, the vitality of trees is improved and the growth rate is accelerated, so as to make trees grow up ahead of time. "Green poplar meets white poplar, long hoe and carry in that year" means that after grafting, trees grow faster and mature ahead of time. 04) overcome the phenomenon that it is not easy to reproduce: some plant varieties in the garden have no seeds or very few seeds to propagate for the purpose of cultivation, and it is difficult to propagate or underdevelop after cutting, so grafting propagation can better complete the work of propagation and breeding. Such as double varieties of garden trees, seedless grapes in fruit trees, seedless oranges, persimmons and so on. 05) expand the propagation coefficient: a large number of rootstocks can be obtained by seed propagation, so that a large number of seedlings can be obtained in a short time, especially the new varieties with bud transformation, and the number of varieties can be rapidly expanded by grafting. 06) cultivation of new varieties: grafting breeding of new varieties is shown in the following three aspects: A. The use of "budding" to cultivate new varieties: budding, which usually refers to the variation of a bud and a branch produced by a bud. This variation is a mutation in the meristem somatic cells of plant buds. Bud transformation often shows new excellent characters, such as high yield, better quality, enhanced resistance to diseases and insect pests and so on. New varieties can be cultivated by grafting and careful management of the shoots after bud transformation. For example, "Dragon claw Robinia pseudoacacia" is selected by grafting and bred by grafting, and the "Hongxing" variety in apple is bred by grafting using the bud transformation of "Marshal" variety. Compared with the original variety, it has the advantages of early coloring and bright red color. b. Grafting breeding: grafting breeding and grafting reproduction, although both have to be grafted, but they are two different concepts. Grafting propagation: is a reproductive process, it is the use of grafting methods to maintain the original good characters, and enhance the ability to adapt and early blossom or fruit or mature wood. Therefore, there is basically no variation in grafting propagation and no new characters appear. Grafting breeding: it is a process of asexual hybridization. It also uses the grafting method, but it is through the interaction between the scion and the rootstock to make the scion or rootstock produce variation, so as to produce new excellent characters. In order to carry out grafting breeding, it is necessary to select hybrid combinations, scions and rootstocks. For example, plants with a short history of phylogeny, young ontogeny, not fully developed characters and hereditary unstereotyped plants are selected as scions, plants with long phylogenetic history, ontogenetic maturity, fully developed characters and hereditary stereotyped plants are selected as rootstocks.-after grafting, the branches and leaves of rootstocks are maintained and the branches and leaves of scions are reduced. In this way, it is possible to make the rootstock affect the scion and make the scion have some kind of variation. After the emergence of the variation, and then through further cultivation, it is possible to breed a new variety. c. Asexual proximity is carried out to create conditions for sexual distant hybridization: sexual distant hybridization, there are often cases of hybrid infertility or hybrid infertility, if the two parents are grafted in advance to make the two parents physiologically close to each other, and then pollination can often achieve success. For example:-- Apple branches are grafted on the crown of a pear and pollinated with pear pollen after flowering to obtain intergeneric hybrids between apple and pear. It cannot be fertilized without grafting. 07) restore tree potential, cure trauma, supplement missing branches, update varieties: aging trees can make use of the advantages of strong rootstocks through bridging, root grafting and other methods to promote growth and restore tree potential. The crown is partial and hollow, and the development direction of the branches can be adjusted by grafting to make the crown plump and beautiful. Plants with bad varieties can be replaced by grafting. For dioecious plants, grafting can be used to change the male and female of the plant. Grafting can also make a tree multiple, multi-headed, multi-flower, and improve its ornamental value. 04. Influencing factors: the main factor affecting the survival of grafting is the affinity of scion and rootstock, followed by the technology of grafting and the management after grafting. The so-called affinity is the ability that scions and rootstocks are the same or similar to each other in internal organizational structure, physiology and heredity, so that they can be combined with each other. High affinity and high survival rate of grafting. On the contrary, the survival rate is low. Generally speaking, the closer the plant relationship is, the stronger the affinity is. For example, apples are connected to sand fruits, pears to du pears and Qiuzi pears, persimmons to black dates, walnuts to Juglans mandshurica and so on. The limitations of grafting: the above grafting can improve or restore the greening and beautification effect of some trees. However, grafting propagation also has some limitations and shortcomings. For example, grafting propagation is generally limited to kinship, requiring strong affinity between rootstocks and scions, so some plants cannot be propagated by grafting; Monocotyledons are difficult to survive because of stem structure. In addition, the life span of grafted seedlings is short, and the operation technology of grafting propagation is also complicated, and the technical requirements are higher; some also need to cultivate rootstocks first, which requires a large investment in manpower and material resources.

Second, the principle and process of grafting survival: after scion and rootstock grafting, the key to survival lies in whether their tissues heal or not, and the main sign of healing is the connection of vascular tissue system. The survival of grafting mainly depends on the affinity between rootstock and scion and the ability of cell growth, division and cambium regeneration around the wound. The cambium is a parenchyma cell layer with strong regeneration ability between xylem and phloem (see below for details).

Vertical and transverse sections of branches: 1, xylem; 2, pith; 3, phloem; 4, epidermis; 5, cambium

Under normal circumstances, the parenchyma cell layer divides, forming xylem inward and phloem outward, making the tree grow thicker; after the tree is injured, the parenchyma cell layer also has the function of forming callus and protecting the wound. Therefore, after grafting, the cambium parenchyma cells of the rootstock and the scion split to form callus and gradually fill the gap of the joint, so that the scion and the new cells of the rootstock are closely connected to form a common cambium. the phloem is produced outward and the xylem is produced inward, and the two heterogeneous parts are combined from then on. In this way, the root system of the rootstock absorbs water and inorganic nutrients from the soil to supply the scion; the branches and leaves of the scion make organic nutrients and transport them to the rootstock, and the two combine to form a new individual that can grow and develop independently. It can be seen that in terms of technical measures, in addition to considering affinity according to the genetic characteristics of tree species, the key to survival of grafting is the close connection of cambium between scion and rootstock, and the larger the joint surface is, the easier it is to survive. Practice has proved that in order to make the cambium of the two closely join, the contact surface between them must be smooth during grafting, and the cambium must be aligned, clamped and fastened. See the following figure for details:

Third, the factors affecting the survival of grafting: the main factors affecting the survival of grafting: the affinity of rootstock and scion; the quality of rootstock and scion; external conditions and grafting techniques are as follows: 01. The internal factors affecting the survival of grafting are the affinity of rootstock and scion, the vitality of rootstock and scion and the biological characteristics of tree species. 01) Affinity of rootstock and scion: grafting affinity is the ability of scion and rootstock to heal and grow after grafting. Specifically, it is the ability of scions and rootstocks to combine with each other because they are identical or similar in shape, structure, physiology and heredity. The affinity of ① grafting is shown in-A. Morphologically and structurally, it is the similarity of the volume and structure of cambium and parenchyma cells. Physiologically and genetically, it is the growth rate of cambium or other tissue cells and the similarity of raw materials and products needed to metabolize each other. Grafting affinity is the most basic condition for graft survival. No matter what kind of plant or grafting method is used, there must be a certain affinity between the rootstock and the scion. If the affinity is high, the survival rate of grafting is also high; on the contrary, the less likely the grafting is to survive. The affinity of ② grafting is related to the genetic relationship of trees. The general rule is that the closer the kinship is, the stronger the affinity is. Therefore,-- grafting between varieties is the easiest, followed by interspecific, followed by different genera. It is more difficult between different departments. 02) the vitality of rootstock and scion and the biological characteristics of tree species: the formation of callus is related to plant species and the vitality of rootstock and ear. Generally speaking, the growth of rootstock and ear is robust, the development of vegetative organs is abundant, the body is rich in nutrients, the growth is exuberant, the division of cambium cells is the most active, and grafting is easy to survive. Therefore, rootstocks should choose plants with strong growth and good development, and scions should also choose fully developed branches from the periphery of the crown of strong mother trees. a. If the rootstock germinates earlier than the scion, it can supply the nutrients and water needed by the scion in time, and the grafting is easy to survive. If the scion germinates earlier than the rootstock, it may die of starvation due to lack of water and nutrients supplied by the rootstock. If the scion germinates too late and the rootstock spills too much liquid, it may also "drown" the scion. Some species, such as persimmon and walnut, are rich in tannin, and the section is easy to form an oxidized tannin isolation layer, which hinders healing; pines are rich in turpentine, and improper treatment will also affect healing. d. The water content of scion will also affect the success of grafting. e. If the water content of the scion is too low, the cambium will stop activity and even die. Generally, the water content of scion should be about 50%. Therefore, the scion should not be too dry and wet during transportation and storage. You should also pay attention to moisturizing after grafting. For example, the earth pile should be built when it is connected low, and the moisturizer should be bound when it is high to prevent moisture from evaporating. f. In addition, if the cell structure and growth rate of rootstock and scion are different, grafting will form the phenomenon of "big foot" or "small foot". For example, grafting five-needle pine on black pine and sweet-scented osmanthus on privet will appear the phenomenon of "small feet". In addition to affecting beauty, the growth is still normal. Therefore, when there is no more ideal rootstock, the above rootstocks can still be used in the cultivation of garden seedlings. 02. The external factors affecting the survival of grafting are mainly the influence of temperature and humidity. Grafting under suitable temperature, humidity and good ventilation conditions is beneficial to healing survival and seedling growth and development. 01) temperature: it has a great relationship between the speed of callus formation and the survival of grafting. At the suitable temperature, the callus forms the fastest and is easy to survive, and the temperature is too high or too low, which is not suitable for callus formation. Generally speaking, when plants are about 25 ℃, grafting is the most suitable, but plants with different phenological phases have different requirements for temperature. The optimum temperature of early phenological phase was lower than that of later phenological phase, such as peach and apricot at 20-25 ℃, and camellia at 26-30 ℃. When branch grafting is carried out in spring, the grafting order of each tree species is mainly determined by this. 02) humidity: it has a great influence on the survival of grafting. On the one hand, the formation of grafted callus needs a certain humidity condition; on the other hand, to maintain the vitality of the scion, it also needs a certain air humidity. If the atmosphere is dry, it will affect the formation of callus and cause scion to lose water and dry up. Soil moisture and groundwater supply are also important. When grafting, if the soil is dry, water should be irrigated first to increase soil moisture. 03) Light: it can obviously inhibit the formation and growth of callus. In the dark conditions, in order to facilitate the formation of callus, therefore, must be shaded after grafting-low grafting soil cover, both moisturizing and shading. In addition, ventilation also has a certain effect on healing and survival. Given certain aeration conditions, it can meet the oxygen needed for the respiration of cambium cells in the junction of rootstock and scion. Grafting quality: in all grafting operations, the technique and speed of using knife is the most important. Whether the cutting surface of ① scion is smooth or not: the key factor of graft survival is the close combination of scion and rootstock cambium. This requires that the cutting surface of the scion must be smooth so that it can fit closely with the rootstock. If the cutting face of the scion is not smooth, the gap between the scion and the rootstock will be large, and there will be more calli to be filled, so it will not be easy to heal. Therefore, the scion cutting knife should be sharp and smooth. Whether the slope and length of the cutting surface of ② scion are appropriate: during grafting, the larger the joint surface of the same type tissue between scion and rootstock, the easier the transport tissue of the two is to communicate, the higher the survival rate is; on the contrary, the survival rate is lower. Whether the cambium of ③ scion and rootstock is aligned or not: the grafting survival of most plants is the result of active division of cambium of scion and rootstock. Therefore, the more accurate the cambium of the two are grafted, the higher the survival rate is. The grafting speed is fast and skilled, which can avoid air-drying or oxidation discoloration of cutting noodles, so as to improve the survival rate. Skilled grafting techniques and sharp knives are the basic conditions for successful grafting. 04. The relationship among the factors affecting the survival of grafting: whether the grafting survived or not is the result of the interaction among various factors. The relationship is shown in the following figure:

Fourth, the interaction between rootstock and scion and the selection of rootstock and scion. 01. Interaction between rootstock and scion: 01) effect of rootstock on scion: general rootstocks have strong and extensive adaptability, such as drought resistance, cold resistance, waterlogging resistance, saline-alkali resistance, disease and insect resistance, etc., so it can increase the resistance of grafted seedlings. For example, using begonia as apple rootstock can not only increase the drought and waterlogging resistance of apple, but also increase the resistance to yellow leaf disease; maple poplar as walnut rootstock can increase the waterlogging and barren resistance of walnut. Some rootstocks can control the scion to grow into a plant size, making it Arbor or dwarf. The rootstocks that can make the grafted seedlings grow vigorously and tall are called "Arbor rootstocks". For example, mountain peaches and apricots are the "Arbor rootstocks" of plum blossoms and green peaches; on the contrary, some rootstocks can weaken the growth of grafted seedlings and dwarf plants, which are called "dwarfing rootstocks". For example, Shouxing peach is the dwarfing rootstock of peach and blue peach. Generally, Arbor rootstock can delay the flowering and fruiting period of grafted seedlings and prolong the life of grafted seedlings, while dwarfing rootstocks can promote the early flowering and fruiting of grafted seedlings and shorten the life span of grafted seedlings. 02) the effect of scion on rootstock: after grafting, the root growth of rootstock depends on the nutrients produced by scion, so scion will also have a certain effect on rootstock. For example, after du pear is grafted into pear, its root distribution is shallow, and root tiller is easy to occur. 02. Selection of rootstocks and scions: 01) selection of rootstocks: rootstocks with excellent characters are important links in cultivating excellent garden trees. The condition of selecting rootstock-① has strong affinity with scion; ② has good effect on scion growth and flowering, and has strong growth, high yield, colorful flowers and long life span; ③ has strong adaptability to the environmental conditions of cultivated area; ④ is easy to propagate; ⑤ has strong resistance to diseases and insect pests. 02) selection of scions: scions should be selected from adult trees with good characters, strong growth, high ornamental value or economic value, and free from diseases and insect pests.

Fifth, the preparation of grafting: before carrying out grafting activities, we should do a good job in the preparation of appliances, rootstocks and scions. 01) cleavage knife: used to split the incision of the rootstock. The blade is used to split the rootstock and the wedge is used to pry open the split of the rootstock. 02) handsaw: used to saw thicker rootstocks. 03) Branch shears: used to cut scions and thinner rootstocks. 04) Bud grafting knife: when budding, it is used to cut the buds and pry open the sprouts. The handle of the budding knife has a horny piece, which will not change chemically with the tannins in the bark when it is used to pry open the incision. 05) pencil sharpener or blade: a rootstock and scion used to cut herbs. 06) pitchers and wet cloth: used to hold and wrap scions. 07) binding material: used to bind the grafting site to prevent water evaporation and to make the rootstock scion close to each other. The commonly used binding materials are plastic strips, horse lily, bushes, cotton thread, rubber bands and so on. 08) Wax grafting: used to cover the interface of bud grafting to prevent water evaporation and Rain Water immersion into the interface. There are two kinds of wax: solid and liquid. ① solid wax: the raw materials are 4 parts of rosin, 2 parts of yellow wax and 1 part of animal oil (or vegetable oil). When preparing, first melt the animal oil by heating, then pour in the rosin and yellow wax, and stir until fully melted. The solid wax usually forms a hard block and needs to be heated and melted when it is used. ② liquid wax: the raw materials are 8 parts of rosin, 1 part of animal oil, 3 parts of alcohol and 0.5 parts of turpentine. When preparing, first heat the rosin and animal oil in the pot, until all melted, cool slightly, slowly pour alcohol and turpentine into it, and stir to serve. When in use, touch the foam interface with a brush and dry as soon as you see the wind. Among the above appliances, all kinds of knives and scissors should be sharpened before use. This is closely related to the survival rate of grafting and must be paid great attention to. 02. Preparation of rootstocks: when grafting is carried out in general cultivation, rootstocks must be sown 1 year or 2-3 years ago. If you want the rootstock to affect the scion, it must be sown 4-5 or even 5-6 years ago, and the specific number of years varies according to the age of the first flower of various trees. If you want to influence the rootstock with scion, the rootstock needs to be young and sowed 1-2 years ago. When grafting, if you plan to cover it with soil after grafting, you must dig up the soil deep in 7~10CM on both sides of the rootstock in advance. During bud grafting of woody plants, if the soil is dry, it should be irrigated the day before to increase the moisture in the tree tissue so as to tear off the bark at the interface of the rootstock when grafting.

03. Scion preparation: generally, new shoots or annual branches with full growth and full buds in the middle and upper parts of the crown are selected as scions. Then select the scion, integrate the small bundle, and mark the variety name. For the new shoots collected in summer, the leaves and the tip of the new shoots with insufficient growth should be removed immediately, and only the petiole should be retained and wrapped in a wet cloth in time to reduce the water evaporation of the branches. If the scion can not be used in time, the lower part of the branch can be immersed in water and placed in the shade. Change the water once or twice a day and keep it for 4 or 5 days in a short period of time. Branch grafting and bud grafting in spring are best combined with winter shearing, or they can be collected 1-2 weeks before sprouting in spring. After the collected branches are wrapped up, they are hung in a well or stored in a cold cellar. It is better if they can be stored in refrigerator or cold storage at a low temperature of about 5 ℃.

6. Grafting methods: according to the different materials, they can be divided into three categories: branch grafting, bud grafting and root grafting. 01. Grafting method: it is mainly used for grafting thicker rootstocks or changing varieties on big trees. Grafting time: generally carried out in the dormant period of trees, especially in the spring when the sap of the rootstock begins to flow, and the scion is best when the scion has not yet sprouted. The advantage of branch grafting is that the seedlings grow fast and neatly after grafting, and they can grow into seedlings in the same year, but they need a large number of scions and can be grafted for a short time. Branch grafting methods: commonly used cutting, abdominal grafting, split grafting and skin grafting and so on. 01) splicing: generally used for small rootstocks with a diameter of about 2CM, it is the most commonly used method in branch grafting (Fig. 5-9). When grafting, first cut the rootstock about 5CM from the ground, then cut it flat; choose the smoother side, and use the cutter to cut vertically down about 2~3CM on one side of the rootstock (slightly xylem, the diameter of the cross section is about 1 2~3CM). When cutting the scion, 2 or 3 full buds should be retained on the scion. The scion should be cut inward to the xylem (not beyond the pith) from the back of the bud closest to the lower incision, then cut down parallel to the end, the cut plane is long 2~3CM, and then cut into a small slope of 0.8~1CM at the end of the back. Insert the cut scion into the incision of the rootstock, so that the cambium of both sides is aligned with the rootstock. The depth of scion insertion should be 0.2~0.3CM exposed at the top of scion cutting surface, which is commonly known as "white exposure", which is beneficial to healing and survival. If the cut of the rootstock is too wide, it can be aligned with one side of the cambium, and then tightly bound from the bottom to the top with a plastic strip to make the cambium close and moisturize the wound. After grafting, bagging, soil sealing and wax coating can be adopted in order to maintain interface humidity and prevent dehydration and wilting. Figure 5-9 splice

01, cutting scion, 02, longitudinally cutting rootstock with slightly xylem, 03, rootstock combination.

02) splicing method: suitable for most deciduous tree species. It is usually used when the rootstock is thicker and the scion is small (figure 5-10). The rootstock was sawed off the 5~10cm off the ground and split straight down from the center of its cross section with a splitter. The cut length was about 3cm, the scion was cut into a wedge, the cutting face was about 3cm, and the outside of the scion was slightly thicker than the inside. After cutting the scion, pry open the split of the rootstock, insert the thick side of the scion outwards and narrowly inward, so that the cambium of the two sides are aligned, and the upper end of the cutting surface of the scion should be higher than the cut 0.2~0.3cm of the rootstock. When the rootstock is thick, 2 or 4 scions can be inserted at the same time. Generally, it is not necessary to bind the interface, but if the rootstock is too thin and the clamping force is not enough, it can be tied with plastic film strip or hemp rope. In order to prevent the water loss of the split from affecting the survival of the grafting, the grafting can be covered with soil or sealed with wax. Figure 5-10 splice picture

01, cutting scion; 02, splitting rootstock; 03, inserting scion.

Gun twist is a kind of splicing. Taking advantage of the fact that it is not easy for Populus tomentosa to take root, but it is easy for black poplar species such as Populus tomentosa to take root, one-year-old branches of Populus tomentosa and other black poplar species are used as scions and rootstocks. The scion is 8~10CM, with 2-3 full buds, and the rootstock is about 10CM. When it is free in winter, it is split indoors, and then it is not bandaged. 50 to 100 roots are bundled into a bundle, erected in the sand in the pit, and the seedlings are raised by cutting next spring. 03) skin grafting: it is the most easy to master in branch grafting and has the highest survival rate. It is required to be used when the rootstock is thick and easy to peel. Generally, cut the anvil at the 5~8CM above the ground, flatten the cross section, select the smooth place, and make a longitudinal incision in the cortex of the rootstock. The length of the scion is 1, 2, 2, 2, 3. The scion should cut the single slope of the growing 3~4CM, the cutting surface should be straight and beyond the pith, the thickness of the 0.3~0.5CM should be thick, and the back end should be cut into a small slope of 0.5~0.8CM or cut off slightly on each side of the back. When grafting, insert the scion from the cut of the rootstock along the middle of the xylem and phloem, the long side facing the xylem, and make the back of the scion align with the cut of the rootstock, and pay attention to "leaving blank" at the upper end of the scion. If the rootstock is thicker or the cortical toughness is better, the rootstock can insert the cut scion directly into the cortex without cutting. Finally, it is bound with a plastic film strip (about the width of 1CM). This method is also often used for high grafting, such as the grafting of Robinia pseudoacacia and the high grafting of flower and fruit trees. If the rootstock is thicker, it can be grafted with 3 or 4 scions at the same time and evenly distributed, and after survival, it can be used as the skeleton of the new plant (see the following picture).

01, cutting scion; 02, cutting rootstock; 03, inserting scion; 04, binding.

04) tongue grafting: tongue grafting is suitable for the grafting of rootstock and scion with 1~2CM thick and similar in size and thickness. The contact area between tongue-grafted rootstock and scion is large, the combination is firm, and the survival rate is high. Both high and low grafting are used in garden seedling production. Cut the upper end of the rootstock into a 3CM long cutting surface, and then cut the longitudinal incision of 1CM from the top to the bottom of the rootstock to form a tongue. At the smooth part of the scion, the oblique cutting plane of 3CM length is cut, and then the same longitudinal cut of 1CM is made at 3 points from the bottom to the top of the slope, which corresponds to the longitudinal incision of the inclined plane of the rootstock. Insert the inner tongue (short tongue) of the scion into the longitudinal incision of the rootstock, cross each other's tongues, tighten each other, and then bind them (see figure below)

1. Cutting of anvil and scion; 2. Combination of rootstock and scion

05) bark-tongue grafting: a tree species that is mainly used for sap flow and easy to peel, but not suitable for splicing. Cut off the rootstock at 5~10CM off the ground, select the straight part of the rootstock, cut off the thick old skin, and expose the tender bark (phloem). Cut the scion into a 5~7CM-shaped single side, pinch open the cutting surface, gently insert the xylem of the scion between the xylem and phloem of the rootstock, insert it into the slightly exposed scion cutting surface, and then bind it (see the following figure for details).

1. Cutting stock; 2. Cutting scion; 3. Cutting scion

06) abdominal grafting: there are two types of common abdominal grafting and subcutaneous abdominal grafting, which are grafted in the abdomen of the rootstock. Often used for the reproduction of coniferous trees, rootstocks do not cut off the head, or only cut off the top tip, and then cut off the branches of the rootstock above the joint after survival. Common web joint: the scion is cut into a wedge, the length of the long cutting surface is about 3CM, the cutting surface is flat and oblique, and the back is cut to grow the short cutting surface around 2.5cm. The rootstock should be cut at an appropriate height, choose the smooth side, make a deep cut from top to bottom, and the incision goes deep into the xylem, but the lower end of the incision should not exceed the pith, and the length of the incision is equal to the length of the scion. Insert the scion length into the incision, pay attention to the alignment of the cambium, and then bind and moisturize. Subcutaneous abdominal connection: subcutaneous abdominal connection, that is, the incision of the rootstock does not hurt the xylem, cut the rootstock transversely and then vertically, showing a "T" incision without injury or slight injury. The long cutting surface of the scion is straight and oblique, and one knife is cut to the tip on both sides of the lower back, in order to show white. Pry open the cortex and insert the scion and tie it (see the following picture for details).

1, cutting (ordinary abdominal grafting) scion; 2, ordinary abdominal grafting; 3, cutting (subcutaneous ventral grafting); 4, subcutaneous ventral grafting

07) abutment: a special form of grafting. The survival rate of relying on grafting is high, which can be carried out during the growing period. However, scions and rootstocks are required to take roots, and then cut off after healing, which is troublesome to operate. It is mainly used for ornamental trees and orange and orange trees where the affinity between scion and rootstock is poor and grafting is not easy to survive.

As flowering plants, people want to meet the needs of our production activities by adjusting the flowering period. in fact, many flowering plants can regulate the flowering period, and the plant growth cycle is affected by external conditions, such as climate, nutrients, photoperiod, and so on. Triangular plum is a strong positive short-day plant, the simplest way can be through shading control method, you can blossom early, if I want to triangular plum blossom after 50 days Shading before 9 o'clock in the morning and after 17:00 in the afternoon, so that shading for 25 to 30 days will certainly blossom after 50 days. It should be noted that during light control, if the light time is less than 9 hours, the growth will weaken and do not bloom.

Water control method: water control method is a method of physical regulation of plants to adapt to the environment. When plants encounter adverse climatic conditions such as drought, in order to reproduce, it will blossom and bear fruit quickly. Therefore, we can adjust the flowering period of triangular plum by controlling water. Water control and flower control can determine the length of water control time according to region, climate, temperature and variety. It is usually appropriate to wilt the whole plant leaves. Such a small amount of water supply can ensure that it will not dry to death, lasting for 3-7 days, and then gradually feed water. In this process, all the leaves of the plant will fall off, and after sprouting, a thin application of phosphorus and potassium fertilizer can be applied. Water is still appropriate, do not have too much water, too much water flower buds will also be transformed into leaf buds. As far as the seedlings are concerned, the effect of the water control method should be controlled several times in a row, and the water control method should be carried out 40-50 days before flowering, and there is also fertilization control method: early flowering can be achieved by applying potassium nitrate and foliar spraying potassium dihydrogen phosphate during the growing period. Potassium nitrate was applied once in 10 days for three times in a row, and potassium dihydrogen phosphate was sprayed on the leaves three times in a row, once a day and three times in a row. This method should be carried out 60 days before flowering. In addition, there are many growth regulators can Cui Hua, not one by one here. If you want to prolong the florescence, the best way is to lower the temperature and control fertilization. Heavy cutting can also prolong the flowering period.

These are the whole contents of the cultivation techniques of triangular plum. Flower growers who have planted triangular plum can learn more!