Brief introduction and planting method of Taxus chinensis

The yew is also called the yew. Also known as red cypress pine. Taxus mairei, a national first-class rare and protected tree species, is a shallow-rooted plant. The main root is not obvious and the lateral root is well developed. It is recognized as an endangered natural rare anticancer plant in the world. It is an ancient tree species left over from Quaternary glaciers and has a history of 2.5 million years on earth. Due to the slow growth rate and poor regeneration ability of Taxus under natural conditions, there has been no large-scale yew raw material forest base in the world for a long time.

Because taxol, the extract of yew (TAXOLPACLITAXEL), has a unique anticancer mechanism, Dr. BRODER, director of the National Institute of Oncology, said that paclitaxel has been considered as a new anticancer drug with good curative effect and little side effect on many kinds of cancer in the past 15 years after doxorubicin and cisplatin. Since the 1980s, the United States, Britain, Russia, South Korea and China have carried out in-depth research one after another. The United States took the lead in applying the research results to medical clinic and achieved remarkable clinical results in the treatment of various cancers. Since then, mankind has made a new breakthrough in the field of anti-cancer. So so far and for quite a long time to come, the most favorable weapon for human beings to fight cancer can only be paclitaxel.

Taxus in addition to important medicinal value, its unique appearance, evergreen bright green, but also a rare green tree species.

The beautiful posture of the yew can be seen in front of the United Nations headquarters in New York, in front of Buckingham Palace in Britain, and in the White House Square in the United States. We hope that the medicinal value of yew can not only benefit mankind, but also hope that in the near future, the beautiful and rich yew can decorate Beijing, which hosted the 2008 Olympic Games, more beautiful and beautiful.

At present, many domestic yew planting enterprises are developing a series of yew products. For example, the yew bonsai can be trimmed into umbrella type, tower type, round type and so on. Yew health care cup, yew handicrafts, yew health products and so on.

The State Forestry Administration has made clear instructions on the current "yew project": "Taxus is a first-class protected tree species in China, with good ecological benefits and high economic value. The state supports the construction of yew forest in an appropriate range, and people from all walks of life to participate in the afforestation and greening cause in the form of contracting, leasing, auction, stock cooperation and other forms should be promoted and encouraged."

Although the resources of Taxus in China account for more than half of that of other countries in the world, the demand for taxol in the world is still far from enough. Since the Food and Drug Administration (FAD) of the United States approved paclitaxel as a drug for the treatment of advanced cancer in 1992, the wild yew resources in China have been over-felled and seriously damaged. Moreover, many biological characteristics of wild yew limit the development of natural community. According to statistics, the annual incidence of cancer in the world is more than 10 million. If paclitaxel is extracted according to 0.006% Mueller Mel 0.06%, yew bark will be consumed 700 Mel Mel 1000 tons annually. Even if all the yew bark is harvested all over the world, it can only maintain short-term needs. And the method of artificial or chemical synthesis of paclitaxel is still in the laboratory stage. Therefore, it is urgent to develop Taxus resources by artificial propagation and to establish a forest base of Taxus medical raw materials.

Several breeding methods of Taxus seedlings at present

1. Pre-breeding planting method

The conservation of Taxus resources and the rapid breeding of seedlings are the basis for the construction of taxol timber forest, and the construction of Taxus plantation in a large area is to solve the shortage of taxol raw materials. When breeding seedlings with Taxus seeds, it is necessary to keep in mind the storage mode of seeds and to store sand seeds or control temperature, which has a good effect on sprouting and breaking dormancy habits after overwintering. Before sowing, the seed coat should be rubbed, the seeds should be soaked in warm water and treated with chemicals and hormones. Shading after emergence is the closure of seedlings to prevent high temperature burning of seedlings to keep moist, light transmittance of 40% is appropriate. The emergence rate of both Taxus mairei and Taxus chinensis var. mairei can reach 70%, and the seedling emergence temperature is required to be higher than 15 degrees.

The dynamic growth of seedlings was as follows: the plant height and stem diameter of seedlings grew slowly in the first two years of emergence, the plant height generally grew about 10CM a year, and the growth accelerated one year after transplanting. 3Murray-5 years, the annual increase can reach 20---30CM.

two。 Tissue Culture and breeding of Taxus mairei

Tissue culture takes advantage of the totipotency and clonability of plant cells. The tender stem, needles, bark, cambium, aril and embryo of Taxus chinensis were used as explants for culture.

(1)。 Excellent varieties of Taxus mairei, such as the high quality organs of Taxus cuspidata (with high taxol content) were selected as explants. In the inoculation medium, a large number of tissue culture seedlings could be obtained in the laboratory after callus formation, rooting, seedling bud formation and so on. After substrate transplanting, seedling training, inspection and epidemic prevention, it becomes a vaccine for production.

(2)。 The ratio of late to early callus formation of Taxus chinensis var. mairei was different among different species and different plants of the same species. At the same time, it is related to the type of explant, sampling site, collection season, light condition, medium type and so on. On the induction medium, Taxus chinensis var. mairei, Taxus chinensis var. mairei and Taxus yunnanensis could form callus. However, the formation is also different due to the species and plants of Taxus.

Studies have shown that a certain degree of hydrolyzed complex protein (CA) can promote the callus growth of Taxus mairei and Taxus mairei, but the concentration of more than 0.5% is not conducive to the formation and accumulation of paclitaxel.

When the concentration is more than 1%, it can promote the healing of callus and form a new growth point, but does not affect the accumulation of paclitaxel.

By comparison, 2 and 4D are also beneficial to the formation of callus and increase the induction rate. The color of callus in 2 and 4D medium was fresh and the callus was big and soft, so it was easy to induce callus of Taxus mairei. However, other medium additives, such as cell suspension culture, B5 medium and carbon sucrose, can also increase the content of paclitaxel. However, glucose in high agricultural sucrose can inhibit the synthesis of paclitaxel. At the same time, galactose can promote cell growth significantly.

The study of GIBSON showed that whether in cell suspension culture or in inducing callus cell growth and paclitaxel content formation, it was better in dark than in light.

No matter what varieties and sites are used in tissue culture, the cells with strong proliferation ability in the middle layer should be selected (the surface cells contain a large number of starch granules, the central cells are nucleless, and the differentiated tubular molecules are easy to appear). This is conducive to the formation of intercellular strands, resulting in the formation of large cell clusters, which is conducive to the signal transmission of small substances between cells. Thus Taxus cells exist in the form of cell clusters, producing functional cell bodies, promoting cell mass regionalization, and cell functional differentiation, which is the prerequisite for the production of metabolites in Taxus mairei.

3. Artificial cutting Propagation of Taxus mairei

With the decrease of yew resources and the increasing demand, it is urgent to make rational use of Taxus and develop Taxus. In line with the principle of "ensuring medicinal use and banning the use of cut-off materials", we should make better use of branches and leaves more effectively. Under the background of the provincial government's "Taxus Project", we should actively advocate national afforestation and tree planting. At the same time of protecting the existing wild yew resources, artificial cutting breeding and planting yew is still the most effective and practical means.

Weihe Forestry Bureau has carried out active exploration in this area for many years and accumulated a wealth of practical experience. In 1984, the first artificial clone cuttage breeding of Taxus mairei was successful in China. And built the first artificial yew forest in the world. At present, Weihe has the largest yew seedling base in the world, and the number of yew seedlings is 5. 5% of the total yew seedlings in the world.

For the cuttage propagation of Taxus mairei, it is better to use twigs in spring and hard branches in autumn. Generally, low-shed shading should be done when cutting. Generally, the survival rate of cutting can reach more than 70%. While conventional cuttings are only about 3% of Murray 20. The shading rate is not less than 60%. The base of cuttings should be treated carefully. The humidity should be kept intermittently at 75 / 85% at the beginning of the humidity. Avoid water loss caused by strong winds.

The factors affecting the survival rate of cutting are generally: tree age, temperature, concentration of chemical treatment, substrate, season, humidity, variety, and other human factors and so on. The data show that the cutting survival rate of several yew species is generally the highest: 95% of Taxus mairei, 95% of Taxus chinensis, 90% of Taxus yunnanensis, 86% of Taxus chinensis.

In the process of rooting in the first year, the aboveground part of cuttings grew slowly, but rooting rapidly and lateral roots developed. After transplanting in the second year, further shading treatment and seedbed management are needed. To ensure the corresponding environmental conditions, the growth is accelerated. The growth rate is the fastest in summer and slow in winter and spring. At this time, we should pay attention to the change of temperature, long-term drying can cause growth inhibition or sudden death. However, after the seedlings are strengthened in the seedling bed, the survival rate of Taxus mairei is very high. Rarely die and grow rapidly.

The application of cutting is the most effective way to solve the shortage of Taxus resources and speed up the construction of Taxus medicinal forest. At the same time, from the current market situation: after the second year from the beginning of cutting, the annual seedling price will be doubled without great interference. In recent years, some enterprises and individuals with economic strength have begun to invest in the project, and some fast-moving enterprises or individuals have already taken advantage of the business opportunities of yew to help the ranks of millionaires and multimillionaires.