Fund Project: Application Value of Yew and Seedling Cultivation Technology

Fund Project: Application Value of Yew and Seedling Cultivation Technology

Fund Project Tongren Science and Technology Plan Project Fund "Tongren Yew Resource Survey and Artificial Cultivation Technology Research" (Tongren Science Research [2020] No. 120).

_ Zai Qingqing

Yew is a general term for yew plants in the yew family, which has a 2.5 million-year-old survival history, is an ancient relict tree species left over from the Quaternary glacier, known as "living fossils in plants", and is the "giant panda" of the plant kingdom. Paclitaxel extracted from yew has anti-tumor, anti-inflammatory, analgesic, antioxidant, hypoglycemic, antibacterial and other effects, and has obvious clinical effects on the treatment of breast cancer, ovarian cancer, leukemia and diabetes. In addition, yew also has a high greening value, can make horticultural bonsai, very environmental protection value and ornamental value. In recent years, with the deepening of the medicinal development of paclitaxel, the market demand for yew seedlings has been increasing, while the growth of wild yew under natural conditions is relatively slow, the regeneration capacity is weak, and the indiscriminate logging in some places has caused a shortage of resources. This requires the vigorous development of large-scale artificial planting of yew trees, on the one hand, it can protect wild resources, and on the other hand, it can meet the development needs of the paclitaxel pharmaceutical industry. Therefore, we should be familiar with the biological characteristics of yew trees and adopt corresponding seedling cultivation technologies in combination with the actual local conditions, so as to ensure that yew seedlings can be supplied to the market in a stable and orderly manner.

1 Biological characteristics

Yew has strong suitability and a wide distribution range in China, which is distributed in most areas, but relatively scattered, such as Anhui, Hunan, Henan, Guizhou, Guangxi and other places. There are 5 species of Yew in China, Yew in China, Yew in The South, Yew in Northeast China and Yew in Tibet. Yew is an evergreen tree or shrub, belongs to the negative tree species, has higher requirements for temperature, humidity, light, etc., likes the air humid, cool environment, is more suitable for growing in acidic, moist, loose, fertile, well-drained sandy soil. The main root of yew is not developed, but the lateral roots are very obvious, it is a shallow root plant, the growth rate is relatively slow, the regeneration ability is poor, the branches are relatively dense, the small branches are alternate, and it can become reddish brown or yellow-green in autumn, and the bark is reddish brown or gray-brown. Hermaphroditic, flowers in April to May, matures in October and November, and is surrounded by a red cup-shaped pseudosecond on the outside of the seed, which is flat-oval or inverted oval.

2 Application value

2.1 Medicinal value

The medicinal value of yew has been recorded as early as in the ancient books of traditional Chinese medicine, saying that yew has the effect of warming the kidneys, diuresis and swelling, dispelling dampness and relieving pain, and can be used for the treatment of kidney disease, diabetes, dysmenorrhea, menstrual irregularities and other diseases. Yew is recognized as the world's endangered natural rare anti-cancer plant, modern pharmacology related studies have shown that yew extract —— — paclitaxel has anti-tumor, anti-inflammatory, analgesic, antioxidant, hypoglycemic, antibacterial and other effects, clinically on breast cancer, ovarian cancer, prostate cancer, leukemia and diabetes has obvious curative effect, has high clinical value and economic value.

2.2 Greening value

Yew can not only absorb formaldehyde, benzene, nicotine, nitrogen peroxide and other harmful gases to purify the air and improve the environment, but also improve the body's immunity, resistance, anti-cancer and anti-cancer effect. Yew has the reputation of "healthy tree" and "longevity tree", and is a commonly used green tree species in environmental protection projects. In addition, as a leafy, unique shape of evergreen tree species, yew is deeply loved by people, especially in the fruit ripening period, the fruit shows a delicate red, green leaves with red beans have a flavor, has a high ornamental value, can be used as a horticultural bonsai, placed indoors, courtyards, streets, can also be planted in tourist resorts, for tourists to appreciate, has a high green value.

2.3 Material value

Yew material is solid, the texture is clear, the structure is tight and shiny, it is not easy to deform, it has strong corrosion resistance, and can be used as high-grade furniture, bridges and other materials. However, yew resources are scarce, the growth rate is slow, and it is generally only used for carvings, musical instruments, stationery and other processed products. These products themselves are beautifully textured, smooth and bright, have high value, and are deeply loved by collectors.

3 Seedling cultivation techniques

3.1 Sowing seedlings

Sowing seedlings mainly includes seed collection and treatment, garden selection and bed making, sowing, seedling management and other aspects. Yew seed collection is generally carried out in October to November every year, because yew seeds have the characteristics of long dormancy period, in natural conditions to experience two winters and one summer before germination, so the rational use of modern technology to break the seed dormancy is the key to seed treatment. The choice of garden land is determined according to the biological characteristics of yew, generally in a wet and cool place, requiring loose and fertile soil, good drainage, and after determining the location, weeding, ploughing, and fertilization are also carried out to meet the growth needs of yew seedlings. There are two main ways to sow seeds, sowing and sowing, wetting the land before sowing, and covering the seeds after sowing. After the emergence of yew seedlings, it is necessary to adopt scientific and reasonable conservation methods, pay attention to avoid direct sunlight, regular watering, weeding, fertilization, etc. In addition, it is also necessary to do a good job in the prevention and control of diseases and insect pests.

3.2 Cuttings for seedlings

The efficiency of cuttings and seedlings is high, which saves time compared with sowing seedlings, and is more commonly used in production, mainly including cuttings collection, cuttings treatment and cutting methods. Cuttings collection time is best in the spring and summer of May to June, the cuttings select the more tender branches of the mother tree of more than 4 years old, take the appropriate length of the cuttings to remove the lower leaves as cuttings, and then peel off an opening of about 1 cm from the base ring, remove the lower part of the opening, and soak in phenylacetic acid for more than 3 h [7]. Insert the prepared cuttings into the prepared seedbed, insert the depth of 3 to 5 cm, maintain a reasonable plant spacing, 8 to 10 cm is appropriate, pour the appropriate amount of water, and carry out fine management and maintenance, and do a good job in pest control.

3.3 Group breeding seedlings

With the entry of paclitaxel into the market, its unique anti-cancer effect not only brings the gospel to cancer patients, but also opens up a broad market for yew resources. Traditional seed propagation and cuttings propagation can no longer meet the market needs of yew trees, so the use of modern technology for yew breeding group breeding technology began to rise. The key factors of its technology mainly include temperature, light, pH, culture medium, explants selection, hormone ratio and use of bacteriostatic drugs, etc. At present, the ex vivo embryo culture method and the tender bud proliferation method are used more, and the 2 methods can expand the breeding coefficient. The practical results of group cultivation seedlings show that the proposed method can achieve a tissue induction rate of 90% of yew trees. However, due to the relatively high technical requirements for somatic embryogenesis and callus regeneration, scientific research units currently use more and production practices apply less.

4 Conclusion

The medicinal value, economic value, social value and ecological value of yew trees have attracted much attention, and the artificial planting of yew trees is also increasing, but due to the lack of clear planting purposes of some farmers, the low level of planting technology, the lack of unified management and the subsequent industrial chain can not be extended, etc., the planting of yew trees in many areas is relatively scattered and not large-scale. This not only requires the relevant government departments to take measures, but also the cooperation of scientific research institutes to tackle key problems, carry out technical training for yew planting to farmers and relevant enterprises, widely apply the technology of seed cultivation, cuttings cultivation and group cultivation of yew seedlings to actual production, and effectively do a good job in large-scale artificial planting of yew to solve the contradiction between supply and demand. In addition, we should also increase capital investment, develop the yew follow-up industry, and continuously improve the resource utilization rate and added value of yew.