Taxus seedling propagation method:

Pre-planting method

The preservation of yew resources and the rapid propagation of seedlings are the basis for solving the construction of paclitaxel timber forest. The large-scale construction of yew plantation is the key to solving the raw material of paclitaxel.

When cultivating seedlings with yew seeds, it is necessary to store the seed in the form of sand, or to mix and control the temperature. This has a good effect on budding and breaking dormancy after wintering. Before sowing, you should injure the seed coat, soak seeds in warm water, and treat with hormones. Shading after emergence is the key to nursery. It can prevent the seedlings from burning at a high temperature and keep the moisture at 40%. The emergence rate of Taxus chinensis and Taxus chinensis var. mairei can reach 70-80%, and the seedling temperature is required to be higher than 15 degrees.

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

2. Tissue culture and breeding of yew

Tissue culture utilizes the pluripotency and clonality of plant cells. The stalks, needles, bark, forming layers, arils, embryos, etc. of the yew plants were used as the implants for culture research.

(1). Select excellent yew varieties, such as the high quality organs of Taxus cuspidata (higher paclitaxel) as explants, inoculation medium, after callus formation, rooting, seedling bud formation, etc. A large number of tissue culture seedlings are available in the laboratory. After the substrate is transplanted, trained, and checked for epidemic prevention, it becomes a production seedling.

(2). The ratio of late to early formation of callus of Taxus, there are differences between different species and different plants of the same species. At the same time, it is related to the type of explant, the sampling site and the collection season, the light conditions, the type of the medium and other factors. On the induction medium, the yew, the southern yew, and the yew of Yunnan can form callus. However, the formation is different depending on the type of yew and the difference in plants.

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

When the concentration is greater than 1%, it can promote the healing of the wounded tissue and form a new growth point without affecting the accumulation of paclitaxel.

By comparison, 2, 4D is also conducive to the formation of wound healing tissue, but also can increase the induction rate. The callus in 2, 4D medium was fresh in color and the block was large and soft, and the callus induction of Taxus was easier. However, other media supplements, such as cell suspension culture, B5 medium, and carbon source sucrose, can also increase the content of paclitaxel. However, glucose in high-amount sucrose inhibits the synthesis of paclitaxel. At the same time, galactose is significant for promoting cell growth.

GIBSON studies have shown that both cell suspension culture and induction of callus cell growth and the formation of paclitaxel content are better in the dark than in the light.

Regardless of the variety and location of the tissue culture method, the cell composition with strong proliferative capacity in the middle layer should be selected (the surface cells contain a large amount of starch granules, the central cells are non-nuclear, and the tubular molecules are prone to differentiation). This is conducive to the formation of cell filaments between cells, thereby forming a large cell mass, which is conducive to the signal transmission of small substances between cells. Thus, the cells of the yew are present in the form of cell clusters, which produce functional cell bodies, promote cell group regionalization, and differentiate cell functions, which is a prerequisite for the production of metabolites of the yew.

3. Artificial cutting propagation of yew

The cuttings of the yew are bred, the spring shoots are good, and the autumn is hard branches. Generally, low-shed shading should be done when cutting. Generally, the cutting survival rate can reach more than 70%. The conventional cuttings are only about 3%~20%. The shading rate is not less than 60%. The cutting base should be carefully rooted. When the humidity starts, it should be kept at 75~85% intermittently. Avoid the loss of water caused by strong winds.

Factors affecting the survival rate of cuttings are generally: age, temperature, concentration of drug treatment, substrate, season, humidity, variety, and other human factors. The data showed that the survival rate of cuttings of several yews was generally 95% for Taxus chinensis, 95% for Taxus chinensis, 90% for Taxus yunnanensis, and 86% for Chinese yew.

During the first year of rooting, the aerial part of the cutting seedling grows slowly, but the rooting is rapid and the lateral roots are developed. After the second year of transplanting, further shading treatment and seedbed management are required. Ensure the corresponding environmental conditions and accelerate growth. It grows fastest in summer and slow in winter and spring. At this time, attention should be paid to changes in temperature, and long-term drying can cause growth inhibition or sudden death. However, after the seedlings are strengthened, the afforestation survival rate of the yew is very high. Very few deaths and rapid growth.

The application of cuttings is the most effective way to solve the shortage of yew resources and accelerate the construction of yew medicinal forest.

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