Container Seedling technique of Taxus mairei

Taxus is an evergreen tree of Taxus, belonging to the national Ⅰ class key protected plant, is a species left over from Quaternary glacier, known as the "living fossil" of the plant kingdom, is a rare and endangered plant in the world, is not only an important timber species, ornamental tree species, but also a precious medicinal plant, branches, leaves, roots, bark can be extracted anti-cancer drug-paclitaxel, has great promotion and utilization value.

Taxus can be propagated by cuttage or seed. Because of the uneven distribution of resources and the difficulty of scion collection, seed propagation is often used. The survival rate of bare-root seedlings of Taxus mairei cultivated by conventional seedlings was lower. In order to solve this problem, after several years of experiments, it is concluded that the container seedling cultivation of Taxus chinensis seedlings has high survival rate (95%), long planting time, low cost, high benefit, simple operation and suitable for popularization.

1 selection of seedling site

Choose the place close to the forest land, flat terrain, convenient transportation, sufficient water and easy management as the seedling land, and it is not suitable to choose the previous crops as vegetables, melons and fruits, potatoes, corn and other plots.

2. Make a bed by preparing the ground.

The seedlings were raised in a high bed with a length of 10m, a width of 1.2m, a high 20cm and a walkway width of 40cm. The bed surface is flat and solid, and the direction of the bed should be north-south. The drainage ditch is dug around the nursery ground so that the internal water does not accumulate and the external water does not flood.

3Seedling substrate

It is ideal to choose a mixture of 70% forest humus soil and 30% loess (or turf soil). In order to increase the substrate fertility, 5kg superphosphate and 2kg urea were added per cubic meter of substrate. In order to prevent the occurrence of diseases and insect pests in seedlings, ferrous sulfate 5kg was used for soil disinfection per cubic meter of substrate, and 20g phoxim could kill all kinds of pests.

4 filling and placement of containers

7cm × 12cm container bag with bottom hole was selected to cultivate 2-year-old container seedlings of Taxus mairei. Before filling the matrix, the various ingredients are fully stirred and mixed, and properly sprinkled, the water content of the matrix is 10% to 15%. The container bag should be packed until it is 1cm away from the upper edge of the container. After the container is loaded with soil, it should be placed neatly in the seedbed, squeezed between the containers, and soil should be cultivated around the seedbed to prevent the container from collapsing.

5 seed treatment

5.1 seed collection

The red fruit was harvested from September to October, rubbed off the red false pericarp and pulp, washed, soaked in 0.5% potassium permanganate solution for 2 hours, and stored in wet sand.

5.2 damaged skin

Rub the seeds with shoe soles or waste tires repeatedly on the rough cement ground to thin the hard seed shell (do not grind the kernels), so that the seeds are easily permeable and breathable, sowing and germinating faster.

5.3 variable temperature treatment

The seed has a long post-ripening period, and the radicle and germ have the characteristics of double dormancy. Under natural conditions, the radicle can only germinate after two winters and one summer. The radicle needs more than 25 ℃ in one month to break dormancy, and the germ needs about-3 ℃ ~-20 ℃ low temperature to break dormancy. In order to promote seed germination, the seeds of Taxus chinensis var. mairei with broken seed coat were mixed with wet sand and frozen in the natural environment below-3 ℃ in the middle of winter for 25 to 40 days to relieve its germ dormancy. In the first ten days of March, the seeds mixed with wet sand should be kept at a suitable humidity, sprinkled at night and mixed and stacked evenly, spread evenly during the day, should not be sprinkled, should be turned frequently, so that the seeds were evenly heated and artificially heated to more than 25 ℃. After 30-40 days, the radicle dormancy could be broken.

5.4 accelerating budding

It began to sprout in early April. The seeds that were screened out were soaked in 0.5% potassium permanganate solution for 2 hours. The indoor temperature is controlled at about 25 ℃ and the air relative humidity is controlled at 80%. Keep proper moisture on the seed surface, it is appropriate to see the moisture but not the water, and keep indoor ventilation until the seeds are white.

6 sowing

Spring sowing should be given priority to, early rather than late. From late April to early May, the temperature rose to more than 15 ℃ and sowed seeds on demand. Select the white seeds from the germinated seeds for sowing on demand. Each container bag was sown with 2 seeds and covered with soil 1~1.5cm. After covering the soil, spray 0.1% potassium permanganate or 1% ferrous sulfate solution, use 2~3kg/ square meters, and spray clean water half an hour later (the dosage is the same as the amount of water used), which not only disinfects the covered soil, but also makes the seeds in close contact with the soil, which is conducive to seed germination. Finally, the sunshade net is used to cover the seedling bed surface with 30cm to keep the bed wet and shady.

7 Seedling stage management

7.1 Prevention and control of birds and animals, diseases and insect pests

The seedling was unearthed with seed shell, and it took about 20 days for the seed shell to fall off by itself. During this period, attention should be paid to prevent birds from damaging seedlings when pecking at the seed shell, especially during the morning and evening every day. In order to prevent rats from stealing seeds, poison bait can be placed on the bed or on the sidewalk. The emergence period of seedlings is a period of frequent occurrence of diseases and insect pests, mainly to prevent yew seedling quenching disease and blight disease. From the time the seedlings are unearthed, 0.2% potassium permanganate and 1% ferrous sulfate solution are sprayed alternately every 7 days to prevent diseases. After spraying, rinse the seedlings with clean water. In the event of a disease, the bed should be sprayed with 2%-3% ferrous sulfate solution or 1% potassium permanganate solution. Rinse the seedlings with clean water before and half an hour after spraying to prevent drug damage, and thoroughly remove the infected seedlings. Sunshade nets can be used to prevent seedlings from being burned by the sun.

7.2 Management of water, fertilizer and grass

The surface layer of the substrate should be kept moist before emergence and during the seedling growth period to ensure the moisture needed for the growth of seedlings. The method of watering properly and using less and more water can not only reduce the surface temperature, but also adjust the relative humidity around the seedlings. Do not sprinkle water when it is hot at noon. Watering should be controlled in the later stage of seedling growth. Water should be watered once before overwintering to improve the cold resistance of seedlings.

Topdressing is an important measure to supplement seedling nutrients, improve matrix nutrition and promote the rapid growth of seedlings. Taxus seedlings began to fertilize from the appearance of primary leaves to the fast-growing stage. Topdressing should be combined with water spraying to prevent fertilizer damage. In June, nitrogen fertilizer was mainly applied, urea with the concentration of 1% was applied once every half month and fertilized twice; in July, potassium fertilizer was mainly applied, and 0.2% potassium dioxin phosphate was applied once every other half month. Fertilization should be stopped when seedlings entered the late growth stage in August, so as to promote the full Lignification of seedlings and facilitate their safe overwintering.

Weeds should be weeded in time at the seedling stage, and the principle of "getting rid of early, good and good" should be mastered so that there are no weeds in containers, beds and walkways. Prevent loosening the roots of seedlings when weeding.

8 transplanting seedlings

2-year-old seedlings were transplanted with nutritious soil. The container seedlings were watered once a day before seedling emergence to make the container seedlings absorb enough water. In the process of seedling raising, transporting and planting, it is necessary to handle and put lightly, so as to make the soil mass in the container bag complete, avoid loosening seedling roots and ensure the survival rate of afforestation. When transplanting, cut the bottom of the container bag to facilitate the seedlings to take root, and the mouth of the container should be flush with the ground. The transplanting density can be determined according to the direction of seedling cultivation and utilization. Five years after transplanting, the soil was loosened and weeded twice a year, fertilized once a year, and each plant was treated with urea and superphosphate 0.1kg to promote the growth of young trees.