A preliminary study on the Propagation of Taxus mairei

Taxus mairei, also known as Taxus mairei, Taxus chinensis and Pinus elliottii, is a rare evergreen tree under national first-class protection. it has beautiful posture, purplish red trunk, red seeds when mature, bright aril and strong regional adaptability. it can be planted from all parts of southern Shaanxi. This tree species likes the humid and cool climate environment, and is suitable for growing in acid to slightly acidic soil with wet, loose and good drainage. It is a semi-negative tree species. The seedlings are resistant to shade, grow slowly, and increase after 3 years. Because of its resistance to barren and strong resistance to diseases and insect pests, it is the preferred tree species for reforestation after pine wood nematode disease in East China. At the same time, this tree species has great economic value, and its branches, leaves, bark and roots can extract expensive anticancer drug paclitaxel. Since the implementation of the provincial agricultural three projects "industrialization Development of Taxus seedlings" in 2000, our institute has accumulated a set of relatively mature breeding techniques, which are introduced as follows:

1 seed propagation

1.1 Collection of seeds: red fruits were harvested in late October, red aril and pulp were rubbed, washed, seeds were soaked and sterilized with 0.05% potassium permanganate solution for 0.5 h, then washed and dried, stored in wet sand.

1.2 damaged seed coat: the seed has a long ripening period and dormant characteristics, and it can only germinate after two winters and one summer, that is, it can be frozen outdoors in winter, receive high temperature and rain in summer, and sow in autumn the following year, such as spring sowing can still be frozen in outdoor soil after winter, sowing in the greenhouse from late March to early April, and seedlings can emerge more than 20 days after sowing. If the seeds can be rubbed repeatedly with coarse sand soles on the rough cement ground to wear out their inconspicuous tough seed coat and thin their hard seed shell (not to grind the seed kernels), the seeds can be easily permeated and breathable, sowing and germinating faster.

1.3 variable temperature treatment: Taxus seeds have the habit of double dormancy of radicle and Hypocotyl. The radicle needs to go through a high temperature stage of more than 25 ℃ for one month to break dormancy, and the Hypocotyl needs to be under the condition of-3 ℃ for 20 ℃ to break dormancy. In order to advance and accelerate seed germination, the seeds of Taxus chinensis var. mairei with damaged seed coat were mixed with wet sand and frozen in the environment below-3 ℃ for 25 days for 40 days, the Hypocotyl dormancy could be released. After sowing in late winter or early spring, the radicle dormancy could be broken and the seeds could germinate and emerge after sowing in late winter or early spring.

1.4 sowing seedlings: strip sowing, furrow distance 20cm, deep 2cm. About 30 days after sowing, seedlings began to emerge from the soil, when it was the spring rain season, and the seedlings suffered from root rot and sudden fall disease due to more Rain Water, high air humidity and easy infection with bacteria, so the seedlings were prevented and treated with 800x topiramate solution every other week; when the seedlings were unearthed, half-dose Bordeaux solution or 800x toposide solution was sprayed every other week. After emergence, the seedlings should be shaded, the seedlings are afraid of sunburn, the light transmittance of the shade shed should be 30%-40%, and weeds should be weeded frequently, and the seedlings should be watered with light urea water or clear dung water once in 15-20 days, and can be transplanted in the open field after 1 year.

2 Cuttage propagation

2.1 collecting cuttings: from May to June at the turn of spring and summer to late November, the shoots of the same year were cut from mother trees over 4 years old as cuttings.

2.2 treatment of cuttings: cut the branches longer than 15cm as cuttings, remove the lower leaves, peel off the wound at the base of the branches, and then cut off the branches from the lower part of the ring after a tumor was formed around the wound. The basal end was soaked in 100 × 10E-6 indole acetic acid or phenylacetic acid for 3 hours, or soaked in 200 × 10E-6ABT2 rooting powder solution for 8 hours.

2.3 cutting method: the treated cuttings were cut on the prepared seedling bed or on the sawing medium of vermiculite plus weathered sand (1 ∶ 1), the cutting depth was 3~5cm and the row spacing was 8~10cm. Pour water thoroughly after insertion and moisturize with a plastic arch cover. Spray water twice a day at first and once a day after 2 weeks. Shade the same seed to raise seedlings. Rooting 45-50 days after insertion and careful management, the seedling rate can reach more than 90%.

3 budding seedling transplanting

About 30 days after sowing, seedlings began to emerge from the soil. When the sprouts grow to the height of 2~3cm and there are 3-4 true leaves (usually in the middle of April), they can be transplanted. When transplanting, first use bamboo chopsticks to insert a small hole in the nutrition bowl, move into the buds, and then press the soil. Transplanting time is best chosen in cloudy days, sunny days should be carried out in the morning and evening, and water should be watered in time after transplanting. 2 plants were transplanted in each nutrition bowl. Preparation of nutritious soil: nutritious soil is prepared according to 40% loess, 40% river sand and 20% humus, crushed and screened. Nutritious soil is disinfected with 0.5% potassium permanganate solution, and ferrous sulfate and 65% Dysen zinc powder can also be used for soil disinfection. Compared with the traditional method, the seedling emergence rate of bud seedling transplanting is higher, the seed and land resources are saved, the seedling quality is good, the seedling yield is high, and the seedling growth period can be obviously prolonged, and the average seedling growth in the same year can reach 15cm. As long as the management technology is in place, the survival rate of afforestation can reach more than 96%.

4 Seedling management and afforestation out of nursery

4.1 Seedling overwintering management: seedlings are afraid of frost, the seedlings should be protected by arch shed in winter, and it is better to cover the plastic film with grass curtain.

4.2Seedling transplanting: after sowing seedlings or cutting seedlings have been cultivated for one year, they should be transplanted to the open field seedling bed according to the row spacing 25~30cm, set up a 1.5m high shading shed of six yin and four yang, often water, and timely apply light urea water or light dung water to cultivate strong seedlings.

4.3 all kinds of insect pests: land tigers, grubs, leaf-eating pests, etc., using 50% dichlorvos EC 6ml plus 2.5% enemy to kill EC 2ml, Leisbon 48% EC and dipterex 90% soluble powder 30g mixed with soil and water 5kg to spray buds, sterilization and insecticidal at the same time, the control effect is better.

4.4 afforestation out of the nursery: the seedlings of Taxus chinensis var. mairei which have been refined for one year can be afforestation out of the nursery when the seedling height is 40~60cm. It was cultivated well in late winter and early spring, and the row spacing of planting plants was 1.6m × 2m.