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Taxus Chinensis

Taxus wallichiana var. chinensis (Pilger) Florin: An evergreen tree or shrub of the genus Taxus, growing up to 30 m tall. Leaves lanceolate or needle-shaped, spirally arranged or alternating; Dioecy; Male bulbs often solitary or spicate; Female bulbs solitary or paired; Seed-berry or drupelike, encased in fleshy arils; The flowering period is from 2 to March, and the fruit period is from October to November. The name comes from the cherry-sized red bean-shaped fruit that grows in the fall.

In China, taxus taxus is generally distributed in subtropical or warm temperate broad-leaved forests, such as Yunnan, Jiangxi, Zhejiang, Fujian and other provinces. Taxus chinensis grows naturally at an altitude of 1000 ~ 1500 meters, the growth environment has the characteristics of shade-loving, drought-tolerant and cold-resistant, and the reproduction methods include seed propagation and asexual propagation.

The medical value of taxus chinensis has long been fully affirmed more than 2000 years ago, the ancient Chinese medical code "Compendium of Materia Medica" has made a detailed record of taxus chinensis, that taxus chinensis through menstruation, diuresis, kidney disease, gastrointestinal disease, diabetes, typhoid fever, cholera has a special effect, often used for treatment, health, health. Scientists have made an anti-cancer drug using taxus extract taxol, which is one of the drugs used to treat metastatic ovarian and breast cancer. Because its leaves are green all year round, yew is sometimes grown as a garden ornamental. Taxus chinensis is an ancient tree species left over from Quaternary glaciers. Because of its slow growth, difficult development and extremely rare, yew is known as the "giant panda of the plant world."

Morphological characteristics

Yew is a tall tree, up to 30 meters tall, with a diameter of 60-100 cm; The bark is grayish brown, reddish-brown or dark brown, broken into strips and falling off; Large branches develop, annual branches green or yellowish

-green, autumn becomes greenish-yellow or reddish brown, two or three years of yellow brown or reddish brown or gray brown; Winter buds yellowish, pale or reddish brown, glossy, triangular-ovate, dorsal without ridge 

or longitudinal ridge, abscisic or few persistent at the base of branchlets.

Leaves arranged in two rows, striated, slightly curved or straight, 1-3 (mostly 1.5-2.2) cm long, 2-4 (mostly 3) mm wide, slightly tapered upper, apex often slightly acute, rarely acute or acuminate, dark green and shiny above, 

pale yellowish-green below, with two stomata bands, midvein with densely uniform but tiny, rounded horny papillae. It is often the same color as the stomatal band, and the thin color is lighter.

The male bulbs are pale yellow, with 8-14 stamens and 4-8 anthers (mostly 5-6). Seeds are born in cup-shaped red fleshy arils, occasionally on submembranous disc-shaped receptores (i.e. pearl receptores that do not develop 

into fleshy arils), often oval, upper tapered, thinly oblate, 5-7 mm long, 3.5-5 mm diameter, slightly oblate or rounded, upper often with two obtuse ridges, upper triangular with three obtuse ridges, apex with a short obtuse cusp. 

Umbilicus subround or broadly oval, thinly triangular.

Distribution range

Taxus taxus is endemic to China. It is found in southern Gansu, southern Shaanxi, Sichuan, northeastern and southeastern Yunnan, western and southeastern Guizhou, western Hubei, northeastern Hunan, northern Guangxi and 

southern Anhui (Huangshan Mountain). It is cultivated in Lushan Mountain of Jiangxi Province.

Growth habit

The dioecy, cross-pollination and plant spacing of Taxus taxus resulted in insemination obstruction and seed reduction. The seeds mature in the year, the arils are thick, and it takes two winters and one summer to sprout under 

natural conditions. Although there are occasional natural seedlings, most seeds have decayed or dried out during dormancy. Slow seedling growth, poor stress resistance and low survival rate determine the dispersion, finiteness 

and development difficulty of wild taxus chinensis resources, which is also the objective reason for the rarity and endangerment of taxus chinensis.

Yew growth is slower, according to the determination of more than 100 years old red beans, diameter of about 40 cm. Artificial cultivation can significantly improve the growth rate. In Lingui, Guangxi, the low mountains with an 

elevation of 560 meters above sea level were planted, and the survival rate of afforestation was 100%. The average height and diameter in 3 years were 91.6 cm and 1.45 cm, and the average annual height and length were about 

30.5 cm. Yew has strong budding strength and is resistant to pruning. Flowering period from February to March, fruit ripening period from October to November.

Growing environment

It is often born at an altitude of 1000-1200 meters above the upper mountain. Taxus chinensis is suitable for planting in all parts of north and south China. It has the characteristics of shade-loving, drought-tolerant and cold-resistant, 

and requires a soil pH value of 5.5-7.0. Habitat shade tolerant, can also grow under dense forests, perennial, not forest. It is more common in mixed forests with red pines. It is found on stony or barren soil on hilltops and is mostly shrubby. 

Most of them are scattered under wet, fertile mixed forest on shady slope or semi-shady slope. It likes cool humid climate, can withstand low temperature below minus 30℃, strong cold resistance, the best temperature 20-25℃, is a negative 

tree species. It likes wetting but is afraid of waterlogging. It is suitable for planting on loose, moist and well-drained sandy loam soil.

The distribution area spans the warm temperate zone to the south of the subtropical zone, and the vertical distribution is mostly in the mountains above 500 meters above sea level. The average annual steam temperature in the north is 10-12℃,

 the average steam temperature in the coldest month is 1-3℃, and the extreme minimum temperature is -15℃. The average annual temperature in the far south is 14-16 ° C, the average steam temperature in the coldest month is 4-6 ° C, and the 

extreme minimum temperature is -8 ° C. The average annual precipitation of 1300-2000 mm, the year round fog, humid air, avoid hot summer, the temperature of more than 30℃ in the low hill hot or dry land, can not grow.

The soil in the distribution area is acidic mountain yellow soil and red yellow soil, but there is no distribution in limestone area. Like rich moist forest soil, heavy soil growth is poor, dry barren land can not grow. Shade tolerant, young trees need to 

grow under the shade, and mature trees also have direct sunlight on the day of death. It is often mixed with broad-leaved trees and rarely becomes a pure forest.

Propagation method

Seed propagation and cutting propagation were adopted, and seedling transplanting was the main method.

sow

Picking seeds to promote germination. Seeds are collected in mid to late October when the fruit is dark red. The seeds are physiologically postripe and need to be stored in wet sand for 1 year before germinating. In order to improve the germination rate, the seeds are often treated by natural wetting sand accumulation. It is usually sown in early spring. After storing the seeds for 1 year, when 30% of the seed cracks are white, the seeds are screened out in time and disinfected in 0.2% potassium permanganate solution for 10 minutes, then washed with clean water, and evenly sown in the ditch after drying the open water. The seed spacing is 5-7 cm. Broadcast seeding can also be used. After sowing, the yellow loam with mycorrhiza and sifted under the pine forest was dug to cover the seeds, the thickness of which was not the seeds. Attention should be paid to shade during the seedling period. It is appropriate to cover the straw with no soil when sowing. Shady sheds should be built during the seedling period, and the light transmittance should be 60%. Moss is then planted to protect the beds from the sun and rain and to keep the soil loose and moist. The seed emergence rate is above 70%.

cutting

The mixed matrix of sand soil, sawdust and perlite was selected as cutting soil during the dormant period of trees. Select 1 to 4 years old woody solid branches, cut the cuttings into 10 cm, 15 cm or 30 cm long segments, in the pruning requires smooth incision, cut the mouth horse shape, 2/3 to the bottom of the leaf. After selecting agents such as ATP, ABT, NAA, IBAA, etc. to treat cuttings and cover films, the survival rate of cuttings is generally above 85%. Keep warm during the seedling period and build a low shelter for shade. Transplant the following year.

Medicinal value

The medicinal value of Taxus taxus is mainly reflected in its extract - secondary metabolic derivative - paclitaxel. Paclitaxel was first isolated from the bark of Taxus brevifolia as an antitumor active component. It is one of the best drugs for the treatment of metastatic ovarian cancer and breast cancer, and also has significant effect on lung cancer and esophageal cancer, and has obvious inhibitory effect on nephritis and parvovirus inflammation.

The roots, stems and leaves of taxus chinensis can be used as medicine, which can treat urinary obstruction, eliminate swelling and pain, and have therapeutic effects on diabetes, irregular menstruation and increased blood volume. Taxus can also be used for postpartum conditioning, and has a certain therapeutic effect on female diseases.