Paclitaxel, extracted from the bark and leaves of the yew tree, has outstanding effects on a variety of late-stage cancers and is known as "the last line of defense in the treatment of cancer." High-purity paclitaxel is expensive, about 2 million yuan per kilogram. However, yew grows slowly and has poor natural renewal ability. Artificial planting of 10 acres can only extract 1kg of yew with 1% purity.
There are 4 species and one variant in our country.
1． Northeastern yew is mainly distributed in the Changbai Mountains of Jilin and Heilongjiang, and a small amount is also distributed in the mountainous areas of eastern Liaoning.
Northeastern yew
Latin name: Taxus cuspidata
Plant name: Northeast yew
Scientific name: taxus cuspidate sieb eb zucc Alias: yew, yew pine, broad-leaf yew
Family name: Taxaceae
Latin family name: Taxaceae
Genus name: Taxus
Northeastern yew is one of the 5 species (4 species with 1 variants) of yew in my country. The other 3 species with 1 variants are: Yunnan yew, Tibetan yew, Chinese yew, and southern yew.
Taxus yew is an evergreen tree. The branchlets turn yellow-green or light reddish brown in autumn. The leaves are strip-shaped, dioecious, and the seeds are oblate. The seeds are used to extract oil and can also be used as medicine. It is a shallow-rooted plant with an inconspicuous main root and well-developed lateral roots. It is 30m high and has a trunk diameter of 1m[2]. The leaves are spiral and alternate, the base is twisted into two rows, the strips are slightly curved, 1~2.5cm long, 2~2.5mm wide, the leaf margin is slightly recurved, the leaf tip is tapered, and there are 2 wide yellow-green or gray stripes on the back of the leaf. Green stomata belt, densely densely distributed small bumps on the midrib, very narrow green belt on the leaf margin, dioecious, male cones are solitary in the leaf axils, and the ovules of female cones are solitary in the upper part of the flower axis, at the top of the lateral short axis, and at the base There are disc-shaped arils. The seeds are flat and oval, with 2 ribs, oval in shape, cup-shaped aril, and red.
The biological characteristics of yew have high requirements on the ecological environment. Generally, it takes 100 to 250 years for an adult tree to grow. Statistics from 2006 show that Yunnan’s wild yew trees account for 55% of the country’s total, of which 110 million trees survive in Lijiang. Yew is a perennial evergreen tree with a huge biomass and a short growth time. Its main root is not obvious, its lateral roots are developed, its branches and leaves are lush, its germination ability is strong, and it is cold-tolerant and can withstand low temperatures of -25°C. It can be grown in most areas of the country. It grows quickly, with annual growth measured at 40 to 50cm and up to 60 to 70cm, which is 300 to 700% of the growth of domestic yew (Chinese yew, Yunnan yew, etc.). The biomass accumulation of 3-4 years old is 600-800/plant·year, and the fresh raw material produced at 5 years of age is more than 1.5kg, which can be used to extract paclitaxel. New branches and leaves can sprout in the following year, and their biomass is greater than the amount harvested in the first year.
Except for the red aril, the whole body of yew is highly toxic. The seeds and aril "stone cells" inside also contain poison. The toxin-making substances in yew are a mixture of plant bases. The compound, collectively known as taxine, can cause gastroenteritis, heart disease and difficulty breathing, and is extremely toxic. It may lead to sudden death. The main symptom is convulsions, and death will occur in five minutes. The growth conditions of wild yew are almost harsh, the growing area is narrow, and it has strict requirements on climatic conditions. Why can there be such a lush growth community in the Ruyuan Mountains? According to Mo Yibin, a local expert who has studied and protected this tree species for many years, the unique geographical environment, humid climate, good ecological environment, and the vigorous protection of the local people are all indispensable. Daqiao Town is an alpine limestone mountainous area with an average altitude of more than 800 meters. The temperature difference between day and night reaches 7°C. The average temperature throughout the year is only 17°C. The climate is relatively humid in spring and summer, which is very suitable for the growth of yew.
Yew is suitable for planting in both north and south. It is shade-loving, drought-tolerant, and cold-resistant [3]. It requires a soil pH value of 5.5 to 7.0. It can be interplanted with other tree species or orchards and is easy to manage. Among them, Northeastern yew is the The ancient tree species left behind by the Quaternary glaciers have lived on the earth for more than 2.5 million years due to their tenacious vitality under harsh climatic conditions. It not only has well-developed lateral roots, luxuriant branches and leaves, and strong germination ability, but also adapts to a wide range of climates and soil requirements. It is also resistant to pruning, cold, and pests and diseases. And it can grow into tall trees, and some single trees can even grow for thousands of years. They can be used as medicinal varieties and greening varieties. In folklore, Northeast yew is known as the "Feng Shui God Tree" called.