Conservation Biology of Endangered Wild Walnut in Tianshan Valley, Xinjiang

. Wild walnut belongs to the walnut family in Tianshan Valley of Xinjiang. Tertiary tree species in Central Asia and endangered plant under state protection. Its main distribution areas are as far as the Western Tianshan Mountains and Pamir-Alai Mountains of the former Soviet Union, and it is only distributed in Dekuztala County of Xinjiang, China. It is of great scientific value to study the origin and evolution of cultivated walnut, paleofloristic changes, paleogeography, Tertiary and Quaternary climatic changes. Due to the narrow distribution of wild walnut in Xinjiang, harsh desert conditions, climate change, human disturbance, habitat fragmentation and other factors, wild walnut in Xinjiang is facing the risk of extinction, and it is urgent to carry out research on conservation biology and conservation genetics. In this paper, floristic, community and plant population research and analysis methods were adopted [1][6] . In this paper, the floristic composition, plant ecological type structure, plant climate and soil water characteristics of wild walnut community, age structure of wild walnut population, fluctuation cycle and evolution trend of population age composition, population growth characteristics, phenotypic plasticity of seeds and compound leaves, and biomass allocation were analyzed comprehensively in Xinjiang Nature Reserve. And put forward scientific protection countermeasures.


Research Background
Plants are the basis of human survival, but the environmental pressure brought by population increase and economic development will make two-thirds of the global plant species endangered [15] Endangered plants refer to the plants that may be listed as "endangered" in the near future due to natural or human deforestation and overexploitation, which lead to the deterioration of the natural environment and threaten the survival of plants [1] [2] . After entering the 20th century, the population of the earth increased rapidly, social and economic development was high, and human's demand for nature was intensifying. Natural ecosystems have been severely damaged by predatory exploitation and the biodiversity of the planet has been greatly reduced. Many species continue to deteriorate in viability, fertility, viability and adaptability, eventually becoming extinct or extinct [4] . It takes hundreds of thousands to millions of years for a species to form, and its destruction can happen overnight. In particular, the loss of the biological environment formed by woody plants and the severing of the food chain could create an existential crisis for dozens of other species. In the 100 centuries since humans began farming, plant extinctions have generally occurred naturally, but in the last 100 years, and especially since the late 2609885636@qq.com 20th century, the rate of extinction has accelerated significantly. The current discontinuous species extinction events are tens of millions of times larger than those of the past hundreds of millions of years, seriously affecting the security of natural ecosystems and human production and quality of life. Xinjiang wild walnut (J. flax Dode) belongs to Juglandaceae. Walnut (Juglans L.) The fruit forests of Tokkuztara and Huocheng in Yili, Xinjiang, belong to the second level of national protection of wild plants in China. It was proved to be the direct ancestor of cultivated walnut in Xinjiang [16] . Xinjiang wild walnut as a vulnerable species for precious tertiary relict of the temperate deciduous broad-leaved forest composition of wild area covers an area of narrow restricted to narrow gong of western tianshan mountains in xinjiang ili valley of daming mountain county, south of Kate remain within the territory of wild walnut ditch and huocheng county bo luo HuoLu-oShan big XiGou and small XiGou inside. Born at 1200 ~ 1600m above sea level on the lower slopes or at the bottom of canyons [16]

Problem Statement and Objectives
Now the wild walnut tree, the growth potential is still good, but the area is small, fewer trees. Its present habitat, from the point of view of its great natural landscape, is surrounded by vast, unfavourable deserts. There is little forest vegetation in Katming Mountain. A few snowrange spruce seen in Wild Walnut Gully a few years ago has been cut down, and a lot of aspen has been cut down. According to the report of wild Walnut Forest farm, the stream flow of Wild Walnut Gully has decreased compared to previous years [12] . In addition, the expansion of herds and uncontrolled grazing caused serious damage to grass and vegetation. This situation posed a great threat to the survival of wild walnut [12] . Through the above understanding, this article will address the endangered status of wild walnut through the content of conservation biology.

In situ protection Law
Higher plants are sedentary and often have a high degree of site specificity. This facilitates the development of logical plans to delineate minimum areas for in situ conservation based on ecological knowledge and island biogeography principles [7] . In 1983, approved by the People's government of Xinjiang Uygur Autonomous Region, the Gongliu Wild Walnut Nature Reserve in Yili Region was established. Wild walnut groove is a national nature reserve, and 4 a grade tourism attractions, although both exist obvious contradiction but from the point of view of protecting wild walnut tourist area provides the reserves to provide a large number of human maintenance such as banning picking protection zone plants, to prevent the herders of cattle into the sanctuary, banned staff outside picking wild walnut fruit, etc., It effectively protects wild walnut and the environment in the area.

Ex situ Protection Act
Planting area and variety selection. Based on the characteristics of walnut tree, the planting location of walnut tree can be selected to ensure the healthy growth of walnut tree in the later stage. Walnut tree love shade, prefer loose deep soil, suitable for planting in conducive to the drainage of mountains, hills and other places. When determining the construction site of walnut orchard, the growth law of walnut tree, walnut storage, fruit transportation and other issues should be considered, and then the appropriate construction area should be locked [18] . The constructed germplasm resources should be collected and the resource nursery should be established for protection [8] . At the same time, the survival environment of wild walnut should be maintained. After all, the long-term effective way to protect wild walnut is to protect the ecosystem on which Xinjiang wild walnut lives.

Tissue culture
Some progress has been made in tissue culture of walnut in China in recent years. Lv Shoufang et al. [17] reported that complete plants were obtained by using stem segments of three cultivated walnut varieties to induce bud differentiation, growth and rooting into seedlings. Wild walnut seeds of the same year growing in Kaitming Mountain in the southern part of Tokkuzliu County, Yili Valley, western Tianshan Mountains, Xinjiang were used as test materials for germination promotion treatment and sowing in nutrient substrate to grow seedlings. Then stem segments were selected to induce buds differentiation, growth and rooting into seedlings [13] . In vitro tissue culture and plant regeneration of Xinjiang wild Walnut were carried out successfully, which provided an effective way for rapid propagation and genetic improvement of Xinjiang wild walnut at cell level.

Conservation Genetics
Conservation genetics, with the development of molecular biology technology and its wide application in conservation genetics [10,11] , has made great progress in the 1990s, and has become a very important branch of conservation biology research with an extension in both research breadth and depth [10] . Conservation genetics research has two aspects, one is to explore the genetic variation of species, the other is to understand the evolutionary history of species (populations). The former mainly investigates the genetic diversity of various populations to understand the genetic structure of various populations and their relationships [13] , determine the priority of population conservation and utilization (such as the size of genetic diversity, whether there are specific alleles), and prevent inbreeding decline and outbreeding decline in in situ and ex situ conservation of populations. The latter mainly uses phylogeny and phylogeography to understand the evolutionary history of species (populations), clarify the position of species (populations) in evolution [14] , and provide information for species conservation.

Importance of protective genetic involvement
Conservation biology has been widely applied in Xinjiang walnut, but the application of conservation genetics as a core part of conservation biology is still lacking. Conservation genetics also integrates the theories and methods of ecology, molecular biology, biogeography, biomamathematics and other disciplines, which has a strong theoretical basis and rich practical connotation [3] . It can be said that biological conservation without the participation of conservation genetics will be rough and unreasonable [14] . People's understanding of Xinjiang wild walnut is often limited to the relationship between its quantity and demand, but ignores the importance of population genetic diversity and the possibility of loss. Actually plant genetic diversity is the result of comprehensive shaping of many factors and the lack of genetic diversity is one of the main factors of rare plants [22] . However, according to the results of molecular marker analysis, Xinjiang wild walnut has a high genetic diversity, indicating that Xinjiang wild walnut is not threatened by the loss of genetic diversity, but caused by other influencing factors, such as natural disasters and human activities [8] .

Necessity of manual management
At the same time, the cultivation and management of Xinjiang walnut are also important. There are a lot of attention points in walnut cultivation management, if we can not reasonably control the site selection, soil management, fertilization and watering, there will be more problems in the later period [19] . In order to ensure the quality of walnut fruit, it is necessary to implement the task of disease and pest control in the growth of walnut tree, to provide good conditions for the growth of walnut tree [21] . The pests that harm walnut are moth and red spider, etc. Physically, the number of diseases and insects in the growing area of walnut tree can be reduced by installing insect control lights and placing armyworm boards, etc. Chemically, pesticides and other substances can be applied to solve the problem of walnut tree infestation by pests, and the natural enemies of walnut pests can be found according to the biological chain relationship of species. In addition, natural enemies are cultivated to the same scale as pests to prey on pests that harm walnut trees [18] .

Why Attach Importance to biodiversity
Human life is highly dependent on biodiversity, and our food is a good example. Our daily meals are composed of rich animals and plants. In addition, various raw materials and medicines in life are also highly dependent on biodiversity, such as fibers, medicines, spices, oils, etc. [20] . Human living environment is inseparable from the role of various environmental microorganisms. On another level, humans can also benefit from biodiversity in tourism and agricultural production. Ecosystem is a unity composed of biological species and their ecological environment at different trophic levels. Among them, each organism plays its due role, and the organism is mutually restricted, interdependent, co-evolution [9] . Organisms in an ecosystem form food webs (chains) based on energy and material. In such a system, the disappearance of some biological species will affect the survival of other biological species, and eventually lead to the collapse of the ecosystem, resulting in ecological imbalance. If the rate of species loss in various ecosystems on Earth increases, the biosphere system on Earth will not function normally, and the living environment of human beings will collapse [5] .

Conclusions
Biodiversity hotspots are affected by temperature, climate and geographical environment, and species richness varies greatly in different regions. It is a real problem how to protect biodiversity in different areas under the circumstance of limited resources. Therefore, whether it is necessary to establish nature reserves, the site selection and construction scale of the reserves, how to divide the reserves, so that the species in need of protection can be effectively protected, we must attach great importance to the problems. In recent years, although the research on protection genetics has been carried out in our country, the research basis is still weak, especially the research on protection genetics, which is just starting and has not received enough attention, and its development speed is far behind the economic development level. Therefore, in order to strengthen our protection and management of rare and endangered wild animals and plants, providing economy. For effective scientific protection countermeasure, our country should strengthen the research of conservation genetics of rare and endangered animals and plants.
When human beings gain benefits from biodiversity, they should also give up, forgetting to cherish and protect the diversity of life. Although the human consciousness of creating protected areas to protect endangered species has matured. But manual technology management and cultivation still need improvement. And the application of conservation genetics can give endangered species a reasonably compliant conservation plan that is more adapted to their species. Only by strengthening the publicity and education of endangered species, enhancing the protection awareness of the whole people, and forming a good atmosphere for everyone to participate in the protection of everyone, can we better carry out the work related to biodiversity protection. Then relevant departments should pay attention to such problems and provide corresponding laws, regulations and economic support.