| Tetraena Mongolica, which is only found to be very xerophytic and gregarious on sandish grassland of West Erdos in Inner Mongolia, belongs to a endangered relic plant species of Zygophyllaceae. Its existence plays an important role both in the flora and systematic evolution and in the protection of ecological environment. In recent years, owing to various factors, its distribution has been becoming dissected and narrower, so this plant species has fallen into the categories of the second-classed protected species by the State. At present, a lot has been made on the research of the exsitu conservation of endangered plant species. There is a lack of a comprehensive understanding on its exsitu conservation biology, although a series of protective biological research on Tetraena Mongolica has also been done, including embryology, species ecology and insitu conservation biology.This paper makes a study of Tetraena Mongolica on the ecological geographic conditions, climatic biological features, client-soil culture (500km away from east Wuhai to Dongsheng) and growth quantity by soil-less culture. In the light of the global chemical cycle and biological adaptability of Tetraena Mongolica in West Erdos area, a study of Tetraena Mongolica and its soil is made on content features of micro-elements, such as Fe, Mn, B, Cu, Zn, Co, Cl, Se and Mo, as well as on the content features of amino acid, so as to analyze and probe the ecological and biological adaptability in the process of exsitu conservation of Tetraena Mongolica. Thus, practical experience and theoretical instruction could be obtained for the conservation of Tetraena Mongolica. The results are as follows:â… . There is a magnificent difference between the growth quantities of Tetraena Mongolica by exsitu conservation culture. The diversity is quite magnificent in the actual plant growth quantity (by multiplying plant dry weight by bulk above ground) of biennial Tetraena Mongolica grown in different soil of different area under different climate, though it is not indifferent soil of the same area under the same climate. The sequence of the growth quantity (dry weight) is: 12.17g(in Wuhai-Dongsheng soil) > 10.57g(in Wuhai-Wuhai soil) > 3.10g (in Dongsheng-Wuhai soil) > 2.59g (in Dongsheng-Dongsheng soil). The biggest is found in Dongsheng soil of the natural habitat area and the smallest is in the soil of exsitu conservation area. It give the facts that will be the suitability for Tetraena Mongolica in natural condition of distributive area, meanwhile, this make known that soil nutrient act on the Tetraena Mongolica growth.II. One of the restrictive factors, which would lead to the successful exsitu conservation, might be the peculiarity of day-night temperature difference in soil and air of the natural habitat area. It is well known that adverse circumstances restrictively cause plant distribution. Judging from the climatic biological diagram and temperature indices, it is clear that the average temperature difference of each month in a year varies greatly both in the natural habitat of Tetraena Mongolica and in exsitu conservation area, and there is a magnificent diversity in the warm indices and cold indices of a whole year. In the growing season of Tetraena Mongolica, the day-night temperature difference in various soil depths is very characteristic. From June to October, soil temperature in 10 cm deep varies greatly, and from July to October the soil temperature in 40 cm varies greatly, while during the whole growing season, the soil temperature differences in 15 cm and 20 cm deep are magnificent. From February to November, the rainfall and vapor vary in Wuhai, Dongsheng and Dengkou. Dongsheng and Wuhai are very different in the humidity indices and hydrothermal synthetic factor indices, whereas Wuhai and Dengkou are not. Since rainfall in arid area will matter to plants, there is monthly difference in rainfall during the growing season of Tetraena Mongolica. Judging from daily sunshine hours from February to November, there is no difference between Dongsheng, Wuhai and Dengkou , except that great differences in these three areas appear during January and December.III. The content of micro-elements in soil is not the restrictive factor for the exsitu conservation and growth. In the Tetraena Mongolica distributing areas, the average contents of 9 micro-elements, except B, are not only obviously higher than the average values of other soil in China but also higher than the values in desert areas. The contents of all micro-elements, except Cu, in the exsitu conservation area are slightly higher than those in the desert and Tetraena Mongolica distributing areas. In Tetraena Mongolica, the contents of the micro-elements Fe, Cu,Zn, B, Se and Co are much higher than those in other plants on steppes. And Mo is higher in value than the average of other plants, but lower in value than that of the grassland plants on desert, only accounting for 50%. The correlation coefficient for the contents of nine trace elements between soil and plants (including grown up and seeding) are not magnificent and also the contents in Tetraena Mongolica are very higher than effective contents in soil. The contents of Fe in Tetraena Mongolica between the natural habitat and exsitu conservation area in Dongsheng-Dongsheng soil and Wuhai-Dongsheng soil are similar in value, while the contents of Cu vary obviously, and the contents of Mn vary magnificently (but not in leaves). Zn and B in Tetraena Mongolica between the natural habitat and the soils of Dongsheng-Dongsheng and Wuhai-Dongsheng are quite different in value, while the contents of Zn and B are equally magnificent in Dongsheng-Dongsheng soil and other soils. The contents of Co in the roots and stems of Tetraena Mongolica between the natural habitat and exsitu conservation area in Dongsheng-Dongsheng soil and Wuhai-Dongsheng soil are similar in value, whereas the contents of Co in the leaves vary obviously. As for the correlation of the trace elements in Tetraena Mongolica between its natural habitat and exsitu conservation area, only Cu-Co and Mn-Zn are magnificently related to each other, with no relation between other micro-elements. Only Fe in Tetraena Mongolica is magnificent in value in soil-less culture in different nutrient liquids, and other five elements do not show magnificent differences.IV. The large accumulation of PRO in the root of Tetraena Mongolica seedling, in favor of its survival, shows its adaptability and evolution to the ecological environment in West Erdos.Amino acid contents of Tetraena mongolica plant sampled from West Erdos region were measured and analyzed in this paper. Results showed that the plant of Tetraena mongolica contained 8 types of amino acids that are indispensable to animals. The content of them was 13.65 g-kg"1 for mature individuals and 15.46 g-kg"1 for seedlings, which accounted for 36.77% and 32.645% of total content of all amino acids, respectively. Amino acid contents in root, shoot, and leaf of both mature individuals and seedlings were different significantly. For almost all amino acids except for THR, contents in seedlings were more than in mature individuals. Contents of 11 amino acids in Tetraena mongolica plant were higher than in Astrgalus adsurgen, Medicago sativa, but lower than the psammophyte shrubs in Caragana korshinskii, Hippophae rhamnides,Hedysaricm scoparium and Tamarix ramosissima. Contents of some kinds of amino acids in this plant were even more than in Vicia sativa and Trifolium repens that are widely used as high quality forages. Comprising with rare and endangered plant species in desert, we founded that PRO content in this plant characterized specially and was meaningful. Particularly for seedlings, content of PRO in root was 2 times as much as in shoot, which showed significant differences.The average PRO content in roots of Tetraena Mongolica in exsitu Dongsheng Dongsheng soil is as high as 34.57 g"kg", accounting for 41.67 percent of amino acid, 2.71 times as much as that in stems, and 3.29 times as much as that in leaves, and 1.88 times as much as that in roots of grown-up plants in the natural habitat, which reveals its very strong xerophilous characteristic. Due to the positive correlation between the PRO content and the xerophilous ability of plants, this is favorable for the surviving of Tetraena Mongolica seedlings greatly, for the large accumulation of PRO in the root of Tetraena Mongolica seedling shows its adaptability and evolution to the ecological environment in West Erdos.V. It is proved that survivorship of soil-contained Tetraena Mongolica grown-ups in exsitu conservation is very small.VI. Some has been made in exsitu conservation of Tetraena Mongolica. Judging from the study of exsitu conservation biological basis of the three growing seasons of Tetraena Mongolica seedlings, the growth is quite good and its growth quantity of exsitu conservation culture is the smallest, though it is unsuccessful for several times in experimenting of exsitu conservation of Tetraena Mongolica. Further and extra research is needed to know weather it can be done from seed to seed.
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