Analysis On The Ecological Adaptability To Drought Stress Of Hippophae Native Species And External Species

Hippophae ramnoides sinensis is a native species which is distributed over arid and semiarid region. Hippophae ramnoiodes, as an external species, has special biological and economic characteristics, and it has been cultivating in our country including Inner Mongolia.Under the condition of different habitats and drought stress in cropland, this thesis made a systematic research on Hippophae ramnoides sinensis and Hippophae ramnoiodes from various aspects, such as anatomical structure, protective enzymes, osmotic adjustment matter, phytohormone, the change of photosynthetic rate and transpiration rate, the relationship between morphological characteristics and genetic traits of Hippophae ramnoides sinensis and Hippophae ramnoiodes. The results as follows:The leaves of Hippophae have relatively highly dense epidermal hair ,which can affect micro-climate to reduce water loss in the case of dryness, the thick periostracum is a effective way to reduce cell dehydration too. The leaves have relatively thicker palisade tissue, so Hippophae has anatomical structure that can adapt to drought stress. The thickness of leave decreases, and development of the palisade is better than spongy tissue's under drought stress, which is a strategy to deal with drought stress. The ratios of palisade tissue to spongy tissue of Hippophae ramnoides sinensis is higher than that of Hippophae ramnoides, the ratio of the male Hippophae is higher than that of female Hippophae. Analysis of anatomical structure show that the adaptability of the native species is better than external species, and the female's is stronger than the male's.By analyzing the changes of proline and soluble saccharin of Hippophae ramnoides sinensis and Hippophae ramnoides under water stress, the results showed that the slope soil's water content is higher than that of the gully's, the levels of proline content and the soluble saccharin content of Hippophae ramnoides sinensis on the slope are higher than those of species in the gully. Under different drought stress conditions in the cropland, the content of proline and soluble saccharinincreases with decreasing of water content of the soil. The ability of accumulation of the proline of Hippophae ramnoides sinensis is greater than that of Hippophae ramnoides , and the female's is greater than that of the male. When it comes to the capacity of accumulation of the soluble saccharin, Hippophae ramnoides > Hippophae ramnoides sinensis, and the female > the male.Under different drought stresses in cropland, SOD liveness in leaves of Hippophae decreases notablely in the beginning stage of drought stress, then decreases with the prolonging of the drought stress, as far as SOD liveness, the results show that male Hippophae ramnoides sinensis>fema\e Hippophae ramnoides>male Hippophae ramnoides> female Hippophae ramnoides sinensis. The liveness of CAT increases in the initial stage of drought stress, then decreased after the initial stage, as to the liveness of CAT, Hippophae ramnoides sinensis >Hippophae ramnoides, the male >female. The content of MD A increases with decreasing of water content of the soil, MDA content in leaves of female is higher than that of male, MDA content in leaves of Hippophae ramnoides is higher than that of Hippophae ramnoides sinensis. Protective enzymes liveness and malondiadehyde content in leaves differ between Hippophae ramnoides sinensis and Hippophae ramnoides under different drought stress, which is their different strategies for adaptation.The content of hormone of Hippophae ramnoides sinensis and Hippophae ramnoides were studied in different soil water condition. It is found that the content of ABA increases with decreasing of water content in the soil, so does the content of IAA and ZR. The content of GA increases in the beginning stage of water stress, then decreases whereafter. It is found that photosynthetic rate and transpiration rate decreases with decreasing of the soil water content under drought stress.The diurnal change of photosynthetic rate and transpiration rate were single summit and twin summit in different soil water condition. The time of the summit changes following the variations of soil water content. In suitable water content the mean photosynthetic rate of the male of Hippophae ramnoides is higher than that of the female Hippophae ramnoides. Under drought stress, the mean photosynthetic rate of female Hippophae ramnoides is higher than that of the male of Hippophae ramnoides. The mean photosynthetic rate of the female Hippophae ramnoides sinensis is higher than that of the male Hippophae ramnoides sinensis. The photosynthetic capacity of Hippophae ramnoides is higher than that of Hippophae ramnoides sinensis. The mean transpiration rate of thefemale of Hippophae ramnoides is higher than that of the male Hippophae ramnoides. The mean transpiration rate of the male and female of Hippophae ramnoides sinensis have difference.The result of Fuzzy synthetic evaluation of adaptability of Hippophae ramnoides sinensis and Hippophae ramnoides are as follows, the female Hippophae ramnoides sinensis >the female Hippophae ramnoides >the male Hippophae ramnoides sinensis >the female Hippophae ramnoides.The analysis of ISSR to Hippophae ramnoides sinensis and Hippophae ramnoides shows that there are distinct differences between Hippophae ramnoides sinensis and Hippophae ramnoides, which proves that these differences are the foundation of different ecological adaptability. The study on drought adaptability of Hippophae ramnoides sinensis and Hippophae ramnoides shows that Hippophae adopts different strategies to adapt the environment while being water deficit. When being slightly water deficit, Hippophae adapts environment by homeostasis, and while being severe water loss, physiological indices vary drastically. This kind of effective swing of indices offers possibility for survival.There are different adaptive characteristics among native species and external species. Hippophae ramnoides sinensis and female Hippophae possess stronger adaptability facing drought stress. These results can provide scientific bases for introduction and usage of Hippophae.