Ultra-dry Conservation Idioplasm Resources Of Three Desert Plant Species In Hexi Region Gansu Province

The seeds ultra-dry store has the hot spot since 1980s and this technology was confirming feasibility from variously ways. The arid wilderness environment to plant's survival is hardly, the plant can survive under this condition, because the seed special dissemination and the germination mechanism close correlation. Established arid and half-arid area plant seed ultra-dry store technology has the vital significance to the ecological environment reconstruction, the biodiversity protects as well as imminent danger plant idioplasm resources effective preservation.In our research we had chosen three desert plants: Zygophyllum xanthoxylon, Limonium aureum and Ammopiptanthus mongolica as trial materials, used the silica gel to dry the seeds, get different MC seeds with aluminum foil or paper bags were stored. The vigor and viability of stored seeds were tested after store for different periods ranging from 1 to 2 years, studied the ultra-dry seeds the most suitable preservation condition. The results were analyzed the relationship between the store temperature and the optimum MC. The longevity and the affecting factors of stored seeds were also researched. Through the testing of relativity electric conductivity, antioxidant system (AOS), content of MDA, volatile aldehydes and LOX and so on, the physiological and biochemical mechanism of ultra-dry seeds were studied. Meanwhile we focused on the mechanism how to maintain the integrity of biological membrane of ultra-dry seeds, we found moderate dry the seeds can decrease the harm of lipid peroxidation and improve storability of ultra-dry seeds. The heredity variations of ultra-dry seeds in molecular level were analyzed with RAPD molecular marker techniques.The research results showed as following:1. Seeds were stored at 45℃, room temperature and 15℃for 2 years, the optimum MC of Z. xanthoxylon are 1.99%, 3.81%-2.41% and 4.81%-1.99%, respectively. The optimum MC of L aureum are 2.88%, 4.67% and 3.54%, respectively. The optimum MC of A. mongolica are 2.24%, 3.73% and below 5%, respectively. The optimum MC of seed decreases as the storage the storage temperature increases. Under the low temperature, the seed's longevity has prolonged with different MC seeds. There is a relationship of logarithm regression between seed MC and seed longevity. Under the high temperature, the longevity and vigor of most seeds decrease, however, as long as appropriate desiccates the seeds, the longevity can increase. Appropriate ultra-dry treatment can improve the seeds storability and stronger the ability of resisting accelerating ageing.2. The pre-humidification treatment and test of the GP, VI and relativity electric conductivity with ultra-dry seeds before germination suggested that the pre-humidification treatment was important to effectively reduce the water absorption rate and engance the membrane restoration during rehydration. Ultra-dry treatment can keep physiological function of cell membrane and make the seed keep higher vigor level.3. Ultra-dry treatments can improve the ability of ageing-resistance of seeds, prolonging the seed's longevity. But, there is a range of moderate MC exists and excessive dehydration under moderate MC (the optimum MC) would not be beneficial. The results also showed that ultra-dry treatments could be applied as a quick method to estate the storability of ultra-dry seeds and measure the optimum MC.4. After accelerating ageing, the activity of LOX, the content of MDA and volatile aldehydes did not increase with reducing of MC of seeds. This indicted that ultra-dry seeds resist lipid peroxidation ability stronger than the high MC seeds. In addition, the ability of eliminating radical was improved, there was no harmful effect on activity of SOD, POD, CAT in ultra-dry seeds, means the system of scavenging active oxygen and the ability of superoxide-resistance in ultra-seeds were better, so preventing the lipid peroxidation and avoiding the damage to membrane system, and maintaining the ultra-dry seed's vigor.5. Through the studying on genetic variation of three desert plants with RAPD, the results showed that ultra-dry treatment itself can not bring genetic variation of ultra-dry seeds in RAPD molecular maker level, and RAPD molecular analyzes is suitable for the hereditary variation of seeds.