Selection Of Suitable Ultra-dry Conservation Scheme And Its Mechanism Of 7 Species Plant Seed

Ultra-dry conservation is the newly arisen germplasm conservation since the eighties of the 20th century. It plays an important role in reducing energy consumption, replacement of cryopreservation, species diversity protection, as well as provides a broad prospect for the long-term and convenient conservation of germplasm.In this paper, the 7 species seed combined with moisture content, packing method, storage temperature and humidification method were stored for 1 year, which used orthogonal design and complete randomized block design. The suitable conservation scheme was selected by testing germinability. The proline (Pro) content, malondialdehyde (MDA) content, total sugar content, fatty acid composition and superoxide dismutase (SOD) activity etc were studied to exploring conservation mechanism. The research results showed that:Conservation effect was influenced by moisture content, packing method, storage temperature and humidification method at different degree. The moisture content, the humidification method were the main factor and the packing method, storage temperature were the inferior factor. The suitable moisture content and humidification method of every species were different. The result of 3 species indicated that the effect of storage temperature on the optimum moisture content was not obvious. The desiccation of oil seeds and large seeds was strong based on the component and morphology of seed. The component and original habitat was the key factor of desiccation tolerance of seed.The suitable conservation scheme of 7 species seed as follows: 1. Albizia kalkora (3.29%moisture content+plastic bag packaging+storage in room temperature+humidification in climate box); 2. Dodonaea viscose (5.25%moisture content+plastic bag packaging+storage in room temperature+humidification in 20%PEG ); 3. Pinus kesiya var langbianensis (4.24%moisture content+plastic bag packaging+storage in room temperature+humidification in 20%PEG); 4. Cajanus cajan (4.94%moisture content+humidification in climate box); 5. Tamarindus indica (5.05%moisture content+humidification in 20%PEG); 6. Jatropha curcas (5.39%moisture content+no humidification); 7. Pinus yunnanensis (7.09%moisture content+humidification in 20%PEG). The preservation effect in this schemes was better than that of control.There were significant differences in the relative electrical conductivity, MDA content, Pro content, total sugar content, fatty acid composition, SOD activity, POD activity and CAT activity of different water gradient and humidification method of conserved seed. There was a significant negative correlation between the relative electrical conductivity, MDA content, total sugar content and the germinability. The Pro content, index of unsturated fatty acid and 3 protective enzyme had a positive correlation with the germinability. The physiological and biochemical mechanism of ultra-dry conservation was that the suitable moisture gradient and humidification method were beneficial to increase of the Pro content, unsturated fatty acid content and 3 protective enzyme and to decrease of the relative electrical conductivity and MDA content, which kept the seed vigor relatively high.The mathematical model of testing the ultra-dry conservation effect was obtained, which awaited to further study of production.