Studies On Ultra-dry Storage Of Salvia Miltiorrhiza Seeds

Objective Salvia miltiorrhiza is a popular traditional Chinese medicine, who usually uses seeds for multiplication. S. miltiorrhiza seeds, with lower germination percentage in normal conditions, were not easy to store for long time, which make the cultivation and germplasm resources preservation harder. Ultra-dry storage is a new method for seeds store, which is simple, convenient and economical. Nowadays, Ultra-dry storage is popular in crop seeds'and tress seeds'store, but rate in medical plants'seeds. I want to study the optimal ultra-dry methods and the optimal moisture content at different storage time for Salvia miltiorrhiza seeds, and find the principle of storability, which will be useful for S. miltiorrhiza seeds store.Methods (1)S. miltiorrhiza seeds were dried by silica gel at room temperature and by the oven at constant temperature 50℃to obtain various moisture(as 1.5%,2.5%,3.5%,4.5%,5.5%,7.5%), before stored sealed at room temperature. The optimal moisture content was forecasted with accelerated aging that is store at 50℃for 10 d. The optimum ultra-dry methods and the optimal moisture content were evaluated by measuring the germination percentage, germination energy, vigor index, etc, which were measured once a month. Structures of seeding root tips were contrasted to study the cytology mechanism why different desiccation way affected seeds differently. Soluble sugar content and MDA content were measured to study the seed storability.(2) S. miltiorrhiza seeds without desiccation were stored sealed respectively at room temperature, 4℃and 0℃. And the germination percentage, germination energy, vigor index, etc were measured five month later, which would be contrast with ultra-dry seeds'to ensure the optimal temperature.Results (1)According to the results of accelerated aging, the optimal moisture content for S. miltiorrhiza seeds desiccated by silica gel storage was among 5.5%~7.5%, while the optimal moisture for S. miltiorrhiza seeds desiccated by the oxen storage was 4.5%. (2)According to the germination percentage, germination energy, vigor index of S. miltiorrhiza seeds with different moisture contents stored at room temperature in different storage time, the optimal moisture content for S. miltiorrhiza seeds storage at room temperature is about 7.5%. (3) Generally speaking, germination percentage, germination energy, and vigor index of seeds desiccated by silica gel were better than seeds desiccated by the oven, and Relative electrical conductivity of silica gel desiccation seeds whose structure and function of membrane were more integrated, were lower than oven desiccation seeds. (4)Contrasting to seeds desiccated by the oven, the seeding root tips of seeds desiccated by silica gel were plumper, the meristem region was wider, the cell nucleuses were bigger, cytoplasm was heavier, the cell boundary was clear, and the mature Region of seedling root tips was more Integrated. (5) Soluble sugar content in S. miltiorrhiza seeds were correspond to MDA content and moisture content in them (6) There were obvious advantages for the ultra-dry storage seeds at the early stage, but with the time passing away, the advantages decreased. (7) Vigour and vitality of S. miltiorrhiza seeds without desiccation which were stored sealed at room temperature and 0℃were much better than those stored at 4℃. Seeds stored at 0℃were not superior than those at room temperature, contrarily, whose Vigour and vitality were badly lower than ultra-dry seeds at 7.5%(MC) desiccation by silica gel.Conclusion (1) The optimal moisture content for S. miltiorrhiza seeds storage at room temperature is about 7.5%, which is not the same as the results of accelerated aging; (2) desiccation by silica gel was more properly than the oven, and seeds desiccated by silica gel were better than seeds desiccated by the oven; (3)Seed storability of S. miltiorrhiza seeds is related to the changes of soluble sugar content in the seeds; (4)the advantages of ultra-dry storage is much more obvious in short term germplasm resources preservation; (5) Ultra-dry stored at room temperature is better than storage at low temperature.