Studies On Seed Storage Behavior Of Chinese Fir And Masson Pine

The cytoplasmic vitrificatoion and frozen temperature of Chinese fir and Masson pine seeds were measured by using differential scanning calorimetry(DSC).And the relationship between seed constituents and formation of glassy state was analyzed.The effects of temperature and moisture content on physiological and biochemical characteristics of Chinese fir and Masson pine seeds were also investigated during a year storage period .The investigating indexes are germination percentage ,vigor index ,the relative electrical conductivity ,protective enzyme activation and MDA content .Besides ,the ultra-structural changes of radical-cell of Chinese fir and Masson pine seeds were observed by using microscope. The results demonstrate as follows: (1) The seeds of Chinese fir are apt to turn into a glassy state, with a critical temperature of -52.4℃,　where as the seeds of Masson pine are reluctant to form that state, whose cytoplasm will frozen in -24.8℃.　The seeds of Chinese fir have lower contents of gross fat while higher contents of Oligosaccharide/Disaccharide than the seeds of Masson pine; (2) By applying HPLC, the stachyose was detected in both seeds of Chinese fir and Masson pine with moisture content of 4%, while no stachyose was detected in Chinese fir seeds with moisture content of 10% and 18% and in Masson pine seeds with moisture content of 8% and 14%; (3) The germination percent and vigor index of both the Chinese fir and Masson pine seeds stored in different temperature were found to reduce over the storage duration. Specifically, the seeds of Chinese fir were observed to be appropriately stored in the temperature of -30℃and -18℃with the moisture content of 4%, while the seeds of Masson pine were stored in the temperature of 3℃and -18℃with the same moisture content. Within such a condition, the seeds vigor can be maintained in the high level. (4) The relative leakage of electrolytes ,protective enzyme activation and MDA content of the seeds of Chinese fir and Masson pine were changed slowly when stored in low temperature and low moisture content. When the storage temperature and moisture content increase, however, the physiological change became fast. When stored in -30℃for one year the seeds of Chinese fir with a moisture content of 4% have the smallest physiological and biochemical change whereas -18℃is the case for the seeds of Masson pine; (5) Based on the correlation analysis of the germination percent and other properties of the Chinese fir and Masson pine seeds, it was found that the germination percent of the seeds was in a positive correlation with the activity of SOD and POD ,but in a negative correlation with the electrical conductivity and MDA content; (6) Both the Chinese fir and Masson pine seeds exhibited a symptom of the destruction of the membrane integrity of their cell if stored in 25℃. The seeds of Chinese fir all retained good membrane integrity of their cells no matter what it was stored in 3℃,-18℃　or　-30℃.The seeds of Masson pine retained good membrane integrity when stored in 3℃　and　-18℃　but lost their integrity when stored in -30℃;...