engleski

The relationships among lipid peroxidation, free proline content and soybean seed vigor loss during storage

Soybean seed vigour loss during storage is dependent on initial seed vigour potential as well as on storage conditions. Two soybean cultivars differing in seed protein and oil content were stored for three months in hermetic sealed chambers (controlled moisture and temperature) and in multi-wall paper bags in a storehouse (seasonal and daily fluctuation of temperature and moisture). Before and after storage, seed vigour was tested by two methods: standard germination test (7 days at 250 C in germinator supplied with lighting at daytime, SG) and cold test (7 days at 100 C and next 5 days at 250 C in dark, CT). Seedlings from both germination tests were analyzed for lipid peroxidation level (TBARS) and free proline content. These indicators of oxidative stress were higher in cotyledons compared to hypocotyls indicating that the oxidative damage occurred in storage tissue. TBARS level was higher in stored seed compared to initial analyses before storage, but different storage conditions did not show significant influence although the oil content significantly declined during storage, especially in storehouse. TBARS level was higher in stored seed tested with SG and lower in stored seed tested with CT, in comparison with initial seed testing. Free proline was also accumulated more in cotyledons than in hypocotyls and storage conditions influenced proline accumulation in seedlings so that it was higher in stored seed. Protein content significantly declined in stored seed, especially in the storehouse. Seed vigour tests, EC and CT, were significantly altered by storage conditions so that seed in sealed chambers showed higher vigour, as compared to seed in storehouse. Oil content that was higher in cultivar Drina was correlated with EC and CT, as well as the seed protein content, with higher value in cultivar Zora. Seed vigour was better preserved in chamber and cultivar Zora showed higher vigour preservation potential. The results indicate that soybean seed deterioration in storage is a consequence of oxidative stress in soybean cotyledons and storage conditions (temperature and humidity) can significantly influence seed vigour loss. Also, the temperature, water availability, soil pathogens and light can greatly influence seedling metabolism and performance. A further research is underway with an aim of seed metabolic pathways better understanding including the role of antioxidants such as tocoferol, izoflavones and antioxidative enzymes activity during storage and germination stage.

seed vigor ; seed storage ; lipid peroxidation ; proline

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