Studies On Maize (Zea Mays L.) Seeds Vigor And The Effect Of Nutrient Elements On Restoring Vigor Of Aged Seeds

In order to discuss physiological activity, emergence ability in the field of aged maize seeds and the effect of nutrients on restoring seeds vigor, studies on physiological activity of different maize hybrids, seed storability, the changes of physiological characters of maize seeds during accelerated aging processes, the relation between seeds vigor and emergence ability in the field, and the effect of nutrients on seeds vigor of aged maize seeds were observed and were expected to provide the theoretical basis for application of aged seeds. The results indicated:1 The research on seed vigor of different maize hybridsThe seed vigor of different maize hybrids was tested in laboratory and field. The results showed that the absorbing characteristics, electronic conductivity, dehydrogenase activity, germination and emergence abilities exhibited a significant difference among the maize hybrids selected. The field emergence rate and emergence potential showed a positive correlation with germination indexes, dehydrogenase activity and the vigor index of accelerated aging seeds. The germination indexes, dehydrogenase activity and the vigor index of accelerated aging seeds can be deemed to the important indexes for testing maize seeds vigor.2 The research on seed storability of different maize hybridsBy testing the different hybrids of maize seeds stored for a year in ambient temperature, the results indicated that the germination rate, the field emergence rate and seedlings quality declined and the electronic conductivity rised. There was a positive correlation between germination indexes and field emergence indexes, but there was not a significant correlation between field emergence indexes and electronic conductivity. The field emergence potential, emergence rate, emergence index of the stored seeds exhibited a positive correlation with the germination indexes, the vigor index of accelerated aging seeds, dehydrogenase activity of the seeds before being stored. These results made it clear that seeds with low vigor and weak germination ability were much susceptive to deterioration during storage, but seeds with higher vigor and strong germination ability possessed higher storability.3 The effect of accelerated aging on seeds vigor and activityThe change of seeds vigor and activity during aging was studied by accelerated aging treatment. The results indicated that maize seeds germination indexes and vigor index, activity of SOD, CAT and dehydrogenase and the content of soluble sugar and soluble protein in germinated seeds declined with seeds aging time, but relative electronic conductivity increased. Activity of SOD, CAT and dehydrogenase and the content of soluble sugar and soluble protein showed a positive correlation with the germination indexes. But there was a negative correlation between the relative electronic conductivity and the germination indexes. The results also indicated that activated oxygen metabolism of aged seeds was decreased and membrane permeability increased which affected the function of membrane. Furthermore, the metabolism of carbon and nitrogen was affected because respiration rate of seeds declined.4 The effects of nutrient elements on restoring vigor of aged seedsThe effects of K, Zn, Mn on germination physiology of aged seeds were studied. The results showed that a certain concentration of nutrient solution could improve the activity of dehydrogenase and antioxidant enzymes , decrease the content of MDA, and increase the content of soluble sugar and soluble protein, however, the effect and mechanism of nutrients varied with maize hybrids. The results made it clear that proper concentration of nutrient solution could restore germination activity of aged maize seeds. The effects of the nutrient elements to restore germination activity of aged maize seed was related to the activity of the dehydrogenase and antioxidant enzyme (CAT, POD, SOD) and metabolism of carbon and nitrogen during germination. Nutrient elements could improve the ability of antioxidant enzyme to clear reactive oxygen species, and maintain integrality of membrane's structure and function during the aged maize seeds germinating. The nutrient elements aslo could increase aerobic reparation rate , carbon and nitrogen metabolism rate to provided matter and energy base for seeds germination.