| Object: Storage of germplasm resources will inevitably lead to seeds aging in production and science research. Seeds aging can cause serious impact on seeds quality, genetic performance and plant growth. The study was done to explore the physiological and biochemical characteristics of barley seeds deterioration. The research laid foundation for the control of barley seeds vigor, and provide theoretical basis for revealing the aging mechanisms of barley seeds.Methods: In this study, artificial aging method with conditions of high temperature and high humidity(40℃, 80%RH)was taken to simulate natural aging process. Indicators which were determined included germination characteristics, seeds vigor indexes, storage substance contents,some antioxidant enzymes’ activities, oxidation contents, reactive oxygen contents and malt qualities.Results:(1) Standard germination tests of barley seeds after different aging time processing were done, and at the same time germination indexes were measured. The results showed that germination potential, germination rate, germination index and vigor index of barley seeds all reduced gradually with the increasing of aging time. Barley seeds vigor was almost completely lost when aging 15 d.(2) Barley seeds with different vigor level were treated with imbibition. And then seeds vigor, soluble sugar and soluble protein contents were measured. The results showed that relative electric conductivity presented erratic fluctuation trends, MDA contents mainly decreased, triphenyltetrazolium chloride reduction intensity increased firstly and fall then, soluble sugar contents did not change significantly, and that soluble protein contents assumed decreasing changes in the artificial aging process.(3)Barley seeds with different vigor level were treated with imbibition. Indicators which were measured included antioxidant enzymes’ activity, contents of oxidation, production rate and contents of reactive oxygen. The results showed that CAT activities mostly increased firstly and decreased then, POD activities descend gradually, SOD activities mainly fall in small extents, GR activities decreased by degrees, DHAR activities presented an obvious drop, contents of GSH declined, contents of Asc assumed unstable change trend in the context of small, and that H2O2 contents were generally on the rise as well as produce rates of O2.-with increasing of aging time.(4)Barley seeds with different vigor level were treated with malting so as to determine the changes of malt qualities. The results showed that indicators which dropped down with increasing of aging time incorporated malt extract contents, ɑ-amino nitrogen contents,Kolbach index, diastatic power. However, viscosity showed a gradual increase during artificial aging.Conclusion:(1)Germination indicators were accurate and sensitive assessment of seeds quality and the vigor level.(2) For barley seeds, relative electric conductivity was complexly regulated by the aging mechanism and affected by different varieties. Triphenyltetrazolium chloride reduction intensity could be used as quality evaluation indicator of some barley varieties. Whether MDA contents can be the evaluation of seeds vigor need for further tests. Soluble sugar and soluble protein contents were not the main cause of seed decay.(3) Antioxidant system was destroyed by seeds aging. Reduction of GSSG might be suppressed, which may be why GSH contents descended. Asc always play the role of removing ROS in the process of seeds aging. Production rate of O2.–and H2O2 contents increase was one of the most important reasons of seeds deterioration.(4)Germination potential, germination rate and germination index could be accurateand sensitive to reflect malt ɑ-amino nitrogen, viscosity, malt extract, Kolbach index and diastatic power. What’s more, they could predict the quality of malt. |
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