Physiological Regulation Of Seed Soaking With Soybean Isoflavones On Drought Tolerance Of Glycine Max And Glycine Soja

In this study, the Glycine max Jackson cultivar (the relatively drought-sensitive), the Glycine soja BB52population (the drought-tolerant one) were used as the experimental materials. First of all, changes in germination parameter, plant height and fresh weight under12%PEG-6000solution were analyzed by seed soaking with Daidzin or Genistin at different concentration, aimed at finding the suitable daidazin and genistin concentration for soaking. And then effects of seed soaking with the suitable daidazin and genistin concentration on growth of this two kinds of soybeans under12%PEG-6000were analyzed, aimed at finding its physiological mechanisms of alleviating the drought stress. The results showed as follows:The relative germination rate, plant height and fresh weight of Glycine max Jackson and Glycine soja BB52were decreased under12%PEG-6000treatment. When these seeds were soaked with daidazin and genistin at different concentrations, the relative germination rate, plant height and fresh weight of Jackson and BB52were increased. And the suitable daidazin or genistin concentration of seed soaking is0.01mg·L-1.Under the12%PEG-6000stress, the relative growth rate, leaf relative water content, osmotic potential, contents of chlorophyll, contents of carotenoids, Pn and Fv/Fm were decreased. After the seeds of the above soybean materials were soaked with daidzin or genistin at0.01mg-L"1, the mentioned indexes above of Jackson and BB52were increased and the effects of mitigation were displayed.Under the drought stress, when the seeds of the above soybean materials were soaked with daidzin or genistin at0.01mg·L-1, the relative electrolytic leakage, contents of TBARS were decreased, and FRAP and DPPH·radical scavenging activity in leaves and root were increased, soybean isoflavone contents in roots, stems and leaves of Jackson were increased, although the contents of soybean isoflavone in roots, stems and leaves of BB52were not obviously increased, they still remained higher when compared to the control.In summary, the treatments of seed soaking with0.01mg·L-1daidzin or genistin could regulate the contents of soybean isoflavone in soybean seedlings and the distribution of soybean isoflavone in roots, stems and leaves under drought treatment. And it enhanced the anti-oxidative activities and photosynthesis, and therefore restored the growth of soybean subjected to drought stress, and the ameliorating effects on the relative electrolytic leakage and content of TBARS in the relatively drought-sensitive Jackson cultivar was more obvious than those in BB52population. The above-mentioned may provide the theoretic basis for the research of soybean isoflavones in the breeding of drought-tolerant soybean cultivar, chemical regulation of soybean drought tolerance and the utilization of arid land in the future.