NaHS对NaHCO3胁迫下黑籽南瓜种子萌发及生理特性的影响

以黑籽南瓜(Cucurbita ficifolia)种子为试材, 研究了外施不同浓度的NaHS对NaHCO₃胁迫下种子萌发及生理特性的影响。结果表明, NaHCO₃胁迫显著抑制了黑籽南瓜种子的发芽率、胚轴长和胚根长, 降低了种子萌发过程中的可溶性糖含量, 抑制了α-淀粉酶、β-淀粉酶、SOD及POD活性。而外施不同浓度的NaHS显著促进了NaHCO₃胁迫下黑籽南瓜萌发种子胚轴和胚根的生长, 提高了可溶性糖含量及α-淀粉酶、β-淀粉酶、SOD和POD活性, 降低了MDA含量; 外施其它盐类(Na₂S、Na₂SO4、NaHSO₄和NaHSO₃)及不同pH值(pH5.8–7.8)的Na₂HPO₄-NaH₂PO₄缓冲液对NaHCO₃胁迫下黑籽南瓜种子的萌发则无影响。外施NaHS可有效缓解NaHCO₃胁迫对黑籽南瓜种子萌发的抑制作用, 其缓解效应可能与其释放的H₂S有关。

Effect of Exogenous NaHS on Seed Germination and Physiological Characteristics of Cucurbita ficifolia Under NaHCO3 Stress

We studied the effect of exogenous NaHS on seed germination and physiological characteristics of Cucurbita ficifolia under NaHCO₃ stress. NaHCO₃ stress inhibited the germination rate, hypocotyl length and radicle length and decreased the soluble sugar content as well as activities of α-amylase, β-amylase, superoxide dismutase (SOD) and peroxidase (POD). While, exogenous NaHS treatment significantly increased hypocotyl length and radicle length as well as soluble sugar content. Moreover, exogenous NaHS treatment increased the activities of α-amylase, β-amylase, SOD and POD and decreased the accumulation of malondialdehyde (MDA). Treatment with other salts including Na₂S, Na₂SO₄, NaHSO₄ and NaHSO₃ had no effect on germination rate under NaHCO₃ stress. Na₂HPO₄-NaH₂PO₄ buffer (pH 5.8–7.8) did not promote seed germination under NaHCO₃ stress as did NaHS treatment could be concluded that exogenous NaHS effectively alleviated the toxic effects of NaHCO₃ stress on seed germination, and the function of NaHS was attributed to H₂S.