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选用抗旱性不同的两个玉米品种农大108(抗旱性强)和掖单13(抗旱性弱)为材料,探讨外源亚精胺(Spd)缓解渗透胁迫对玉米胚芽鞘的氧化伤害机理。结果如下:渗透胁迫下,掖单13的质膜NADPH氧化酶活性和丙二醛(MDA)含量的上升幅度明显大于农大108,而农大108的Spd含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(ASP)活性的上升幅度明显大于掖单13;Spd浸种,掖单13胚芽鞘中Spd的含量和3种抗氧化酶活性显著提高,而其质膜NADPH氧化酶活性的上升幅度显著下降,Spd浸种对农大108影响不大。这些结果表明,Spd浸种通过提高渗透胁迫下抗旱性弱的玉米品种胚芽鞘中Spd含量,导致胚芽鞘细胞质膜NADPH氧化酶活性下降和抗氧化酶活性升高,从而缓解活性氧的伤害。
Two corn cultivars with different drought resistance, Nongda 108 (strong drought tolerance) and Yedan 13 (weak drought tolerance), were used as materials to investigate the mechanism of oxidative damage induced by exogenous spermidine (Spd) on osmotic stress of corn coleoptile. The results were as follows: under osmotic stress, the increase of plasma membrane NADPH oxidase activity and malondialdehyde (MDA) content of Yedan 13 was significantly greater than that of Nongda 108, but Nongda 108’s Spd content and superoxide dismutase (SOD) CAT and ascorbate peroxidase (ASP) increased significantly more than that of Yedan 13; Spd content and three antioxidant enzymes activity in Spd soaked, Yedan 13 significantly increased, NADPH oxidase activity of the membrane increased significantly decreased, Spd soaking on Nongda 108 little effect. These results indicated that Spd soaking could reduce the damage of reactive oxygen species by increasing the content of Spd in the coleoptile sheath of corn with weak drought resistance under osmotic stress, resulting in the decrease of NADPH oxidase activity and antioxidant enzyme activity in the germ sheath cell plasma membrane.