亚精胺缓解渗透胁迫对玉米胚芽鞘的氧化伤害

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。

Spermidine Alleviates Oxidation Injury Resulted from Osmotic Stress to Maize Coleoptile

In this paper,two different drought resistant maize(Zea mays L.) cultivars,Nongda108 and Yedan13(with the tolerant former and the sensitive latter),were used as research materials to probe mechanism by which exogenous spermidine(Spd) alleviated oxidation injury resulted from osmotic stress to maize coleoptile.The results were as follows:Under osmotic stress,malonic dialdehyde content and plasma membrane(PM)-NADPH oxidase activity in Yedan13 increased more significantly,while Spd level and activities of superoxide dismutase(SOD),catalase(CAT) and ascorbate peroxidase(ASP) in Nongda108 increased more significantly.In coleoptile of Yedan13 with spermidine seed-soaking,spermidine content and activities of three antioxidation enzymes increased markedly and PM-NADPH oxidase activity decreased significantly,while the effect of spermidine seed-soaking on Nongda108 was slight.The results suggested that under osmotic stress,spermidine seed-soaking increases the spermidine content to alleviate reactive oxygen injury on maize coleoptile via inhibiting PM-NADPH oxidase activity and increasing SOD,CAT and ASP activities in coleoptiles of drought-sensitive maize cultivar.