不同抗旱性小麦叶片膜脂过氧化的氮素调控机制

在田间条件下研究了施氮对不同抗旱性冬小麦叶片全生育期黄嘌呤氧化酶(XOD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及过氧化氢(H2O2)和丙二醛(MDA)含量的影响。结果表明,施氮提高了叶片CAT和SOD活性,降低了XOD活性和MDA含量,以N180处理效果最明显,而且产量最高,表明N180处理对小麦膜脂抗过氧化能力和产量形成最为适宜;不施氮(N0)处理条件下,旱地品种较水浇地品种具有较高的保护酶系活性和较低的XOD活性、MDA含量。而适量氮素能够提高叶片保护酶系活性和降低XOD活性、MDA含量,所以氮素能够通过提高叶片膜质抗过氧化能力来增强小麦对干旱的适应。由于降低了超氧阴离子的生成量,使XOD活性降低和CAT活性提高,H2O2和MDA含量维持在较低水平,最终提高小麦产量。

Nitrogen regulatory mechanism in leaf membranes superoxidize of different drought resistance ability winter wheat

The effects of nitrogen fertilization on activities of leaf xanthine oxidase(XOD),superoxide dismutase(SOD),catalase(CAT) and the content of H₂O₂ and MDA were studied in two winter wheat cultivars(irrigated cultivar and dryland cultivar).The results showed that N supplication promoted leaf CAT and SOD activities;while depressed XOD activity and reduced MDA content,among which it had the most striking influence on N180.Moreover,the highest yield was obtained for N180.Therefore we could conclude that N 180 kg/ha was the recommended application rate for the winter wheat production at the local condition.Comparing to irrigated cultivar,dryland cultivar had higher SOD and CAT activities and lower XOD activity and MDA content under N0 treatment,thereby,the tested items could be adapted to(evaluate) the drought resistance of winter wheat,furthermore,rational nitrogen supplying could promote leaf CAT and SOD activities and decrease XOD activity and MDA content.So that N could improve drought-tolerance ability through increasing the ability of leaf membranes superoxidize resistance. We could conclude that rational application of nitrogen could enhance the drought-tolerance ability by decreasing the MDA and H₂O₂ content,and increasing SOD and CAT activities.