以冬小麦小偃22为试验材料，在120 kg hm-2施氮水平和基本苗为130~150万 hm-2下，研究常规栽培(CK)、覆草栽培、地膜覆盖3种栽培模式下灌浆期冬小麦顶三叶衰老与活性氧代谢特性。结果表明，覆草栽培模式下，叶绿素含量显著高于常规栽培，叶片衰老速度缓慢，代谢强度降低缓慢，饱满指数及产量显著高于常规栽培；地膜覆盖栽培模式下，灌浆前期叶绿素含量显著高于常规栽培，叶片中过氧化物酶（POD）和过氧化氢酶（CAT）活性高于常规栽培，丙二醛（MDA）含量显著低于常规栽培，膜脂过氧化程度低；灌浆后期叶绿素含量急剧下降，叶片衰老速度加快，膜脂过氧化程度加剧。POD、CAT参与了小麦叶片衰老进程的调控，并通过协同作用来保护叶片，减轻活性氧伤害，延长功能期，提高产量。
Chlorophyll and soluble protein break down and reactive oxygen species metabolism is maladjustment in the process of leaf aging. The damage action of reactive oxygen species is one of the reasons for plant leaf aging. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) are important defending enzymes that can eliminate reactive oxygen species and inhibit plant aging. The experiment was carried out to study the effects of three cultivation modes (flat planting, straw mulching, plastic film-mulching) with the 120 kg N ha-1 application and planting density of 130–150×104 plants ha-1 on leaf aging of the winter wheat (Triticum aestivum L.) cultivar Xiaoyan 22. The results showed that leaf aging and reactive oxygen species metabolism varied with the cultivation modes. Compared with flat farming, straw mulching could increase leaf chlorophyll, slow the speed of leaf aging and the extent of declining metabolism. At the early filling stage, plastic film-mulching could increase leaf chlorophyll, enhance POD, CAT activities, and lower the malondialdehyde (MDA) content. At the late filling stage, there were a remarkable decline of leaf chlorophyll, a quick leaf aging and a marked increase of MDA. The POD and CAT were involved in leaf aging regulation, synergistically protecting the leaves by reducing the damage from reactive oxygen species, prolonging the functional period of leaves and increasing the yield. We can use straw mulching to regulate the leaf aging of winter wheat, and improve the yield and quality of winter wheat in the south of Loess Plateau.
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