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在非生物胁迫条件下，海藻糖可以提高植物的抗逆性，减少逆境胁迫对植物组织的伤害，维持植物的相对正常生长。为了解其具体的作用机制，以小麦为材料，通过检测高温胁迫及室温恢复过程中丙二醛(MDA)含量、过氧化氢（H₂O₂）含量、超氧自由基（O·-₂）含量、抗氧化物质［抗坏血酸(AsA)、还原型谷胱甘肽(GSH)］含量、抗氧化酶［超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）］活性及其基因转录的表达调控，以探究外源海藻糖对小麦幼苗抗氧化系统的影响。结果表明，在高温胁迫下外源海藻糖处理主要提高了AsA含量，增强了CAT和APX活性，同时上调了Mn-SOD、Cu/Zn-SOD、CAT、POD和APX的相对表达量，从而降低了MDA及H₂O₂的产生。而随后的室温恢复过程基本与高温胁迫的结果一致，也提高了这些酶的基因转录水平以及AsA含量，主要差别是对抗氧化酶活性的影响，即室温恢复阶段外源海藻糖主要提高了POD和APX活性。综合来看，外源海藻糖在小麦幼苗的高温胁迫及室温恢复过程中，通过促进抗氧化酶基因的上调表达，提高抗氧化酶活性和抗氧化物质含量，以酶促和非酶促两种机制共同清除高温胁迫产生的活性氧，减少氧化胁迫的损伤，维持小麦幼苗的生长。

英文摘要:

Trehalose can improve stress tolerance of plants and maintain relatively normal growth of plants under abiotic stress conditions. However, its specific mechanism is not clear. In this research, the wheat seedlings were used to study the effects of exogenous trehalose on the antioxidant system of wheat seedlings by detecting the contents of malondialdehyde(MDA), hydrogen peroxide(H₂O₂), superoxide radical(O·-₂), ascorbic acid(AsA) and reduced glutathione(GSH) in non enzymatic mechanism, the activities of superoxide dismutase(SOD), peroxidase(POD), catalase(CAT) and ascorbate peroxidase(APX) in enzymatic mechanism and their gene transcriptional levels under heat stress and subsequent recovery processes. The results showed that, under high temperature stress, exogenous trehalose pretreatment mainly increased AsA content and the activities of CAT and APX, and up-regulated the relative expressions of antioxidant enzymes including Mn-SOD, Cu/Zn-SOD, CAT, POD and APX, thereby reduced the production of MDA and H₂O₂. Basically consistent with the results under heat stress, the results obtained from subsequent recovery processes showed that transcriptional levels of these antioxidant enzymes and AsA content were enhanced by exogenously-supplied trehalose, and the main differences between them were the activities of antioxidant enzymes including POD and APX were mainly increased in exogenous trehalose-pretreated plants. In summary, exogenous trehalose improves the activities of antioxidant enzymes and antioxidant contents, and increases gene relative expression levels of antioxidant enzymes in wheat seedlings under high temperature stress and the recovery processes. The enzymatic and non enzymatic mechanisms jointly scavenge ROS and protect wheat from oxidative stress to maintain relatively normal growth of wheat.

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