摘要：

探究不同程度干旱胁迫对小麦抗氧化酶活性、丙二醛(MDA)含量、光合特性以及产量构成的影响,为优化小麦节水生产提供理论依据和技术支撑。于2023—2025年在山东省农业科学院龙口试验田设置重度干旱(I-hd)、中度干旱(I-md)、轻度干旱(I-fd)和适宜水分(I-sm)4种土壤水分梯度,系统分析了不同干旱胁迫下小麦抗氧化酶活性、MDA含量、光合特性以及籽粒产量构成。结果表明:相较于中度和重度干旱,轻度干旱和适宜水分均有利于优化穗数、穗粒数和千粒质量,从而显著提高籽粒产量,增产幅度2 a均值达11.1%~51.0%。轻度干旱和适宜水分下各生育时期超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等抗氧化酶活性显著提升,各生育时期叶片MDA含量显著降低,对降低细胞膜脂氧化程度和延缓植株衰老具有重要作用。轻度干旱和适宜水分条件下孕穗、开花和灌浆中期叶片叶面积指数(LAI)、叶绿素相对值(SPAD值)和净光合速率(Pn)均维持在较高水平,为光合速率的提升提供生理基础,而中度及重度干旱条件下上述指标全生育期大幅降低。相关分析表明,抗氧化酶(SOD、POD、CAT)活性与MDA含量呈显著负相关,与光合特性(LAI、SPAD、Pn)及产量构成要素(穗数、穗粒数、千粒质量)呈显著正相关,为保持较高光合能力提供生理保障。综上,轻度干旱与适宜水分均会大幅提高各生育时期叶片SOD、POD、CAT等抗氧化酶活性,降低MDA等有害物质含量,并且优化叶片LAI和SPAD值进而改善叶片Pn,最终籽粒产量提高11.1%~51.0%。然而,轻度干旱与适宜水分下籽粒产量、抗氧化酶活性及光合特性间差异较小,因此,本研究认为轻度干旱条件下,可通过优化光合特性和叶片抗氧化能力来实现小麦稳产高产,为作物节水生产提供可靠的实践途径。

关键词: 小麦, 干旱胁迫, 产量, 抗氧化酶, 光合特性

Abstract:

The effects of different degrees of drought stress on antioxidant enzyme activity, malondialdehyde(MDA)content,photosynthetic characteristics,and yield composition of wheat were investigated to provide a theoretical basis and technical support for optimizing water-saving production of wheat.From 2023 to 2025,four soil water gradients of heavy drought(I-hd),moderate drought(I-md),mild drought(I-fd)and suitable water content(I-sm)were set up in the Longkou Experimental Station of Shandong Academy of Agricultural Sciences.The antioxidant enzyme activity,MDA content,photosynthetic characteristics and grain yield composition of wheat under different drought stress were systematically analyzed.The results showed that compared with moderate and heavy drought,mild drought and suitable water were beneficial to optimize spike number,grain number per spike and 1000-grain weight,thus significantly increasing grain yield,and the average grain yield in two years increased by 11.1%—51.0%.The activities of antioxidant enzymes such as superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)were significantly increased at each growth stage under mild drought and suitable water,and the MDA content in leaves was significantly decreased at each growth stage,which played an important role in reducing the degree of cell membrane lipid oxidation and delaying plant senescence.The leaf area index(LAI),chlorophyll relative value(SPAD value)and net photosynthetic rate(Pn)of leaves at booting,flowering and mid-filling stages were maintained at a high level under mild drought and suitable water conditions,which provided a physiological basis for the improvement of photosynthetic rate,while the above indices were significantly reduced during the whole growth period under moderate and severe drought conditions.The results of correlation analysis showed that the activities of antioxidant enzymes(SOD,POD,CAT)were significantly negatively correlated with MDA content,and significantly positively correlated with photosynthetic characteristics(LAI,SPAD,Pn)and yield components(spike number,grain number per spike,1000-grain weight),which provided physiological guarantee for maintaining higher photosynthetic capacity.In summary,both mild drought and suitable water significantly increase the activities of antioxidant enzymes such as SOD,POD,and CAT in leaves at each growth stage,reduce the content of harmful substances such as MDA,and optimize LAI and SPAD values to improve the photosynthetic rate of leaves.The final grain yield increased by 11.1%—51.0%.However,there was no significant difference in grain yield,antioxidant enzyme activity and photosynthetic characteristics between mild drought and suitable water.Therefore,it is concluded that under mild drought conditions,high and stable yield of wheat can be achieved by optimizing photosynthetic characteristics and leaf antioxidant capacity,which provides a reliable practical approach for water-saving crop production.

Key words: Wheat, Drought stress, Yield, Antioxidant enzyme, Photosynthetic characteristic

中图分类号: 

• S512.1小麦