Abstract:

About one-third of the world’s arable land is susceptible to drought, leading to a decrease in the yield of grain crops. This study selected conventional japonica rice varieties Suijing 309 (drought-tolerant type) and Suijing 318 (drought-sensitive type) as experimental varieties. Based on four levels of drought stress conditions, two treatments were set up with no salicylic acid spraying and foliar spraying of salicylic acid (concentration of 100 mg/L). The growth morphology, physiological and biochemical characteristics, oxidative characteristics, nutrients, and yield of the two varieties under different treatments were measured and analyzed. The results indicated that drought stress decreased the water and gas exchange parameters in rice leaves. Drought stress exacerbated oxidative damage to rice characterized by an increase in malondialdehyde and hydrogen peroxide, an increase in reactive oxygen species production, and a rise in sodiumion content in rice tissues. Foliar spraying with salicylic acid enhanced the activity of antioxidant enzymes such as catalase, ascorbic acid peroxidase, peroxidase and superoxide dismutase, and reduced the degree of oxidative damage in rice. Drought stress reduced the ascorbic acid content, total soluble protein content, total soluble sugar content, total soluble phenol content, proline content, anthocyanin content, salicylic acid content and α-amylase activity, whereas these substance all increased after foliar spraying with salicylic acid. Foliar spraying of salicylic acid not only improved the rice biomass and metabolic activities but also eliminated the toxic effects brought by drought stress, enhanced the antioxidant capacity and improved rice nutritional status, and thereby increased rice yield. Drought-tolerant varieties have a better ability to drought stress than drought-sensitive varieties.

Key words: rice, salicylic acid, drought stress, oxidative damage, yield

摘要：

全世界约三分之一的耕地易受干旱影响，从而导致粮食作物产量下降。本研究选取常规粳稻绥粳309（耐旱型）和绥粳318（敏旱型）作为试验品种，基于4种水平的干旱胁迫条件，设置不喷施水杨酸和叶面喷施水杨酸（浓度为100 mg/L）2种处理，测定和分析了这2个品种在不同处理下的生长形态、生理生化、氧化特性、营养物质和产量等指标。结果表明，干旱胁迫导致水稻叶片水分和气体交换参数下降；干旱胁迫加剧了水稻氧化损伤，具体表现为植株丙二醛和过氧化氢含量上升，活性氧产生增加，水稻组织中钠离子含量升高。叶面喷洒水杨酸后，由于过氧化氢酶、抗坏血酸过氧化物酶、过氧化物酶、超氧化物歧化酶等抗氧化酶活性增强，水稻氧化损伤程度减轻。干旱胁迫导致水稻抗坏血酸含量、总可溶性蛋白质含量、总可溶性糖含量、总可溶性酚含量、脯氨酸含量、花青素含量、水杨酸含量和α-淀粉酶活性均有所下降，但叶面喷施水杨酸后这些物质的含量或活性均得到不同程度提高。叶面喷施水杨酸不仅能够提高水稻的生物量和新陈代谢活动，还能够消除干旱胁迫所带来的毒性效应，提升水稻抗氧化能力，改善水稻营养状况，进而提高水稻产量。耐旱型品种对干旱胁迫的承受能力比敏旱型品种好。

关键词: 水稻, 水杨酸, 干旱胁迫, 氧化损伤, 产量