ABSTRACT Abscisic acid (ABA) is an important plant hormone that plays significant roles in cold tolerance regulation. However, whether ABAimproves cold tolerance by increasing the activities of antioxidant enzymes in wheat remains unknown. In this study,the activities of antioxidant enzymes of the winter wheat variety ‘dongnongdongmai 1ʹ (‘dn1ʹ)afterthe application of exogenous ABA under low temperature (0°C, −10°C, −20°C, and −25°C) were investigated. Results showed that cold stress significantly increased H2O2 and relative conductivity, whileABA significantly reduced this effect. ABA enhanced cold tolerance in both leaves and rhizomes at −10°C and −20 °Cby increasing CAT, SOD, POD, APX, GR, DHAR, and MDHAR. However, this tolerance was weakenedat −25°C with decreasing ASA, GSH, APX, DHAR, and MDHARthan at-10°C and −20°C.POD, GR, and DHARlevels peaked at −10°C, while CAT, SOD, GSH, APX, and MDHAR content in rhizomes peaked at −20°C. The rate of returning green was significantly increased after ABA treatment than in controls (93.5% vs 83.6 %). In ‘dn1ʹ, rhizomes had a higher cold tolerance than leaves. Thereby, exogenous ABA could enhance cold tolerance byincreasing the activities of antioxidant enzymes.

中文翻译：

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ABA 通过增加 ROS 清除系统增强小麦 'dn1' 的耐寒性

【摘要】：脱落酸(ABA)是一种重要的植物激素,在耐寒调节中起重要作用。然而，ABA是否通过增加小麦抗氧化酶的活性来提高耐寒性仍然未知。本研究考察了冬小麦品种'东农冬麦1ʹ('dn1ʹ)在低温(0°C、-10°C、-20°C和-25°C)下施用外源ABA后抗氧化酶的活性被调查。结果表明，冷胁迫显着增加了 H2O2 和相对电导率，而 ABA 显着降低了这种影响。ABA 通过增加 CAT、SOD、POD、APX、GR、DHAR 和 MDHAR 在 -10°C 和 -20°C 下增强叶片和根茎的耐寒性。然而，这种耐受性在 -25°C 时随着 ASA、GSH、APX、DHAR 和 MDHAR 的降低而减弱，在 -10°C 和 -20°C 下。POD、GR、DHAR 含量在 -10°C 达到峰值，而根茎中 CAT、SOD、GSH、APX 和 MDHAR 含量在 -20°C 达到峰值。ABA 处理后的返青率比对照组显着增加（93.5% 对 83.6%）。在'dn1ʹ，根状茎比叶子具有更高的耐寒性。因此，外源性ABA可以通过增加抗氧化酶的活性来增强耐寒性。