pH缓冲液诱导冬小麦苗期抗寒的生理机理

Effects and Physiological Mechanism of Different pH Buffer on Cold Resistance of Winter Wheat at Seedling Stage

为探讨外源pH缓冲液喷施诱导冬小麦苗期抗寒的生理机理,以济麦22为材料,采用盆栽试验的方法,分析了pH缓冲液处理后经低温胁迫的冬小麦叶片相对电导率、相对含水量、气孔导度、丙二醛(MDA)含量和抗氧化酶活性的变化。结果表明,随着低温胁迫时间的延长,冬小麦叶片相对电导率和MDA含量均增加。与对照相比,喷施pH 6.5和pH 6.0的缓冲液降低了相对电导率和MDA含量,且减少了超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的下降幅度,以pH 6.0缓冲液处理效应最为显著,经该处理6d时叶片相对含水量和气孔导度也比对照明显提高。说明适宜的外源pH缓冲液处理可诱导冬小麦酶促和非酶促防御系统抗逆机能的增强,有利于植株经受更长时间低温胁迫。

The present study was designated to explore the effects and physiological mechanism of cold resistance enhanced by different pH buffer in winter wheat.Using Jimai 22 as the material,a pot experiment was conducted to investigate the effects of different pH buffer on MDA content,electrical conductivity,antioxidative enzymes activity,relative water content and stomatal conductance of winter wheat seedlings under low temperature stress for 9 d.The results showed that the electrical conductivity and malondialdehyde（MDA） content in the seedlings increased with the prolongation of low temperature stress.But in the pH 6.5 and pH 6.0-treated winter wheat seedlings,the MDA content and electrical conductivity decreased under low temperature stress comparing with the control,the effects of pH 6.0 treatment was better after 9 d stress.The activities of SOD,POD and CAT increased at the first 1 or 4 days of low temperature stress,and then decreased.The decline of the activities of SOD,POD and CAT in the pH 6.0 treatment was obviously less than that of CK with the most significant differences.The relative water content and stomatal conductance at 6 d after spraying pH 6.0 buffer was 33.19% and 49.49% higher than that of CK,respectively.These suggested that exogenous pH 6.0 buffer could enhance antioxidant ability of enzymatic and non-enzymatic defense system and provided an optimal internal environment for intracellular material metabolism and photosynthesis to maintain the higher level of cold resistance under the followed durative low temperature stress.