五种脱落酸功能类似物对提高小麦抗盐胁迫的效应和机理

Effects of five functional analogues of abscisic acid on improving salt stress tolerance of wheat and their mechanism

土壤盐渍化是降低作物产量的非生物胁迫因素之一,对小麦种子出苗和苗期生长造成严重影响。本研究以小麦品种“鲁原502”为材料,采用室内水培法探讨了5种脱落酸(ABA)功能类似物——萘酮戊酸(natenpac,NA),quinabctin(QB)及其3种结构类似物tetrafluoroquinabctin(TFQB)、indabactin(IQB)和tetrafluorothioquinabctin(TFTQB)对提高其幼苗抗盐性的影响。结果表明:苗期喷施上述5种化合物均能显著促进在300 mmol/L氯化钠胁迫下小麦幼苗的生长,其中喷施TFQB、TFTQB和NA的效果最好;NA和TFTQB能够通过增加根长、根表面积和根体积而显著促进盐胁迫下小麦幼苗的根系生长,从而增强小麦幼苗根系的吸水能力;5种ABA功能类似物对盐胁迫下小麦幼苗的光合效应、抗氧化酶活性、细胞膜受损状况、渗透调节物质积累等均有显著改善,其中NA处理可显著减轻PSⅡ最大光能转换效率(Fv/Fm)下降的幅度,维持胞间二氧化碳(CO_(2))浓度的功能优于其他4种化合物;除IQB外,其他4种化合物均能有效降低丙二醛(MDA)含量、显著降低内源生长素(IAA)含量并提高内源ABA含量,其中NA在启动ABA信号途径以提高抗盐胁迫方面比其他4种化合物更有效。本研究结果对揭示ABA功能类似物的作用机制、提高小麦耐盐性具有重要的理论意义和潜在的应用价值。

Soil salinization is one of the abiotic stress factors that reduce crop yield and exerts a serious impact on wheat seed germination and seedling growth.In this paper,"Luyuan 502"wheat was employed as the material,and the effects of five functional analogues of abscisic acid(ABA)on improving the salt tolerance of the seedlings were studied by hydroponics.The results showed that five functional analogues could significantly promote the growth of wheat seedlings under 300 mmol/L NaCl stress,among which TFQB,TFTQB,and natenpac(NA)performed better.NA and TFTQB treatment greatly promoted the root growth of wheat seedlings under salt stress by increasing root length,root surface area,and root volume,thus enhancing the water absorption capacity of wheat seedling roots.All five ABA functional analogues could increase the photosynthetic effect,antioxidant enzyme activity,and osmotic adjustment substance accumulation,and decrease cell membrane damage of wheat seedlings under salt stress.NA treatment alleviated the decrease of Fv/Fm and maintained the concentration of intercellular CO_(2),which is superior to QB and its analogues.Except for IQB,the other four compounds significantly reduced the content of malondialdehyde,and endogenous IAA,but increased endogenous ABA content.NA exhibited a more predominant effect than QB analogues in stimulating ABA signaling pathway against salt stress.Overall,this study is theoretically significant for revealing the action mechanism of ABA functional analogues,and also provides potential application values of ABA functional analogues for improving the salt tolerance of wheat.