外源吲哚乙酸、脱落酸调控下水翁水淹胁迫耐受性比较

Effects of exogenous indoleacetic acid and abscisic acid on the tolerance of Cleistocalyx operculatus to waterlogging stress

水翁[Cleistocalyx operculatus(Roxb.)Merr.]是具有重要经济价值的耐水淹陆生植物.为了解水翁水淹耐受性机制及激素作用,以盆栽水翁幼苗为试验材料,通过叶片喷施外源生长激素吲哚乙酸(IAA)、胁迫激素脱落酸(ABA),或在水中添加IAA、ABA两种不同处理模式下,比较研究外源IAA、ABA调控水翁水淹(土壤表层以上10 cm)胁迫耐受性差异.结果表明:经历120 d的水淹植株存活率为100%,但水淹胁迫对水翁幼苗造成显著的负面影响.不同方式施加外源IAA、ABA后对水淹胁迫下水翁的负面影响缓解效果不同.其中水中直接加入ABA的处理最能缓解水淹对水翁负面影响,正向调控作用最强;与水淹组相比,水淹+ABA组的植株在株高增长量、叶片数和叶面积分别增加了23.7%、30.4%、37.6%;光合速率显著增强;丙二醛含量和可溶性蛋白含量无显著性差异;相对电导率、脯氨酸含量、超氧阴离子自由基含量、还原型谷胱甘肽含量及抗氧化酶活性显著降低.隶属函数分析结果表明外源激素缓解水淹胁迫作用效果从大到小排序为水淹+ABA组>水淹+叶片喷施ABA组>水淹+IAA组>水淹+叶片喷施IAA组.在同一施用方式下,外源ABA比外源IAA缓解水淹胁迫作用更强;同一种外源植物激素加入根部水溶液的作用方式比叶面喷施同浓度外源激素的作用效果更显著.本研究结果可为激素提高植物水淹胁迫抗性提供科学依据.

Cleistocalyx operculatus(Roxb.)Merr.is a waterlogging-tolerant terrestrial plant species with important economic value.In this study we explored the effect of the exogenous growth hormone indoleacetic acid(IAA)and stress hormone abscisic acid(ABA)on waterlogging tolerance of C.operculatus.C.operculatus seedlings were used to investigate the effects of exogenous hormones on the growth and physiological characteristics of the plant under waterlogging stress(10 cm above the soil surface).Two different methods of application of exogenous hormones were employed:waterlogging+leaf spraying exogenous hormones,and waterlogging+exogenous hormone solutions.The results showed that all plants survived after 120 d of waterlogging,and waterlogging stress had significant negative effects on C.operculatus seedlings.The different methods of application of exogenous IAA and ABA had different alleviating effects on waterlogging stress in C.operculatus.Among the different treatments of exogenous IAA and ABA application,ABA solution treatment had the most significant effect on improving the waterlogging tolerance of C.operculatus.Compared with waterlogged seedlings,seedlings that underwent treatment with ABA showed increase in plant height growth,number of leaves,and leaf area by 23.7%,30.4%,and 37.6%,respectively.Further,photosynthetic rate increased significantly and insignificant differences in malondialdehyde and soluble protein content were observed.Significant decreases in relative conductivity,proline content,superoxide anion free radical(O2·-),and reduced glutathione(GSH),and antioxidant enzyme activities were also observed.According to the results of subordinate function analyses,the alleviating effects on waterlogging stress in C.operculatus were ranked as follows:ABA solution treatment>leaf spraying ABA treatment>IAA solution treatment>leaf spraying IAA treatment.Exogenous ABA application had more significant effects on waterlogging stress in C.operculatus than exogenous IAA application.Hormone solution treatments had universally better effects on C.operculatus than leaf spraying hormone solution treatments,for both IAA and ABA.These findings could provide scientific guidance for the application of exogenous hormones to improve waterlogging-stress tolerance in plants.