生态学报2017，Vol.37Issue(7)：2244-2252,9.DOI:10.5846/stxb201601040020
盐旱复合胁迫对小麦幼苗生长和水分吸收的影响
Effects of salt with drought stress on growth and water uptake of wheat seedlings
摘要
Abstract
Salt and drought stress are two major limiting factors to wheat (Triticum aestivum L.) productivity.In north or northwest China,salt and drought stress often occur simultaneously owing to less rainfall and higher evaporation in winter and spring,which results in higher wheat yield loss.Recently,several studies have indicated that certain crop species exhibit lower growth inhabitation under the combined stress of salt and drought compared with salt and drought stress separately,but less information about adaptation mechanisms of these plants is available.Drought-tolerant and susceptible cultivars may possess variable morphological and metabolic adaptation processes in response to salt and drought stress that may contribute differently to their adaptation capability towards stress conditions.This study aims to investigate the combined effects of salt with drought stress (SD) on wheat seedling growth and water absorption characteristics,therefore providing a theoretical basis for wheat cultivation and management under salt and drought stress conditions.For this purpose two wheat cultivars,Yangmail6 (drought-susceptible) and Luohan7 (drought-tolerant),were used in a hydroponic experiment to investigate the effects of SD on root morphology,photosynthesis,and water absorption characteristics at the seedling stage of wheat.Sodium chloride(NaCl) and polyethylene glycol 6000 (PEG) were applied to solution to simulate salt and drought stress,respectively.Leaf gas exchange,chlorophyll fluorescence parameters,leaf water potential and root hydraulic conductivity was determined,and hormone concentrations were estimated according to the enzyme-linked immunosorbent assay method.The results showed that both salt and drought stress significantly affected the plant growth and physiological activities for both wheat cultivars.However,the combined effects of SD on plant growth and dry matter production reduction were lower than their sole effects.The root length,root surface area and root volume in SD-treated plants were higher than those in single stress treated plants although these were significantly lower when compared with the control.This indicates that SD has less negative effects on root growth than the single stress does.Similarly,chlorophyll content,chlorophyll fluorescence parameters (Fv/Fm or Fv'/Fm'),net photosynthetic rate,and stomatal conductance under SD treatment were all significantly higher than the single salt or drought stress,showing that SD caused less damage to the photosynthetic apparatus than their single application.Root hydraulic conductivity and xylem sap intensity under SD were observed to be significantly higher than those for the single stress,which resulted in higher leaf water potential and relative water content under SD than under single stress.The Na+/K+ ratio in leaves and roots under SD treatment were significantly lower than that for the single salt stress,and the abscisic acid (ABA) content in SD-treated plants was lower than that in single stresstreated plants,although those were significantly higher than those for the control,indicating that SD could reduce root ABA formation as compared to single stress.Compared with single salt and drought stress,SD not only improved the root water uptake capacity and leaf water status,but also decreased the Na+/K+ and ABA content,hence alleviating inhibition of leaf photosynthetic capacity.Overall,maintaining a higher water absorption capacity and photosynthesis were the major contributors for wheat seedlings to adapt SD.Luohan7 and Yangmai16 responded similarly to salt and SD,whereas Luohan7 showed more obvious tolerance to drought stress than Yangmai16.关键词
小麦/盐旱复合胁迫/光合作用/根系水导速率/水分吸收Key words
wheat/salt combined with drought/photosynthesis/root hydraulic conductivity/water uptake引用本文复制引用
翁亚伟,张磊,张姗,田中伟,靳雪莹,李梦雅,余钟毓,姜东,戴廷波..盐旱复合胁迫对小麦幼苗生长和水分吸收的影响[J].生态学报,2017,37(7):2244-2252,9.基金项目
国家自然科学基金资助项目(31471443,31501262) （31471443,31501262）
江苏省自然科学基金资助项目(BK20140705) （BK20140705）
