苜蓿根系构型及生理特性对干旱复水的响应  

Response of alfalfa root architecture and physiological characteristics to drought and rehydration

作　　者：李振松 万里强[1] 李硕 李向林[1] LI Zhen-song;WAN Li-qiang;LI Shuo;LI Xiang-lin(Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China)

机构地区：[1]中国农业科学院北京畜牧兽医研究所,北京100193

出　　处：《草业学报》2021年第1期189-196,共8页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(31772671)资助。

摘　　要：为了研究苜蓿根系构型及生理特性对干旱复水后的响应,对肇东苜蓿进行盆栽控水试验。设置正常供水(CK)、轻度干旱(LS)、中度干旱(MS)和重度干旱(SS)4个处理,在干旱处理4周后进行复水,研究各处理间根系构型及生理指标的差异。结果表明:干旱处理对根干重和根尖数有极显著影响(P<0.01),对比根长、根表面积、根体积和根密度有显著影响(P<0.05)。干旱胁迫抑制了根系的生长,降低了根干重、根长、根表面积、根体积、根密度和根尖数等形态指标,促进了比根长的增加。各处理间拓扑指数差异显著(P<0.05),干旱促进苜蓿根系从二分枝型向人字形结构转变。干旱胁迫极显著(P<0.01)增加了根系丙二醛(MDA)和超氧负离子(O2-)的含量,同时超氧化物歧化酶(SOD)活性和谷胱甘肽(GSH)含量也极显著增加(P<0.01),从而保持体内活性氧处于较低水平。脱落酸(ABA)含量在干旱胁迫下极显著(P<0.01)增加,通过其生理作用及信号传导途径提高苜蓿抗旱性。The objective of this research was to understand the response of alfalfa(Medicago sativa)root architecture and physiological characteristics to drought and rehydration regimes.Four water regime treatments were imposed on plants of the alfalfa cultivar Zhaodong in a pot experiment:normal water supply(CK),low water stress(LS),moderate water stress(MS)and severe water stress(SS).We studied the differences in root architecture and physiological indicators between treatments under rehydration after 4 weeks of drought treatment.It was found that drought treatment had an extremely significant(P<0.01)effect on root dry weight and root tip number and a significant effect on root length,root surface area,root volume and root density(P<0.05).Drought stress inhibited root growth,reduced root dry weight,root length,root surface area,root volume,root density,and the number of root tips,and promoted an increase in rooting depth.There was a significant difference in topological index between treatments(P<0.05),and drought induced a transformation of the alfalfa root system from dichotomous branching to herringbone branching.Drought stress resulted in an extremely significant(P<0.01)increase in the content of root malondialdehyde(MDA)and superoxide anion(O2-),and in the activities of superoxide dismutase(SOD)and glutathione(GSH).The content of abscisic acid(ABA)increased extremely significantly under drought stress(P<0.01).These physiological changes would have kept reactive oxygen species to low levels,and improved the drought resistance of alfalfa as a result of the drought-induced changes to physiological status and signal transduction pathways.

关 键 词：紫花苜蓿 根系构型 抗氧化系统 脱落酸 干旱复水 

分 类 号：S541[农业科学—作物学]