苜蓿根系构型及生理特性对干旱复水的响应

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...

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

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 （O^2-）， 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.