干旱胁迫对持绿性高粱叶片渗透调节及叶绿体超微结构的影响

Impacts of drought stress on leaf osmotic adjustment and chloroplast ultrastructure of stay-green sorghum

在盆栽条件下，研究了开花期和灌浆期干旱胁迫（土壤含水量为田间最大持水量的45％～50％）对持绿性高粱（B35）和非持绿性高粱（三尺三）叶片水分、渗透调节物质以及叶绿体超微结构的影响．结果表明：干旱胁迫下，两高梁品系叶片自由水含量下降，束缚水含量增加，相对含水量降低，水分饱和亏缺增加，相对电导率增大，但三尺三各指标的变化幅度均大于B35．对于渗透调节物质，干旱胁迫下，三尺三可溶性糖含量的增幅大于B35，脯氨酸含量的增幅小于B35，可溶性蛋白含量的降幅大于B35．干旱胁迫下，B35与三尺三的叶绿体超微结构均受到一定程度的破坏，但B35叶绿体结构保持相对完好，受损程度明显小于三尺三．在干旱胁迫下，持绿性高粱通过较强的渗透调节表现出更好的干旱适应能力．

Taking stay-green sorghum （B35） and non-stay green sorghum （Sanchisan） as test ma- terials, a pot experiment was conducted to study their leaf osmotic adjustment and chloroplast ultra- structure at flowering and filling stages under impacts of drought stress （45%-50% of maximum field capacity）. For the two sorghum lines, drought stress caused the reduction of their leaf free wa- ter content and relative water content, and increased the leaf bound water content, water saturation deficit, and electrical conductivity, with the increment or dement being larger for Sanchisan than for B35. Drought stress increased the leaf soluble sugar content and proline content, with the increment of the soluble sugar content being larger for Sanehisan and the increment of the proline content being larger for B35, while decreased the leaf soluble protein content, with the decrement being larger for Sanchisan than for B35. The chloroplast uhrastructure of both B35 and Sanchisan under drought stress was damaged to some extent, but the damaged degree was obviously lower for B35 than for Sanchisan. The findings indicated that stay-green sorghum had a greater adaptation to drought stress through stronger osmotic adjustment.