干旱及增强UV-B胁迫对金荞麦光合色素的影响

目的]研究干旱胁迫和增强UV-B辐射对金荞麦光合色素的影响,以期为金荞麦规范化种植提供理论依据。方法]采用盆栽试验的方法,测定金荞麦在不同程度干旱胁迫和UV-B辐射处理下光合色素的含量,并计算光合色素比值。结果]金荞麦叶绿素a含量、叶绿素b含量、总叶绿素含量、叶绿素a/叶绿素b、类胡萝卜素含量都随干旱程度的加重而降低,类胡萝卜素/叶绿素在处理中后期基本随干旱程度的加深而有升高的趋势,在后期达到显著水平;在水分充足的状况下,增强的UV-B辐射降低了叶绿素a、叶绿素b和总叶绿素含量,显著提高了类胡萝卜素含量和类胡萝卜素/叶绿素;在干旱胁迫下,增强的UV-B辐射提高了叶绿素b和总叶绿素含量。结论]金荞麦光合色素对干旱胁迫敏感,且在一定程度上能指示反映叶片受伤害程度,并反映土壤干旱水平;增强的UV-B辐射能减小由干旱胁迫带来的金荞麦光合色素变化。

Influences of Drought and Enhanced UV-B Radiation on the Photosynthetic Pigment of Fagopyrum dibotrys

Objective] To study the influences of drought stress and enhanced UV-B radiation on photosynthetic pigment of Fagopyrum dibotrys(D.Don) Hara,so as to provide a theoretical basis for the cultivation of F.dibotrys.Method] By experiment of potted plant,the photosynthetic pigments of F.dibotrys under different drought stresses and UV-B radiations were determined and its ratio was calculated.Result]Chlorophyll a,chlorophyll b,total chlorophyll,carotenoid contents and ratio of chlorophyll a/streophyll b in F.dibotrys reduced with the severity of drought.Ratios of carotenoid to chlorophyll in F.dibotrys showed a rising trend with the deepening drought and reached a significant level at the later stage.Under conditions of adequate water,enhanced UV-B radiation significantly reduced chlorophyll a,chlorophyll b and total chlorophyll contents in F.dibotrys,and it also significantly increased the ratios of carotenoid/chlorophyll in F.dibotrys.Under conditions of drought stress,enhanced UV-B radiation increased chlorophyll b and total chlorophyll contents in F.dibotrys.Conclusion] Photosynthetic pigment of F.dibotrys was sensitive to drought stress,and indicative of the injury of leaves to a certain extent,and can reflect the drought of soil.The changes caused by drought stress in photosynthetic pigment of F.dibotrys could be reduced by enhanced UV-B radiation.