水分胁迫对2种基因型杜鹃生理生化特性的影响

Effects of water stress on physiological and biochemical characteristics in two genotypic Rhododendron

以盆栽西洋杜鹃(Rhododendron hybridum)和毛鹃(Rhododendron pulchrum)为材料,研究了在连续干旱、水湿胁迫下两种杜鹃所发生的生长和生理生化响应。试验表明:随着干旱胁迫程度的加深,西洋杜鹃和毛鹃叶片的相对含水量及叶绿素含量显著下降,叶片出现不同程度的干枯和死亡现象;MDA含量和叶片电导率显著上升;可溶性糖含量上升,而可溶性蛋白质含量下降;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及过氧化物酶(POD)活性先上升后下降,其中SOD活性在中度干旱胁迫下达到最大值,CAT和POD则在轻度胁迫时含量最高;随着干旱胁迫程度的加深,各项生理指标对比表明西洋杜鹃比毛鹃耐旱。在水湿胁迫下,西洋杜鹃和毛鹃植株受害较轻,未出现死亡现象,叶片各项生理指标变化相对平缓,且与对照相比差异不明显;随着水湿胁迫程度的加强,西洋杜鹃的叶绿素含量与抗氧化酶活性等比毛鹃下降更明显,表明毛鹃更耐水湿胁迫。本研究表明,在一定时间内杜鹃属植物能更好地适应水湿环境。

A series of experiments were conducted using Rhododendron hybridum and Rhododendron pulchrum to un- derstand the effects on physiological and biochemical characteristics under different water stress. The results indicated that leaves relative water content and chlorophyll concentration of both decreased significantly and leaves appeared senescence even death with the increase of drought stress; The concentration of malondialdehyde （MDA） and leaves relative conductivity increased significantly; The concentration of solube sugar increased while soluble protein decreased, and the superoxide dismutase （ SOD）, 9ernxidase （POD） and catalase （CAT） activity increased at first then decreased; But SOD activity increased to the highest level in moderate drought while CAT and POD activity under mild water stress ; Comparison of various physiological indicators showed that Rhododendron hybridum is more drought tolerant than Rhododendron pulchrum. Under waterlogging stress, two kinds of Rhododendron did not damaged seriously and the physiological indicators varied gently, and there were little significant changes compared with the control. But as the moisture stress increased, Rhododendron hybridum chlorophyll content and antioxidant enzymes activity decreased more significantly than Rhododendron pulchrum, which indicated that Rhododendron pulchrurn was more water-wet tolerant than Rhododendron hybridum. This study showed that Rhododendron plants were suitable for growing in the water sufficient soil.