长期高温对黄瓜生理生化特性的影响

摘要

高温是热带地区夏季黄瓜产量的一个重要限制因子.本试验中以"新泰密刺"为材料,研究了长期高温(32～38℃)和适温(22～29℃)对黄瓜叶片和根生理生化特性的影响.结果表明,高温处理前期的叶片生长比对照快,高温处理后期叶片面积小于对照.长期高温使黄瓜的产量、叶片光合速率、叶绿素含量、叶绿素a/b、根活力都明显降低.在长期高温条件下,叶片和根中SOD活性的降低幅度大于对照,POD活性和MDA含量的增加幅度亦大于对照.14C示踪结果表明,长期高温处理使分配到根中的同化产物也明显低于对照.%High temperature is a major factor limiting the production of cucumber planted in tropical regions during summer months.The objective of this study was to determine the detrimental effects of prolonged high temperature on cucumber leaves and roots.Shoots and roots were exposed to two different temperature regimes in growth chambers,22～29℃ (control) and 32～38℃(high temperature).the cucumber yielded much less at prolonged high temperature than at normal temperature (control).The leaf area increased more quickly than that of the contorl at the early stage,but less than that of the control at the late stage.Ratio of root to shoot,mature leaf net photosynthesis,chlorophyll contents,chlorophyll a/b ratio,and root activity all decreased more significandy in the treatment with prolonged periods of hiigh temperature than in the control.The cucumber treated at 32～38 ℃ had lower SOD activity and higher POD activity and MDA content than those treated at 22～29℃.The proportions of newly assimilated 14C translocated to roots were also lower in high temperature treatment than in the control.