低温弱光对黄瓜类囊体膜耦联状态的影响

Effect of low temperature and low light treatment on the coupling state of cucumber thylakoid membrane

与低温黑暗处理相比 ,低温弱光处理使黄瓜叶片的放氧活性显著降低 ,2℃黑暗处理 6.5h后黄瓜叶片的放氧活性降低到处理前的 66% ,2℃ 35μmol/(m2· s)处理6.5h后则降低到处理前的 - 50 %。研究结果显示 ,在 5℃低温条件下 1 0 0 μmol/(m2· s)光照使黄瓜发生下列变化 :叶片毫秒延迟发光的慢相强度显著降低 ;从叶片中提取的叶绿体的PS 及 PS +PS 的电子传递速率显著升高 ;加 NH4 Cl和加 ADP+Pi的 Hill反应活性与基础 Hill反应活性相差不大 ;从叶片中提取的叶绿体 9- AA荧光猝灭能力消失。以上结果证明低温下光照处理使黄瓜类囊体膜解耦联。

In contrast to treatment with low temperature and darkness,treatment of cucumber leaves with low temperature and low light reduced oxygen evolution activity dramatically.While 2 ℃ & darkness for 6.5 h reduced cucumber leaf oxygen evolution activity to 66% of pre-treatment,2 ℃ treatment in 35 μmol/(m 2·s) reduced to -50% of that of the control.The results indicated that illumination with 100 μmol/(m 2·s) superimposed on 5 ℃ low temperature made millisecond delayed emission (ms-DLE) from cucumber leaf decrease significantly,that the chloroplants isolated from such treated leaves showed electron transport rate of PSⅠ and PSⅠ+PSⅡ increased.Their uncoupled Hill reaction activity with NH 4Cl was nearly equal to basic Hill reaction activity without NH 4Cl and coupled Hill reaction activity with addition of ADP+Pi.In addition,chloroplasts from thus treated leaves almost lost the ability to quench 9-AA flourescence.It is concluded that thylakoids from cucumber leaves treated with low temperature and low light were in uncoupled state.