小麦叶片光合作用对不同干旱方式的反应

小麦在缓慢干旱下受到的水分亏缺程度大于快速干旱,渗透调节能力在缓慢干旱下随土壤含水量的降低而增强,而在快速干旱下很小.在干旱胁迫下,小麦叶片CO₂气体交换参数的变化趋势相同,但各参数对不同方式干旱的反应不同,表现在快速干旱处理的CO₂气体交换参数的响应值大于缓慢干旱处理下的响应值,经过缓慢干旱处理的小麦叶片具有一定的光合机构调节能力,其叶绿体光合活性、RuBP羧化酶的再生能力及羧化效率在低水势下受到的抑制程度明显小于快速干旱处理的叶片.

The Response of Photosynthesis to Different Kind of Water Deficits in Wheat Leaves

The objective of this study was to differentiate between slow soil drought and fast soil drought on photosynthesis as it was reduced during developing water deficit stress.The stress was induced by with holding water to potted plants of the winter wheat cultivar Triticum aestivum cv.Fengkang 13.Under slow drought condition.the capacity of osmotic adjustment of wheat leaves increased to a certain extent with the decreased of soil water content,and was absent under fast drought condition.The rate of photosynthesis and leaf water potential decreased with increasing length of time under water stress.Concomitantly,there were proportional,parallel decreases in stomatal conductance,Ru BP regeneration capacity,carboxylation efficiency,and photo-synthetic quantum yield.The response of parameters of photosyn thesis to different kind water deficits is not the same in their value.The value of parameters of photosynthesis in slow drought was more sensitive than in fast drought.To sum up.photosynthesis apparatus adjustment was occurred in suffering slow soil drought.