小麦水分胁迫影响因子的定量研究 Ⅰ.干旱和渍水胁迫对光合、蒸腾及干物质积累与分配的影响

Quantification of Water Stress Factor for Crop Growth Simulation Ⅰ. Effects of Drought and Waterlogging Stress on Photosynthesis, Transpiration and Dry Matter Partitioning in Winter Wheat

通过冬小麦盆栽水分控制 ,研究了干旱和渍水胁迫下冬小麦水分生理生态关系。结果表明 ,存在凌晨叶水势临界值 ,当凌晨叶水势低于临界值后 ,植株叶片净光合速率显著降低 ,凌晨叶水势临界值可运用模糊聚类方法确定。在水分亏缺条件下 ,相对蒸腾速率和净光合速率随土壤水分变化的关系不相同 ,相对蒸腾速率与土壤相对含水量为直线关系 ,而净光合速率与土壤相对含水量之间为曲线关系。渍水胁迫对叶片蒸腾速率和净光合速率具有同等的影响 ,蒸腾速率和净光合速率随渍水持续天数的延长降幅增大 ,尤其在小麦生育中后期显著。干旱和渍水胁迫均降低了小麦植株总干物重 ,并使各器官间的干物质分配比例发生变化 。

Pot experiments were conducted to study the crop water relations under drought and waterlogging condition The results showed that predawn leaf water potential (PLWP) was fallen significantly with the decrease of soil water content or soil water potential The relationship between PLWP and soil water content could be expressed by a retardant equation Below a threshold value, predawn leaf water potential resulted in the obvious decline in the single leaf net photosynthetic rate With the deficiency of soil water, the responses of photosynthesis( P n) and transpiration( T r) to soil water content were different T r went down linearly with the decrease of soil moisture, but P n was stable before soil water was below a threshold value Under waterlogging condition, P n and T r had the same response and both decreased with the prolongation of waterlogging durations, especially after jointing stage Drought and waterlogging stress both strongly reduced the total biomass and changed the dry matter partitioning indexes of top and root in winter wheat