栽培条件对冬小麦叶片水分利用效率的影响

通过对冬小麦孕穗一开花期叶片光合速率和蒸腾速率的系统测定，研究了叶片水分利用效率（WUE）对栽培措施（水分、氮肥、密度）的响应。结果表明，在一定范围内，水分、不施氛、低密度均可以提高冬小麦叶片WUE，其中以低密度效果最明显，水分处理次之，再次是不施氮肥。各栽培因素对WUE存在明显的互作效应。水分不足时低密度比氮肥对叶片WUE的提高效果更明显。低氮条件下，改善土壤水分和降低密度均可提高WUE，但降低密度效果最为显著。密度过高对提高作物WUE不利，改善土壤水分和增施肥料可减弱这种影响，但改善土壤水分条件对提高WUE的效果最为显著。

EFFECTS OF CULTURAL PRACTICES ON WATER USE EFFICIENCY OF WINTER WHEAT LEAVES

Field experiments were conducted in Yangling District in a semi-humid area easy to drought, using wheat as an indication plant. During the spike forming to flowering stage of winter wheat. photosynthesis rate(Pn) and transpiration rate(Tr) were all determined for treatment with different cuitivated measures in order to study the effects of cultivated factors on leaf water use efficiency(WUE). The analysis of synthetic action of main cultivate factors(irrigation. nitrogen and density of crop planting) on WUE of winter wheat showed that the importarice of factors to WUE was in order of density, irrigation and nitrogen, low-density was more sensitive to WUE than that of supply nitrogen under limited water supply. The interaction among cultural pratices combination was obviously. Under low nitrogen conditions,irrigation and low-density stimulated WUE to increase, and the effect of low-density on WUE more than that of irrigation. The WUE decreases gradually with high-density. Irrigation and supply nitrogen may reduce the effect of high-density on WUE, but the promotion of irrigation on WUE was much stronger than that of supply fertilizer.