保水剂和负压供水对玉米生理生长及水分利用效率的影响

采用一种负水头供水控水系统，通过调节供水负压值来控制不同的土壤含水率，研究3种供水负压（3、6、9 kPa）下，保水剂对玉米生理、生长性状以及节水效果的影响。结果表明：在供水负压为3 kPa时，保水剂使玉米株高降低了7.4%，叶面积降低了14.9%，地上部干物质量降低了12.4%，地下部干物质量降低了7.3%，水分利用效率降低了12.6%。在供水负压为6 kPa和9 kPa时，保水剂使玉米株高分别增加了10.0%、37.9%，叶面积分别增加了14.2%、90.8%，地上部干物质量分别显著增加40.4%、104.6%，地下部干物质量分别增加了35.3%、83.8%，水分利用效率分别显著提高了26.9%、65.7%。同时，与无保水剂的相比，玉米叶片水势分别增加7.1%、19.2%，叶片相对含水率、净光合速率、胞间CO2浓度、蒸腾速率也较高。表明在水分受限制条件下，保水剂能够改善植株的生理生长特性，提高水分利用效率。

Effects of water-retaining agent and water supply tension on physiology, growth and water use efficiency of corn

A new type of negative hydraulic pressure controlled auto irrigator was used to designed different levels of water supply tension to control different soil moisture regime. The objective was to study physiological growth of corn(Zea mays L.) and soil water conservation using water-retaining agent under three irrigation levels(3, 6 and 9 kPa). Under 3 kpa, plant height decreased by 7.4%, leaf area decreased by 14.9%, shoot dry weight decreased by 12.4%, root dry weight decreased by 7.3%, the water use efficiency decreased by 12.6% due to application of SAP. Under 6 and 9 kpa, plant height increased by 10.0% and 37.9%, leaf area increased by 14.2% and 90.8%, shoot dry weight increased by 40.4% and 104.6%, root dry weight increased by 35.3% and 83.8% respectively, the water use efficiency increased by 26.9% and 65.7% substantially respectively for SAP application. At the same time, leaf water potential exceeded that without SAP by 7.1% and 19.2% respectively. Higher relative water contents in leaves as well as intercellular carbon dioxide concentration, net photosynthesis and transpiration rate was maintained. Our results indicated that SAP can improve physiological growth of corn and increased its water use efficiency under water limited condition.