玉米根系分区交替供应水氮的效应与高效利用机理

用营养液培养进行玉米根系分区交替供应水氮的模拟实验，在不同时间测定了玉米各1/2根系的根系活力和根分泌物、根系和地上部干重及其含氮量。结果表明，处理1 d、3 d、5 d时，半边根系充分供应水分和（或）氮素，供应边根系活力显著大于胁迫边和对照；处理6 d时，半边供氮的根系分泌草酸显著增多，半边根系供水和半边根系供

Effects and Mechanisms of Alternate Water and Nitrogen Supply to Partial Root Zone of Maize

Effects of alternate water and (or) nitrogen supply to partial root zone of maize were studied by using split-root and solution culture technique. The results showed that the dry weight of maize shoots for alternate supply of water and N (AWN) was significantly raised but not for alternate water supply (AW) and alternate N supply (AN). In contrast, combined root dry weight and nitrogen use efficiency increased markedly for all stress treatments. After 6 days of treatment, the amount of oxalic acid exudated from the non-stressed half root system of AN increased markedly but not for the stressed half. Exudation of all half roots of AW and AWN decreased. For each treatment, the root activity of the non-stressed half root system increased a great deal as compared with that of the other half and the control after 1, 3 and 5 days of treatment. After each alternation, the rates of biomass accumulation of the all previously stressed half roots were significantly higher than those of the other half and the control. These results suggested that compensation effect occurred in the process of alternate water and (or) N supply to partial root zone of maize.