局部恢复水氮供应对玉米根系氮素吸收与分配的影响  

Effects of Partial Water and Nitrogen Resupplies on Maize Root Nitrogen Absorbing Capacity and Distribution

作　　者：牛晓丽[1] 胡田田[1] 张富仓[1] 王丽[1] 刘杰[1] 冯璞玉 杨硕欢 宋雪[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院/旱区农业水土工程教育部重点实验室/中国旱区节水农业研究院,陕西杨凌712100

出　　处：《中国农业科学》2016年第14期2737-2750,共14页Scientia Agricultura Sinica

基　　金：国家自然科学基金(51079124);国家"863"计划(2011AA100504);中央高校基本科研业务费专项(QN2011067);教育部高等学校创新引智计划(B12007)

摘　　要：【目的】验证水分或养分胁迫后恢复供应显著提高根系吸收能力,且局部水分或氮素供应有效刺激供应区根系吸收的补偿效应,为进一步揭示水氮双重胁迫后局部恢复供应条件下影响根系氮素吸收能力的因素以及玉米各器官氮素分配状况提供依据。【方法】采用分根技术,水培模拟局部根区水氮同时恢复供应,其中以聚乙二醇6000(PEG 6000)模拟营养液的渗透势,并用相应的供氮水平模拟氮素胁迫。试验设置4个水氮双重胁迫(也即4个局部恢复供应)处理:正常供应水氮、轻度水氮胁迫、中度水氮胁迫和重度水氮胁迫。双重胁迫6 d后一半根区恢复正常供应,于处理后0、1、3、5、7、9 d连续动态监测各根区根系氮素吸收速率、含氮量以及氮素累积量。【结果】水氮双重胁迫后局部恢复供应,持续胁迫区根系吸收速率、含氮量以及氮素累积量均显著小于恢复供应区(P<0.05)。1—3 d时,轻度和中度胁迫处理持续胁迫区根系氮素吸收速率比恢复供应区分别减小38.2%和48.7%;7—9 d时分别减小84.9%和86.4%。对于恢复供应区,局部水氮同时恢复供应1 d内,根系氮素吸收速率较前期胁迫明显增大,且在0—1 d和7—9 d时,经中度及其以下胁迫程度时,根系氮素吸收速率显著大于对照(P<0.05),产生根系氮素吸收能力的补偿效应,但3—7 d时消失。而且,恢复供应区根系含氮量和氮素累积量分别于1 d和5 d后恢复到对照水平,导致植株氮素生产效率最终与对照无显著差异。另外,各处理地上部氮素来自15N肥料的分配比例显著小于对照(P<0.05),且随胁迫程度而逐渐减小,恢复供应区根系则有相反的规律,持续胁迫区根系表现为,轻度胁迫与对照无明显差异(P>0.05),中度和重度胁迫显著大于对照和轻度胁迫(P<0.05),且3—9 d时,中度和重度胁迫间无明显差异(P>0.05)。【结论】前期中度以下程度(水分-0.4 MPa+氮素1 mmol·L【Objective】Water and nitrogen （N） resupplies can significantly enhance root absorbing capacity. Partial water and N supplies can stimulate the compensation effect of root absorbing capacity at the non-stressed sub-root zone. The objective of this study is to identify the dynamics and influencing factors of the compensation effect of maize roots （Zea mays L. hybrid cv. Aoyu No. 3007） N absorbing capacity under partial resupply after previous water and N stresses.【Method】With the split-root technology, a hydroponic experiment was conducted to analyze the root zone water and N stresses, where the water stress was stimulated by the osmotic potential of a nutrient solution （PEG 6000） and N stress was stimulated by different N levels. There were three water and N stress levels, i.e., mild, moderate, severe water and N stresses and a control treatment （CK, both sides of the root zone supplied with sufficient water and N）. The root N inflow rate, N content and accumulation of each root zone were measured at 0, 1, 3, 5, 7 and 9 d of resupplying water and N in half of root-zone 6 d after water and N stresses.【Result】Compared with non-stressed sub-root, the root N inflow rate, N content and accumulation in stressed sub-root were significantly decreased under partial resupply after water and N stresses. During 1-3 days after treatment （DAT）, the root N inflow rate in stressed sub-root reduced by 38.2% and 48.7%, respectively, and was 84.9% and 86.4% lower than that in non-stressed sub-root. For non-stressed sub-root, partial water and N resupplies significantly enhanced the root N inflow rate compared with previous water and N stresses during 0-1 DAT. When water and N stresses did not exceed moderate stress level, partial water and N resupplies significantly increased root N inflow rate compared with control treatment during 0-1 and 7-9 DAT. However, during 3-7 DAT, the root N inflow rate was similar to or lowers than control treatment. The root N content and accumulation in mild and moderate

关 键 词：局部恢复水氮供应 胁迫程度 局部恢复供应时间 根系氮素吸收速率 补偿效应 玉米 

分 类 号：S513[农业科学—作物学]