植物营养与肥料学报2010,16(6)：1299-1305 Plant Nutrition and Fertilizer Science
不同氮素形态下小麦叶片光合气体交换参数
对蒸汽压亏缺的反应李秧秧，张萍萍2，赵丽敏2，邵明安
（1西北农林科技大学水土保持研究所，黄土高原土壤侵蚀与旱地农业国家重点实验室，陕西杨凌712100；
2西北农林科技大学资源环境学院，陕西杨凌712100）
摘要：利用溶液培养试验，研究了不同氢素形态下小麦叶片光合气体交换参数对蒸汽压亏缺（VPD）的反应，以揭示不同氮索形态影响水分利用效率（WUE)的生理机制。结果表明：铵态氮处理显著降低了小麦的叶面积和根长，提高了小麦的瞬时和长期水分利用效率。不同氮素形态下，叶片光合气体交换参数对蒸汽压亏缺的反应不同。随 VPD增加，确态氮处理的净光合速率尤变化，但铵态氮和硝酸铵处理的净光合速率则明显下降。所有处理的叶片气孔导度均随VPD增加而下降，其中硝态氮和硝酸铵处理的下降幅度明显高于铵态氮处理。硝态氮和硝酸铵处理的细胞间隙CO，浓度也随VPD增加面下降，但铵态氮处理未发生变化。所有氮处理的蒸腾速率均随VPD增加呈现出二次抛物线变化，叶水势并未随VPD增加发生变化，表明气孔对VPD的反应符合前馈机制。3个处理的瞬时
WUE均随VPD增加而下降，高VPD下铵态氮引起小麦叶片气孔的关闭是其WUE提高的重要原因之-关键调：小麦：氮索形态；光合气体交换；蒸汽压亏缺
中图分类号：S512.1.01
文献标识码：A
文章编号：1008-505X(2010)061299-07
Responses of leaf photosynthetic gas exchange parameters to vapor pressure
deficitinwheatunderdifferentnitrogenforms LI Yang-yang", ZHANG Ping-ping",ZHAO Li-min’, SHAO Ming-an
(I State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,
Institute of Soil and Water Conservation, Northwest A &F Uninersity,Yangling,Shaanxi 712100, China; 2 College of Resourees and Environment, Northwest A &F Uninersity, Yangling, Shaanxi 712100, China)
Abstract: Aimed to examine the mechanism of nitrogen forms affecting water use efficiency (WUE), a hydroponic experiment was conducted to study the responses of leaf photosynthetic gas exchange parameters to vapor pressure deficit (VPD) in wheat. Results indicated that ammonium nitrogen decreased leaf area and root length, while increased instantaneous and long-term WUE significantly. The responses of photosynthetic gas exchange parameters to VPD were inconsistent under different N forms. With the increase of VPD, net photosynthetic rate (P,) was kept consistent with the presence of nitrate nitrogen, while it decreased with the presence of the other two N forms. A declination of stomatal conductance (G,) of all treatments with the increasing VPD was observed, with a more remarkable decrease for the treatments of nitrate nitrogen and ammonium nitrate than ammonium nitrogen treatment. Intercellular CO, concentration of (C,) under both nitrate nitrogen and ammonium nitrate treatment decreased with the increasing of VPD while it keep constant under ammonium nitrogen treatment. Transpiration rate (T,) was qua+ dratically related with VPD, and leaf water potential did not change with VPD, indicating a feed forward mechanism of stomatal response to VPD. Instantaneous WUE decreased with the increasing of VPD for all treatments. The closure of stomata with the presence of ammonium nitrogen under high VPD might be one domain reason resulting in a higher WUE.
收稿日期：2010-01-05
接受日期：2010-04-15
基金项目：中科院创新团队国际合作伙伴计划项目；黄土高原土壤侵蚀与早地农业国家重点实验室专项经费资助。
作者简介：李秧秧（1968一），女，陕西成阳人，研充员，主要从事植物水分与养分生理生态方面的研究工作。E-mail：yli@m。万方数据