氮素营养对旱作小麦光合特性的调控

水分和氮素营养对小麦光合特性具有明显的调控作用，其中土壤水分状况直接影响到氮素营养的作用强度。氮素营养在不同土壤水分条件下对作物光合的影响不同，表现在叶片气体交换参数值、光合受抑部位及冠层结构等有所不同。在干旱条件下，光合速率主要受制于非气孔因素，此时氮素可加剧对叶绿体光合能力的抑制。作物生产上的施肥与耕作等措施都应适宜于当时的田间水分状况，这样才能充分协调作物与环境的关系，使作物光合机构运转处于较高水平，以实现合理利用水肥资源和增加产量的目的。

REGULATION OF NITROGEN NUTRITION ON PHOTOSYNTHETIC CHARACTERISTICS OF WINTER WHEAT ON DRYLAND

The regulation of nitrogen nutrition on photosynthetic characteristics of winter wheat were studied under dryland condition. The results showed that soil water and nitrogen nutrition can markable improved the photosynthetic characteristics of winter wheat and the regulatre capability of nitrogen nutrition was influenced by soil water status. The effects of nitrogen nutrition on wheat gas exchange parameters and the limited factors to photosynthesis and canopy structure parameters were not identical under different soil water status, such as, under soil drought, photosynthetic rate decrease mainly resulted from mesophyll factor, at the same time, nitrogen nutrition can intensity the inhibition of the activities of photosynthetic apparatus. According to the soil water status, enriching the nitrogen can benefit to fully coordinate the relationship between crop and environment, and can maintain the high level of photosynthesys, to increase the soil water use efficiency and benefit of nitrogen nutrition, and so to get high crop yield.