南方稻茬小麦氮素高效利用的“光-苗-根-土”互馈调控机制

南方稻茬小麦因生态条件与土壤特性不同于北方旱茬小麦，氮肥施用量偏高、氮肥利用效率低是制约其持续安全高产的重要因子之一。本项目选择采用水培、土培、大田试验相结合的方法，筛选出近亲缘不同年代育成的小麦品种8-15个和氮效率差异显著的品种3-5个，并结合RTLs群体，探讨小麦根系硝态氮高亲和基因NRT的表达特征，揭示小麦氮素吸收差异的分子机理；设计不同耕种方式、不同氮肥种类试验，分析稻茬麦田土壤养分纵向与横向分布特征及其对根系形态建成、地上部形态的影响，重点明确根系构型、根系生理、地上部株型与氮高效吸收利用的关系；从光合功能、酶学、激素含量与平衡等方面阐明其影响稻茬小麦NUE的机理，从而明确稻茬小麦小麦氮营养高效吸收机理以及C/N平衡的响应机制，从"光-苗-根-土"系统提出稻茬小麦氮高效的实现途径与生理生化机理。

The high nitrogen application and low efficiency of nitrogen has been becomed the the key restricting nutrient element on wheat yield and its growing environment of rice-wheat system. The effects on NUE are studied using the different methods of hydroponics,soild culture and field treatment with 12 relative wheat varieties which were bred at different eras and 3 to 5 wheat varieties which have significant different nitrogen efficiency. Characterization of the expression of NRT in wheat root is also studied using RTLs group.Different farming methods and nitrogen fertilizers are used to study the distribution characteristics of soil nutrient and its relationship with the morphochoresis of roots and plant morphology. The mechanism of NUE was analyed based on photosynthetic function, enzymology, hormone balance and contents of hormones to highe N absorption efficiency mechanism of wheat of rice-wheat system and the response feature of C/N balance.