碳水化合物的分配在玉米杂交种耐低氮中的作用

探明玉米耐低氮的生理机制有利于促进氮高效遗传改良的进度.本试验选用对氮反应有典型差异的两个玉米杂交种西玉3号和高光效1号,采用盆栽试验,设3个氮水平,探讨了苗期玉米对低氮环境的适应性机制,结果表明:两品种在高低氮条件下的地上部干物重差异都不显著,但冠/根比存在显著差异.在低氮下西玉3号的根长、根表面积及根重增加幅度大,超过高光效1号,因而它具有较强的截获氮素养分的能力,以适应低氮环境.低氮下西玉3号有较大的叶面积,可产生大量的光合产物.其叶片光合产生的可溶性糖向根系的大量运输,即有利于根系生长,又可以为氮的吸收同化提供充足的能量和碳架。

Role of Carbohydrate Partitioning in Tolerance to Low Nitrogen of Maize Hybrids

Physiological knowledge on tolerance to low nitrogen (N) may help facilitate the improvement of N use efficiency (NUE) in maize by breeding In the present study, two hybrids with different response to low N were chosen to investigate the physiological mechanism of maize's tolerance to low N at seedling stage by pot experiment with 3 N levels No difference in above-ground biomass was found between the two genotypes However, N-efficient Xi yu 3 had higher rootshoot ratio (R/S) than the inefficient Hi-Pn 1 Xiyu 3 got longer heavier roots, larger root surface area which was beneficial for absorbing N from low N environment Xi yu 3 had larger leaf area and higher soluble sugar concentration in both shoot and root, indicating that it had higher photosynthesis activity which could be important for enhancing root growth as well as providing energy and carbon skeleton for N uptake and assimilation