不同氮效率小麦品种苗期根系氮代谢及其吸收能力差异分析

为了解不同氮效率小麦品种根系氮代谢特征及其吸收能力的差异,明确小麦氮高效利用的生理机制,在水培条件下,研究了氮高效小麦品种漯麦18和氮低效小麦品种西农509的根系氮代谢特征和对NO-3、NH+4吸收的动力学特征。结果表明,漯麦18的根系GS活性、硝酸还原酶活性、游离氨基酸含量、可溶性蛋白质含量均高于西农509;而西农509的根系硝态氮和铵态氮含量高于漯麦18;漯麦18根系对NO-3、NH+4吸收的最大吸收速率(Vmax)显著高于西农509;漯麦18根系对NO-3、NH+4的亲和力(以Km的倒数衡量)低于西农509。结果说明,氮高效型小麦品种根系对NO-3、NH+4的吸收能力和同化能力均显著高于氮低效型小麦品种;小麦根系对NO-3、NH+4的吸收和同化是相互促进的关系。

Analysis of Nitrogen Metabolism in Roots and Uptake Characteristic of Wheat Cultivars with Different Nitrogen Efficiency at Seedling Stage

In order to clarify the physiological mechanisms of higher nitrogen use efficiency of wheat,the difference of nitrogen metabolism in roots and uptake characteristics of wheat cultivars with different nitrogen efficiency were investigated.Under hydroponic conditions,the nitrogen metabolism in roots and uptake kinetics to NO^-₃ and NH⁺₄ of N high efficiency wheat variety Luomai 18 and N low efficiency wheat variety Xinong 509 were studied.The results showed that the GS activity,NR activity,free amino acids concentration and soluble protein concentration in root of Luomai 18 were higher than those of Xinong 509.But the nitrate concentration and ammonium concentration in root of Xinong 509 were higher than those of Luomai 18.The maximum absorption rate(V_max) to NO^-₃ and NH⁺₄ of Luomai 18 were higher than those of Xinong 509.But the affinity(1/K_m) of Xinong 509 was higher than that of Luomai 18.In conclusion,the root absorptive capacity to NO^-₃ and NH⁺₄ and assimilative capacity of Luomai 18 was significantly higher than that of Xinong 509.There is a mutually reinforcing relationship between wheat roots absorption and assimilation to NO^-₃ and NH⁺₄.