低氮胁迫下不同小麦品种苗期性状差异分类研究

Study on differential classification of different wheat varieties at seedling stage under low nitrogen stress

筛选耐低氮能力强的小麦基因型并应用于大田生产是提高小麦氮素利用效率的有效途径之一。选用来自不同省份的57个小麦品种,研究水培低氮胁迫条件下苗期不同性状的变化特征,分类比较不同性状的耐低氮指数差异。结果表明:茎叶和根系的硝态氮与铵态氮含量及积累量、地上部干重、根冠比变异系数均大于20%,地上部干重耐低氮指数变异范围为0.56~1.45,变异系数为22.99%,品种间差异极显著。根据植株地上部干重耐低氮指数差异,将品种分为3种类型,分别为耐低氮品种、中度耐低氮品种和低氮敏感品种,其中地上部干重、地上部与根系的氮含量与积累量均表现为耐低氮型品种依次高于中度耐低氮型品种、低氮敏感型品种;地上部与根系的含氮量耐低氮指数、根系干重及其耐低氮指数类型间差异不显著。该研究还讨论了植株地上部干重耐低氮指数分类指标界值(0.7和0.9)应用于品种耐低氮特性早期分类研究的价值。

To improve nitrogen use efficiency(NUE) in wheat, one of the most effective strategy is to screen wheat genotypes that tolerate low-nitrogen condition with high NUE. In this study, 57 wheat varieties were selected in wheat production provinces in the middle and lower reaches of the Yangtze River. The characteristics of the different traits in seedling stage under low-nitrogen stress were investigated using the hydroponics. The results showed that the coefficients of variation of the content and accumulation of nitrate and organic nitrogen(including stems, leaves and roots), the dry weight of shoots, and root-shoot ratio were all over 20%. The low-nitrogen tolerance index could reflect the difference in the nitrogen uptake capacity of shoots and roots among the different genotypes. According to the difference of the above-ground dry weight of plants with low nitrogen tolerance index(LNTI) the varieties were divided into three types: low-nitrogen tolerant, moderate low-nitrogen-tolerant and low-nitrogen sensitive varieties. Under low nitrogen stress, the dry weight of shoots and the nitrogen of shoots and roots were in the order as follows: low-nitrogen-tolerant varieties> moderate low-nitrogen-tolerant varieties> low-nitrogen-sensitive varieties. The dry weight of shoots and the accumulation of nitrogen in the shoots and roots were in the order as follows: low-nitrogen-tolerant varieties> moderate low-nitrogen-tolerant varieties> moderate low-nitrogen-tolerant varieties> low-nitrogen sensitive varieties.The nitrogen content of shoots and roots had no significant difference in low-nitrogen tolerance index,root dry weight and low-nitrogen tolerance index types.It can be concluded that it is appropriate to classify low-nitrogen tolerance characteristics through a relatively fixed above-ground dry weight index classification(0.7 and 0.9).