不同氮反应冬小麦品种幼苗素质及氮代谢关键酶活性的耐低氮差异研究

Difference of Low-Nitrogen Tolerance in Seedling Quality and Activity of Nitrogen Metabolism Related Key Enzymes between Nitrogen Responding Types of Winter Wheat Varieties

为了明确不同氮敏感型冬小麦品种的幼苗对低氮胁迫的反应,基于小麦籽粒产量和籽粒氮含量的耐低氮指数,对24个冬小麦品种进行了耐低氮丰产型和氮敏感型分类,并以典型品种为材料,比较了其幼苗(5叶龄)在不施氮(0)和施氮(16 mmol·L^(-1))条件下,地上部和根部的干物质积累量、氮含量、氮积累量及其叶片和根部的硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性。结果显示,与施氮处理相比较,不施氮处理小麦品种的幼苗根部干物质积累量、根冠比均增加,地上部干物质积累量、氮含量和氮积累量、根部氮含量和氮积累量以及NR和GS活性均降低。在不施氮处理下,耐低氮丰产型小麦品种的幼苗地上部干物质积累量的降幅小于氮敏感型品种,根部干物质积累量和根冠比的增幅均大于氮敏感型品种;耐低氮丰产型小麦品种幼苗总根长和总根表面积显著增加,根直径显著下降;氮敏感型小麦品种幼苗根直径和总根体积显著降低。与氮敏感型品种相比,耐低氮丰产型小麦品种幼苗地上部、根部的氮吸收能力较高,NR和GS两种酶活性降幅较小。

In order to clarify the response of winter wheat seedlings to low nitrogen stress,based on the low nitrogen tolerance index of wheat grain yield and grain nitrogen content,24 winter wheat varieties were classified into low nitrogen tolerant and high yield type and nitrogen sensitive type.The typical materials were further treated under the conditions of no nitrogen application(0)and nitrogen application(16 mmol·L^(-1)).The dry matter accumulation,nitrogen content,nitrogen accumulation and nitrate reductase(NR)and glutamine synthetase(GS)activities in leaves and roots were measured.The results showed that the dry matter accumulation in root and root-shoot ratio increased,while the dry matter accumulation,nitrogen content and nitrogen accumulation in shoot,nitrogen content and nitrogen accumulation in root,NR and GS activity decreased under no nitrogen treatment compared with those under nitrogen treatment.Under the conditions of no nitrogen treatment,the decrease of above ground dry matter accumulation of low nitrogen tolerant and high yield wheat varieties was less than that of nitrogen sensitive varieties,and the increase of root dry matter accumulation and root-shoot ratio was greater than that of nitrogen sensitive varieties.The total root length and total surface area increased significantly,while the root diameter decreased significantly.The root diameter and total root volume of nitrogen sensitive wheat seedlings decreased significantly.Compared with the nitrogen sensitive varieties,the nitrogen absorption capacity of the low nitrogen tolerant and high yield wheat varieties was higher,and the activities of NR and GS decreased less.