模拟氮沉降对两种草地植物氮同化物积累的影响

Effects of simulated nitrogen deposition on accumulation of nitrogen assimilation of grassland plants

为了揭示大气氮沉降对栽培草地植物氮同化物积累的影响,本试验以无芒雀麦(Bromus inermis)和白三叶(Trifolium repens)为对象,通过人工增氮试验(浓度设置为0、6、12和24g N.m-2.a-1)来研究豆科和禾本科牧草的氮同化物积累的变化规律。结果表明,在不同氮浓度处理下,叶绿素、叶全氮、可溶性蛋白、精氨酸和脯氨酸等氮同化物含量变化极显著(P<0.01),在氮沉降浓度为12g N.m-2.a-1范围内随氮沉降浓度增加而呈增加趋势(除脯氨酸含量),但是两种牧草氮同化物的积累量差异较大,氮沉降对禾本科牧草的氮同化物积累的影响高于豆科牧草。精氨酸含量与氮沉降浓度间存在极显著正相关(R2均达到0.99),因此,精氨酸可作为草本植物对氮沉降增加的敏感指标。

This research aimed to reveal impacts of atmospheric nitrogen deposition on artificial grassland plants.Bromus inermis and Trifolium repens plants were treated with 0（CK）,6 g N·m-2·a-1（low N）,12 g N·m-2·a-1（medium N） and 24 g N·m-2·a-1（high N） to explore the effects of simulated nitrogen deposition on accumulation of partial nitrogen assimilation.The results indicated that nitrogen deposition significantly affected the accumulation of nitrogen assimilation（P0.01）,and nitrogen addition at all levels affected contents of chlorophyll,leaf nitrogen,Arg and soluble protein of B.inermis and T.repens plants.All of these contents except for the proline content ascended as increasing of nitrogen concentration until the concentration reached 12 g N·m-2·a-1.However,effects of nitrogen deposition on accumulation of nitrogen assimilation were different between B.inermis and T.repens,and the influence on grasses was higher than that on legumes.There was a significant positive correlation bewteen Arg content and concentration of N deposition（R2=0.99）.Arg content could be used as a sensitive indicator for nitrogen deposition of herb plants.