缺镁胁迫对龙眼苗期氮代谢的影响

Effect of magnesium deficiency on nitrogen metabolism of longan (Dimocarpus longana Lour) seedlings

采用溶液培养方法研究了缺镁胁迫对龙眼苗期氮代谢的影响。结果表明 ,缺镁胁迫下 ,龙眼叶片硝酸还原酶 (NR)活性下降 ,游离氨基酸总量增加 ,水解氨基酸总量减少 ,蛋白质合成受阻而分解加剧 ;核酸酶 (RNase)活性提高 ,核糖核酸 (RNA)、脱氧核糖核酸 (DNA)含量降低 ,缺镁对RNA的影响比DNA大 ;活性氧 (O2 ·-)净产生速率增加。统计分析表明 ,缺镁胁迫下 ,龙眼核酸和蛋白质含量下降是其合成受阻。

The effect of magnesium deficiency on nitrogen metabolism of longan (Dimocarpus Longana Lour) seedlings was studied using solution culture In leaves with Mg deficient , the activity of nitrate reductase,the total amount of hydrolytic amino acids decreased,whereas the total amount of free amino acids increased.With the increase in severity of Mg deficiency,the activities of RNase and protease in leaves increased markedly.As a result, the degradation of RNA and protein were promoted and their contents reduced; the content of DNA,to a less extent than RNA, also declined.Furthermore, the net rate of O 2 ·- generation increased in Mg deficiency leaves Statistics analysis showed that the decrease of nucleic acid and protein in Mg deficient longan leaves were the comprehensive results of synthesis retardation, degradation aggravation and active oxygen stress.