模拟酸雨对杜仲叶氮代谢的影响

 探讨了春夏两季模拟酸雨对杜仲(Eucommia ulmoides Oliv.)叶氮代谢的几个关键酶及相关物质含量的影响。结果表明：春夏两季杜仲叶硝酸还原酶(NR)、谷酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)和谷丙转氨酶(GPT)活性在一定pH值酸雨胁迫下随酸雨pH值的降低而降低，夏季各酶活性下降率比春季高。杜仲叶可溶性蛋白质和总氮含量春夏两季也随酸雨pH值降低而降低(夏季可溶性蛋白含量与pH值呈正相关)，总游离氨基酸含量则随pH值的降低而升高(二者呈负相关)。由此可见，酸雨对杜仲叶氮代谢产生了显著影响。

THE EFFECTS OF SIMULATED ACID RAIN ON NITROGEN METABOLISM OF EUCOMMIA ULMOIDES LEAVES

The effects of simulated acid rain on important N-metabolism enzymes and correlated substances were studied by treating spring and summer leaves of Eucommia ulmoides to simulated rain with varying pH levels. In both seasons it was found that below a threshold value of pH the activities of nitrate reductase (NR), glutamine synthetase (GS), glutamate dehydrogenase (GDH) and glutamic-pyruvic transaminase (GPT) declined with decreasing pH, though the rate of decrease of these enzymes were higher in the summer. It was also found that soluble protein and total nitrogen content decreased with decreasing pH of acid rain. Total free amino acid content was negatively correlated with pH in both seasons. We conclude from these results that simulated acid rain had significant effects on N-metabolism of Eucommia ulmoides leaves.