中文摘要：

以不同耐旱型棉花品种＂新陆早7号＂和＂新陆早24号＂幼苗为试材,研究持续干旱胁迫及复水对棉花幼苗根系氮代谢关键酶活性、可溶性蛋白质、总氮和游离氨基酸含量的影响。结果显示：随着干旱胁迫天数的增加,＂新陆早7号＂和＂新陆早24号＂硝酸还原酶（NR）活性与对照相比分别降低45.03%和62.37%,谷氨酰胺合成酶（GS）活性分别降低53.22%和67.23%,谷氨酸合成酶（GOGAT）活性分别降低54.92%和79.28%,谷氨酸脱氢酶（GDH）活性在处理4d达到最大值,5d时下降,可溶性蛋白质含量分别增加了87.38%和77.12%,总氮含量分别增加了14.01%和12.14%,铵离子含量分别增加了232.02%和263.47%。干旱胁迫使＂新陆早7号＂在胁迫前期游离氨基酸含量增加慢,后期增加快,＂新陆早24号＂游离氨基酸含量的变化趋势与＂新陆早7号＂则相反。复水后,＂新陆早7号＂NR活性、GS活性、GOGAT活性和GDH活性恢复较快,内肽酶活性和游离氨基酸、铵离子、可溶性蛋白质和总氮含量下降也较快。试验表明,耐旱型棉花品种具有较强的铵离子同化能力,可增加渗透调节物质游离氨基酸含量,特别是脯氨酸含量,有助于增强其耐旱性。

英文摘要：

Using two kinds of cotton of different drought resistance as material,some indexes were invested under progressive drought and re-watering treatment,including nitrogen metabolism key enzyme activities,soluble proteins,total nitrogen and free amino acids contents.Results showed that under progressive drought treatment,the activity of nitrate reductase（NR）,glutamine synthetase（GS） and glutamate synthetase（GOGAT） all decreased in two kinds of cotton roots.After 5 d treatment,NR activity decreased 45.03% and 62.37%,respectively,GS activity decreased 53.22% and 67.23%,respectively,GOGAT decreased 54.92% and 79.28%,respectively,the activity of glutamate dehydrogenase（GDH） reached maximum value on the fourth day,and it decreased on the fifth day,in Xinluzao-7 and Xinluzao-24-root,compared with control,respectively.Under drought stress treatment,four indexes increased in two kinds of cotton roots,including total nitrogen content,soluble proteins,ammonium content and free amino acids content.After 5 d treatment,total nitrogen content increased 14.01% and 12.14%,soluble proteins for 87.38% and 77.12%,ammonium content for 233.02% and 263.47% in Xinluzao-7 and Xinluzao-24-root,compared with control,respectively.The free amino acids content increased slowly during the early stage of drought treatment,then increased rapidly during the latter stage of drought treatment in Xinluzao-7,while the situation was just opposite in Xinluzao-24.After re-watering treatment,four indexes recovered more rapidly,including NR activity,GS activity,GOGAT activity and GDH;but the other four indexes decreased more rapidly,including endopeptidase activity,free amino acids content,soluble proteins and total nitrogen content in Xinluzao-7 than Xinluzao-24.These results suggested drought-resistant type cotton had strong assimilative capacity of ammonium,so it could increased osmotic adjusted substance,especially proline,thus it could improve its drought resistance.