The cucumber cultivar Xintaimici of weak heat resistance was selected as material to investigate the effects of exogenous proline pretreatment on the growth, NO3-N and NH4+ -N contents and NR activity of cucumber seedling under high temperature stress with hydroponics in climate chambers. The results showed that compared with the water treatment, dry weight of cucumber seedlings, NO3-N content were significantly increased in proline pretreatment under high temperature stress ( P＜0. 05 ), and nitrate reductase activity in leaves of cucumber seedlings were also significantly increased in proline pretreatment under high temperature stress for 8 h and 12 h (P＜0. 05), while NH4+-N concentration decreased under high temperature stress for 12 h ( P＜0. 05 ). These indicated that exogenous proline could reduce the impact of high temperature on nitrogen metabolism of cucumber seedlings and alleviate injury of high temperature stress on cucumber seedlings.%以抗热性较弱的黄瓜品种新泰密刺为材料,在人工气候箱内采用营养液栽培法,探讨外源脯氨酸(Pro)预处理对高温胁迫下黄瓜幼苗生长、硝态氮(NO3--N)含量、铵态氮(NH4+-N)含量以及硝酸还原酶(NR)活性的影响.结果显示:与高温胁迫对照相比,喷施脯氨酸后高温胁迫处理黄瓜在高温胁迫不同时间下幼苗干重和幼苗叶片中硝态氮含量均显著升高,并且高温胁迫8 h、12 h的硝酸还原酶活性显著升高,而高温胁迫12 h的铵态氮含量则降低.表明外源脯氨酸可减缓高温胁迫对黄瓜幼苗氮代谢的影响,从而缓解高温胁迫对黄瓜幼苗的伤害.
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