咪唑乙烟酸对大豆根瘤固氮酶和硝酸还原酶活性的影响

【目的】明确咪唑乙烟酸对大豆根瘤固氮酶及硝酸还原酶活性的影响,为正确评价咪唑乙烟酸施用后对大豆氮代谢的影响提供依据。【方法】采用田间试验方法研究咪唑乙烟酸土壤和茎叶处理后对大豆根瘤固氮酶和硝酸还原酶活性的影响。【结果】咪唑乙烟酸土壤和茎叶处理对大豆根瘤固氮酶活性均具有显著的抑制作用。土壤处理后随着时间的延长,对根瘤固氮酶活性的抑制作用增强,至75d咪唑乙烟酸62.5,125和250ga.i.·hm-2用量下,根瘤固氮酶活性分别降低0.2186,0.2198和0.2471mmolC2H4·g-1·h-1。茎叶处理后随着时间的延长对固氮酶活性的抑制作用减小,至38d咪唑乙烟酸62.5和125ga.i.·hm-2用量下,根瘤固氮酶活性分别降低0.1778和0.2177mmolC2H4·g-1·h-1。根系硝酸还原酶活性在咪唑乙烟酸土壤和茎叶处理后受到显著的抑制作用,表现为先增高后降低。叶片硝酸还原酶活性在咪唑乙烟酸茎叶处理后30d内受到较强的抑制作用,而土壤处理后的75d,叶片硝酸还原酶只有在咪唑乙烟酸250ga.i.·hm-2时酶活性才受到显著抑制。【结论】咪唑乙烟酸土壤和茎叶处理使大豆根瘤固氮酶活性和硝酸还原酶活性显著降低,对大豆氮代谢具有显著的抑制作用。

Effect of Imazethapyr on Nodule Nitrogenase and Nitrate Reductase Activity in Soybean

【Objective】 To determine the effects of imazethapyr on nitrogenase and nitrate reductase activity in soybean and give evidence to assess the influence on nitrogen metabolism correctly after herbicide application. 【Method】 A field experiment was conducted to study the effects of imazethapyr on nitrogenase and nitrate reductase activity (NRA) after imazethapyr preemergence and postemergence applied. 【Result】 Nitrogenase was significantly reduced by imazethapyr in both treatments of preemergence and postemergence application. Although the reduction of nitrogenase activity was increased with time prolonging after imazethapyr preemergence, the nitrogenase activity was still reduced by 0.2186, 0.2198 and 0.2471 mmolC2H4?g-1?h-1 when imazethapyr was applied at 62.5, 125 and 250 ga.i.?hm-2 75 days after treatment. The reduction of nitrogenase activity was gradually decreased as time goes on after application of imazethapyr postemergence and 38 days after treatment, the nitrogenase activity was reduced by 0.1778 and 0.2177 mmolC2H4?g-1?h-1 at the application rates of 62.5 and 125 ga.i.?hm-2. Root NRA was significantly decreased after application of imazethapyr preemergence and postemergence and the reduced NRA gradually increased over time regardless imazethapyr application rate and application methods. Leaf NRA was strongly reduced within 30 days after application of imazethapyr postemergence. Leaf NRA was significantly reduced only at the application rate of 250 ga.i.?hm-2 75 days after preemergence application. 【Conclusion】 Nodule nitrogenase, root and leaf NRA were significantly reduced after application of imazethapyr preemergence and they have significant effect on inhibition of nitrogen metabolism of soybean.