不同氮肥施用量对阴山北麓饲用燕麦抗氧化酶活性的影响

目的] 探讨内蒙古阴山北麓饲用燕麦抗氧化酶活性对氮肥的生理响应及差异变化,研究适宜的施氮量。方法] 以饲用燕麦（Avena sativa）“三星”为材料,设置0、150、200、250、300、350 kg/hm²施氮水平,在苗期、分蘖期、拔节期、孕穗期分别追施氮肥用量的15%、35%、30%和20%,于孕穗期、抽穗期、灌浆期测定分析饲用燕麦叶片中3种抗氧化酶活性及丙二醛（MDA）含量。结果] 随着施氮量的增加,孕穗期、抽穗期和灌浆期饲用燕麦叶片的超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性呈现先增加后降低的趋势,MDA的含量逐渐降低。3个时期的饲用燕麦叶片POD活性均在施氮水平为250 kg/hm²时最高;孕穗期和灌浆期的饲用燕麦叶片SOD活性在施氮水平为250 kg/hm²时最高;孕穗期和抽穗期饲用燕麦叶片CAT活性在施氮水平为300 kg/hm²时最高,灌浆期CAT活性在施氮水平为250 kg/hm²时最高。结论] 内蒙古阴山北麓施氮肥对饲用燕麦抗氧化酶活性的影响为低氮促进、高氮抑制,适宜施氮量为250 kg/hm²。

Effects of Different Nitrogen Fertilizer Application Rates on Activities of Antioxidant Enzymes in Feed Oat（Avena sativa）at the Northern Foot of Yinshan Mountain

Objective] To assess the physiological response and differential changes of the activities of antioxidant enzymes in feed oat （Avena sativa） to nitrogen fertilizer at the northern foot of Yinshan Mountain, and to determine the optimal nitrogen fertilizer application rate. Method] Using feed oat species ′Sanxing′ as the material, the nitrogen fertilizer application rates of 0, 150, 200, 250, 300 and 350 kg/hm² were set, and additional 15%, 35%, 30%, and 20% of the nitrogen fertilizer was applied at seedling stage, tillering stage, jointing stage, and booting stage for each nitrogen fertilizer application rate, respectively. The activities of three types of antioxidant enzymes and the level of malondialdehyde （MDA） in feed oat leaves were evaluated at booting stage, heading stage and grain filling stage. Result] As the increase of nitrogen fertilizer application rates, the activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） in feed oat leaves at booting stage, heading stage, and grain filling stage increased first and then declined, and the level of MDA reduced progressively. At all of the three observed growth stages, the highest POD activity in feed oat leaves was found at the nitrogen fertilizer application rate of 250 kg/hm². At booting stage and grain filling stage, feed oat leaves had the highest SOD activity at the nitrogen fertilizer application rate of 250 kg/hm². The highest CAT activity was observed at the nitrogen fertilizer application rate of 300 kg/hm² at booting stage and heading stage, and at grain filling stage, that was observed at the nitrogen fertilizer application rate of 250 kg/hm². Conclusion] At the northern foot of Yinshan Mountain, lower application rate of nitrogen fertilizer enhances the activities of antioxidant enzymes in feed oat, and higher rate exerts the reverse effect. The appropriate nitrogen fertilizer application rate is 250 kg/hm².