氮素对紫花苜蓿根茎叶氮含量及硝酸还原酶活性的影响  

Effects of nitrogen on nitrogen content and nitrate reductase activity in root stem and leaf of alfalfa

作　　者：于铁峰[1] 刘晓静[1] 张晓玲[1] 郝凤[1] 

机构地区：[1]甘肃农业大学草业学院/草业生态系统教育部重点实验室/甘肃省草业工程实验室/中-美草地畜牧业可持续发展研究中心,甘肃兰州730070

出　　处：《草原与草坪》2017年第5期14-20,共7页Grassland and Turf

基　　金：公益性行业(农业)科研专项(201403048-8);国家自然科学基金项目(31460622);甘肃省科技支撑项目(1504NKCA003)资助

摘　　要：采用营养液砂培方法进行室内盆栽试验,以紫花苜蓿品种甘农3号(Medicago sativa cv.Gannong No.3)和陇东苜蓿(Medicago sativa cv.Longdong)为材料,比较研究了2种氮素形态(铵态氮、硝态氮)和5个氮素水平(0、105、210、315、420 mg/L)对现蕾期紫花苜蓿各部位氮含量及硝酸还原酶活性(NR)的影响。结果表明:2种氮素形态均能显著提高紫花苜蓿根茎叶中硝态氮含量,铵态氮含量、全氮含量及硝酸还原酶活性,且随着氮水平的提高呈先增大后减小的趋势,在210 mg/L处理达峰值。从氮素形态分析,铵态氮肥有利于铵态氮含量的增加,且根茎叶中铵态氮含量、全氮含量在铵态氮210 mg/L处理达到最大值,且显著高于其他处理;硝态氮肥有利于硝态氮含量的增加,且根茎叶中硝态氮含量、硝酸还原酶活性(NR)在硝态氮210 mg/L处理达到最大值,且显著高于其他处理。各部位中,相同氮素形态下,根茎叶中铵态氮含量、硝态氮含量、全氮含量及NR活性均表现为叶片>根部>茎部,且甘农3号表现优于陇东苜蓿。基于经济效益和生态效益考虑,铵态氮210 mg/L是培养紫花苜蓿较好的形态和水平。The nitrogen content and nitrate reductase activity（ NR） in alfalfa organs were studied based on 2 nitrogen forms（ nitrate nitrogen and ammonium nitrogen） and 5 nitrogen levels（ 0,105,210,315,420 mg/L）.Two cultivars,Medicago sativa cv.Gannong No.3 and Medicago sativa cv.Longdong,were selected as materials at squaring stage,and the experiment was conducted outdoors（ in flashing net room） using sand culture method.The results showed that the content of NO3^--N,the content of NH4^＋-N and total nitrogen content in root and stem and leaf of alfalfa under two nitrogen treatments were significantly higher（ P0.05）,and showed a trend of increased first and then decreased with the increase of nitrogen level,peaked at 210 mg/L.The content of NO3^--N,the content of NH4^＋-N and total nitrogen content in root,stem and leaf of alfalfa under 2 nitrogen treatments were significantly higher（ P0.05）,and showed a trend of increased first and then decreased with the increase of nitrogen level,peaked at 210 mg/L. NH4^＋-N was beneficial to content of NH4^＋-N,The content of NH4^＋-N and total nitrogen content reached peak and significantly higher than other treatments（ P〈 0.05） at the NH4^＋-210; The content of NO3^--N and the nitrate reductase activity reached peak and significantly higher than other treatments（ P〈0.05） at the NO3^--210; Analysis of organ,the maximum of the contents of ammonium nitrogen,nitrate nitrogen,total nitrogen and NR were found at leaves,minimum in stem under the same nitrogen form,and Gannong No.3 was better than that of Longdong.Based on the economic benefit and ecological benefit,the NH4^＋-210 was better.

关 键 词：铵态氮 硝态氮 紫花苜蓿 硝酸还原酶活性 

分 类 号：S541.9[农业科学—作物学]