低温胁迫下丛枝菌根真菌对玉米幼苗氮代谢的作用

摘要

旨在了解菌根真菌参与宿主抗寒的潜在作用，为开发生物肥料，推动农业可持续发展提供参考。利用盆栽试验，研究了低温胁迫下丛枝菌根（ AM）真菌接种处理对玉米生物量、总氮、硝态氮、铵态氮、蛋白和氨基酸合成及氮代谢相关酶活性的影响。研究结果显示，低温胁迫下对比未接种处理，接种AM真菌提高玉米地上生物量。低温胁迫降低了玉米叶片总氮、硝态氮和可溶性蛋白的含量以及根部总氮含量，增加了叶片铵态氮的含量和根部可溶性蛋白含量。接种AM真菌均能增加玉米幼苗单位质量叶片的总氮、硝态氮和可溶性蛋白的含量。常温下，接种AM真菌能够增加玉米叶片铵态氮浓度，而低温下，接种AM真菌却降低玉米叶片铵态氮浓度。低温处理均降低玉米根部所有氨基酸和总氨基酸含量；接种AM真菌均增加玉米根部所有氨基酸和总氨基酸含量。 AM真菌接种和温度均显著影响玉米硝酸还原酶和谷丙转氨酶活性，而谷氨酰胺合成酶活性仅被温度影响，谷草转氨酶活性仅受AM真菌接种处理影响。研究结果表明，低温对玉米幼苗的生长和氮吸收代谢造成严重伤害；低温胁迫下，接种AM真菌能够通过自身的氮吸收运输，改善玉米生理生长及玉米氮吸收代谢酶活性，保护低温下玉米氮吸收代谢系统，增强玉米幼苗的低温抗寒能力。%We aimed to reveal the potential effects of AM fungi on low temperature resistance of host plants , and provide reference for developing biological fertilizer and promoting agricultural sustainable development .Using pot experiment,the influences of AMF inoculation to biomass,total nitrogen(N),NO3--N,NH4+-N,protein,amino acid and relative N metabolism enzyme of maize seedlings were studied under low temperature stress .Study results showed that AMF inoculation increased aboveground biomass of maize seedlings compared with non -inoculation treatment under low temperature .Low temperature stress decreased total N ,NO3--N and soluble protein content of maize leaf,and total N content of maize root ,but increased NH 4+-N content of maize leaf and soluble protein content of maize root.AMF inoculation could increase total N ,NO3--N and soluble protein content of unit mass maize leaf . At ambient temperature ,AMF inoculation could increase NH 4+-N concentration of maize leaf ,however at low temper-ature ,AMF inoculation decreased NH 4+-N concentration of maize leaf .Low temperature decreased each amino acid and total amino acid content of maize root ,AMF inoculation increased each amino acid and total amino acid content of maize root .Both AMF inoculation and temperature significantly impacted NR and GPT activity ,however ,GS ac-tivity only significantly was impacted by temperature ,GOT activity only was impacted by AMF inoculation .Study re-sults showed that low temperature intensely damaged the growth and N absorption metabolism of maize seedling .Un-der low temperature stress ,AMF inoculation could improve physiological growth and N absorption metabolism en-zyme activity of maize through personal N absorption and transportation ,and further to increase low temperature re-sistance of maize seedlings .