为研究外源苯肽胺酸对玉米幼苗抗低温的调控效应，以“郑单 958”为试材，设常温下喷施清水（CK）、常温下喷施苯肽胺酸（PA）、低温下喷施清水（LT）和低温下喷施苯肽胺酸（LT+PA）4个不同处理，低温处理7d后将玉米幼苗移入常温环境下恢复3d，测定各处理幼苗生长情况、细胞质膜透性、活性氧（ROS）、抗氧化酶活性和氮代谢相关指标。结果表明，低温胁迫下，幼苗叶片活性氧和丙二醛（MDA）含量显著增加，膜透性增大，胁迫前期会诱导酶促抗氧化防御系统活性增强，随胁迫时间延长，抗氧化酶活性均呈下降趋势；氮素吸收量逐步减少，氮代谢相关酶活性呈明显降低趋势；玉米幼苗生长受到严重抑制。叶面喷施苯肽胺酸可显著减少膜损伤来促进根系对NO3-的吸收和提高抗氧化酶活性，同时氮代谢关键酶活性的上升和GS/GOGAT代谢途径的正常运行在氮代谢中发挥积极作用，从而提高低温抗性，有效改善低温胁迫下玉米幼苗生长情况。

In order to study the regulation effect of exogenous N-phenyl-phthalamic acid on the resistance of maize seedlings to low temperature, we used "Zhengdan 958" maize variety as experimental material, set four different treatments: normal temperature water spraying (CK), normal temperature N-phenyl-phthalamic acid spraying (PA),??low temperature water spraying (LT) and low temperature N-phenyl-phthalamic acid spraying (LT+PA). After low temperature treatment for 7 days, the maize seedlings were moved to normal temperature environment to recover for 3 days. The growth, plasma membrane permeability, reactive oxygen species, antioxidant enzyme activity and nitrogen metabolism of seedlings were measured. The results showed that under low temperature stress, the content of reactive oxygen species (ROS) and malondialdehyde (MDA) in the leaves of seedlings increased significantly, and the membrane permeability increased. In the early stage of stress, the activity of antioxidant defense system was enhanced, and the activity of antioxidant enzyme decreased with the stress time.The nitrogen absorption decreased gradually, and the activities of enzymes related to nitrogen metabolism decreased significantly, and the growth of maize seedlings was severely inhibited. Foliar spraying of N-phenyl-phthalamic acid can significantly reduce membrane damage to promote the absorption of NO3- by roots and increase the activity of antioxidant enzymes. Meanwhile, the increase in the activity of key enzymes in nitrogen metabolism and the normal operation of GS/GOGAT metabolic pathway play a positive role in nitrogen metabolism, thus improving low temperature resistance and effectively improving the growth of maize seedlings under low temperature stress.

黑龙江省自然科学基金联合引导项目(LH2021C024)、东北农业大学“青年才俊”项目(20QC02)、农业部种子管理局“绿色品种特性鉴定评价专项 ” (111721301354052342)