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以郑单958和丰单3号的3展叶期幼苗为材料,在人工气候室进行盆栽试验,研究4℃低温胁迫至幼苗死亡过程中叶片氮素代谢关键酶活的变化规律及聚糠萘水剂(PKN)的调控效应。结果表明,低温胁迫打破了氮素代谢平衡,致使氮素同化相关酶硝酸还原酶活性(NRA)、谷氨酰胺合成酶活性(GSA)和谷氨酸-草酰乙酸转移酶活性(GOTA)于胁迫初期升高,之后迅速下降,且GSA和GOTA降低比NRA提前2 d。随低温胁迫时间的延长,玉米幼苗受害加重,蛋白酶、肽酶活性增加,叶片可溶性蛋白与游离氨基酸含量升高。PKN处理提高了NRA、GSA、GOTA,降低了蛋白酶、肽酶活性,维持氮素代谢稳定,促进单株干物重增加,提高了玉米幼苗抗冷性。
Taking potted plants of Zhengdan 958 and Fengdan 3 as explants, the pot experiments were conducted in the artificial climate chamber to study the changes of the key enzyme activities of leaf nitrogen metabolism during the low temperature stress of 4 ℃ and the death of seedlings, Regulatory effect of water agent (PKN). The results showed that under low temperature stress, the balance of nitrogen metabolism was broken, and the activities of nitrate reductase (NRA), glutamine synthetase (GSA) and glutamate oxaloacetate transferase (GOTA) Stress increased early, then decreased rapidly, and GSA and GOTA decreased 2 d earlier than NRA. With the prolonging of cold stress time, the damage of corn seedling was aggravated, the activities of protease and peptidase increased, and the content of soluble protein and free amino acid in leaves increased. PKN treatment increased NRA, GSA and GOTA, reduced protease and peptidase activities, maintained stable nitrogen metabolism, increased dry matter weight per plant, and increased chilling tolerance of maize seedlings.