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探讨黄瓜叶片氮代谢关键酶类活性与果实氮化物含量的相互关系,为黄瓜氮素的高效利用和品质优化提供依据。采用二因素裂区设计,研究了氮肥用量对黄瓜叶片氮代谢酶活性和结果盛期果实氮化物含量的影响。结果表明:在225~375 kg/hm~2施氮情况下,随施氮量增加功能叶片硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸草酰乙酸转氨酶(GOT)和谷氨酸丙酮酸转氨酶(GPT)的活性逐渐升高,处理间差异显著,施氮量超过375 kg/hm~2其酶活性增加不明显且有下降的趋势。不同品种间酶活性大小依次为津优35号、园丰元6号、永昌9618,博特202,其中津优35号与园丰元6号酶活性差异不显著,与永昌9618和博特202差异显著。果实中氮化物的含量随施氮量的增加逐渐提高;施氮量为375 kg/hm~2时游离氨基酸、可溶性蛋白及粗蛋白含量达到最大值;增加到450 kg/hm~2时3种氮化物含量均下降,而硝酸盐含量持续增加;在525 kg/hm~2时含量最高,津优35号硝酸盐和游离氨基酸含量最低,可溶性蛋白和粗蛋白含量最高,博特202与之相反。相关分析表明,果实中硝酸盐含量与NR和GS活性呈显著正相关关系,与GPT和GOT无显著相关关系;可溶性蛋白和粗蛋白含量与4种酶类存在显著或极显著正相关关系。不同品种间果实氮化物的差异是氮素吸收同化综合作用的结果。选择氮素吸收同化能力强的品种,既有利于提高氮素利用,又可改善产品质量。
The relationship between the key enzyme activity of nitrogen metabolism and the content of nitrogen in fruit was studied to provide the basis for efficient use and quality optimization of cucumber. A two-factor split design was used to study the effect of nitrogen fertilizer on the activities of nitrogen metabolism enzymes in cucumber leaves and the fruit nitrogen content in the peak. The results showed that nitrate reductase (NR), glutamine synthetase (GS), glutamate oxaloacetate aminotransferase (GOT) And glutamate pyruvate aminotransferase (GPT) activity gradually increased, the difference was significant between the treatments, the nitrogen rate of more than 375 kg / hm ~ 2 its enzyme activity increased slightly and decreased. The enzyme activities of different cultivars were as follows: Jinyou 35, Yuanfengyuan 6, Yongchang 9618 and Bot 202, among which the enzyme activities of Jinyou 35 and Yuanfengyuan 6 were not significantly different from those of Yongchang 9618 and Bot 202 Significant. The content of nitrides in fruit increased with the increase of nitrogen application rate. When the amount of nitrogen was 375 kg / hm ~ 2, the contents of free amino acids, soluble protein and crude protein reached the maximum value. When the nitrogen content increased to 450 kg / hm ~ 2, Nitrate content decreased while nitrate content continued to increase. The content of nitrate and free amino acid was the lowest at 525 kg / hm ~ 2, while the highest was soluble protein and crude protein . Correlation analysis showed that there was a significant positive correlation between nitrate content and NR and GS activity and no significant correlation between nitrate content and GPT and GOT. Soluble protein and crude protein content had significant or extremely significant positive correlation with four kinds of enzymes. The differences of nitrogen compounds in different varieties are the result of nitrogen absorption and assimilation. Select varieties of nitrogen absorption and assimilation ability, both conducive to improving nitrogen utilization, but also improve product quality.