关键词: 葡萄, 氮代谢酶, 水氮胁迫, 氮含量, 最佳施氮量

Abstract: In order to study the effect of water and nitrogen coupling on nitrogen metabolism of grape leaves at seedling stage and the formulation of optimal nitrogen application, the annual "Hongti" grape was used as the research material. A comprehensive design of four levels of water and nitrogen in the greenhouse was used to carry out the experiment under the artificial environment control method. The water treatments were as follows: normal irrigation W1 (70%−80% of maximum water capacity in the field), mild stress W2 (60%−70%), moderate stress W3 (50%−60%) and severe stress (30%−40%).The levels of nitrogen application were as follows:1.5 times recommended fertilization N1 (pure nitrogen 25.5g·m⁻²), normal recommended fertilization N2(17g·m⁻²), 0.5 time recommended fertilization N3(8.5g·m⁻²), no nitrogen fertilizer N4(no nitrogen application).The treatment time was 10, 20, 30, 40 days. The results showed that the content of nitrate reductase (NR), glutamine synthetase (GS),glutamine-oxoglutarate aminotransferase(GOGAT), soluble protein and free amino acid increased with the increase of nitrogen application when moisture conditions were appropriate. When drought stress was mild, increased application of nitrogen fertilizer can alleviate drought stress .When drought stress was severe, high nitrogen treatment reduced the activities of nitrogen metabolism enzymes , the content of free amino acids and soluble proteins in the leaves of the grape. The nitrogen content in the leaves of grape always decreased with the increase of treatment time. Under mild water stress, the nitrogen transport rate was higher. When the water stress was severe, the nitrogen transport rate of treatment under high nitrogen and no nitrogen were lower. Finally, under the suitable water conditions (W1) and mild water stress (W2), the nitrogen metabolism ability of grape leaves under N1 (purified nitrogen 37.5g·m⁻²) was the highest. Under moderate water stress (W3) and severe water stress (W4), N3 (pure nitrogen 12.5g·m⁻²) and N4 (no nitrogen application) had the highest nitrogen metabolism capacity. The research results provide a theoretical basis for the prevention and control of drought disasters in the actual production of grapes, which can effectively alleviate the harm caused by water stress, and avoid the waste of fertilizer in production, so as to achieve less fertilizer efficiency.

Key words: Grape, Nitrogen metabolism, Water and nitrogen stress, Nitrogen content, Optimum N application