氮钾互作对番茄叶片碳氮代谢及产量和品质的影响

在温室基质栽培条件下，以番茄材料A20为试材，采用2因素5水平响应面中心复合设计，研究不同的氮钾营养组合处理对番茄单株产量、果实品质及叶片碳氮代谢产物和酶活性的影响。结果表明，随着氮营养的增加（74～414 mg · L^-1范围内），番茄叶片碳氮代谢产物和酶活性均呈先上升后下降趋势；随着钾营养的增加（101～525 mg · L^-1 范围内），番茄叶片糖含量和蔗糖磷酸合成酶（SPS）、酸性转化酶（AI）、中性转化酶（NI）活性呈增加趋势，而氮代谢产物和蔗糖合成酶（SS）、硝酸还原酶（NR）、谷氨酰胺合成酶（GS）、谷氨酸合成酶（GOGAT）活性呈先上升后下降趋势。通过建立各指标与氮钾二因子的二次回归方程发现，氮钾营养是影响番茄叶片氮代谢和碳代谢的主要因子，氮钾互作对叶片游离氨基酸含量和谷氨酰胺合成酶活性影响显著。相关性分析显示番茄产量、品质与叶片碳氮代谢之间具有较高的相关性，氮钾共同作用于番茄叶片的碳氮代谢过程，进而影响番茄产量和品质。综合分析试验结果，当营养液氮营养为300～350 mg · L^-1、钾营养为370～520 mg · L^-1 时，番茄叶片碳氮代谢旺盛，产量和品质达到较高水平。

Effects of Potassium and Nitrogen Interaction on Carbon and Nitrogen Metabolism of Tomato Leaves，Fruit Yield and Quality

Under the condition of substrate cultivation in greenhouse，taking tomato‘A20’as test material，this experiment adopted response surface central composite design with 2 factors and 5 levels；and studied the effects of different N and K nutrient combination treatments on tomato single plant yield，fruit quality，carbon and nitrogen metabolite，and enzyme activities of tomato leaf blades．The results showed that with the increase of nitrogen nutrient（within the scope of 74-414 mg · L^-1），carbon and nitrogen metabolite，and enzyme activities of tomato leaf blades showed the tendency of first rise then decrease．With the increase of potassium nutrition（within the scope of 101-525 mg · L^-1），the sugar content and sucrose phosphate synthase（SPS），activities of acid invertase（AI）and neutral invertase（NI）in tomato leaf blades showed an increasing tendency．While，the nitrogen metabolites and activities of Sucrose synthetase （SS），Nitrate reductase（NR），Glutarmine synthetase（GS）and Glutaymate synthase（GOGAT）increased initially and then decreased．Through constructing quadratic regression equation between various index and nitrogin/potassium 2 factors，we found that nitrogen and potassium nutrient was the main factor affecting nitrogen and carbon metabolism in tomato leaf blades．The interaction of nitrogen and potassium had significant effect on free amino acid content and Glutamine synthetase（GS）activity in tomato leaves．The correlation analysis showed that there was a high correlation between tomato yield，fruit quality and carbon and nitrogen metabolism in leaves．Nitrogen and potassium nutrition worked together on the process of carbon and nitrogen metabolism in leaf blades，and then to affect tomato yield and quality．Therefore，in actual vegetable production，reasonable combined application of nitrogen and potassium nutrient could promote carbon and nitrogen metabolism，thus acheiving high yield and superior quality．After we comprehensively analyzed the experement result，we understand that when the nitrogen content in nutrient solution was 300-350 mg · L^-1 and potassium nutrient was 370-520 mg · L^-1，the carbon and nitrogen metabolism in tomato leaf blades was exuberant，and tomato yield and fruit quality could reach a higher level．