Tomato fruits of high quality and yield are of interest to greenhouse growers. As potassium (K) and calcium (Ca) have been associated with fruit quality, we studied the effect of the balance between such cations and the electrical conductivity (EC) on fruit yield and quality. Plants were fertigated with K (K ext ) and Ca (Ca ext ) balances in the nutrient solution varying from 0.54–1.22 and 0.69–1.44 at ECs of 2.3 ± 0.1 dS m −1 and 2.7 ± 0.1 dS m −1 , respectively. Optimum balance for fruit yield was 0.82–0.85, and it was associated with high fruit K internal (K int ) concentration (~ 200 mmol kg −1 ). Higher EC increased firmness when the balance was ≤ 1.00, with the optimum at 0.85; firmness was correlated with Ca int when EC was 2.3 dS m −1 ; however, at 2.7 dS m −1 , increasing K ext increased firmness and intensified the effect of Ca ext . Increasing a* values were associated with high lycopene and uniform maturation when that balance was 0.82 and 1.00 at low and high EC, respectively. Highest a* values were observed when K int in the fruit was ~ 200 mmol kg −1 , while 91 to 130 mmol kg −1 were associated with lower a* values. Fruits contained higher starch (+ 20%), total (+ 12%), and reducing sugars (+ 29%) at high EC. The optimum K and Ca balance, 0.82–0.85, is independent of their concentration and was associated with high yield and firmness, improved fruit color, and increased lycopene and sugar concentrations.

中文翻译：

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番茄果实产量、质量和营养状况对钾的反应：营养液中的钙平衡和电导率

温室种植者对高质量和高产量的番茄果实感兴趣。由于钾 (K) 和钙 (Ca) 与果实品质有关，我们研究了这些阳离子与电导率 (EC) 之间的平衡对果实产量和品质的影响。用营养液中的 K (K ext ) 和 Ca (Ca ext ) 平衡在 2.3 ± 0.1 dS m -1 和 2.7 ± 0.1 dS m -1 的 EC 分别为 0.54–1.22 和 0.69–1.44 的情况下对植物施肥。果实产量的最佳平衡为 0.82–0.85，这与高果实内钾 (K int ) 浓度 (~ 200 mmol kg -1 ) 相关。当平衡≤1.00时，较高的EC增加了硬度，最佳值为0.85；当 EC 为 2.3 dS m -1 时，硬度与 Ca int 相关；然而，在 2.7 dS m -1 时，增加 K ext 会增加硬度并加强 Ca ext 的效果。当在低和高 EC 下平衡分别为 0.82 和 1.00 时，增加 a* 值与高番茄红素和均匀成熟相关。当水果中的 K int 为～200 mmol kg -1 时观察到最高的 a* 值，而 91 至 130 mmol kg -1 与较低的 a* 值相关。水果在高 EC 下含有较高的淀粉 (+ 20%)、总淀粉 (+ 12%) 和还原糖 (+ 29%)。最佳 K 和 Ca 平衡为 0.82-0.85，与它们的浓度无关，并且与高产量和硬度、改善果实颜色以及增加番茄红素和糖浓度有关。而 91 至 130 mmol kg -1 与较低的 a* 值相关。水果在高 EC 下含有较高的淀粉 (+ 20%)、总淀粉 (+ 12%) 和还原糖 (+ 29%)。最佳 K 和 Ca 平衡为 0.82-0.85，与它们的浓度无关，并且与高产量和硬度、改善果实颜色以及增加番茄红素和糖浓度有关。而 91 至 130 mmol kg -1 与较低的 a* 值相关。水果在高 EC 下含有较高的淀粉 (+ 20%)、总淀粉 (+ 12%) 和还原糖 (+ 29%)。最佳 K 和 Ca 平衡为 0.82-0.85，与它们的浓度无关，并且与高产量和硬度、改善果实颜色以及增加番茄红素和糖浓度有关。