Influence of phosphorus supply on tomato plant nutrition

Four nutrient solutions with different P‐levels (0.2; 0.5; 2.0 and 4.0 mmol P/l) were studied in order to optimize P nutrition of the tomato plant. A N/P ratio decrease in sap and the leaf was observed when P supply increased. Moreover, excessive and deficient P levels in the nutrient solution resulted in a flavonol glycosides decrease in leaves, specially at flowering. Chlorophyll a/chlorophyll b ratios and chlorophyll a percentages, as compared with the total, were lower in the P‐0.2 and P‐0.5 treatments than in the P‐2.0 treatment.