Phosphorus status affects postharvest respiration, membrane permeability and lipid chemistry of European seedless cucumber fruit (Cucumis sativus L.)

Fruit of European seedless cucumber were grown in a greenhouse under low and high phosphorus (P) fertilization regimes. Tissue P concentration of fruit (number one grade) from low-P plants was, on average, 45% of that of fruit from high-P plants. Fruit P status affected membrane lipid chemistry and fruit respiration after harvest. Mesocarp tissue of low-P fruit had a lower concentration of phospholipids, lower level of unsaturation in various pools of fatty acids, and a greater rate of electrolyte leakage than that of high-P fruit. On average, respiration of low-P fruit was 21% higher than that of high-P fruit over a 16-day postharvest interval at 23 degreesC. Moreover, low-P fruit experienced a climacteric in respiration that began about 40 h after harvest, reached a maximum at 72 h, and declined to preclimacteric levels by 90 h. The difference in respiration rate between low- and high-P fruit was as high as 57% during the climacteric. The respiratory climacteric was unique to the low-P fruit and was not associated with an increase in fruit ethylene concentration or ripening. Phosphorus nutrition can thus alter the postharvest physiology of cucumber fruit by affecting membrane lipid chemistry, membrane integrity and respiratory metabolism. (C) 2001 Elsevier Science B.V. All rights reserved.