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 an d high phosphorus (P) fertilization regimes. Tissue P concentration of frui t (number one grade) from low-P plants was, on average, 45% of that of frui t 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 poo ls of fatty acids, and a greater rate of electrolyte leakage than that of h igh-P fruit. On average, respiration of low-P fruit was 21% higher than tha t of high-P fruit over a 16-day postharvest interval at 23 degreesC. Moreov er, low-P fruit experienced a climacteric in respiration that began about 4 0 h after harvest, reached a maximum at 72 h, and declined to preclimacteri c 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 climacte ric was unique to the low-P fruit and was not associated with an increase i n fruit ethylene concentration or ripening. Phosphorus nutrition can thus a lter the postharvest physiology of cucumber fruit by affecting membrane lip id chemistry, membrane integrity and respiratory metabolism. (C) 2001 Elsev ier Science B.V. All rights reserved.