EFFECT OF P DEFICIENCY ON TRANSLOCATION AND REDISTRIBUTION OF PHOSPHATE IN INTACT PLANTS OF CUCUMBER

Experimental-based modelling technique (Jeschke Pate, 1991) was applied to describe quantitatively the uptake, translocation and redistribution of cucumber (Cucumis sativus L.) which was cultured either 0.25 mmol/L H2PO-4or P-free in nutrient solution. 5d after -P treatment, not only relative more P translocated to young leaves (36.1% to total P content in a plant) and root (13.5% to total P content in a plant), but also the growth rate of root was higher than that in +P plants. P content in young leaves and root of +P plants was only 22.4% and 6.34% respectively to total P content in a plant; At 10d after treatment, the growth of shoot was restricted heavily, considerable remobilization of P from older leaves led to young leaves via phloem. The P concentration in young leaves was 47% higher than that in old leaves, and the decrease of P content in root was little. Even in +P plants a large ammount of P in old leaves translocated to young leaves via phloem. Young leaves and root acted as major sinks either in -P plants or +P plants. Translocation and redistribution of phosphate was different in -P plants and +P plants.