Effect of phosphite suplly in nutrient solution on yield, phosphorus nutrition and enzimatic behavior in common bean (Phaseolus vulgaris L.)

Abstract

Aim of this study was to (i) understand the phosphite action used as P source on growth and grain yield, (ii) measure P concentration and accumulation in shoot and root, and (iii) evaluate enzymatic behaviour in common bean (Phaseolus vulgaris L.) plants grown in nutrient solution under phosphate starvation. Experimental design was completely randomised with 7 levels of phosphite (0, 16, 32, 64, 128, 256 and 512 µM) and 2 levels of phosphate (80 and 800 µM, corresponding to phosphate-starved plants and phosphatesufficient plants, respectively) in nutrient solution. Common bean plants were evaluated at 2 different growth stages: flowering and mature grain stages. For plants harvested at the mature grain stage, two more treatments (additional treatments) were added: –P = no P supply in nutrient solution; and +Phi = all the P (800 µM) from nutrient solution was supplied only as Phi. This study revealed that growth and grain yield in plants grown under phosphate starvation presented negative repercussions on these parameters, in which treatments with 64, 128, 256 and 512 µM of phosphite resulted in no-filled grains. Concentration and accumulation of P in shoot and root of phosphate-starved plants was increased with increasing phosphite levels in nutrient solution, but this additional P concentration did not convert into grain yield. The phosphite application in phosphate-starved plants promoted a decrease in acid phosphatase (EC 3.1.3.4.1) activity, while catalase (EC 1.11.1.6) activity was increased up to 32 µM of phosphite and was reduced at higher levels of phosphite.