The effect of phosphate deficiency on sugars and organic acids accumulation in bean roots

The objective of this study was to evaluate the influence of phosphate deficiency on malate dehydrogenase activity and on sugars and organic acids concentrations in bean roots (Phaseolus vulgaris L.) plants. In P-deficient plants, glucose and fructose concentration were always higher than in control plants. The sucrose concentration in roots of both P-deficient and P sufficient plants was similarly increasing during the experiment. The concentration of the organic acids determined was always higher in the roots of P-deficient plants as compared to +P plants. The root total malate dehydrogenase (MDH) activity was similar in P-deficient and control plants up to 18 days of growth. On the other hand, the activity of the mitochondrial isoforms in -P plants was lower than in the control. The higher soluble sugars concentration in P deficient roots is an evident symptom of the reduction of the catabolism of the carbon photosynthates.