Changes induced by low oxygen concentration in photosynthetic and respiratory CO2 exchange in phosphate-deficient bean leaves

Effect of phosphorus deficiency on photosynthetic and respiratory CO2 exchanges were analysed in primary leaves of 2-week-old bean ( Phaseolus vulgaris L. cv. Golden Saxa) plants under non-photorespiratory (2% O-2) and photorespiratory (21 % O-2) conditions. Low P decreased maximum net photosynthetic rate (P-Nmax) and increased the time necessary to reach it. In the leaves of P-deficient plants the relative decrease of P-Nmax at 2 % O-2 was larger than at 21 % O-2. The results suggested the influence of photorespiration in the cellular turnover of phosphates.