Mobilization and uptake of insoluble phosphorus by different common bean genotyes

Solution culture and sand pot experiments were carried out to study the mobilization and uptake of phosphorus compounds ( K-P, Ca-P, Al-P and Fe-P) by different common bean(Phaseolus vulgaris L.)genotypes as affected by organic acid exudates The results showed that common bean had a significant variation in response to insoluble P compounds Generally, the growth of plant and P uptake by the largerseeded genotypes from the Andean gene pool was better that by middle and smallseeded genotypes from the Middle American gene pool The genotype G19839 from the Andean gene pool had better tolerance of low P stress and adaptation to Fe-P. Under low-P stress, root exudates had higher ability to mobilize insoluble Fe-P and Al-P than that at normal P supply The roots secreted citric acid, formic acid and acetic acid, and the citric acid is more effective than formic acid and acetic acid in mobilizing insoluble Fe-P and Al-P, indicating that citric acid may play an important role in mobilizing the insoluble P