Root exudation of organic acids in selected genotypes under phosphorus deficient condition in blackgram (Vigna mungo L. Hepper)*

摘要

Availability of Phosphorus (P) under P deficient condition and its acquisition by plants is affected by the release?of root production and root exudates. An experiment in nutrient solution was conducted to identify the exudation of organic?acids under by phosphorus deficiency condition. A 15 DAS old germinated Blackgram seedlings grown in vermiculite media?were transferred to test tubes containing low P and high P Hogland’s nutrient solution. Citric acid and oxalic acids were?released by the genotypes in higher quantities under P deficient condition, but on a contrary under P sufficient condition these?acids were also secreted but only in trace quantity. Simultaneously genotypes were grown under vermiculite culture in pots?for 45 days and their variability for mean P uptake performance and root traits were analyzed under both P deficient and sufficient conditions. The results indicated that organic acid (root exudates) release and root production were enhanced in?times of nutrient stress and responsive genotypes were found to be superior in both acquisition and utilization of phosphorus in P stress condition due to enhanced root production and shoot expansion, respectively. So the increased release of citric acid?and oxalic acid coupled with increased root volume may provide a mechanism by which P deficient plants can enhance the?availability of P in the rhizosphere.