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Effect of phosphorus deficiency on aluminium‐induced citrate exudation in soybean ( Glycine max )
Author(s) -
Nian Hai,
Ahn Sung Ju,
Yang Zhen Ming,
Matsumoto Hideaki
Publication year - 2003
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2003.1170210.x
Subject(s) - phosphorus deficiency , phosphorus , chemistry , citric acid , stomatal conductance , transpiration , toxicity , glycine , photosynthesis , zoology , biochemistry , biology , amino acid , organic chemistry
Aluminium (Al) toxicity or phosphorus (P) deficiency can induce exudation of organic acids from the roots of some plants, which is believed to be a tolerance mechanism against Al toxicity or P deficiency. In the present study, the effect of P deficiency on Al‐induced citrate exudation was investigated in three soybean varieties differing in low‐P tolerance. P starvation alone failed to induce secretion of organic acids from all three soybean varieties. However, P deficiency altered Al‐induced citrate exudation over time, showing a complex interaction. Short × term P starvation (4 days) produced up to 50% increase in Al‐induced citrate secretion, while longer‐term (10 days) starvation reduced Al‐induced citrate secretion to trace amounts. However, after a further 1 day in complete nutrient solution for recovery, Al‐induced citrate exudation from the recovered roots was approximately 6 times higher than that from the continuously P‐starved plants, but still approximately 3.6 times lower than that from the P‐sufficient control. With increasing P or Al supply, Al‐induced citrate exudation increased, while Al accumulation in soybean roots decreased in parallel with the decrease of P supply. The photosynthetic rate, stomatal conductance and transpiration were decreased by P deficiency, whereas the intracellular CO 2 concentration was increased. These findings indicate that P nutrition has a significant effect on Al‐induced citrate exudation and Al accumulation in soybean root apices.