Effect of aluminium on exudation of organic acid anions in tea plants

Abstract

The exudation of organic acid anions from roots of tea plants (Camellia sinensis var. sinensis cv. Yabukita) was examined with or without aluminium (Al) treatment. Oxalate was the main organic acid anion exuded from roots and the exuded amount was much higher in Al-treated plants. Low amounts of malate and citrate were exuded. In Al-treated roots, content of water-soluble oxalic acid was approximately 5 times higher than that of controls. Oxalate exudation from the roots was compared among 3 species belonging to the Genus Camellia and differences in the amounts of oxalate were observed. These results suggest that oxalate exudation and oxalic acid metabolism are related to Al accumulation in the roots, Al detoxification and solubilisation of phosphorus by Camellia.