Secretion of organic acid anions and potassium from root apices under Al stress in Secale cereale L.

Aluminum(Al)-induced secretion of organic acid anions and potassium from root apices as the effects of several inhibitors and ABA in rye(Secale cereale L.)were investigated in the presented study using pharmacological methods. Under Al stress(100, 200 and 300 μmol/L AlCl3), the secretions of citrate, malate and potassium increased with the increase of Al concentration. This secretion was inhibited by the treatment with anion channel inhibitor phenylglyoxal(0.1,0.2 mmol/L PG). Moreover, treatments with potassium channel inhibitors tetraethyl ammonium(20,40 mmol/L)or Cs+(10,20 mmol/L CsCl)blocked remarkably the secretion of organic acid anions, which was coupled with the inhibition of potassium secretion. In addiction, the secretion of both organic acid anions and potassium was much more robust with the exposure of root apices to Al and ABA(25 or 50 μmol/L). Niflumic acid(0.4 or 0.8 mmol/L NA), an anion channel inhibitor, suppressed remarkably the secretion of organic acids, while the secretion of potassium was not depressed. The potassium secreted under Al stress was depressed after the treatment with ATPase inhibitor, vanadate(0.25,0.50 or 2.00 mmol/L), while the organic acids were increased significantly after the treatment. These results suggest that potassium involves in Al-induced secretion of organic acids in rye as an accompanied cation instead of a regulator factor.