A comparative study on aluminum induced oxalate secretion in Polygonum aviculare L and citrate secretion in Vigna umbellata Ohwi & Ohashi

To clarify the processes of aluminum(Al)-induced organic acid anions secretion in different plants with different patterns,the characteristics of Al induced organic acid anions efflux in the roots of rice bean(Vigna umbellataThunbOhwi Ohashi)and Polygonum aviculare L.was investigated.Oxalate secretion in P.aviculare roots occurred within 30 min of Al exposure,while citrate secretion in rice bean roots was induced by at least 4 h Al exposure.Therefore,the former was classified to be pattern I,and the latter pattern II.A broad protein-synthesis inhibitor CHM(cycloheximide) had no obvious effect on the Alinduced oxalate secretion in P.aviculare,but inhibited the Al-induced citrate secretion in rice bean roots by about 84%.This suggested that novel protein synthesis didn't involved in the Al-induced oxalate secretion in P.aviuculare,but was essential in regulating the Al-induced citrate secretion in rice bean.Al exposure did not affect the oxalate content in P.aviculare root apices, but stimulate citrate synthesis in rice bean.The oxalate secretion in P.aviculare was sensitive to anion channel blocker PG(phenylglyoxal) and the citrate secretion in rice bean was sensitive to A-9-C(anthrancene-9-carboxylic acid),indicating anion channels involved in organic acids secretion in both plants but their pharmacological properties were different from each other.