Genotypic Difference in Aluminum Resistance and Oxalate Exudation of Buckwheat

Abstract Genotypic difference in aluminum (Al) resistance of buckwheat (Fagopyrum esculentum Moench.) was first tested using a simple salt solution (0.5 mM CaCl2) containing 25 µM AlCl3. Two contrasting genotypes, resistant 92‐1 vs. sensitive Liangqiao 1, were selected out of five, and further tested by a long‐term Al treatment in 1/5 strength of Hoagland solution. Consistent results were obtained by the two methods although much higher Al3+ concentration was needed to cause the genotypic difference in the culture solution (up to 2000 µM compared with 25 µM Al3+ in simple salt solution). Oxalate content and exudation was decreased when the plants were subjected to the long‐term Al treatment of both genotypes, 92‐1, however, excreted more oxalate than Liangqiao 1 either in Al‐treated or non‐treated plants. If the plants were treated with 100 µM Al3+ in 0.5 mM CaCl2 solution for 24 h, oxalate exudation was very significantly induced: 4‐fold increase for 92‐1 and 1‐fold increase for Liangqiao 1. This support...