Assessment of tolerance to Aluminum toxicity in olive (Olea europaea) based on root growth and organic acid Al3+ exclusion mechanism

Abstract

This work was done with the objective of evaluating the Al tolerance of six principal olive genotypes: ‘MGSASC 315’; ‘Barnea’; ‘Leccine’; ‘CLO0025’; ‘Coratina’ and ‘Mission’ based on relative root growth, organic acid exudation, and root apex hematoxylin staining analysis. For root growth and hematoxylin staining, the experiment was laid on 4 x 6 factorial (4 doses of AlCl3 (0, 250, 500 and 1000 µM), 6 genotypes of olive) in hydroponic solution under greenhouse condition. The analysis of organic acid exudation after 24 and 48h exposure to Al3+ showed citric acid involved on Al tolerance mechanism in olive, whereas malate and oxalic acid did not. Among the olive genotypes MGS ASC 315, Barnea and Leccine recorded high relative root growth and high citric acid exudation under Al stress that showed these genotypes are tolerant for Aluminum stress.