Aluminium Tolerance in Species within the Genus Agrostis

Abstract

The growth of four Agrostis spp. in soils of different pH and Al status lead to the proposal that the species represent a graded series of decreasing Al tolerance with A. setacea the most tolerant, A. canina and A. tenuis of intermediate tolerance and A. stolonifera least tolerant. This proposition was examined in water culture experiments. Root growth of A. stolonifera showed distinct signs of toxicity in 0.2 m[image] Al or greater. A. canina first showed toxicity symptoms in 0.4 m[image] Al whereas in A. setacea and A. tenuis no symptoms were noted in 0.8 m[image] Al. A. setacea grew in concentrations as high as 1.6 m[image] but root growth of A. tenuis was completely inhibited at these higher concentrations. The appearance of P-deficiency symptoms in the shoots of plants was not correlated with inhibition of root growth. High levels of Ca in the solution did not increase the resistance of A. stolonifera to Al toxicity. The inhibition of root growth was found to be caused by rapid cessation of cell division in root apices. An Al-EDTA chelate did not inhibit cell division. Mechanisms which may account for tolerance are discussed.