The effect of aluminium on the growth of a range of temperate legume species and cultivars: A summary of results

Abstract

The aluminium (Al) tolerance of 35 temperate legumes (136 accessions) was determined in 74 experiments over a 2-year period in a low ionic strength (2730 micro M) solution culture. For each accession, the relationship between solution Al 3+ activity ( micro M) and relative root yields was determined using polynomial exponential splines, and the Al 3+ activity associated with a 50% reduction in root yield (Al RY50) was calculated. All species tested in the genera Adesmia, Medicago and Melilotus tended to be very sensitive to aluminium (Al RY50 <1). Dorycnium pentaphyllum was sensitive, whereas the Al RY50 of the D. hirsutum lines ranged from 1.4 to 2.4 (mean 1.9). In Lotus and Trifolium, the order of tolerance for each species (based on the Al RY50 mean over lines) was L. tenuis, T. resupinatum (Al RY50 <0.5) T. balansae, T. fragiferum, T. hybridum and T. pratense (Al RY50 0.5-1) L. angustissimus, L. corniculatus, L. subbiflorus, T. ambiguum, T. dubium, T. glomeratum (Al RY50 1-1.5) T. amabile, T. repens, T. semipilosum, T. striatum, T. tumens (Al RY50 1.5-2) T. medium, T. polymorphum (Al RY50 2-3) T. subterraneum (Al RY50 3-4) L. pedunculatus [ L. uliginosus ] (Al RY50 4). Significant differences in Al tolerance between the lines were noted for (with the range in Al RY50 in parenthesis) T. amabile (0.1-2.6), T. ambiguum (0.8-1.6), T. medium (1.5-4.1), T. repens (0.6-3.1), T. polymorphum (1.5-2.6), T. semipilosum (1.2-2.0) and T. subterraneum (1.8-5.9).