Evaluation of the aluminium-induced root growth inhibition in isolation from low pH effects in Glycine max, Pisum sativum and Phaseolus vulgaris

Abstract

The interaction between proton and aluminium toxicities was examined in soybean (Glycine max L.), pea (Pisum sativum L.) and bean (Phaseolus vulgaris L.). Accurate characterization of genotype Al-sensitivity in solution culture experiments, employing a continuous Al-exposure, required response definition at both growth-enhancing and growth inhibiting activities. Essentially, this involved multiple controls to account for the interactive effects. Experiments measuring growth during a recovery period in Al-free solution were more successful in distinguishing genotypic response to Al, especially in species demonstrating high H+ -sensitivity. The time, concentration and basal solution dependencies of the characteristic genotype response for the three species examined were consistent with the hypothesis that responses of genotypes may be predicated upon conditions emphasizing irreversible (cell division) effects. Cell extension effects, however, appear to be rapid, largely-reversible and often not different between differentially Al-sensitive genotypes growing in a complete nutrient solution.

Proton toxicity interferes with the screening of common bean (Phaseolus vulgaris L.) genotypes for aluminium resistance in nutrient solution

“…1a). This is in agreement with Lazof and Holland (1999), who clearly showed the high proton sensitivity of two common bean genotypes. They concluded that screening bean for Al resistance is not possible at pH 4.05 and proposed to evaluate recovery from Al stress as indicator of Al resistance.…”

“…The relative sensitivity to protons of three legume species increased in the order Pisum sativum < Glycine max < Phaseolus vulgaris (16%-65% inhibition of root elongation, respectively) when the pH of the nutrient solution was reduced from 6.0 to 4.05 (Lazof and Holland, 1999).…”

The plasma membrane strength of the root-tip cells and root phenolic compounds are correiated with Al tolerance in several common woody plants

“…However, a strong interaction between Al ions and H+ has been reported among maize cultivars (Llugany et ai. 1995) and crop plant species (Lazof and Holland 1999). Stimulation of growth or elongation of roots at low pH in the presence of Al ions often observed (Mullette 1975;Konishi et ai.…”

Aluminum Accumulation at Nuclei of Cells in the Root Tip. Fluorescence Detection Using Lumogallion and Confocal Laser Scanning Microscopy

“…With cell cycles at the root meristem of about 18 to 24 h (Gunning and Steer, 1996), it is unlikely that decreased cell division could be responsible for the rapid decreases in root extension occurring within the 1st h of Al exposure (Jones and Kochian, 1995;Llugany et al, 1995;Sivaguru et al, 1999). Nonetheless, a substantial growth inhibition extending over periods of hours or days would have to be associated with decreased cell production (Lazof and Holland, 1999).…”