In vitro and in vivo response to Al3+ of Vigna unguiculata

Lines TVu91 (tolerant of Al toxicity) and TVu1977 (sensitive) were compared in in vivo and in vitro experiments. In the in vivo tests, root elongation was the parameter most inhibited by Al. After 1 month of hydroponic culture in the presence of 165-330 µM Al, injury ratings were 10-40% for TVu91 and 50-70% for TVu1977. Differences between genotypes were evident from the second week of treatment. The inhibition of root development in TVu1977 was even faster when using a germination test on moist filter paper. In protoplast culture experiments, plating efficiency in the presence of Al in the medium was 79% of the control in TVu91 and 40% in TVu1977. Removal of the toxic ion from the medium after 5 days almost doubled the plating efficiency of stressed TVu1977 protoplasts.