Uptake of aluminium by the root tips of an Al-sensitive and Al-tolerant cultivar of Zea mays

Uptake and compartmentation of Al in the roots tips were investigated in two corn (Zea mays L.) cultivars (HS7777 single sensitive hybrid and C525-M single tolerant hybrid). Seedlings were grown for 24 h in nutrient solution at pH 4.4 characterized by low ionic strength (2,06 microM) and low Al3+ activity (10.3 microM). The root elongation decreased strongly for the sensitive cultivar. There were no differences in the contents of total Al in the entire roots between cultivars. Nonexchangeable-Al and exchangeable-Al contents were higher in the root tips of HS7777. The sensitive cultivar also showed higher total and exchangeable-Al contents in excised root tips in 180 min of Al uptake. Al uptake for both cultivars increased in solution containing 0.1 mM of 2,4-dinitrophenol. Al contents were higher for the tolerant cultivar. (Résumé d'auteur