Root Structure Reflects Differential Aluminum Tolerance in Wheat Varieties¹

Differential Al tolerance of Atlas 66 and Monon wheat varieties was associated with morphological damage of root tips and lateral roots. The response of the root systems to Al was controlled by the sensitivity of the roots, as well as by the concentration of soluble Al in the growth medium. The action of Al was local rather than systemic, and was restricted for the most part to the sensitive root tips and lateral roots. More resistant meristematic areas remained functional, as evidenced by the emergence of new roots when the Al stress was removed.