Threshold aluminum toxicity in maize

Abstract

The threshold value of aluminum (Al) toxicity in maize was determined by growing two‐week‐old plants for 20 days in a medium with low ionic strength having Al concentrations ranging from 0 to 81 mg L‐¹. It was found that biomass production decreased in both roots and shoot at 81 mg L‐¹ Al. The maize plants grown displayed two distinct Al accumulation phases in roots. A slow phase accumulation occurred between 0 and 9 mg L"¹ Al, and a faster phase between 9 and 81 mg L‐¹ Al. In both phases, Al content in plant tissue increased with Al concentration in the nutrient solution. Threshold toxicity, as expressed by reduced root length, was found to be 13 μg g‐¹ Al in plant tissue.