Induced toxicities of aluminum and Manganese in Sweet Sorghum: I. Relations between P, Ca and Al

Abstract

Four sweet sorghum cultivars, CMSXS603 Br 500, Sart and Br 602 were grown in nutrient solution with varying levels of Al, P and Ca in a fatorial design. Main conclusions were the following: (1) Aluminum reduced top dry matter more severely than root weight. Root development, however provided a better indication of the relative tolerance to aluminum toxicity. (2) As long as P was sufficiently high in the nutrient solution, raising the Ca level increased tolerance of the various cultivars to high levels of Al in the substrate. (3) The diferent levels of Al in the nutrient solution affected the content of Ca, Mg, K and P in the tops. (4) Phosphorus levels in the nutrient solution were the single most important factor to increase tolerance to Al toxicity.