Mineral acquisition of aluminum‐tolerant and ‐sensitive sorghum genotypes grown with varied aluminum

Abstract

A constraint to plants grown on acid soils is commonly aluminum (Al) toxicity. Plants grown with excess Al normally have imbalanced minerals compared to plants grown without Al. This study was conducted to determine differences among 25 sorghum [Sorghum bicolor (L.) Moench] genotypes with broad genetic backgrounds for Al, phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu) acquisition when grown with 0, 200, 400, 600, and 800 μM Al in nutrient solutions (pH 4.0). Genotypes were categorized into “Al tolerant”;, “Al sensitive”;, “intermediate Al tolerant”;, and SC 283 (an Al‐tolerant standard) according to net main axis root length (NMARL) of plants grown with 400 UM Al. Shoot and root concentrations of minerals were generally lower as Al increased, and some minerals changed more than others. The Al‐tolerant genotypes generally had higher concentrations of Mn in shoots and K in roots, lower concentrations of Ca in shoots and roots, and lower concentrations of P, Mg, and Mn in roots than Al‐sensitive genotypes. Except for Zn concentrations in shoots, concentrations of minerals in the intermediate Al‐tolerant group generally appeared between the Al‐tolerant and Al‐sensitive groups. Mineral concentrations in SC 283 generally followed the Al‐tolerant group, except for shoot P concentration (lower) and root S concentration (higher) than the other genotypic groups. Mineral acquisition in shoots and roots of the sorghum genotypes used was not a good indicator for distinguishing tolerance to Al toxicity.