Wheat (Triticum aestivum L.) response to manganese in a sand culture

Abstract

Wheat acreage is expanding rapidly to include otherwise highly leached and manganese-rich soils of the tropics. A laboratory study was conducted to evaluate the response of Abe wheat to a range of Mn2+ concentrations in a sand culture. Shoot and root dry matter yield (DMY), root length, and shoot and root accumulation of Mn were measured. All parameters responded positively to increasing Mn2+ concentrations. Based on shoot DMY, 0.1 mg Mn2+ L1 of treatment solution was the lowest concentration at which Mn ceased to limit growth. According to root DMY, 5- 20 mg Mn2+ L-1 was the sufficiency range. The highest rate of Mn accumulation by shoots and roots occurred between 0-5 mg Mn2+ L-1 of growth solution and coincided with the Mn2+ concentration range over which plant growth responded markedly. Critical deficiency of 96 and less than 182 mg Mn kg-1 contents for shoot and roots, respectively) and toxicity of 242 and more than 182mg Mn kg-1 for shoot and roots, respectively limits for Abe wheat were established. Dry matter yield and Mn content were consistently greater in the shoots than in the roots. Higher shoot Mn accumulation was attributed to faster rate of Mn translocation to the shoots from the roots than the rate uptake. Abe wheat inbred is responsive to both deficient and toxicity concentrations of Mn in the growth solution.