Ameliorative effects of calcium on growth and mineral uptake of salt-stressed amaranth

Abstract

The detrimental effects of salinity stress in plants may be ameliorated by calcium. However, little is known concerning the efficacy of different calcium sources, especially in amaranth. Two amaranth genotypes (Amaranthus tricolor and A. cruentus) were grown in a greenhouse to investigate the efficacy of supplementary calcium in ameliorating salinity stress effects. Treatments were (1) standard nutrient solution (C); (2) nutrient solution plus 100 mM NaCI (C+S); (3) nutrient solution + 100 mM NaCI + 10 mM supplemental Ca as CaSO4 (C+S+CaSO4) and (4) nutrient solution + 100 mM NaCI + 10 mM supplemental Ca as CaCI2 (C+S+CaCI2). The effect of supplementary Ca on growth, gas exchange, membrane permeability and mineral uptake of NaCI-stressed amaranth plants was investigated. Dry matter production, stomatal conductance and photosynthetic rate of salt-stressed plants were less than those of control plants. Supplementary Ca ameliorated the negative effects of salinity on these parameters. Membrane leakage, as well as sodium (Na+) and chloride (??) concentrations in plant tissues increased in both genotypes in NaCI-treated plants but to a greater extent in A. tricolor than in A. cruentus. The concentrations of K+ and Ca2+ in the shoots of NaCI-treated plants were reduced. In general, supplemental Ca partly ameliorated the negative salt stress effects in amaranth regardless of the source of calcium. © 2006, Taylor & Francis Group, LLC.