Effects of Salinity on Growth, Ionic Relations and Solute Content of Sorghum Bicolor (L.) Monench

The effects of increasing levels of calcium (Ca2+), potassium (K+), and sodium chloride (NaCl) salinity on the growth and ionic relations of Sorghum bicolor (L.) Monench, cv. 'ICI-5521' seedlings are reported. Increasing levels of Ca2+ in the solution culture enhanced growth, lowered sodium (Na+) uptake, and increased K+: Na+ ratio significantly. Elevated K+ level also improved growth significantly, but had no significant effect on Na+, Ca2+, or magnesium (Mg2+) accumulation of either roots or shoots. Accumulation of K+ and consequently K+:Na+ ratio increased with external K+ concentration. The effects of sodium chloride (NaCl) versus potassium chloride (KCl) salinity on the growth and ionic relations of sorghum ('ICI-5521') were also examined. Growth inhibition was greatest when KCl alone (160 mM) was used, but was enhanced when a mixture of NaCl and KCl (15:1) was used. The influence of salinity on the accumulation of proline, amino acids and carbohydrates and total osmolality is also discussed.