GROWTH, ION AND SOLUTE CONTENTS OF SORGHUM GROWN UNDER NACL AND NA2SO4 SALINITY STRESS

Sorghum (Sorghum bicolor (L.) Moench, cv. IS-4807) was grown in nutrie nt solution with or without supplemented NaCl (0-100 mmol L(-1)) or Na 2SO4 (0-50 mmol L(-1)). The concentrations provided identical amounts of Na+, on equimolar basis, from both the salts. After four weeks of g rowth, biological yield was reduced at the higher level of salts and N aCl was more suppressive than Na2SO4. The concentrations of Na+ and Cl - ions were 29-36 times higher in plants raised under NaCl stress (100 mmol L(-1)), and increase in Na was accompanied by a loss of K+ in th e leaves, stems and roots. Under Na2SO4 stress (50 mmol L(-1)), leaf N a+ and SO4- concentration was 21-23 times higher than those raised in the absence of the salt. On equimolar basis, Na+ uptake and K+ loss wa s less in Na2SO4 than in the NaCl stressed plants. Proline, betaine an d sugars were enhanced, under both the salts, to similar extent.