SALINITY STRESS EFFECTS ON [C-14-1]-GLUCOSE AND [C-14-6]-GLUCOSE METABOLISM OF A SALT-TOLERANT AND SALT-SUSCEPTIBLE VARIETY OF WHEAT

The effect of salt (sodium sulfate) on carbohydrate metabolism was stu died in a salt-tolerant (Kharchia-65) variety and a salt-susceptible ( Fielder) variety of wheat (Triticum aestivum L.) by comparing their re sponses under control and stress conditions. Leaf segments of Kharchia -65 showed increased activity through both the pentose phosphate pathw ay (PPP) and the glycolytic pathway of glucose oxidation, with the for mer being comparatively more active in response to salt. In Fielder, t here was an increase in PPP activity at the expense of glycolytic path way activity. Label from glucose was found in the lipid, neutral sugar , amino acid, organic acid, and phosphate ester fractions in all treat ments. On the basis of the label distribution patterns, it appears tha t Fielder leaves incubated with [C-14-6]-glucose were not able to util ize glucose efficiently under saline conditions. This finding was furt her supported by decreased label incorporation into all the fractions, especially the amino acid and organic acid fractions. Adenosine phosp hate and reduced pyridine nucleotide concentrations were consistent wi th these observations. We conclude therefore that the salt-tolerant va riety had an enhanced metabolic activity compared with the salt-suscep tible variety, which contributed to its ability to overcome the advers e effects of salt.