EFFECT OF SULFUR DEFICIENCY ON METABOLISM OF GREENGRAM (PHASEOLUS-RADIATUS)

An experiment was conducted during 1989-90 at Lucknow to find out the effect of sulphur deficiency on 'K 851' greengram (Phaseolus radiatus L.) in refined sand at 0.02 mM (deficient) and 2 mM (adequate) sulphur supply. Sulphur deficiency induced the chlorosis of young leaves, which later changed to bleaching, necrosis of margins and inward curling. The growth of main shoot was checked and a number of lateral branches developed in the sulphur-deficient plants. Low sulphur supply reduced the dry weight (73%), seed yield (40%), tissue sulphur, concentration of chlorophyll, soluble proteins, starch, DNA and RNA, and increased the concentration of total and reducing sugars, nitrate-nitrogen, activities of peroxidase and ribonuclease. Resumption of supply to sulphur-deficient plants increased the biomass, concentration of chlorophyll, leaf sulphur and soluble protein.