STUDIES ON THE CHANGES IN PEROXIDASE, ACID-PHOSPHATASE, PHENOLS AND DEGREE OF COLORATION OF 8 CULTIVARS OF RED ONION (ALLIUM-CEPA L) BULBS DURING DEVELOPMENT

Developing bulbs of eight red onion varieties have been assayed for pe roxidase, acid phosphatase, phenols and degree of colouration at seven growth stages, beginning at 30 days after transplanting (DAT), at 15 day intervals, till maturity. specific activity of peroxidase was foun d to be maximum at 45 DAT, decreased continuously afterwards and at ma turity, no peroxidase activity was detected. The specific activity of acid phosphatase increased upto 60 DAT and declined thereafter. Phenol content of bulbs remained almost static upto so DAT, followed by an i ncreased upto 90 DAT and decreased thereafter till maturity. The degre e of colouration exhibited the same trend. The varieties had considera ble variability for the parameters determined not only at maturity, bu t also prior to maturity.