Enhancement in the formation of shoot initials by phytochrome in stem callus cultures of Brassica oleracea var. botrytis

Abstract

Dark grown (20 - day - old) callus obtained from explants of Brassica oleracea var. botrytis formed shoot initials 12 days after transfer to light. However, if 15 - day - old dark grown callus was exposed to continuous white light the production of shoot initials was hastened as compared to dark control. Instead of the white light, if red light was given for 5 min each day for a total period of 5 days, the shoot initiation started on 3rd day and the response was higher than that found in dark grown cultures. Far-red light given for 10 min showed no effect and if it followed red light, the effect of red light was annuled. These experiments suggest that involvement of phytochrome in shoot initiation in this system.