Effect of carbohydrates on callus induction and regeneration ability in Brassica napus L.

The effect of 1%, 3% and 10% fructose, glucose, sucrose and ribose on callu s induction and organogenesis was studied in Brassica napus L. cv. Evita. H ypocotyls and cotyledons of 7-day-old seedlings were used as explants. MS ( Murashige and Skoog, 1962) was the basal medium. Calluses were produced fro m both types of explants in the presence of 2,4-D. There were significant d ifferences in the frequency of callus induction between ribose and other su gars tested, as well as between low (1% and 3%) and high (10%) sugar concen trations. Irrespective of sugar type, callus induction was significantly lo wer on ribose- containing media and at high concentration. On hormone-free media, callus tissue formed very exceptionally and only from cotyledons. Th e amounts of callus tissue produced were highest on MS with glucose, follow ed by sucrose and fructose. In the regeneration experiments, explants were cultured on MS with 2,4-D as the sole growth regulator, and with NAA and ki netin. No regeneration occurred on medium with 2,4-D. In the presence of NA A and kinetin, organogenesis was observed only on media with 1% and 3% suga rs, but on ribose the number of organs produced was very low. The highest r egeneration ability occurred on sucrose-based medium.