Exogenous Carbohydrate Utilisation by Explants of Brassica napus Cultured in vitro

Abstract

The influence of carbohydrate type (sucrose, maltose, glucose and fructose) used as carbon source in the medium on particular carbohydrates content in hypocotyls of Brassica napus cv. Topas during in vitro culture was studied. The variability in sugar composition in the explants depending on carbon source in the medium and duration of culture was found. The type of sugar did not influence the growth of cultured tissues during the first 15–20 days of culture. Sugars in the medium were main source of substrates for sucrose synthesis in growing explants. Significant re-synthesis of sucrose in the hypocotyls after the uptake of hexoses was found. Maltose was detected only in traces in tissues cultured on media devoid of this sugar. In the case of glucose and fructose, medium was the main source of these monosaccharides for tissues. In explants cultured on maltose-based medium, glucose content was lower comparing to hypocotyls cultured on sucrose medium. The highest fresh weight (FW) was noticed on the media supplied with sucrose and glucose. Changes in sugar content in culture media were also studied. Autoclaving hydrolysed ∼7% of the initial sucrose into glucose and fructose. The most distinct changes were noticed in the media supplied with sucrose and maltose. Glucose- and fructose-based media remained stable during whole period of culture.