Enzymes of sucrose metabolism in groundnut (Arachis hypogaea) callus and devloping cotyledons

Abstract

Groundnut (A. hypogaea L.) calli were cultured on three MS-media differing in carbon sources namely fructose (callus-F), glucose (callus-G) and sucrose (callus-S). Developing cotyledons of field grown plants and three calli developed in vitro were analysed for glucose, fructose and sucrose contents and activities of sucrose phosphate synthase (SPS), sucrose synthase (SS) and invertase. Sucrose was 81, 91, 125, and 82 μmole/g fr wt in cotyledons, callus-F, callus-G, and callus-S, respectively. Glucose and fructose contents varied widely. Callus-F was characterised by high sucrose and fructose contents, callus-G by high sucrose and glucose contents, and callus-S by high sucrose and low glucose contents. Compared to SS, both SPS and invertase were insignificant in callus-F and callus-G, On the basis of relative abundance of SS and SPS in three calli, the presence of sucrose in callus-F and callus-G was ascribed to de novo synthesis of sucrose by SS.