Temperature-dependent impact of 24-epibrassinolide on the fatty acid composition and sugar content in winter oilseed rape callus

The aim of this experiment was to study the effect of 24-epibrassinolide (BR27) on fatty acids composition and sugar content in winter oilseed rape callus cultured at 20 and 5°C. Studies have showed that BR27 action is highly temperature-dependent. The increase in sugar content (sucrose, glucose and fructose) by BR27 in concentration 100 nM was observed only in calli cultured at 20°C. At 5°C, quite the opposite effect of BR27 action was observed; where cold increased the sugar content, BR27 decreased it. BR27 at 20°C had a similar effect on the fatty acid composition of phospholipids (PL) as the cold in the process of frost hardening of oilseed rape calli. BR27 decreased the 16:0, 18:1 and 18:2 and increased the 18:3 fatty acid content. At 5°C, BR27 (100 nM) generally did not influence the fatty acid composition of PL. In case of digalactosyl diacylglycerols and monogalactosyl diacylglycerols, the influence of BR27 on the fatty acid composition is ambiguous but still depends on temperature.