Study on Brassinosteroid-Enhanced Sugar Accumulation in Cucumber Epicotyls

Abstract

Exogenous epibrassinolide (EBR) treatment promoted elongation of cucumber epicotyls and at the same time, enhanced sugar accumulation in the epicotyls. This accumulation was concomitant with the elongation. Accordingly, it was suggested that the sugar accumulation is closely related to the promotion of elongation. Furthermore, the components of the soluble sugar were researched. By EBR treatment, the amount of glucose was remarkably increased, although sucrose was not affected. The amount and transport of ¹⁴C-assimilates in EBR-treated cucumber were analyzed. EBR treatment had no effect on the amount of ¹⁴CO₂ assimilation but they promoted the transport of ¹⁴C-photosynthates to epicotyls. In addition, the amount of ¹⁴C-labeled glucose transported to epicotyl was remarkably increased. In conclusion, these changes enhanced by EBR seem to be a cause of glucose accumulatilon in cucumber epicotyls.