Figure 4.

The effect of illumination and carbohydrates on MCC-A promoter-mediated GUS expression. MCC-A:GUS transgenic Arabidopsis seedlings were grown for 8 d on Murashige and Skoog medium containing the indicated concentration of Suc (A), sorbitol (C), and 1.5% (w/v) of the indicated monosaccharides (D). Seedlings were grown either under continuous illumination (□) or transferred to darkness for the last 2 d of growth (■), and GUS activity was determined in protein extracts. The bars represent the mean ± se from three replicates using three independent transgenic lines. B, Histochemical staining of GUS activity in 8-d-old MCC-A:GUS transgenic Arabidopsis plants that were maintained in darkness for the last 2 d of growth. Seedlings were grown in Murashige and Skoog agar medium containing the indicated concentration of Suc.