Effect of Epibrassinolide on Pigment Content, Total Protein Amount and Peroxidase Activity in Excised Cucumber Cotyledons

ABSTRACTBrassinosteroids (BRs) are a group of plant steroids that are known to elicit remarkable growth responses such as growth, seed germination, rhizogenesis, senescence, flowering, abscission, maturation, and also confer resistance on plants against various abiotic stresses. Brassinosteroids increase chlorophyll breakdown and inhibit anthocyanin biosynthesis. In this study the effect of epibrassinolide (epi-BL) on pigment content, soluble protein content, and peroxidase (POD) activity was investigated in excised cotyledons of cucumber seedlings. The cucumber seedlings were grown in dark conditions for 9 days and then their etiolated cotyledons were harvested. After that, they were transferred into Petri dishes containing 10−7 mol/L, 10−9 mol/L and 10−11 mol/L epi-BL. Cotyledons were incubated for 14 h in the dark at room temperature, then they were incubated in light for 3 h. Results showed that epi-BL affected the chlorophyll and carotenoid content, but no significant changes were observed when compa...