Anatomical Changes Linked Lerformance of Two Indigenous Medicinal Plants, Withania Somnifera Dunal and Coleus Forskohlii Briq. Exposed to Supplemental Ultraviolet-B Radiation

Abstract

Supplemental ultraviolet-B (s-UV-B) radiation (ambient+3.6kJm -2 day -1 ) was given to two medicinal plants Withania somnifera and Coleus forskohlii for 3 h day -1 during the solar noon period. Changes at the anatomical level were studied in leaves and roots of the plants. Variations were observed in all s-UV-B treated plant-parts (except roots of W. somnifera). The changes included increased leaf thickness (W. somnifera), enhanced accumulation of UV-B absorbing compounds in leaves of both plants and roots of C. forskohlii, and reduced thickness of cork-and cambial cell layers in C. forskohlii. Due to reduction in the number of oil bodies in cork cells, essential oil content of C. forskohlii also reduced. The results suggest that the test plants are capable of defending themselves (at least partially) against s-UV-B; further in-depth studies are required to derive more substantial results linking the cellular level changes to the overall plant performance.