Changes in ultrastructure, photosynthetic abilities, and secondary metabolite due to individual and interactive effects of chromium and ultraviolet-B radiation in Adhatoda vasica

Abstract

Abbreviations : BCF – bioconcentration factor; C i – intercellular CO 2 concentration; E – transpiration rate; eUV-B – elevated UV-B; F 0 – minimal fluorescence; F m – maximum fluorescence; F m /F 0 – electron transport rate through PSII; F v – variable fluorescence; F v /F 0 – the activity of PSII; F v /F m – maximum quantum yield of PSII; g s – stomatal conductance; P N – net photosynthetic rate; RDM – root dry mass; RSR – root-to-shoot ratio; SDM – shoot dry mass; TF – translocation factor. Acknowledgments : The authors are grateful to the Head of the Department of Botany, Banaras Hindu University, for providing all the necessary laboratory facilities. Coordinator, Centre of Advanced Study (CAS), Department of Botany, Department of Science and Technology (DST-FIST), and Interdisciplinary School of Life Sciences (ISLS) are acknowledged for all research facilities. We are thankful to CSIR-CIMAP, Lucknow, India, for providing plantlets of Adhatoda vasica and Sophisticated Analytical Instrumentation Facility, AIIMS, New Delhi for TEM analysis. University Grants Commission (UGC) and Council of Scientific and Industrial Research (CSIR), India are greatly acknowledged for providing financial support in the form of Senior Research Fellowship to Avantika Pandey and Emeritus Scientist Project to Prof. S.B. Agrawal, respectively. The declare that The study was executed to assess individual and interactive effects of elevated ultraviolet-B (eUV-B) radiation and chromium (Cr) on a medicinal plant Adhatoda vasica Nees. The experiment was conducted under field conditions involving control, Cr, eUV-B, and Cr+eUV-B treatments. The results showed that Cr content was the highest in roots as compared to other parts under Cr+eUV-B. Significant reductions in photosynthetic rate, intercellular CO 2 concentration, and stomatal conductance were observed under all treatments with maximum under Cr+eUV-B. Chlorophyll (Chl) fluorescence parameters showed variable responses under Cr and Cr+eUV-B. Chl content showed reductions under all treatments whereas Chl a / b ratio and carotenoids showed increment under eUV-B and reductions under Cr and Cr+eUV-B. The ultrastructure of leaves showed changes in chloroplasts under treatments. Vasicine (medicinally important secondary metabolite) increased under treatments. Our study revealed that A. vasica showed variable responses towards individual and interactive stress of Cr and eUV-B.