Growth and physiological potential of Terminalia arjuna under elevated CO2 levels in Open top chamber condition

Abstract

Terminalia arjuna is native to India and occurs naturally along the banks of streams and rivers. The species is characterized to dry deciduous forests. The present study was carried out for the growth and physiological changes of T. arjuna in different elevated CO2 levels. Open top chambers were used to expose plants to ambient and elevated CO2 concentrations (400 and 800 ppm). The experiment was conducted in the month of March to August in 2019 for six months. The results showed that the growth parameters, i.e. plant height, collar diameter, the number of leaves, were found to be increased in elevated CO2 conditions. The percentage increase in physiological parameters like photosynthetic rate (28.82), mesophyll efficiency (60 % more in elevated CO2 condition), CO2 concentration (55 % more in elevated CO2), vapour pressure deficit (4.83 at 800 ppm) and water use efficiency (5.94 at ppm) increased. In contrast, transpiration rate (5.38 at 800 ppm and 10.11 ppm at ambient condition) and stomatal conductance (30% less in 800 ppm) decreased under elevated CO2 compared to ambient conditions. The study concluded that changing climatic conditions and significantly elevated CO2 in future may profoundly influence plant growth and the physiological response of T. arjuna.