Influence of Elevated CO2 Concentration on Photosynthesis and Biomass Yields in a Tree Species, Gmelina Arborea Roxb

Abstract

The present study dissects out the CO2 fertilization effects on photosynthetic gas exchange characteristics, key responses of photosynthetic and carbohydrate metabolizing enzymes and overall plant growth performance in a fast growing tree species, Gmelina arborea Roxb (Verbenaceae). The main objective of this investigation was to unravel and evaluate the role of elevated CO2 on tree photosynthesis and productivity. Gmelina plants were grown under ambient (360 μmol mol−1) and CO2-enriched conditions (460 μmol mol−1) in open top chambers for two marked growth seasons, subsequently for three years. The leaf gas exchange characteristics and associated biochemical measurements were carried out at regular intervals. Gmelina plants were harvested and growth parameters were measured at the end of two growth seasons for three consecutive years. Gmelina plants significantly responded to CO2 enrichment. Gmelina plants grown under elevated CO2 showed 52% more plant biomass compared with those grown under ambient CO2. We conclude that fast growing tree species like Gmelina, exhibiting high CO2-mediated photosynthetic up-regulation, can be used as potential tree species for efficient carbon sequestration under predicted future climate change scenario.