The impact of global elevated CO < inf > 2 < /inf > concentration on photosynthesis and plant productivity

Abstract

The alarming and unprecedented rise in the atmospheric concentration of greenhouse gases under global climate change warrants an urgent need to understand the synergistic and holistic mechanisms associated with plant growth and productivity. Photosynthesis is a major process of sequestration and turnover of the total carbon on the planet. The extensive literature on the impacts of climate change demonstrates both positive and negative effects of rising CO2 on photosynthesis in different groups of higher plants. Significant variation exists in the physiological, biochemical and molecular responsiveness to elevated CO2 atmosphere, among terrestrial plant species including those with C3, C4 and crassulacean acid metabolic (CAM) pathways. However, the regulatory events associated with the inter- and intraspecific metabolic plasticity governed by genetic organization in different plants are little understood. The adaptive acclimation responses of plants to changing climate remain contradictory. This review focuses primarily on the impacts of global climate change on plant growth and productivity with special reference to adaptive photosynthetic acclimative responses to elevated CO2 concentration. The effects of elevated CO2 concentration on plant growth and development, source-sink balance as well as its interactive mechanisms with other environmental factors including water availability, temperature and mineral nutrition are discussed.