Interactive Effects of Elevated CO2, Drought, and Warming on Plants

Adverse climate change attributed to elevated atmospheric carbon dioxide concentration (CO2) and increased temperature components of global warming has been a central issue affecting economic and social development. Climate change, particularly global warming, imposes a severe impact on the terrestrial ecosystem. Elevated CO2, drought, and high temperature have been extensively documented individually; however, relatively little is known about how plants respond to the interaction of these factors. To summarize current knowledge on the response of plants to global change factors, we focus on the interactive effects of CO2 enrichment, warming, and drought on plant growth, carbon allocation, and photosynthesis. Stimulation due to elevated CO2 might be suppressed under other negative climatic/environmental stresses such as drought, high temperature, and their combination. However, elevated CO2 could alleviate deleterious effects of moderate drought via reducing stomatal conductance, altering leaf surface, and regulating gene expression. High CO2 levels and rising temperatures may result in opposite responses in plant water use efficiency. Stimulation of plant growth due to elevated CO2 for C3 species occurs regardless of water conditions, but only under a water deficit for C4 species. The positive effect of elevated CO2 on C4 species is derived mainly from the improved water status. Plant adaptive or maladaptive responses to multivariate environments are interactive; thus, researchers need to explore the ecological underpinnings involved in such responses to the multiple factors involved in climate change.