Effects of Elevated Carbon Dioxide and Drought Stress on Agricultural Crops

An increase in atmospheric CO2 concentration has been expected and intensification of drought in some regions has been projected for the future. The impacts of elevated CO2 and drought stress on various crops have been studied extensively at many different regions. The purpose of this review is to provide an overview of the growth and development of agricultural crops under elevated CO2 and drought stress based on field experiments and crop modeling studies. This review suggests that the drought stress on crop could be more serious during some phenological stages such as flowering periods. The rising CO2 concentration contributes an increase in CO2 diffusive transfer and photosynthetic rates. Consequently the elevated CO2 decreases transpiration and improves crop water use efficiency and yield. In general, elevated CO2 contributes to increases in crop growth and frequent yield. Crops with a C3 pathway usually exhibit greater growth responses compared to those with a C4 pathway. Elevated CO2 improves plant–water relations by reducing transpiration and increasing water use efficiency, implying less water use. In contrast, drought stress reduces leaf area, plant height, growth, and development leading to smaller organs and decreases in yields, and subsequently, less water use efficiency. We expect that this review can provide a better understanding of the interactive effects of elevated CO2 and drought stress on crop growth and development.