Scholar Indian Institute of Technology Madras Chennai, Tamil Nadu, India
Body of Abstract: Stomatal opening controls the trade-offs between CO2 uptake and water loss in response to the surrounding environment. Crop water use efficiency (WUE) improvement through stomatal conductance (gs) reduction has been shown to increase the survival rates of crops under harsh conditions. However, these analyses were performed under controlled conditions with limited environmental stress and showed decreased photosynthesis rates (Anet). We used a process-based steady-state C4 leaf model to analyze the impact of gs reduction on maize leaves under elevated CO2, low light, drier air, and higher temperature. Additionally, we examined the detrimental secondary effects of gs reduction to understand the viability of this approach. We found that there exists an optimal gs reduction for maize leaves which increases WUE without any impact on Anet. Our analysis showed that this gs reduction potential varies based on the changing environmental conditions, with higher gains observed under elevated [CO2], lower light, humid air, and lower temperatures. Lower canopy leaves show higher gs reduction potential compared to their upper counterparts. Further, analysis of simulation results revealed that the secondary effects reduce the possibility of higher gs reduction through increased transpiration and a further decline in Anet. We found a gs reduction of 30% and 20% optimal under current ([CO2] 420 ppm, 30oC, 70%) and future ([CO2] 550 ppm, 35oC, 50%) conditions without significant impact on Anet (ΔAnet < 2%).