C4 photosynthesis and climate through the lens of optimality

摘要: CO2, temperature, water availability, and light intensity were all potential selective pressures that determined the competitive advantage expansion of C4 photosynthetic carbon-concentrating mechanism over last ∼30 My. To tease apart how varied along ecological trajectory dominance, we coupled hydraulics to photosynthesis models while optimizing stomatal resistance leaf/fine-root allocation. We further examined importance nitrogen reallocation from dark reactions. show here primary favoring dominance changed through course evolution. The higher leaf-to-root ratios enabled by led an without any initial difference in hydraulic properties. predict a reorganization system leading turgor-loss points possibly lower conductance. Selection on with CO2 concentration. Through paleoclimate model simulations, find limitation was driver for advantage, atmospheric as high 600 ppm, thus confirming molecular-based estimates evolution Oligocene. Under these high-CO2 conditions, necessary. Low light, but not reallocation, drivers mid- late-Miocene global C4. also predicted timing spatial distribution origins dominance. are broadly consistent prior estimates, expand upon them include center origin northwest Africa Miocene-long Australia.