PJB-2021-612
Effects of elevated temperature and CO2 concentration on plant growth and leaf photosynthesis associated with changes in stomatal traits, leaf anatomy, and foliar carbohydrates of winter wheat (Triticum aestivum L.)
Zhijie Chang
Abstract
Understanding the key processes and potential mechanisms of crops in response to elevated atmospheric CO2 concentration and climate warming may further shed lights on the impacts of climate change on global agriculture productivity. Here, we examined the effects of elevated CO2 concentration (e[CO2]), experimental warming (Warming) and the two combined environmental factors (e[CO2] × Warming) on the plant biomass, stomatal traits, leaf gas exchange, foliar anatomy and biochemistry as well as the Rubisco activity and gene express of winter wheat with environmental growth chambers, where the temperature was set at 21/16°C (day/night) or 26/21°C and the CO2 concentration was controlled at 400 µmol mol−1 or 800 µmol mol−1, respectively. We found that the plant biomass and leaf photosynthesis were dramatically decreased by e[CO2] × Warming (all p<0.05), although elevated temperature and CO2 concentration barely changed the biomass accumulation and net photosynthetic rate of winter wheat (all p>0.05). This down-regulation of leaf photosynthesis at e[CO2] × Warming may partially attribute to the limited effect of CO2 diffusion processes relating to the declined regularity of stomata distribution, as evidenced by the decrease of stomatal conductance under e[CO2] × Warming. Furthermore, the accumulation of nonstructural carbohydrates in leaves of winter wheat also contributed to the declines of leaf photosynthesis and plant biomass at e[CO2] × Warming. Our results suggest that current process-based ecological models may overestimate the CO2 fertilization effect on winter wheat, and meanwhile underestimate the impacts of climate change on global wheat production when the elevated atmospheric CO2 concentration confounded with warming under future climate change.
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