The relationships between photosynthesis and stomatal traits on the Loess Plateau

Stomata control the water loss for transpiration and the CO₂ uptake for photosynthesis. However, the relationships between photosynthesis and stomatal traits across a wide range of species are largely been unknown. Here, we tested the relationships among maximum photosynthetic rate (A_max), stomatal density (SD), stomatal length (SL) and maximum stomatal conductance to water vapour (g_max) across 45 woody plants on the Loess Plateau. We found the correlations of stomatal traits with A_max and g_max were different. Specifically, g_max was positively correlated with SD. A_max was negatively correlated with SD and positively correlated with SL, which were inconsistent with previous findings focusing on a few of species. Our results indicated that plants with large and few stomata could possess low g_max and maintain an appropriate photosynthetic rate, suggesting that it will benefit plants under increased CO₂ and decreased water availability environments in the future. Indeed, further work is needed to investigate the effects of stomata, mesophyll and biochemical process on photosynthesis under different environmental conditions.