Intraspecific variation in stomatal architecture, gas exchange, and drought response of a dominant prairie grass sourced from broad climatic gradients.

premiseUnderstanding how plant populations adapt to water limitation through stomatal traits is key to predicting drought responses. The dominant C

methodsWe measured stomatal architecture and gas exchange in 25 populations sourced across temperature (4-21°C) and precipitation (350-1400 mm yr⁻¹) gradients under well-watered conditions. Eight populations (precipitation: 472-1356 mm yr⁻¹) were then subjected to drought (~15% moisture) or were well-watered (30% control) to assess trait plasticity. Stomatal traits were measured using epidermal peels and light microscopy, gas exchange with a LI-COR 6400, and network analyses were used to characterize adaptive strategies.

resultsArid populations exhibited smaller, denser stomata compared to wet populations, and networks demonstrated a trade-off between stomatal size and density. In the experimental drought, stomatal size decreased. while density increased, with dry populations showing fewer changes than wet populations. Key traits in the network were stomatal size and water-use efficiency.

conclusionsAndropogon gerardi demonstrated adaptive changes in stomatal architecture. Our findings emphasize the interplay between adaptation and climate, providing important insights into how plants may respond to increased droughts.