Abstract: Intrinsic water use efficiency (iWUE) is an important trait that influences crop productivity. Building on recent work that highlighted a strong correlation between iWUE and leaf width (LW) in diverse C4 grasses, I aimed to identify leaf morphological traits that correlate with high iWUE in C4 Sorghum. The general objectives were to 1) find out how leaf anatomical features covary 2) how the coordination of those anatomical variables influences gas exchange and 3) how do those relationships respond to environmental pressure such as different growth temperature. In short, Stomatal conductance (gs) and LW correlated negatively with iWUE across genotypes and growth temperatures. Stomatal size and operational aperture were the main determinants of gs, not stomatal density. Narrow leaves were characterised by higher vein density, smaller epidermal, mesophyll and bundle sheath cell sizes, lower cross-sectional surface area of intercellular airspaces and were generally thinner. Ultimately, Increasing growth temperature increased LW likely due to cell expansion, and not cell division.

Biography: I complete my Bachelor of Science (2014) and Master of Science (2017) at the University of Essex, UK. Where I was part of Prof. Tracy Lawson’s lab. My BSc and MSc theses both concentrated on the anatomical and physiological evolution of lineages that evolved under different CO2 concentrations. In September 2017, I came to Australia to start my PhD in A/Prof. Oula Ghannoum’s group at the Hawkesbury Institute for the Environment, Western Sydney University. My thesis generally examined controls on intrinsic water use efficiency in the C4 crop Sorghum bicolor. I submitted my thesis in April 2021 and I’m currently awaiting my results!