The impact of heterogeneity in stomatal anatomical characters on stomatal function and physiology in wheat

Factors affecting food insecurity include the effects of climate change, losses of agricultural land to urbanization and increasing competition for non-food uses of crops. Stomatal anatomical characteristics including stomatal denFactors affecting food insecurity include the effects of climate change, losses of agricultural land to urbanization and increasing competition for non-food uses of crops. Stomatal anatomical characteristics including stomatal density (SD), size (SS) and pore aperture determine stomatal conductance (gs) where changes in anatomy impact gs and photosynthetic assimilation (A) which is known to be linked with crop yield. This study presents heterogeneity of SD and SS between elite MAGIC wheat cultivars (EW) and wheat wild relatives (WWR), and the affect these changes had on stomatal kinetics. Results propose that WWR may be better-able to deal with elevated temperatures and dynamic light environments due to faster stomatal kinetics and higher gs facilitating greater evaporative cooling in well-watered condition, however, where water is less available, higher gs would have deleterious effects; the ‘slow and steady’ approach found in EW is more beneficial. To explore differences in stomatal anatomy between the two leaf surfaces a novel gas chamber was constructed to measure separate but simultaneous leaf gas exchange of each leaf surface in real time. The adaxial leaf surface boasted higher SD, higher gs and A compared with the abaxial leaf surface and when the abaxial leaf surface gs was blocked, the leaf could not compensate for the loss, suggesting that both leaf surfaces are crucial to overall leaf gs and A, albeit with unequal contributions. Differences in wheat species with varying ploidy grown at differing CO2 concentrations revealed that diploid species have a reduced SD and increased SS in plants grown at elevated CO2 concentrations whereas tetraploid species showed the opposite. Furthermore, although gs changed between ploidy, it did not affect the overall A. The interest in understanding plant adaptations and natural variants with interesting anatomical features are to assist in targeting traits for enhanced water-use efficiency and, moreover, crop productivity.sity (SD), size (SS) and pore aperture determine stomatal conductance (gs) where changes in anatomy impact gs and photosynthetic assimilation (A) which is known to be linked with crop yield. This study presents heterogeneity of SD and SS between elite MAGIC wheat cultivars (EW) and wheat wild relatives (WWR), and the affect these changes had on stomatal kinetics. Results propose that WWR may be better-able to deal with elevated temperatures and dynamic light environments due to faster stomatal kinetics and higher gs facilitating greater evaporative cooling in well-watered condition, however, where water is less available, higher gs would have deleterious effects; the ‘slow and steady’ approach found in EW is more beneficial. To explore differences in stomatal anatomy between the two leaf surfaces a novel gas chamber was constructed to measure separate but simultaneous leaf gas exchange of each leaf surface in real time. The adaxial leaf surface boasted higher SD, higher gs and A compared with the abaxial leaf surface and when the abaxial leaf surface gs was blocked, the leaf could not compensate for the loss, suggesting that both leaf surfaces are crucial to overall leaf gs and A, albeit with unequal contributions. Differences in wheat species with varying ploidy grown at differing CO2 concentrations revealed that diploid species have a reduced SD and increased SS in plants grown at elevated CO2 concentrations whereas tetraploid species showed the opposite. Furthermore, although gs changed between ploidy, it did not affect the overall A. The interest in understanding plant adaptations and natural variants with interesting anatomical features are to assist in targeting traits for enhanced water-use efficiency and, moreover, crop productivity.