| Patchy stomatal conductance, wherein stomata are coordinated at small scales and discoordinated at large scales, affects scaling of gas exchange measurements and implies interactions among stomata. A model of leaf gas exchange was used to determine how patchy conductance distributions influence the leaf-scale relationship between photosynthesis rate and within-leaf CO2 level; bimodal, right-skewed, and left-shifted conductance distributions most significantly affected this relationship. A model of leaf energy balance and gas exchange was used to characterize the topology of the leaf-scale relationship between photosynthesis and transpiration rates, and to study effects of patchiness on carbon-water balance under various topological regimes; patchiness improved carbon-water balance in leaves that were strongly decoupled from the air or exposed to high air temperatures or radiation loads. To study interactions between patches, transpiration was varied independently in two adjacent regions of a wheat leaf; conductance responded in a manner consistent with xylem-mediated hydraulic interactions. |
