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Intracanopy Adjustment Of Leaf-Level Thermal Tolerance Is Associated With Microclimatic Variation Across The Canopy Of A Desert Tree (Acacia Papyrocarpa), Ellen M. Curtis, Charles A. Knight, Andrea Leigh

Biological Sciences

Tree crowns are spatially heterogeneous, sometimes resulting in significant variation in microclimate across the canopy, particularly with respect to temperature. Yet it is not known whether such localised temperature variation equates to intracanopy variation in leaf-level physiological thermal tolerance. Here, we studied whether microclimate variation across the canopy of a dominant desert tree equated to localised variation in leaf thermal thresholds (T₅₀) among four canopy positions: upper south, upper north, lower south, lower north. Principal component analysis was used to generate a composite climatic stress variable (C_STRESS) from canopy temperature, vapour pressure deficit, and …