Stomatal behavior of ozone-sensitive and -insensitive coneflowers ( Rudbeckia laciniata var. digitata ) in Great Smoky Mountains National Park

Abstract

• Morphological and physiological attributes were assessed to elucidate the underlying mechanisms of ozone (O₃) sensitivity in a highly sensitive species, cutleaf coneflower (Rudbeckia laciniata var. digitata). • Foliage at the same height in the canopy on paired O₃-sensitive and -insensitive cutleaf coneflowers was assessed for level of foliar symptoms, stomatal density, stomatal responsiveness to dynamic changes in light and leaf-to-air vapor pressure deficit (VPD), steady-state responses to light and CO₂, intrinsic transpirational efficiency, and plant water balance. • There were no morphological differences between the sensitivity types that might have contributed to greater O₃ uptake in sensitive individuals. Stomata of sensitive plants were less responsive than those of insensitive plants to experimentally increased and decreased light intensities, and to increased VPD. O₃-insensitive plants had greater intrinsic transpirational efficiencies, greater maximum assimilation rates under saturating CO₂ and light, and greater carboxylation rates. • Different physiological attributes vary independently within an individual plant, which collectively confer sensitivity or insensitivity to O₃ injury.

Citation

Grulke, N. E.; Neufeld, H. S.; Davison, A. W.; Roberts, M.; Chappelka, A. H. 2006. Stomatal behavior of ozone-sensitive and -insensitive coneflowers ( Rudbeckia laciniata var. digitata ) in Great Smoky Mountains National Park . New Phytologist. 173(1): 100-109. https://doi.org/10.1111/j.1469-8137.2006.01872.x.