Department of Biology, 572 Rivers St., Appalachian State University, Boone, NC 28608, USA.
Environ Pollut. 2012 Jan;160(1):74-81. doi: 10.1016/j.envpol.2011.09.010. Epub 2011 Oct 14.
Ozone-sensitive and -tolerant individuals of cutleaf coneflower (Rudbeckia laciniata L.) were compared for their gas exchange characteristics and total non-structural carbohydrates at Purchase Knob, a high elevation site in Great Smoky Mountains National Park, USA. Photosynthesis and stomatal conductance decreased with increased foliar stipple. Sensitive plants had lower photosynthetic rates for all leaves, except the very youngest and oldest when compared to tolerant plants. Stomatal conductance decreased with increasing leaf age, but no ozone-sensitivity differences were found. Lower leaves had less starch than upper ones, while leaves on sensitive plants had less than those on tolerant plants. These results show that ambient levels of ozone in Great Smoky Mountains National Park can adversely affect gas exchange, water use efficiency and leaf starch content in sensitive coneflower plants. Persistence of sensitive genotypes in the Park may be due to physiological recovery in low ozone years.
比较了美国大烟山国家公园高海拔地点 Purchase Knob 的皱叶金鸡菊（Rudbeckia laciniata L.）的臭氧敏感型和耐受型个体，分析了它们的气体交换特征和总非结构性碳水化合物。随着叶斑的增加，光合作用和气孔导度降低。与耐受型植株相比，敏感型植株除了最年轻和最老的叶片外，所有叶片的光合作用速率都较低。气孔导度随叶片年龄的增加而降低，但未发现臭氧敏感性差异。下部叶片的淀粉含量低于上部叶片，而敏感型植株叶片的淀粉含量低于耐受型植株叶片。这些结果表明，大烟山国家公园的环境臭氧水平可能会对敏感型金鸡菊植物的气体交换、水分利用效率和叶片淀粉含量产生不利影响。在公园中，敏感型基因型的存在可能是由于在低臭氧年份中的生理恢复。
