Michigan Technological University, Houghton, 49931, USA.
Environ Pollut. 2010 Apr;158(4):992-9. doi: 10.1016/j.envpol.2009.10.009. Epub 2009 Oct 24.
The effect of elevated CO(2) and O(3) on apparent quantum yield (varphi), maximum photosynthesis (P(max)), carboxylation efficiency (V(cmax)) and electron transport capacity (J(max)) at different canopy locations was studied in two aspen (Populus tremuloides) clones of contrasting O(3) tolerance. Local light climate at every leaf was characterized as fraction of above-canopy photosynthetic photon flux density (%PPFD). Elevated CO(2) alone did not affect varphi or P(max), and increased J(max) in the O(3)-sensitive, but not in the O(3)-tolerant clone. Elevated O(3) decreased leaf chlorophyll content and all photosynthetic parameters, particularly in the lower canopy, and the negative impact of O(3) increased through time. Significant interaction effect, whereby the negative impact of elevated O(3) was exaggerated by elevated CO(2) was seen in Chl, N and J(max), and occurred in both O(3)-tolerant and O(3)-sensitive clones. The clonal differences in the level of CO(2)xO(3) interaction suggest a relationship between photosynthetic acclimation and background O(3) concentration.
在两个具有不同臭氧耐受能力的白杨（Populus tremuloides）克隆中，研究了大气 CO2 和 O3 升高对不同冠层位置表观量子产量（varphi）、最大光合作用（P(max)）、羧化效率（V(cmax)）和电子传递能力（J(max)）的影响。每个叶片的局部光照条件用冠层上方光合光子通量密度的百分比（%PPFD）来表征。单独升高 CO2 不会影响 varphi 或 P(max)，并且增加了 O3 敏感克隆但未增加 O3 耐受克隆的 J(max)。大气 O3 降低了叶片叶绿素含量和所有光合作用参数，特别是在较低的冠层，并且 O3 的负面影响随时间增加。在 Chl、N 和 J(max)中观察到大气 O3 的负面影响被大气 CO2 升高放大的显著交互作用，并且在 O3 耐受和 O3 敏感克隆中都发生。CO2xO3 相互作用水平的克隆差异表明光合作用适应与背景 O3 浓度之间存在关系。
