Elevated CO₂ response of photosynthesis depends on ozone concentration in aspen

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• 作者：Asko Noormets ; Olevi Kull ; Anu Sô ; ber ; Mark E. Kubiske ; David F. Karnosky
• 关键词：Electron transport ; Elevated CO₂ ; Elevated O₃ ; Interactive effects of elevated CO₂ ; O₃ and light ; Leaf photochemistry ; Light harvesting
• 刊名：Environmental Pollution
• 出版年：2010
• 出版时间：April 2010
• 年：2010
• 卷：158
• 期：4
• 页码：992-999
• 全文大小：442 K

文摘

The effect of elevated CO₂ and O₃ on apparent quantum yield (), 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 O₃ tolerance. Local light climate at every leaf was characterized as fraction of above-canopy photosynthetic photon flux density ( % PPFD). Elevated CO₂ alone did not affect or P_max, and increased J_max in the O₃-sensitive, but not in the O₃-tolerant clone. Elevated O₃ decreased leaf chlorophyll content and all photosynthetic parameters, particularly in the lower canopy, and the negative impact of O₃ increased through time. Significant interaction effect, whereby the negative impact of elevated O₃ was exaggerated by elevated CO₂ was seen in Chl, N and J_max, and occurred in both O₃-tolerant and O₃-sensitive clones. The clonal differences in the level of CO₂ × O₃ interaction suggest a relationship between photosynthetic acclimation and background O₃ concentration.