INTERACTION OF OZONE POLLUTION AND LIGHT EFFECTS ON PHOTOSYNTHESIS IN A FOREST CANOPY EXPERIMENT
INTERACTION OF OZONE POLLUTION AND LIGHT EFFECTS ON PHOTOSYNTHESIS IN A FOREST CANOPY EXPERIMENT
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DOI：
10.1111/j.1365-3040.1995.tb00598.x
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发表时间：
1995-08-01
影响因子：
7.3
通讯作者：
REICH, PB
中科院分区：
文献类型：
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作者：
TJOELKER, MG;VOLIN, JC;REICH, PB
臭氧污染可能会减少森林中的净碳增益，但来自成熟树木的数据很少，光照对光合作用对臭氧的响应的影响仍未得到验证，我们使用了一个露天系统，暴露10个分支内的18米高的糖枫（Acer saccharum Marsh）的上层树冠。相对于10对未处理的对照组（45 nmol mol mol（-1）），在3个月内，将分支对置于两倍环境浓度的臭氧（95 nmol mol mol（-1），0900至1700，1 h平均值）中。沿着对从相对高的辐照度（PPFD 14.5 mol m（-2）d（-1））至深阴影（0.7 mol m（-2）d（-1））的梯度选择。臭氧减少光饱和速率的净光合作用（A（sat））和增加暗呼吸高达56酸40%，分别。与阳光叶片相比，遮荫叶片表现出更大的比例减少A（sat）和较低的叶绿素浓度，量子效率，和叶片吸收率与臭氧处理时，相对于对照组。随着时间的推移，随着臭氧剂量的增加，A（sat）成为脱钩从气孔导度的内部到外部的二氧化碳浓度的比例增加，降低水的利用效率。臭氧降低净光合作用和受损的气孔功能，这些影响取决于冠层叶片的辐照环境，增加臭氧的敏感性阴叶片相比，阳光叶片冠层净碳增益的后果。
Ozone pollution may reduce net carbon gain in forests, yet data from mature trees are rare and the effects of irradiance on the response of photosynthesis to ozone remain untested, We used an open-air system to expose 10 branches within the upper canopy of an 18-m-tall stand of sugar maple (Acer saccharum Marsh.) to twice-ambient concentrations of ozone (95 nmol mol(-1), 0900 to 1700, 1 h mean) relative to 10 paired, untreated controls (45 nmol mol(-1)) over 3 months, The branch pairs were selected along a gradient from relatively high irradiance (PPFD 14.5 mol m(-2) d(-1)) to deep shade (0.7 mol m(-2) d(-1)). Ozone reduced light-saturated rates of net photosynthesis (A(sat)) and increased dark respiration by as much as 56 acid 40%, respectively, Compared to sun leaves, shade leaves exhibited greater proportional reductions in A(sat) and had lower chlorophyll concentrations, quantum efficiencies, and leaf absorptances when treated with ozone relative to controls. With increasing ozone dose over time, A(sat) became uncoupled from stomatal conductance as ratios of internal to external concentrations of carbon dioxide increased, reducing water-use efficiency. Ozone reduced net photosynthesis and impaired stomatal function, with these effects depending on the irradiance environment of the canopy leaves, Increased ozone sensitivity of shade leaves compared to sun leaves has consequences for net carbon gain in canopies.