SCALING CARBON-DIOXIDE AND WATER-VAPOR EXCHANGE FROM LEAF TO CANOPY IN A DECIDUOUS FOREST .1. LEAF MODEL PARAMETRIZATION
SCALING CARBON-DIOXIDE AND WATER-VAPOR EXCHANGE FROM LEAF TO CANOPY IN A DECIDUOUS FOREST .1. LEAF MODEL PARAMETRIZATION
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DOI：
10.1111/j.1365-3040.1995.tb00625.x
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发表时间：
1995-10-01
影响因子：
7.3
通讯作者：
BALDOCCHI, DD
中科院分区：
文献类型：
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作者：
HARLEY, PC;BALDOCCHI, DD
为了对冠层气体交换模型中的叶片子模型进行参数化，对白色栎叶片进行了一系列光合作用和气孔导度的测量（Quercus alba L.）和红枫（Acer rubrum L）在田纳西州橡树岭附近的成熟落叶林中，测定了30 m冠层顶部阳生叶和3-4 m深阴生叶的气体交换特性。在叶温为30摄氏度时，测定的净光合速率和饱和光合光子通量密度（以叶面积为基础表示），阴生叶（7.9 μ mol m（-2）s（-1））显著低于阳生叶（11.5 μ mol m（-2）s（-1））（P = 0.01; n = 8）。比叶面积随冠层深度的增加而显著增加，当光合速率以干物质表示时，阴生叶和阳生叶的光合速率无显著差异，叶氮含量随冠层高度的变化不显著;因此，以每单位氮为基础表示的比率在遮荫叶和阳光叶中也没有显着差异，一个广泛使用的光合作用和气孔导度模型被独立地参数化为阳和阴叶片，使我们能够成功地模拟光合作用和蒸散的日变化的两类叶片，光合作用模型的关键参数被发现与叶片氮水平成比例，叶模型参数化，然后被纳入到一个冠层尺度的气体交换模型，讨论和测试的配套文件（Baldocchi和哈雷1995年，植物，细胞和环境18，1157-1173）。
In order to parametrize a leaf submodel of a canopy level gas-exchange model, a series of photosynthesis and stomatal conductance measurements were made on leaves of white oak (Quercus alba L,) and red maple (Acer rubrum L,) in a mature deciduous forest near Oak Ridge, TN, Gas-exchange characteristics of sun leaves growing at the top of a 30 m canopy and of shade leaves growing at a depth of 3-4 m from the top of the canopy were determined, Measured rates of net photosynthesis at a leaf temperature of 30 degrees C and saturating photosynthetic photon flux density, expressed on a leaf area basis, were significantly lower (P = 0.01; n = 8) in shade leaves (7.9 mu mol m(-2) s(-1)) than in sun leaves (11.5 mu mol m(-2) s(-1)). Specific leaf area increased significantly with depth in the canopy, and when photosynthesis rates were expressed on a dry mass basis, they were not significantly different for shade and sun leaves, The percentage leaf nitrogen did not vary significantly with height in the canopy; thus, rates expressed on a per unit nitrogen basis were also not significantly different in shade and sun leaves, A widely used model integrating photosynthesis and stomatal conductance was parametrized independently for sun and shade leaves, enabling us to model successfully diurnal variations in photosynthesis and evapotranspiration of both classes of leaves, Key photosynthesis model parameters were found to scale with leaf nitrogen levels, The leaf model parametrizations were then incorporated into a canopy-scale gas-exchange model that is discussed and tested in a companion paper (Baldocchi & Harley 1995, Plant, Cell and Environment 18, 1157-1173).