A test of the 'one-point method' for estimating maximum carboxylation capacity from field-measured, light-saturated photosynthesis
A test of the 'one-point method' for estimating maximum carboxylation capacity from field-measured, light-saturated photosynthesis
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DOI：
10.1111/nph.13815
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发表时间：
2016-05-01
期刊：
影响因子：
9.4
通讯作者：
Domingues, Tomas F.
中科院分区：
文献类型：
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作者：
De Kauwe, Martin G.;Lin, Yan-Shih;Domingues, Tomas F.
陆地生物圈模型对光合作用的模拟通常需要一个最大羧化速率（V-cmax）的规格。使用A-C-i曲线（净光合作用，A，相对于胞间CO2浓度，C-i）估计该参数是费力的，这限制了V-cmax数据的可用性。然而，许多多物种现场数据集包括净光合速率在饱和辐照度和环境大气CO2浓度（A（sat））的测量，从V-cmax可以提取使用一个点的方法。我们使用了A-C-i曲线的全球数据集（来自46个田间站点的564个物种，涵盖一系列植物功能类型）来测试通过这种一点法从A（sat）估计V-cmax的替代方法的有效性。如果能准确地知道叶片白天的呼吸强度，则可以估算V-cmax，其r（2）值为0.98，均方根误差（RMSE）为8.19molm（-2）s（-1）。然而，通常必须估计R日。将R-day估计为V-cmax的1.5%，我们发现V-cmax可以用0.95的r（2）和17.1molm（-2）s（-1）来估计。一点法提供了一个强大的手段来扩展目前的数据库的实地测量的V-cmax，提供新的潜力，以改善植被模型和量化的V-cmax变化的环境驱动因素。
Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate (V-cmax). Estimating this parameter using A-C-i curves (net photosynthesis, A, vs intercellular CO2 concentration, C-i) is laborious, which limits availability of V-cmax data. However, many multispecies field datasets include net photosynthetic rate at saturating irradiance and at ambient atmospheric CO2 concentration (A(sat)) measurements, from which V-cmax can be extracted using a one-point method'. We used a global dataset of A-C-i curves (564 species from 46 field sites, covering a range of plant functional types) to test the validity of an alternative approach to estimate V-cmax from A(sat) via this one-point method'. If leaf respiration during the day (R-day) is known exactly, V-cmax can be estimated with an r(2)value of0.98 and a root-mean-squared error (RMSE) of 8.19molm(-2)s(-1). However, R-day typically must be estimated. Estimating R-day as 1.5% of V-cmax,V- we found that V-cmax could be estimated with an r(2)of0.95 and an RMSE of 17.1molm(-2)s(-1). The one-point method provides a robust means to expand current databases of field-measured V-cmax, giving new potential to improve vegetation models and quantify the environmental drivers of V-cmax variation.