叶片气体交换测量是推断植物光合生化的重要工具。在大多数情况下,光合CO2同化对可变细胞间CO2浓度的响应(A/Ci响应曲线)用于模拟通过核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco,Vcmax)和给定入射光合有效辐射通量密度(PAR;JPAR)下的光合电子传输速率。标准的Farquhar-vonCaemmerer-Berry模型通常与Rubisco动力学值和源自烟草的叶肉对CO2的电导率(gm)的默认参数一起使用,这些参数可能不适用于物种。为了研究使用这些参数对其他物种的意义,在这里,我们测量了棉花中关键的体外Rubisco催化特性和gm的温度响应(陆地棉cv。Sicot71)并从棉花A/Ci曲线中导出Vcmax和J2000(在2000µmolm-2s-1PAR下的JPAR,该曲线在15°C-40°C下使用棉花和其他特定物种的输入参数集通过我们的新型自动拟合R包“OptiFitACi”增量测量。值得注意的是,通过一组烟草参数进行参数化,在25°C下产生不切实际的J2000:Vcmax比率<1,高于15°C的Vcmax估计值高出两到三倍,J2000的估计值高达2.3倍,Vcmax和J2000的变量估计值高达2.3倍,对于我们的棉花数据,与具有棉花衍生值的模型参数化进行比较。我们确定使用gm时会出现错误,25的2.3molm-2s-1MPa-1或更低,在25°C下21%O2(KC21%O2)中的RubiscoCO2-亲和力超出46-63Pa的范围,以模拟A/Ci在棉花中的响应。我们展示了“OptiFitACi”的A/Ci建模能力是如何作为一个强大的,用户友好,通过提供简化的温度敏感性和物种特异性参数化功能来减少Vcmax和J2000建模时的变异性,从而灵活扩展“plantechophis”。
Leaf gas exchange measurements are an important tool for inferring a plant\'s photosynthetic biochemistry. In most cases, the responses of photosynthetic CO2 assimilation to variable intercellular CO2 concentrations (A/Ci response curves) are used to model the maximum (potential) rate of carboxylation by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, Vcmax) and the rate of photosynthetic electron transport at a given incident photosynthetically active radiation flux density (PAR; JPAR). The standard Farquhar-von Caemmerer-Berry model is often used with default parameters of Rubisco kinetic values and mesophyll conductance to CO2 (gm) derived from tobacco that may be inapplicable across species. To
study the significance of using such parameters for other species, here we measured the temperature responses of key in vitro Rubisco catalytic properties and gm in cotton (Gossypium hirsutum cv. Sicot 71) and derived Vcmax and J2000 (JPAR at 2000 µmol m-2 s-1 PAR) from cotton A/Ci curves incrementally measured at 15°C-40°C using cotton and other species-specific sets of input parameters with our new automated fitting R package \'OptiFitACi\'. Notably, parameterisation by a set of tobacco parameters produced unrealistic J2000:Vcmax ratio of <1 at 25°C, two- to three-fold higher estimates of Vcmax above 15°C, up to 2.3-fold higher estimates of J2000 and more variable estimates of Vcmax and J2000, for our cotton data compared to model parameterisation with cotton-derived values. We determined that errors arise when using a gm,25 of 2.3 mol m-2 s-1 MPa-1 or less and Rubisco CO2-affinities in 21% O2 (KC 21%O2) at 25°C outside the range of 46-63 Pa to model A/Ci responses in cotton. We show how the A/Ci modelling capabilities of \'OptiFitACi\' serves as a robust, user-friendly, and flexible extension of \'plantecophys\' by providing simplified temperature-sensitivity and species-specificity parameterisation capabilities to reduce variability when modelling Vcmax and J2000.