The photosynthetic rates of leaves depend on the vertical position and cultivation conditions. However, few models have been proposed to express photosynthesis according to leaf position, and there was a lack of quantitative analysis between physiological indicators and model parameters. The objectives of this study were to analyze the leaf photosynthetic characteristics of paprika plants according to leaf vertical position using photosynthesis models, and to analyze the relationship between the total nitrogen content and the photosynthetic model parameters. Leaf photosynthetic rates at different vertical positions were measured under varying light intensities and CO 2 concentrations in triplicate. Rectangular hyperbola and FvCB (Farquhar, von Caemmerer, and Berry) models were selected, calibrated, and validated as multivariable photosynthesis models. Total nitrogen contents and SPAD values were measured at each leaf position and the coefficients of the photosynthetic rate models were compared. The R 2 values for the rectangular hyperbola and FvCB models were 0.86 and 0.91, and the RMSE values were 4.651 and 2.104, respectively. Total nitrogen content linearly increased with increasing vertical leaf position and it was linearly related to the maximum carboxylation capacity and maximum electron transport rate, estimated in the FvCB model. In this study, the FvCB model was considered more suitable for expressing the relationship between total nitrogen contents and plant’s physiological responses according to the vertical position of leaves. The vertical leaf photosynthetic rate models established in this study will contribute to determining optimal environmental conditions for maximizing crop photosynthesis and establish the criteria for precise CO 2 enrichment in greenhouses.

中文翻译：

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使用多变量光合作用模型根据垂直位置分析水培辣椒 (Capsicum annuum L.) 植物的叶片光合速率

叶片的光合速率取决于垂直位置和栽培条件。然而，很少有人提出根据叶片位置来表达光合作用的模型，并且缺乏生理指标和模型参数之间的定量分析。本研究的目的是利用光合作用模型根据叶片垂直位置分析辣椒植物的叶片光合特性，并分析总氮含量与光合模型参数之间的关系。在不同的光强度和 CO 2 浓度下测量不同垂直位置的叶片光合速率，一式三份。矩形双曲线和 FvCB（Farquhar、von Caemmerer 和 Berry）模型被选择、校准、并验证为多变量光合作用模型。在每个叶片位置测量总氮含量和SPAD值，并比较光合速率模型的系数。矩形双曲线和 FvCB 模型的 R 2 值分别为 0.86 和 0.91，RMSE 值分别为 4.651 和 2.104。总氮含量随着垂直叶片位置的增加而线性增加，并且与 FvCB 模型中估计的最大羧化能力和最大电子传输速率线性相关。在本研究中，FvCB 模型被认为更适合根据叶片的垂直位置表达总氮含量与植物生理反应之间的关系。