Estimation of Whole Plant Photosynthetic Rate of Irwin Mango under Artificial and Natural Lights Using a Three-Dimensional Plant Model and Ray-Tracing

Abstract

Photosynthesis is an important physiological response for determination of CO2 fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango (Mangifera indica L. cv. Irwin) grown in greenhouses. In the case of mangoes, it is difficult to measure actual light interception at the canopy level due to their vase shape. A two-year-old Irwin mango tree was used to measure the whole plant photosynthetic rate. Light interception and whole plant photosynthetic rate were measured under artificial and natural light conditions using a closed chamber (1 × 1 × 2 m). A 3D plant model was constructed and ray-tracing simulation was conducted for calculating the photosynthetic rate with a two-variable leaf photosynthetic rate model of the plant. Under artificial light, the estimated photosynthetic rate increased from 2.0 to 2.9 μmolCO2·m−2·s−1 with increasing CO2 concentration. On the other hand, under natural light, the photosynthetic rate increased from 0.2 μmolCO2·m−2·s−1 at 06:00 to a maximum of 7.3 μmolCO2·m−2·s−1 at 09:00, then gradually decreased to −1.0 μmolCO2·m−2·s−1 at 18:00. In validation, simulation results showed good agreement with measured results with R2 = 0.79 and RMSE = 0.263. The results suggest that this method could accurately estimate the whole plant photosynthetic rate and be useful for pruning and adequate CO2 fertilization.

Plant phenotyping relevance

3D植物モデルとレイトレーシングにより個体全体の光合成速度を推定する手法を開発・検証しており、植物生理形質の取得が研究の中心です。

Code and data availability

The article describes 3D plant model construction, ray-tracing simulation, and whole-plant photosynthesis measurements of Irwin mango, but contains no data availability statement, no public dataset or image deposit, and no code/model availability language. The only URL present is the standard CC BY license notice, and

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