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Sweet Pepper ( Capsicum annuum L.) Canopy Photosynthesis Modeling Using 3D Plant Architecture and Light Ray-Tracing

View Article: PubMed Central - PubMed

ABSTRACT

Canopy photosynthesis has typically been estimated using mathematical models that have the following assumptions: the light interception inside the canopy exponentially declines with the canopy depth, and the photosynthetic capacity is affected by light interception as a result of acclimation. However, in actual situations, light interception in the canopy is quite heterogenous depending on environmental factors such as the location, microclimate, leaf area index, and canopy architecture. It is important to apply these factors in an analysis. The objective of the current study is to estimate the canopy photosynthesis of paprika (Capsicum annuum L.) with an analysis of by simulating the intercepted irradiation of the canopy using a 3D ray-tracing and photosynthetic capacity in each layer. By inputting the structural data of an actual plant, the 3D architecture of paprika was reconstructed using graphic software (Houdini FX, FX, Canada). The light curves and A/Ci curve of each layer were measured to parameterize the Farquhar, von Caemmerer, and Berry (FvCB) model. The difference in photosynthetic capacity within the canopy was observed. With the intercepted irradiation data and photosynthetic parameters of each layer, the values of an entire plant's photosynthesis rate were estimated by integrating the calculated photosynthesis rate at each layer. The estimated photosynthesis rate of an entire plant showed good agreement with the measured plant using a closed chamber for validation. From the results, this method was considered as a reliable tool to predict canopy photosynthesis using light interception, and can be extended to analyze the canopy photosynthesis in actual greenhouse conditions.

No MeSH data available.


Daily changes in CO2 concentration in the closed chamber with light intensity above the plant on 15 October 2014.
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Figure 2: Daily changes in CO2 concentration in the closed chamber with light intensity above the plant on 15 October 2014.

Mentions: To measure the daily CO2 consumption of an entire plant, a closed chamber (1 × 1 × 2 m) was designed and constructed using transparent polycarbonate. A closed chamber on the photosynthesis system was set at 25°C for the leaf temperature and 60–70% for the relative humidity (Figure 1); this is referred to as an open chamber system (Garcia et al., 1990). The CO2 concentration inside the chamber was set to range between 80 and 200 Pa to measure the photosynthesis rate of the entire plant while maintaining a CO2 level above the saturation points (Shin et al., 2011). An additional supply of CO2 gas was implemented when the CO2 concentration in the chamber was ~80 Pa. The CO2 concentrations inside the chamber were detected using a CO2 analyser (LI-820, LI-COR, USA). CO2 leakage of the chamber was about 0.2–0.3 μmol CO2 s−1 under the experimental CO2 condition (Figure S1). Irradiance inside the chamber was measured using an irradiation sensor (BF5, Delta-T Devices, UK) and the diffuse ratio was also determined. To maintain the temperature and CO2 concentration inside the chamber, two radiators circulating cool water were placed along each sidewall. A fan was passed through the radiators and blown toward the chamber wall to maintain equal ventilation. The temperature inside the chamber was maintained at 25°C by circulating cooled water controlled by a condenser (DH-003A, Daeho-condenser, Korea). The CO2 concentration, irradiance, and temperature inside the chamber were stored in a data logger every 10 s. Silica gel was used in the air circulation process to control increased humidity from the transpiration of the plant. A plant was selected from among five samples and was placed in the chamber from 9:00 to 18:00. Whenever the CO2 concentration reached approximately 100 Pa, additional CO2 was supplied to retain a saturated CO2 condition (Figure 2).


Sweet Pepper ( Capsicum annuum L.) Canopy Photosynthesis Modeling Using 3D Plant Architecture and Light Ray-Tracing
Daily changes in CO2 concentration in the closed chamber with light intensity above the plant on 15 October 2014.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016622&req=5

Figure 2: Daily changes in CO2 concentration in the closed chamber with light intensity above the plant on 15 October 2014.
Mentions: To measure the daily CO2 consumption of an entire plant, a closed chamber (1 × 1 × 2 m) was designed and constructed using transparent polycarbonate. A closed chamber on the photosynthesis system was set at 25°C for the leaf temperature and 60–70% for the relative humidity (Figure 1); this is referred to as an open chamber system (Garcia et al., 1990). The CO2 concentration inside the chamber was set to range between 80 and 200 Pa to measure the photosynthesis rate of the entire plant while maintaining a CO2 level above the saturation points (Shin et al., 2011). An additional supply of CO2 gas was implemented when the CO2 concentration in the chamber was ~80 Pa. The CO2 concentrations inside the chamber were detected using a CO2 analyser (LI-820, LI-COR, USA). CO2 leakage of the chamber was about 0.2–0.3 μmol CO2 s−1 under the experimental CO2 condition (Figure S1). Irradiance inside the chamber was measured using an irradiation sensor (BF5, Delta-T Devices, UK) and the diffuse ratio was also determined. To maintain the temperature and CO2 concentration inside the chamber, two radiators circulating cool water were placed along each sidewall. A fan was passed through the radiators and blown toward the chamber wall to maintain equal ventilation. The temperature inside the chamber was maintained at 25°C by circulating cooled water controlled by a condenser (DH-003A, Daeho-condenser, Korea). The CO2 concentration, irradiance, and temperature inside the chamber were stored in a data logger every 10 s. Silica gel was used in the air circulation process to control increased humidity from the transpiration of the plant. A plant was selected from among five samples and was placed in the chamber from 9:00 to 18:00. Whenever the CO2 concentration reached approximately 100 Pa, additional CO2 was supplied to retain a saturated CO2 condition (Figure 2).

View Article: PubMed Central - PubMed

ABSTRACT

Canopy photosynthesis has typically been estimated using mathematical models that have the following assumptions: the light interception inside the canopy exponentially declines with the canopy depth, and the photosynthetic capacity is affected by light interception as a result of acclimation. However, in actual situations, light interception in the canopy is quite heterogenous depending on environmental factors such as the location, microclimate, leaf area index, and canopy architecture. It is important to apply these factors in an analysis. The objective of the current study is to estimate the canopy photosynthesis of paprika (Capsicum annuum L.) with an analysis of by simulating the intercepted irradiation of the canopy using a 3D ray-tracing and photosynthetic capacity in each layer. By inputting the structural data of an actual plant, the 3D architecture of paprika was reconstructed using graphic software (Houdini FX, FX, Canada). The light curves and A/Ci curve of each layer were measured to parameterize the Farquhar, von Caemmerer, and Berry (FvCB) model. The difference in photosynthetic capacity within the canopy was observed. With the intercepted irradiation data and photosynthetic parameters of each layer, the values of an entire plant's photosynthesis rate were estimated by integrating the calculated photosynthesis rate at each layer. The estimated photosynthesis rate of an entire plant showed good agreement with the measured plant using a closed chamber for validation. From the results, this method was considered as a reliable tool to predict canopy photosynthesis using light interception, and can be extended to analyze the canopy photosynthesis in actual greenhouse conditions.

No MeSH data available.