Using a Full Spectral Raytracer for Calculating Light Microclimate in Functional-Structural Plant Modelling

Raytracers that allow the spatially explicit calculation of the fate of light beams in a 3D scene allow the consideration of shading, reflected and transmitted light in functional-structural plant models (FSPM). However, the spectrum of visible light also has an effect on cellular and growth processes. This recently created the interest to extend this modelling paradigm allowing the representation of detailed spectra instead of monochromatic or white light and to extend existing FSPM platforms accordingly. In this study a raytracer is presented which supports the full spectrum of light and which can be used to compute spectra from arbitrary light sources and their transformation at the organ level by absorption, reflection and transmission in a virtual canopy. The raytracer was implemented as an extension of the FSPM platform GroIMP

Using a Full Spectral Raytracer for Calculating Light Microclimate in Functional-Structural Plant Modelling

Raytracers that allow the spatially explicit calculation of the fate of light beams in a 3D scene allow the consideration of shading, reected and transmitted light in functional-structural plant models (FSPM). However, the spectrum of visible light also has an e ect on cellular and growth processes. This recently created the interest to extend this modelling paradigm allowing the representation of detailed spectra instead of monochromatic or white light and to extend existing FSPM platforms accordingly. In this study a raytracer is presented which supports the full spectrum of light and which can be used to compute spectra from arbitrary light sources and their transformation at the organ level by absorption,reection and transmission in a virtual canopy. The raytracer was implemented as an extension of the FSPM platform GroIMP

Helios: A Scalable 3D Plant and Environmental Biophysical Modeling Framework.

This article presents an overview of Helios, a new three-dimensional (3D) plant and environmental modeling framework. Helios is a model coupling framework designed to provide maximum flexibility in integrating and running arbitrary 3D environmental system models. Users interact with Helios through a well-documented open-source C++ API. Version 1.0 comes with model plug-ins for radiation transport, the surface energy balance, stomatal conductance, photosynthesis, solar position, and procedural tree generation. Additional plug-ins are also available for visualizing model geometry and data and for processing and integrating LiDAR scanning data. Many of the plug-ins perform calculations on the graphics processing unit, which allows for efficient simulation of very large domains with high detail. An example modeling study is presented in which leaf-level heterogeneity in water usage and photosynthesis of an orchard is examined to understand how this leaf-scale variability contributes to whole-tree and -canopy fluxes

3차원 식물모델을 이용한 LED 식물공장 재배 상추의 수광량 및 광합성 속도의 예측

학위논문(석사)--서울대학교 대학원 :농업생명과학대학 식물생산과학부(원예과학전공),2019. 8. 손정익.In plant factories, light use efficiency (LUE) should be improved to reduce electrical cost. To evaluate LUE, light interception should be estimated under different lighting conditions. The objective of this study was to estimate the light interception, photosynthetic rate, and LUE of lettuces grown under LEDs. 3D-scanned plant models and ray-tracing simulation were used to estimate the light interception. Canopy photosynthetic rate was estimated by modified Farquhar-von, Caemmerer-Berry (FvCB) model based on simulation result. To analyze the accuracy, measured light intensities and canopy photosynthetic rates in a growth chamber with LEDs were compared with simulated values. Under several scenarios, changes in light interception under different light environments were analyzed. Light intensities and canopy photosynthetic rates obtained by simulation showed good agreements with measured ones. Canopy light distribution was affected by planting distance, but whole light interception was almost similar. The canopy light interception was gradually increased with decreasing lighting distance, but rather decreased at too intact lighting due to heterogenetic light distribution. With high floor reflectance, canopy light interception was more increased at larger planting distance. It was confirmed that this method could quantify the light environments and photosynthetic rate at various electrical light conditions and is useful tool to estimate LUE in plant factories.식물공장에서 전기 에너지 비용을 줄이기 위해서는 광 이용 효율을 높이는 것이 요구되며, 광 이용 효율을 평가하기 위해서는 다양한 인공광 조건에 대한 작물 수광의 예측이 필요하다. 본 연구의 목적은 시뮬레이션 방법을 통해 인공광 환경 하에서 작물의 수광과 광합성 속도 및 광 이용 효율을 예측하는 것이다. 작물의 수광량 예측을 위하여 3차원 스캐너를 통해 구축된 식물 모델과 광 추적 시뮬레이션이 이용되었다. 작물 군락의 총 광합성은 수정된 Farquhar-von, Caemmerer-Berry (FvCB) 엽 광합성 모델과 시뮬레이션 결과를 바탕으로 추정되었다. 본 방법론의 정확성에 대한 검증은 실제 생장 챔버에서 측정된 광도와 광합성 속도를 시뮬레이션을 통해 얻어진 결과와 비교함으로써 이루어졌다. 또한 시나리오 분석을 통해 다양한 인공광 환경에서 작물 군락의 수광 변화를 분석하였다. 시뮬레이션을 통해 도출된 광도의 분포와 광합성 속도를 측정값과 비교한 결과 높은 정확성을 보이는 것이 확인되었다. 서로 다른 재식간격에서 군락 광 분포는 다르게 나타났지만 총 수광량은 유사하였다. 예측된 광합성 속도를 기반으로 광 이용 효율을 분석한 결과, 상추 군락의 재식 간격에 따른 광 이용 효율은 유사하였고 낮은 광도에서 약 30% 낮은 광 이용 효율을 보였다. 시나리오 분석 결과 광원과 군락 간의 거리가 멀어질수록 총 수광량은 점차적으로 감소하는 경향을 보였으나, 그 거리가 지나치게 가까울 경우 불균등한 광 분포로 인하여 오히려 수광량이 감소하였다. 재배상 표면에 높은 반사율을 적용하였을 경우에는 재식 간격이 클수록 총 수광량이 증가하였다. 본 연구에서 제시한 방법을 활용하여 식물공장의 광환경과 광합성 속도를 정량화하였고 광이용 효율을 추정할 수 있음이 확인되었다.INTRODUCTION 1 LITERATURE REVIEW 4 MATERIALS AND METHODS 7 RESULTS 19 DISCUSSION 32 CONCLUSION 38 LITERATURE CITED 39 ABSTRACT IN KOREAN 45 APPENDICE 47Maste

Integrating morphological and physiological responses of tomato plants to light quality to the crop level by 3D modeling

Next to its intensity, the spectral composition of light is one of the most important factors affecting plant growth and morphology. The introduction of light emitting diodes (LEDs) offers perspectives to design optimal light spectra for plant production systems. However, knowledge on the effects of light quality on physiological plant processes is still limited. The aim of this study is to determine the effects of six light qualities on growth and plant architecture of young tomato plants, and to upscale these effects to the crop level using a multispectral, functional-structural plant model. Young tomato plants were grown under 210 μmol m-2 s-1 blue, green, amber, red, white or red/blue (92%/8%) LED light with a low intensity of sunlight as background. Plants grown under blue light were shorter and developed smaller leaves which were obliquely oriented upward. Leaves grown under blue light contained the highest levels of light harvesting pigments, but when exposed to blue light only, they had the lowest rate of leaf photosynthesis. However, when exposed to white light these leaves had the highest rate of photosynthesis. Under green light, tomato plants were taller and leaves were nearly horizontally oriented, with a high specific leaf area. The open plant structure combined with a high light transmission and reflection at the leaf level allowed green light to penetrate deeper into the canopy. Plants grown under red, amber and white light were comparable with respect to height, leaf area and biomass production. The 3D model simulations indicated that the observed changes in plant architecture had a significant impact on light absorbance at the leaf and crop level. The combination of plant architecture and spectrum dependent photosynthesis was found to result in the highest rate of crop photosynthesis under red light in plants initially grown under green light. These results suggest that dynamic light spectra may offer perspectives to increase growth and production in high value production systems such as greenhouse horticulture and vertical farming.</p

Exploring and modelling the influence of spectral light composition on soybean (Glycine max (L.) Merr.)

The development of soybean cultivars for the climatic conditions in Europe is an urgent need in order to increase the European production and to decrease the dependence of imported soybean. A speed breeding system can accelerate the process of developing new cultivars by growing more generations per season in climate chambers. The project MoLED-Plant aimed towards the development of a speed breeding system for soybean under LED lighting. The major objectives of this thesis were to: (i) construct a three dimensional model of an LED chamber to simulate micro-light climate, (ii) develop a functional-structural plant (FSP) model of soybean and derive a blue photon flux density (BPFD) response curve from simulations, (iii) apply the FSP model with the integrated response curve for spectral optimization, (iv) explore the influence of BPFD under constant photosynthetic photon flux density (PPFD), and (v) disentangle the influence of red to far-red ratio (R:FR) and PPFD on the shade avoidance response (SAR). The objectives were fulfilled with a combination of FSP modelling in the Growth Grammar-related Interactive Modelling Platform (GroIMP) and plant experiments under multiple spectra in LED chambers. The presented LED chamber model was the first three dimensional environment, which was developed for spectral optimizations in indoor farming using FSP modeling. Measurements performed with a spectrometer in multiple heights and orientations were compared to simulations recorded with a virtual sensor at the same locations. The model was evaluated as a tool for assessment of spectral light heterogeneity under an alternative placement of the LED modules. Applying the model can assist in choosing the best chamber design and placements of LEDs to assure homogeneous light conditions. Subsequently, static soybean plants were incorporated into the chamber model. Comparison of light simulations and measurements from below the soybean canopy in four reconstructed scenarios assured a good simulation of micro-light climate. The model was applied to simulate the effect of an increased plant density in an experiment in the chamber. The simulations of light homogeneity in the experimental setup can assist in choosing the optimal design. The developed dynamic FSP model of soybean within the chamber model represents the first FSP model with an integrated response to BPFD. The soybean model was calibrated with data from BPFD experiments. From simulations, a common response curve of internode elongation to the perceived BPFD was derived for the second and third internode. The response curve was integrated in the model and was applied for spectral optimization in a chamber scenario with an alternative high reflective bottom material. The soybean response to BPFD under constant PPFD and the influence of R:FR and PPFD on SAR was explored by designing specific spectra from LEDs. Soybean experiments were performed under six levels of BPFD (60-310 µmol m-2 s-1) and constant PPFD (400 µmol m-2 s-1). Plant height and biomass decreased, leaf mass ratio increased and the ratio of stem biomass (internode plus petiole) translocated to the internode decreased under high BPFD. Three soybean cultivars were grown under nine light treatments to disentangle the effect of R:FR and PPFD. Internode elongation responded mainly to low PPFD with an additive effect from low R:FR, whereas petiole elongation was influenced to a great extent by low R:FR. In the context of SAR, petiole elongation can be seen as the main response to the threat of shade (high PPFD and low R:FR) and both petiole and internode elongation as the response to true shade (low PPFD and low R:FR). This thesis showed how PPFD, BPFD and R:FR work both independently, antagonistically and synergistically on the physiology and morphology of soybean. The increased insight in these responses can e.g. support crop breeding and spectral optimization in indoor farming. Furthermore, interesting and important objectives for future research were identified. These experiments should include physiological measurements for a deeper understanding of interactions and underlying mechanisms. Spectral optimization of indoor farming depends on the purpose of the production. For instance, a high BPFD of 260 µmol m-2 s-1 was optimal for speed breeding, whereas an intermediate BPFD would be preferable to increase biomass. Comprehensive investigation of spectral influence on plant physiology and morphology is necessary to fully utilize the spectral flexibility of LED lighting. The developed FSP model of soybean in a virtual LED chamber represents an important step towards utilizing the advantages of FSP modelling by simulation of a wide variety of scenarios. The model can be adjusted or extended depending on the purpose of the model. It can be calibrated for other crop species and the setting of the chamber dimensions can be changed.Die Züchtung von Sojabohnensorten für europäische Klimabedingungen ist eine dringende Notwendigkeit, um die europäische Produktion zu steigern. Speed-züchtung kann den Prozess der Entwicklung neuer Sorten beschleunigen, indem mehr Generationen pro Saison in Klimakammern wachsen. Das Projekt MoLED-Plant zielte auf die Entwicklung eines Speed-Züchtungssystems für Sojabohne unter LED-Beleuchtung ab. Wichtig für das Speed-Züchtungssystem war es, ein Spektrum zu definieren, dass die Blüte nicht verzögert, um die Ernte von mindestens einem Sojabohnensamen in kurzer Zeit zu ermöglichen. Außerdem sollte das Spektrum niedrige Pflanzen fördern, um Platz für mehr übereinanderstehende Pflanzen zu schaffen. Die Hauptziele dieser Arbeit waren: (i) ein dreidimensionales Modell einer LED-Kammer zur Simulation des Mikrolichtklimas zu konstruieren, (ii) ein funktional-strukturellen Pflanzen (FSP)-Modell von Sojabohne zu entwickeln und eine blauen Photonen-Flussdichte (BPFD)-Reaktionskurve aus Simulationen abzuleiten, (iii) das FSP-Modell mit der integrierten Reaktionskurve zur spektralen Optimierung anzuwenden, (iv) den BPFD unter konstanter photosynthetische Photonen-Flussdichte (PPFD) zu untersuchen und (v) den Einfluss von Rot-Fernrot-Verhältnis (R:FR) und PPFD auf Schattenvermeidungsreaktion (SAR) zu trennen. Die Ziele wurden mit einer Kombination aus FSP-Modellierung in der Growth Grammar-related Interactive Modelling Platform (GroIMP) und Pflanzenversuchen unter mehreren Spektren in LED-Kammern erreicht. Das vorgestellte LED-Kammermodell war die erste dreidimensionale Umgebung, die für spektrale Optimierungen des Indoor-Farmings mittels FSP-Modellierung entwickelt wurde. Messungen wurden mit einem Spektrometer in mehreren Höhen und Orientierungen durchgeführt und mit Simulationen verglichen, die mit einem virtuellen Sensor an den gleichen Stellen aufgezeichnet wurden. Das Modell wurde als Instrument zur Beurteilung der spektralen Lichtheterogenität mit einer alternativen Platzierung der LED-Module bewertet. Die Anwendung des Modells kann bei der Auswahl des besten Kammerdesigns und der besten LED-Platzierung helfen, um homogene Lichtverhältnisse zu gewährleisten. Anschließend wurden statische Pflanzen in das Kammermodell integriert. Der Vergleich von Lichtsimulationen und Messungen unterhalb der Sojablätter in vier rekonstruierten Szenarien stellte eine gute Simulation des Mikrolichtklimas sicher. Das Modell wurde angewendet, um den Effekt einer erhöhten Pflanzendichte auf die Lichthomogenität in der Kammer zu simulieren. Die Simulationen können bei der Auswahl des optimalen Versuchsaufbaus helfen. Das entwickelte dynamische FSP-Modell mit der Sojabohne innerhalb der Kammer stellt das erste FSP-Modell mit einer integrierten Reaktion auf die BPFD dar. Das Sojabohnenmodell wurde mit Daten aus BPFD-Versuchen kalibriert. Aus Simulationen wurden für das zweite und dritte Internodium eine gemeinsame Reaktionskurve der Internodienstreckung auf die wahrgenommene BPFD abgeleitet. Die Reaktionskurve wurde in das Modell integriert und zur spektralen Optimierung in einem Kammerszenario mit einem alternativen hochreflektierenden Bodenmaterial eingesetzt. Die Reaktion der Sojabohne auf BPFD bei konstanter PPFD und der Einfluss von R:FR und PPFD auf SAR wurde durch die Gestaltung spezifischer Spektren von LEDs untersucht. Es wurden Versuche mit Sojabohnen unter sechs Stufen von BPFD (60-310 µmol m-2 s-1) und konstanter PPFD (400 µmol m-2 s-1) durchgeführt. Pflanzenhöhe und Biomasse wurden verringert, das Blattmassenverhältnis wurde erhöht und der Anteil der Stängelbiomasse (Internodium plus Blattstiel), die in die Internodien verlagert wurde, nahm unter hoher BPFD ab. Drei Sojabohnensorten wurden unter neun Lichtbehandlungen angebaut, um den Einfluss von R:FR und PPFD zu trennen. Die Internodienstreckung reagierte hauptsächlich auf niedrige PPFD mit einem additiven Effekt von niedrigem R:FR, während die Blattstielstreckung weitestgehend durch niedriges R:FR beeinflusst wurde. Diese Arbeit zeigte, wie PPFD, BPFD und R:FR sowohl unabhängig als auch antagonistisch und synergistisch die Physiologie und Morphologie der Sojabohne beeinflussen. Der erhöhte Einblick in diese Reaktionen kann z.B. die Pflanzenzüchtung und die spektrale Optimierung im Indoor-Farming unterstützen. Außerdem wurden interessante und wichtige Ziele für die zukünftige Forschung identifiziert. Diese Versuche sollten physiologische Messungen zum tieferen Verständnis von Wechselwirkungen und zugrundeliegenden Mechanismen beinhalten. Das entwickelte FSP-Modell der Sojabohne in einer virtuellen LED-Kammer stellt einen wichtigen Schritt dar, um die Vorteile der FSP-Modellierung durch Simulation verschiedener Szenarien zu nutzen

Exploring and modelling the influence of spectral light composition on soybean (Glycine max (L.) Merr.)

The development of soybean cultivars for the climatic conditions in Europe is an urgent need in order to increase the European production and to decrease the dependence of imported soybean. A speed breeding system can accelerate the process of developing new cultivars by growing more generations per season in climate chambers. The project MoLED-Plant aimed towards the development of a speed breeding system for soybean under LED lighting. The major objectives of this thesis were to: (i) construct a three dimensional model of an LED chamber to simulate micro-light climate, (ii) develop a functional-structural plant (FSP) model of soybean and derive a blue photon flux density (BPFD) response curve from simulations, (iii) apply the FSP model with the integrated response curve for spectral optimization, (iv) explore the influence of BPFD under constant photosynthetic photon flux density (PPFD), and (v) disentangle the influence of red to far-red ratio (R:FR) and PPFD on the shade avoidance response (SAR). The objectives were fulfilled with a combination of FSP modelling in the Growth Grammar-related Interactive Modelling Platform (GroIMP) and plant experiments under multiple spectra in LED chambers. The presented LED chamber model was the first three dimensional environment, which was developed for spectral optimizations in indoor farming using FSP modeling. Measurements performed with a spectrometer in multiple heights and orientations were compared to simulations recorded with a virtual sensor at the same locations. The model was evaluated as a tool for assessment of spectral light heterogeneity under an alternative placement of the LED modules. Applying the model can assist in choosing the best chamber design and placements of LEDs to assure homogeneous light conditions. Subsequently, static soybean plants were incorporated into the chamber model. Comparison of light simulations and measurements from below the soybean canopy in four reconstructed scenarios assured a good simulation of micro-light climate. The model was applied to simulate the effect of an increased plant density in an experiment in the chamber. The simulations of light homogeneity in the experimental setup can assist in choosing the optimal design. The developed dynamic FSP model of soybean within the chamber model represents the first FSP model with an integrated response to BPFD. The soybean model was calibrated with data from BPFD experiments. From simulations, a common response curve of internode elongation to the perceived BPFD was derived for the second and third internode. The response curve was integrated in the model and was applied for spectral optimization in a chamber scenario with an alternative high reflective bottom material. The soybean response to BPFD under constant PPFD and the influence of R:FR and PPFD on SAR was explored by designing specific spectra from LEDs. Soybean experiments were performed under six levels of BPFD (60-310 µmol m-2 s-1) and constant PPFD (400 µmol m-2 s-1). Plant height and biomass decreased, leaf mass ratio increased and the ratio of stem biomass (internode plus petiole) translocated to the internode decreased under high BPFD. Three soybean cultivars were grown under nine light treatments to disentangle the effect of R:FR and PPFD. Internode elongation responded mainly to low PPFD with an additive effect from low R:FR, whereas petiole elongation was influenced to a great extent by low R:FR. In the context of SAR, petiole elongation can be seen as the main response to the threat of shade (high PPFD and low R:FR) and both petiole and internode elongation as the response to true shade (low PPFD and low R:FR). This thesis showed how PPFD, BPFD and R:FR work both independently, antagonistically and synergistically on the physiology and morphology of soybean. The increased insight in these responses can e.g. support crop breeding and spectral optimization in indoor farming. Furthermore, interesting and important objectives for future research were identified. These experiments should include physiological measurements for a deeper understanding of interactions and underlying mechanisms. Spectral optimization of indoor farming depends on the purpose of the production. For instance, a high BPFD of 260 µmol m-2 s-1 was optimal for speed breeding, whereas an intermediate BPFD would be preferable to increase biomass. Comprehensive investigation of spectral influence on plant physiology and morphology is necessary to fully utilize the spectral flexibility of LED lighting. The developed FSP model of soybean in a virtual LED chamber represents an important step towards utilizing the advantages of FSP modelling by simulation of a wide variety of scenarios. The model can be adjusted or extended depending on the purpose of the model. It can be calibrated for other crop species and the setting of the chamber dimensions can be changed.Die Züchtung von Sojabohnensorten für europäische Klimabedingungen ist eine dringende Notwendigkeit, um die europäische Produktion zu steigern. Speed-züchtung kann den Prozess der Entwicklung neuer Sorten beschleunigen, indem mehr Generationen pro Saison in Klimakammern wachsen. Das Projekt MoLED-Plant zielte auf die Entwicklung eines Speed-Züchtungssystems für Sojabohne unter LED-Beleuchtung ab. Wichtig für das Speed-Züchtungssystem war es, ein Spektrum zu definieren, dass die Blüte nicht verzögert, um die Ernte von mindestens einem Sojabohnensamen in kurzer Zeit zu ermöglichen. Außerdem sollte das Spektrum niedrige Pflanzen fördern, um Platz für mehr übereinanderstehende Pflanzen zu schaffen. Die Hauptziele dieser Arbeit waren: (i) ein dreidimensionales Modell einer LED-Kammer zur Simulation des Mikrolichtklimas zu konstruieren, (ii) ein funktional-strukturellen Pflanzen (FSP)-Modell von Sojabohne zu entwickeln und eine blauen Photonen-Flussdichte (BPFD)-Reaktionskurve aus Simulationen abzuleiten, (iii) das FSP-Modell mit der integrierten Reaktionskurve zur spektralen Optimierung anzuwenden, (iv) den BPFD unter konstanter photosynthetische Photonen-Flussdichte (PPFD) zu untersuchen und (v) den Einfluss von Rot-Fernrot-Verhältnis (R:FR) und PPFD auf Schattenvermeidungsreaktion (SAR) zu trennen. Die Ziele wurden mit einer Kombination aus FSP-Modellierung in der Growth Grammar-related Interactive Modelling Platform (GroIMP) und Pflanzenversuchen unter mehreren Spektren in LED-Kammern erreicht. Das vorgestellte LED-Kammermodell war die erste dreidimensionale Umgebung, die für spektrale Optimierungen des Indoor-Farmings mittels FSP-Modellierung entwickelt wurde. Messungen wurden mit einem Spektrometer in mehreren Höhen und Orientierungen durchgeführt und mit Simulationen verglichen, die mit einem virtuellen Sensor an den gleichen Stellen aufgezeichnet wurden. Das Modell wurde als Instrument zur Beurteilung der spektralen Lichtheterogenität mit einer alternativen Platzierung der LED-Module bewertet. Die Anwendung des Modells kann bei der Auswahl des besten Kammerdesigns und der besten LED-Platzierung helfen, um homogene Lichtverhältnisse zu gewährleisten. Anschließend wurden statische Pflanzen in das Kammermodell integriert. Der Vergleich von Lichtsimulationen und Messungen unterhalb der Sojablätter in vier rekonstruierten Szenarien stellte eine gute Simulation des Mikrolichtklimas sicher. Das Modell wurde angewendet, um den Effekt einer erhöhten Pflanzendichte auf die Lichthomogenität in der Kammer zu simulieren. Die Simulationen können bei der Auswahl des optimalen Versuchsaufbaus helfen. Das entwickelte dynamische FSP-Modell mit der Sojabohne innerhalb der Kammer stellt das erste FSP-Modell mit einer integrierten Reaktion auf die BPFD dar. Das Sojabohnenmodell wurde mit Daten aus BPFD-Versuchen kalibriert. Aus Simulationen wurden für das zweite und dritte Internodium eine gemeinsame Reaktionskurve der Internodienstreckung auf die wahrgenommene BPFD abgeleitet. Die Reaktionskurve wurde in das Modell integriert und zur spektralen Optimierung in einem Kammerszenario mit einem alternativen hochreflektierenden Bodenmaterial eingesetzt. Die Reaktion der Sojabohne auf BPFD bei konstanter PPFD und der Einfluss von R:FR und PPFD auf SAR wurde durch die Gestaltung spezifischer Spektren von LEDs untersucht. Es wurden Versuche mit Sojabohnen unter sechs Stufen von BPFD (60-310 µmol m-2 s-1) und konstanter PPFD (400 µmol m-2 s-1) durchgeführt. Pflanzenhöhe und Biomasse wurden verringert, das Blattmassenverhältnis wurde erhöht und der Anteil der Stängelbiomasse (Internodium plus Blattstiel), die in die Internodien verlagert wurde, nahm unter hoher BPFD ab. Drei Sojabohnensorten wurden unter neun Lichtbehandlungen angebaut, um den Einfluss von R:FR und PPFD zu trennen. Die Internodienstreckung reagierte hauptsächlich auf niedrige PPFD mit einem additiven Effekt von niedrigem R:FR, während die Blattstielstreckung weitestgehend durch niedriges R:FR beeinflusst wurde. Diese Arbeit zeigte, wie PPFD, BPFD und R:FR sowohl unabhängig als auch antagonistisch und synergistisch die Physiologie und Morphologie der Sojabohne beeinflussen. Der erhöhte Einblick in diese Reaktionen kann z.B. die Pflanzenzüchtung und die spektrale Optimierung im Indoor-Farming unterstützen. Außerdem wurden interessante und wichtige Ziele für die zukünftige Forschung identifiziert. Diese Versuche sollten physiologische Messungen zum tieferen Verständnis von Wechselwirkungen und zugrundeliegenden Mechanismen beinhalten. Das entwickelte FSP-Modell der Sojabohne in einer virtuellen LED-Kammer stellt einen wichtigen Schritt dar, um die Vorteile der FSP-Modellierung durch Simulation verschiedener Szenarien zu nutzen

Consequences of interplant trait variation for canopy light absorption and photosynthesis

Plant-to-plant variation (interplant variation) may play an important role in determining individual plant and whole canopy performance, where interplant variation in architecture and photosynthesis traits has direct effects on light absorption and photosynthesis. We aimed to quantify the importance of observed interplant variation on both whole-plant and canopy light absorption and photosynthesis. Plant architecture was measured in two experiments with fruiting tomato crops (Solanum lycopersicum) grown in glasshouses in the Netherlands, in week 16 (Exp. 1) or week 19 (Exp. 2) after transplanting. Experiment 1 included four cultivars grown under three supplementary lighting treatments, and Experiment 2 included two different row orientations. Measured interplant variations of the architectural traits, namely, internode length, leaf area, petiole angle, and leaflet angle, as well as literature data on the interplant variation of the photosynthesis traits alpha, Jmax28, and Vcmax28, were incorporated in a static functional–structural plant model (FSPM). The FSPM was used to analyze light absorption and net photosynthesis of whole plants in response to interplant variation in architectural and photosynthesis traits. Depending on the trait, introducing interplant variation in architecture and photosynthesis traits in a functional–structural plant model did not affect or negatively affected canopy light absorption and net photosynthesis compared with the reference model without interplant variation. Introducing interplant variation of architectural and photosynthesis traits in FSPM results in a more realistic simulation of variation of plants within a canopy. Furthermore, it can improve the accuracy of simulation of canopy light interception and photosynthesis although these effects at the canopy level are relatively small (&lt;4% for light absorption and&lt;7% for net photosynthesis)