Estimation of light absorption by plants in situations with artificial light : Contribution of 3 dimensional virtual plants in Helianthus annuus and Arabidopsis

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Estimation of light absorption by plants in situations with artificial light :

Contribution of 3 dimensional virtual plants in

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and Arabidopsis

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1INRA, UMR lEPSE, 2 place Viala, 34060 Montpellier, France - chenu@supagroJnra.fr

2ClRAD, UMR AMAP, Montpellier, F-34398 France 35upAgro, UMR LEPSE, 2 place Viala, 34060 Montpellier, France

Aim -

Light interception is a major componen! of biomass production. Classical approaches

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adapled for experimental situations wilh artificial lighting. Models of 30 virtual plants and light calculalfon were used here to calculate lhe light

balance for Arabido{}sis andHelianlhusplants grown in growth chamber and greenhouse.

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Construction of 3D virtual plants

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Virtual plants were built from measurements

performed on plant over development (Fig. 2) using the piani archiiecture simulator AMAPsim (Barczi

et al. in press) for different genoiypes of

Arabidopsis (Chenu et al. 2005 and 2007) and Helianihus (Rey et al. in press),

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Variability of incident light in artificial situations

Artificial lighting and supporting structures make incident light very heterogeneous in

growth chamber and greenhouse (FIQ. 1). The spatial variability of incident and

directional light were characterised for eaCtl experimental zone and each lighting situation (e.g. natural tlght plus artificial lights of the greenhouse). Data were integraled in the light calculation model ARCHIMED (Dauzat et al. In press)

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30 virtual plants are placed in virtual plot where the MMR mOdel

simuiates the tight cJimate and

calculates the amount of light

absorbed by the plant.

The fraction of intercepted light was

adequately simulated wlth a

coefficient determination of 0.990 and CVe Iower than 4% (Fig. 4).

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Measuremeoto 30 plant Viflual scene Absorbed rad,aticlt

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Estimation of light absorption

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Comparison with classical method of estimation of absorbed radiation

lnArebidopsis, estimation of light absorption by the product plant Ieaf

area x incident light shouk:l be adjusted by a correction factor, genotype-specifie. The developed mOdel allows to estimate Ihis factor for different genoiypes.

ln Helianfhus, the Beer's law is an efficient way to estimate light

absorption for developeo' crop in field, whereas 30 virtual plant coupled with microclimatic model are still adapted for other situations such as eany stages of crop development, or culture in artificial light environments.

Conclusion •

Coupling 3D virtual plants with -a radiative model allows the estimation of light

interception in any situations. This is of particular interest for artificial environments such as growth

chamber and greenhouse, or for situations where cJassical approaches are not appropriate,e.g. for early

developed crop in field when plants are small and the canopy highty helerog8n80us.

The daveloped mOdel also allows comparisons between genoiypes and studies on plant architecture plasticily through the impact of various architectural traits on plantlight interceptiOn.

References

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ct..u K et .1. (2005\ fUl'Cliorull PWiI ElioIogy 32,"23-11300.

ct..uKet.1.12007) ,..,., F'I1j'101Og1s1175:.n-78',

Oou<a1JetIl...1.of 6otony...PI"'· RIyH Il .1. AnnoISofBolotly,inPI'"