Towards a 3d Structural Tomato Model for Calculating Light Interception

Abstract

A number of physiological tomato models have been proposed the last decades, their main challenge being the correct simulation of fruit yield. For this, an accurate simulation of light interception, and thus photosynthesis, is of primary importance. Light interception is highly dependent of the canopy structure which is affected amongst others by distance between plant rows, distance of plants within the row, leaf pruning and crop variety. In order to simulate these processes, a functional structural tomato model for the simulation of light interception on an individual leaf basis is proposed. The 3D model was constructed using L-systems formalism. For the architectural part of the model, manual measurements of leaf length, width, angle of the leaf main stem to plant stem and leaf orientation were conducted. The diurnal pattern of leaf orientation was also tested. The architectural model was coupled with a nested radiosity model for light calculation. Area per individual leaflet served as input of the light module for calculation of reflection, absorption and transmission of light. The model was used to test different crop planting scenarios on their effect on light interception. Results were then compared with light simulation for a totally homogeneous canopy. INTRODUCTIONA number of tomato models have been proposed over the years (e.g., Gary et al., 1995;Marcelis et al., 1998Marcelis et al., , 2009 Heuvelink, 1999; Boote and Scholberg, 2006). These models offer an accurate description of plant growth and its interactions with the environment providing a useful tool in our understanding of plant functioning. Although they make a distinction between different plant organs, they do not consider the plant structure in space. Especially functions like light interception, environmental plant adaptation, competition within and between species for light or nutrients, and assimilate allocations cannot be easily explained if plant structure in space is not taken into account.Functional-structural plant models (FSPM) or virtual plant models (Hanan, 1997;Sievänen et al., 2000; Godin and Sinoquet, 2005;Vos et al., 2007) are terms used to refer to models explicitly describing the development in time of the 3D architecture or structure of plants as driven by physiological processes. These physiological processes are the result of environmental factors. Functional-structural plant models were proposed the last decade as a means to investigate the function of plant structure in plant development combining traditional plant modeling with a 3D structure (Vos et al., 2007). For light extinction in particular the knowledge of how the plant develops in space is essential. So the use of such a model for light calculations would probably improve our knowledge of light distribution inside the crop canopy.Light extinction inside a plant canopy can reach up to 60% while for a crop canopy the light extinction can be up to 90% (Valladares, 2003). This variation in incident light availability inside the crop canopy induces extensi...

Crop growth and development in closed and semi-closed greenhouses

“…The light intercepted by the canopy is determined by LAI and light extinction coefficient (k). Light interception by the canopy is highly affected by canopy structure, which depends on plant density, leaf pruning, growth conditions and variety (Sarlikioti et al 2011a). In our research, the LAI and k were the same for the semi-closed greenhouse and open greenhouse (Fig.…”

Variability in light absorption and photosynthesis within tomato canopies: a 3D model assisted analysis

“…Various FSPM studies have been conducted for greenhouse cultivated crops, such as cutrose (Buck-Sorlin et al, 2011;Zhang et al, 2021) and tomato (Sarlikioti et al, 2009;Sarlikioti et al, 2011b;Kang et al, 2011;de Visser et al, 2010;de Visser et al, 2014). Those studies aim to either optimize lighting strategies, plant architecture or planting densities to increase interception of light.…”