LEAFC3-N photosynthesis, stomatal conductance, transpiration and energy balance model: Finite mesophyll conductance, drought stress, stomata ratio, optimized solution algorithms, and code

Can the Responses of Photosynthesis and Stomatal Conductance to Water and Nitrogen Stress Combinations Be Modeled Using a Single Set of Parameters?

“…Some efforts have been devoted to predict g s under drought conditions using the BWB-type model by introducing proper approaches to adjust parameter values used in the model. In general, most studies kept g 0 (residual stomatal conductance when the irradiance approaches to zero) as a fixed value and adjusted the value for the slope (roughly represents a 1 and b 1 in the BWB-Leuning-Yin model used in our study) by introducing a modifying factor of soil moisture (Egea et al, 2011; Li et al, 2012), or precipitation and evaporation (Baldocchi, 1997), or predawn xylem water potential (Sala and Tenhunen, 1996), or leaf nitrogen content and leaf water potential (Müller et al, 2014). Leuning (1995) suggested that the BWB-type model should be able to predict g s under water-deficit conditions by only adjusting the value for a 1 .…”

“…However, a 1 and b 1 were little affected by nitrogen availability (Table 4) and no correlation between a 1 and N a , nor between b 1 and N a , under different water and nitrogen conditions was found in our study. The approach introducing a modifying factor of leaf nitrogen content on the slope (Müller et al, 2014) is able to predict g s in response to drought, and this could merely be due to similar responses of leaf nitrogen content and the slope to soil water condition rather than because a functional relationship exists between the slope and leaf nitrogen content. Our study did not present a quantitative relationship of a 1 and b 1 with water supply conditions since there were only two water-level treatments.…”

“…The coupled FvCB and BWB model has been increasingly used to model photosynthesis in response to environmental changes such as elevated CO 2 (Harley et al, 1992) and drought stress (Keenan et al, 2010; Müller et al, 2014) and seasonal changes (Kosugi et al, 2003). Normally in those previous studies, values of the biochemical parameters were related to the leaf nitrogen content and values of the stomatal conductance model parameters were changed according to the CO 2 level (Harley et al, 1992), leaf water potential (Müller et al, 2014), or growth season (Kosugi et al, 2003).…”

“…The original BWB-type model does not capture stomatal responses to soil water status, thus some efforts were made toward modifying the BWB-type model to predict g s under drought. Either the slope used in the BWB-type model (describing the response of g s to photosynthetic rate, relative humidity or vapor pressure deficit (VPD) and CO 2 concentration) (Tuzet et al, 2003; Maseyk et al, 2008; Héroult et al, 2013) or the residual stomatal conductance (the value of g s when irradiance approaches to zero) (Misson et al, 2004) was reported to decrease under drought, and was related to soil moisture or leaf water potential (Baldocchi, 1997; Wang and Leuning, 1998; Misson et al, 2004; Keenan et al, 2010; Egea et al, 2011; Li et al, 2012; Zhou et al, 2013; Müller et al, 2014). In another study, however, neither of these two parameters was affected by drought (Xu and Baldocchi, 2003).…”

Editorial of the Special Issue of the 4th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications (PMA’12)

“…Complex physical processes are considered at the organ level in order to simulate leaf gas exchanges (Müller et al, 2014), leaf starch dynamics (Feugier and Satake, 2014) or phloem transport in trees (Sellier and Harrington, 2014). A mechanistic eco-evolutionary model coupling water uptake and light interception was developed based on a schematic description of plant structure and aiming to understand the role of deep roots on plant diversity and drought (Lindh et al, 2014).…”