Seasonal, diurnal and vertical variation in photosynthetic parameters in Phyllostachys humilis bamboo plants

In recent years, temperate bamboo species have been introduced in Europe for multiple uses such as renewable bio-based materials (wood, composites, fibres, biochemicals…) and numerous ecological functions (soil and water conservation, erosion control, phytoremediation…). Despite their interesting potential, little is known on the ecophysiology of these plants in their new habitat. Therefore, we studied gas exchange parameters on a full soil bamboo plantation of Phyllostachys humilis on a test field in Ireland (Europe). We evaluated the seasonal, diurnal and vertical variation of the parameters of two commonly used photosynthetic models, i.e. the light response curve (LRC) model and the model of Farquhar, von Caemmerer and Berry (FvCB). Furthermore, we tested if there were environmental effects on the photosynthetic parameters of these models and if a correlation between photosynthetic parameters and fluorescence parameters was present, fluorescence parameters can be easily and fast determined. Our results show that the gas exchange parameters do not vary diurnally or vertically. Only seasonal variations were found and should, therefore, be taken into account when using the LRC or FvCB model when modelling canopy growth. Therefore, a big-leaf model or a sunlit-shade model can be used for modelling bamboo growth in Western Europe. There is no straightforward relation between environmental variables and the photosynthetic parameters. Although fluorescence parameters showed a correlation with the photosynthetic parameters, application of such correlation may be limited.