Special issue in honour of Prof. Reto J. StrasserSeasonal monitoring of PSII functionality and relative chlorophyll content on a field site in two consecutive years: A case study of different oak species

2020 Photosynthetica (Praha)  
In search for practical silvicultural management tools to identify alternative tree species for predicted Central European climate conditions, a cross-species survey with five evergreen, semi-evergreen, and deciduous Quercus taxa with contrasting morphological leaf traits was performed. Fast chlorophyll fluorescence induction of PSII and relative leaf chlorophyll contents were performed to assess the overall plant vitality at any point in time during two complete vegetation periods in
more » ... eriods in consecutive years (2012 and 2013). Maximum photochemical efficiency of PSII and the performance index on absorption base showed a very conservative relationship to each other and a similar intra-annual progress in all deciduous species, but with a different speed of increase and decrease during leaf development and senescence and thus a different length of vegetation period. The intra-annual variability of OJIP and chlorophyll content parameters is considered with respect to the practicability of measurements in the field for management purposes. Abbreviations: Chl -chlorophyll; doy -day of year; F -fluorescence; M0 -approximated initial slope of the fluorescence transient; PIabs -performance index on absorption basis; Q. -Quercus; RC/ABS -QA reducing reaction centres per PSII antenna; ϕPo -maximum photochemical efficiency of PSII; ψEo -probability that an electron moves further than QA -. Acknowledgments: The present study was financially supported by the research funding programme 'LOEWE -The Landes-Offensive in development of scientific and economic excellence in Hesse'. bility of key functional leaf traits for the estimation of plant vitality in oak species of differing natural distributions and adaptations have been monitored under Central European conditions in a common garden type forest experimental plantation in Southern Hesse. Alterations in morphological and pigment leaf traits, changes in the fast chlorophyll (Chl) fluorescence induction transient, and phenological alterations are responses of plants to their environment which occur at different time scales, intensities, and taxa specificity, affecting the potential carbon acquisition capacity of a leaf to different degrees. During leaf development, the leaf is a carbon sink (Thomas and Ougham 2014) and the structure for light capturing is built with species-specific differences in the amount of invested biomass per area of potential light harvest (Wright et al. 2004 ). The concomitant increase in pigments per chloroplast and chloroplasts per cell determine the maximal light-harvesting capacity per time and area (De Pury and Farquhar 1997) . On the larger time scale, the potential annual carbon acquisition is furthermore determined by the time of bud break, the end of leaf development, the length of the core vegetation time, the beginning of senescence, and the rate of decline during senescence. At the level of the chloroplast, the
doi:10.32615/ps.2019.163 fatcat:zydsxauchbbaja2efsqkhrk7yu