Insight into the photosynthetic apparatus in evergreen and deciduous European oaks during autumn senescence using OJIP fluorescence transient analysis

Abstract

Climate change is one of the major issues nowadays, and Mediterranean broadleaf species have been suggested to fill possible future gaps created by climate change in Central European forests. To provide a scientific-based foundation for such practical strategies, it is important to obtain a general idea about differences and similarities in the physiology of Central European and Mediterranean species. In the present study, we evaluated the onset of leaf senescence of a broad spectrum of oak species under the Central European climate in a common garden experiment. Degradation of the photosynthetic apparatus of evergreen (Quercus ilex, Q. suber), semi-evergreen (Q.×turneri, Q.×hispanica) and deciduous oaks (Q. robur, Q. cerris, Q. frainetto, Q. pubescens) was monitored as chlorophyll content and analysed chlorophyll fluorescence induction transients. In the deciduous species, a significant decline in chlorophyll content was observed during autumn/winter, with Q. pubescens showing the slowest decline. Analysis of fluorescence induction transients revealed a significant decline in quantum efficiency of the primary photochemistry and reaction centre density and later, a decrease in quantum efficiency of end acceptor reduction. Alterations in fluorescence parameters were compared to the decline in chlorophyll content, which occurred much more slowly than expected from the fluorescence data. The evergreen species showed no decline in chlorophyll content, nor different chlorophyll a fluorescence induction behaviour despite temperature falling below 0 °C. The hybrids showed intermediate behaviour between their parental evergreen and deciduous taxa.

Special issue in honour of Prof. Reto J. Strasser - The JIP-test as a tool for forestry in times of climate change

“…The strong shading of Q. frainetto at SAN probably resulted in an earlier onset of (partial) leaf yellowing (senescence) already in September, as reflected in lower Chl contents (data not shown). Decreasing RC/ABS ratios have also been reported during leaf senescence in oaks, with Q. frainetto showing stronger and much earlier effects than Q. pubescens (Holland et al 2014).…”

Special issue in honour of Prof. Reto J. Strasser - Seasonal variation and trade-off between frost resistance and photosynthetic performance in woody species

“…They are quicker and simpler to describe photosynthetic performance than measuring photosynthetic rates (Strasser and Srivastava 1995, Strasser et al 2000, Bucher et al 2018a. Chl fluorescence has been proven to indicate plant stress, such as ozone stress (Clark et al 2000), water stress (Živčák et al 2008), temperature stress, such as frost or heat (Neuner et al 1999, Maxwell and Johnson 2000, Neuner and Pramsohler 2006, Sharma et al 2015, Bucher et al 2018c, as well as the onset of autumn senescence (Holland et al 2014).…”

“…Plants harden in autumn and gradually deharden in spring, reducing the investment in FR during the summer (Aulitzky 1961, Sakai and Larcher 1987, Körner 2003, Neuner and Pramsohler 2006, Bucher et al 2018b. Photosynthetic rates usually show higher values in summer and lower in winter (Larcher 1994, Öquist and Huner 2003, Adams et al 2004, Neuner and Pramsohler 2006, Holland et al 2014, Bucher et al 2018b. Chloroplasts break down very early during leaf senescence, so metabolically, carbon assimilation is replaced by catabolism of the Chl and other macromolecules (Lim et al 2007).…”

Variations in seasonal drought tolerance rankings

“…), this occurred on the 23rd September 2015 (autumn). Initial measurements for each season were confirmed to demonstrate a "normal" polyphasic OJIP fluorescence rise to ensure immaturity or senescence would not influence results (data not shown) (Holland et al 2014). Immediately after removal, all leaves were sealed in Ziploc plastic bags and kept in the dark while being transferred to the laboratory.…”

“…'Emerald Queen' Upright when young, leaves have a reddish Ɵnt in spring and are bright yellow in autumn (Hillier 1993) Less tolerant than 'Summershade' similar to 'Deborah' (Fini et al 2009). One of the best Norway Maples for urban planƟngs (Dirr 1990).…”