Photosynthetic properties of Quercus × hispanica Lam. and Q. suber L. under harsh Central European winter conditions

Abstract

In search for new forestation tree species for future Central European climate conditions, Mediterranean evergreen oak taxa are investigated for their summer drought-and winter frost-hardiness. Here we report on the winter performance of the photosynthetic apparatus of Quercus × hispanica Lam. and its evergreen parental species Q. suber L. under extraordinary harsh winter conditions. Both taxa showed a strong decline of photosystem II (PSII) quantum efficiency (F v /F m ) with a concomitant increase in the deepoxidation state (DES) of the xanthophyll pigments depending on (severe) frost events during winter, and these parameters significantly correlated with minimum air temperatures during periods of chronic photoinhibition at mid-winter, but not at the onset of winter in response to the first frost nights. F v /F m and DES correlated with each other in both taxa throughout the winter.

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

“…1C) only showed small or moderate declines in chl content, intermediate between the parental species but more similar to the evergreen parent. Intermediate behaviour of the hybrids during winter has also been found in other parameters (Holland & Br€ uggemann 2011;Pflug & Br€ uggemann 2012). The results of in vitro chlorophyll content analysis correlated significantly with the SPAD data in all taxa except Q. suber due to the similarity of all data points in this taxon.…”

“…Earlier studies on Mediterranean oaks in winter found similar results, i.e . the photosynthetic apparatus was practically unaffected as long as temperatures did not decrease below 0 to −5 °C (Holland & Brüggemann ; Pflug & Brüggemann ). In European oaks, the deciduous trait is realised in subgenus Quercus (including Q. robur , Q. frainetto , Q. pubescens ) and Q. cerris , which is part of a sister clade to the evergreen species of the subgenus Ilex (Papini et al .…”