Photosynthesis studies on European evergreen and deciduous oaks grown under Central European climate conditions: II. Photoinhibitory and light-independent violaxanthin deepoxidation and downregulation of photosystem II in evergreen, winter-acclimated European Quercus taxa

Abstract

In the context of the search for future forestry species in Central Europe under climate change scenarios, the evergreen Mediterranean Quercus taxa Q. ilex ssp. ilex and Q. suber and the semideciduous hybrids. Q. 9 turneri and Q. 9 hispanica were studied in relation to their photochemical efficiency of photosystem II and to the activity of the xanthophyll cycle under Central European winter conditions. The evergreen taxa were remarkably insensitive to winter stress in the field and reacted towards frost periods with the phenomenon of ''chronic photoinhibition'', i.e. a decrease in pre-dawn F v /F m and an increase in the deepoxidation state of the xanthophylls. Under dark and warmer conditions (room temperature), winter-acclimated leaves of the evergreen taxa except for Q. 9 turneri produced zeaand antheraxanthin and decreased F v /F m , possibly by creation of a chlororespiratory pH-gradient. It is suggested that the ability for dark violaxanthin deepoxidation may contribute to the winter hardiness of the evergreen taxa.

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

“…Recently, Peguero-Pina et al (2009) showed that only Q. ilex and not Q. suber uses high predawn DES as a photoprotective mechanism under summer drought conditions. Our data of short-term frost effects (Brüggemann et al 2009) and the present field study indicate that Q. suber, however, may well use high morning DES as a photoprotective mechanism under winter frost stress conditions, and it inherits this trait to the hybrid, Q. × hispanica.…”

“…3E,F) or the two processes are not coupled at this stage of winter acclimation. It has been shown earlier that in winter-acclimated evergreen Quercus and other sclerophyllous species F v /F m and DES often are (Verhoeven et al 1999, Brüggemann et al 2009), but need not always be (Fig. 3 in Martinez-Ferri et al 2004) coupled to each other.…”

“…× hispanica showed increases of the deepoxidation state (DES) of the ---xanthophyll pigments, i.e. a conversion of viola-(V) to anthera-(A) and zeaxanthin (Z) (Brüggemann et al 2009). Similar punctual findings have been reported for Q. ilex (e.g.…”

“…Frost hardiness of Q. ilex and Q. suber tissues has been reported to reach significantly below -20°C (Larcher 2000); however, severe frost-induced xylem embolism may occur at much milder frost degrees and may significantly affect the plants during springtime until either refilling of the vessels or new vessel formation is possible (Nardini et al 2000, Cavender-Baras et al 2005, with Q. suber being regarded as slightly less frosttolerant than Q. ilex. Under severe winter conditions, the evergreen Mediterranean species Q. ilex and Q. suber showed transient strong decreases of the efficiency of PSII, as evaluated by the gross annual courses of the chlorophyll (Chl) fluorescence parameter F v /F m (Aranda et al 2005, Brüggemann et al 2009). At subzero temperatures, winter-acclimated Q. suber and Q.…”

Photosynthesis studies on European evergreen and deciduous oaks grown under Central European climate conditions. I: a case study of leaf development and seasonal variation of photosynthetic capacity in Quercus robur (L.), Q. ilex (L.) and their semideciduous hybrid, Q. × turneri (Willd.)

“…We here present evidence that such intermittent decreases of photosynthetic activity during winter are not necessarily just a result of changing weather conditions influencing the measurements in situ, but may well reflect either reversible ''damage'' of the photosynthetic apparatus by ''dynamic'' photoinhibition or down-regulation of PS II by ''chronic'' photoinhibition (Adams et al 2004). Evidence for this interpretation has been found in an adjacent survey (Brüggemann et al 2009). It can, however, not be ruled out, that low, especially sub-freezing temperatures, may also have affected other cellular components such as membrane integrity or enzymatic activity of Calvin cycle enzymes.…”