Journal Article

Susceptibility to low-temperature photoinhibition in three conifers differing in successional status

Piotr Robakowski

in Tree Physiology

Volume 25, issue 9, pages 1151-1160
Published in print September 2005 | ISSN: 0829-318X
Published online September 2005 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/25.9.1151
Susceptibility to low-temperature photoinhibition in three conifers differing in successional status

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Susceptibility to photoinhibition of the evergreen conifers Abies alba Mill., Picea abies (L.) Karst. and Pinus mugo Turra was investigated in an unheated greenhouse during winter and spring 2003. Photosynthetic performance of the seedlings was assessed by chlorophyll a fluorescence and analyses of chlorophyll and total carotenoid concentrations in needles. During winter months, maximum quantum yield of PSII photochemistry (ratio of variable to maximum fluorescence, Fv/Fm) was significantly greater in A. alba than in P. abies and P. mugo. Abies alba also sustained higher maximum apparent electron transport rate (ETRmax) than P. abies and P. mugo. Total concentrations of chlorophyll and carotenoids in needles decreased during the winter in P. mugo and P. abies, but remained stable in A. alba. For all species, Fv/Fm decreased from December until February and then increased to a maximum in April. Photoinhibition was greatest (Fv/Fm < 0.80) in all seedlings in February, the month with the lowest mean temperature. Saturating photosynthetic photon flux (PPFsat) and ETRmax were positively related to air temperature. All species had lower values of ETRmax and PPFsat in winter than in spring. Non-photochemical quenching of chlorophyll fluorescence (NPQ) was highest at low air temperatures. Differences among species in susceptibility to winter photoinhibition resulted from their specific light preferences and led to different mechanisms to cope with photoinhibitory stress. The more shade-tolerant A. alba sustained a higher photosynthetic capacity in winter than P. abies and P. mugo. Winter photoinhibition in P. abies, P. mugo and, to a lesser extent, in A. alba may reflect adaptive photoprotection of the photosynthetic apparatus in winter.

Keywords: Abies alba; carotenoids; chlorophyll; chlorophyll a fluorescence; light response curves; photosynthetic capacity; Picea abies; Pinus mugo; winter temperatures

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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