COLD-HARDENING-INDUCED RESISTANCE TO PHOTOINHIBITION OF PHOTOSYNTHESIS IN WINTER RYE IS DEPENDENT UPON AN INCREASED CAPACITY FOR PHOTOSYNTHESIS
1993 (English)In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 189, no 1, 150-156 p.Article in journal (Refereed) Published
Analyses of chlorophyll fluorescence and photosynthetic oxygen evolution were conducted to understand why cold-hardened winter rye (Secale cereale L.) is more resistant to photoinhibition of photosynthesis than is non-hardened winter rye. Under similar light and temperature conditions, leaves of cold-hardened rye were able to keep a larger fraction of the PS II reaction centres in an open configuration, i.e. a higher ratio of oxidized to reduced Q(A) (the primary, stable quinone acceptor of PSII), than leaves of non-hardened rye. Three fold-higher photon fluence rates were required for cold-hardened leaves than for non-hardened leaves in order to establish the same proportion of oxidized to reduced Q(A). This ability of cold-hardened rye fully accounted for its higher resistance to photoinhibition; under similar redox states of Q(A) cold-hardened and non-hardened leaves of winter rye exhibited similar sensitivities to photoinhibition. Under given light and temperature conditions, it was the higher capacity for light-saturated photosynthesis in cold-hardened than in non-hardened leaves, which was responsible for maintaining a higher proportion of oxidized to reduced Q(A). This higher capacity for photosynthesis of cold-hardened leaves also explained the increased resistance of photosynthesis to photoinhibition upon cold-hardening.
Place, publisher, year, edition, pages
1993. Vol. 189, no 1, 150-156 p.
IdentifiersURN: urn:nbn:se:umu:diva-46872ISI: A1993KD46000020OAI: oai:DiVA.org:umu-46872DiVA: diva2:455544