Departament de Biologia Vegetal, Unitat de Fisiologia Vegetal, Universitat de Barcelona, 08028 Barcelona, Spain.
Evaluation of the role of damage to photosystem II in the inhibition of CO2 assimilation in pea leaves on exposure to UV-B radiation
Article first published online: 28 APR 2006
Plant, Cell & Environment
Volume 18, Issue 7, pages 781–787, July 1995
How to Cite
NOGUÉS, S. and BAKER, N. R. (1995), Evaluation of the role of damage to photosystem II in the inhibition of CO2 assimilation in pea leaves on exposure to UV-B radiation. Plant, Cell & Environment, 18: 781–787. doi: 10.1111/j.1365-3040.1995.tb00581.x
- Issue published online: 28 APR 2006
- Article first published online: 28 APR 2006
- Received 15 July 1994; received in revised form 22 November 1994; accepted for publication 28 November 1994
- CO2 assimilation;
- photosystem II;
- ultraviolet B radiation
Mature pea (Pisum sativum L., cv. Meteor) leaves were exposed to two levels of UV-B radiation, with and without supplementary UV-C radiation, during 15 h photoperiods. Simultaneous measurements of CO2 assimilation and modulated chlorophyll fluorescence parameters demonstrated that irradiation with UV-B resulted in decreases in CO2 assimilation that are not accompanied by decreases in the maximum quantum efficiency of photosystem II (PSII) primary photochemistry. Increased exposure to UV-B resulted in a further loss of CO2 assimilation and decreases in the maximum quantum efficiency of PSII primary photochemistry, which were accompanied by a loss of the capacity of thylakoids isolated from the leaves to bind atrazine, thus demonstrating that photodamage to PSII reaction centres had occurred. Addition of UV-C to the UV-B treatments increased markedly the rate of inhibition of photosynthesis, but the relationships between CO2 assimilation and PSII characteristics remained the same, indicating that UV-B and UV-C inhibit leaf photosynthesis by a similar mechanism. It is concluded that PSII is not the primary target site involved in the onset of the inhibition of photosynthesis in pea leaves induced by irradiation with UV-B.