(1) Botanisches Institut, Olshausenstrasse 40, D-24098 Kiel Germany, DE;(2) Biological Sciences, University of Waikato, Hamilton, New Zealand, NZ;(3) Australian Antarctic Division, Kingston, Tasmania, Australia, AU
Abstract:
A lichen growing in a continental Antarctic region with low temperatures and strong irradiance in summer was investigated
for evidence of photoinhibition. Field experiments with Umbilicaria aprina from a sheltered site with heavy snowpack showed no effects of photoinhibition when the lichen was exposed to strong sun
irradiance for nearly 11 h a day. This was evident from CO2 exchange and simultaneous chlorophyll a fluorescence measurements. CO2 exchange was also not affected if quartz glass allowing greater UV penetration, was used as a lid for the cuvette. The dependency
of net photosynthesis on photosynthetic photon flux density suggests that the lichen is photophilous.
Received: 2 April 1997 / Accepted: 11 August 1997