Evolution and plasticity of photosynthetic thermal tolerance, specific leaf area and leaf size: congeneric species from desert and coastal environments

• We examined whether increased high temperature photosynthetic thermal tolerance (PT), reduced specific leaf area (SLA) and reduced leaf size represent correlated and convergent adaptations for recently diverged Encelia, Salvia, Atriplex and Eriogonumcongeneric species pairs from contrasting thermal and water environments (the Mojave Desert and coastal California). We also studied whether variation in PT is associated with inducible small heat shock protein expression (sHsp). • Traits were measured in a common environment (CE) and in the field to partition effects of phenotypic plasticity and genetic divergence. • We found little evidence for convergent adaptation of PT (CE measurements). Field measurements revealed significant plasticity for PT, which was also associated with increased sHsp expression. Compared to coastal congeners desert species had lower SLA in the CE. These differences were magnified in the field. There was a negative correlation between SLA and PT. Desert species also tended to have smaller leaves both in the CE and in the field. • SLA and leaf size reductions represent repeated evolutionary divergences and are perhaps convergent adaptations for species radiating into the desert, while PT is highly plastic and shows little evidence for convergent adaptation in the congeneric species pairs we studied

A tribute to Ulrich Heber (1930–2016) for his contribution to photosynthesis research: understanding the interplay between photosynthetic primary reactions, metabolism and the environment

Dietz K-J, Krause GH, Siebke K, Krieger-Liszkay A. A tribute to Ulrich Heber (1930–2016) for his contribution to photosynthesis research: understanding the interplay between photosynthetic primary reactions, metabolism and the environment. Photosynthesis Research. 2018;137(1):17-28

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists