I read this study in the latest issue of the International Journal of Plant Sciences. I thought that it was a really neat study and is an easily accessible piece of scientific literature for folks to read who are not professional bryologists.
The premise - In stressful environments, studies suggest that sexual reproduction is favored. Researchers examine this idea in mosses across a geothermal gradient in Lassen Volcanic National Park in California.
Methodology - They collected data on sporophyte and gametoecia production from species in the field. (Yeah, gametoecia. I had to look this word up. It is both the gametangia and the surrounding leaves together.) They also collected data on temperature. The collection locations were divided up into geothermal and nongeothermal sites based on the temperature measures.
Also they ran a common garden experiment with Pohlia nutans to look at whether a genetic adaptation was limiting sporophyte production or if alternatively the extreme stress was the cause of low sporophyte production.
Results - Their results indicate that there were lower rates of sporophyte production, due to lower rates of gametoecia formation at the geothermal sites. These rates for both sporophyte and gametoecia production were higher at the nongeothermal sites. When plants from both types of sites were grown in greenhouse conditions these relationships disappear.
Implications - This study does not support the idea that sexual reproduction is favored in stressful environments. It actually shows the complete opposite for this species of mosses. Sexual reproduction decreases with increased temperature stress. The authors state that the "regression between temperature and sporophyte production was not high." And go on to suggest that other stresses such as heavy metals may be involved. They discuss that other studies in fungi and mosses have shown similar patterns and cite several studies.
I was wondering whether they thought that differences in light or perhaps levels of desiccation could be an influence too.