Just been walking the dog on Hounslow Heath. Sort of hinting at spring, today, but still quite cold. The highlight of the walk was finding some beautiful epiphytes (a term used to describe plants growing on other plants) – mosses and lichens, to be specific, on the trunk of a tree.
Lest you think me a very sad individual, let me try to explain my fascination with these organisms. When I was in the final year of my degree, I did a project on the one of the algal partners in lichens. As you probably know, a lichen is a not a single organism, but actually a commensal symbiosis between a fungus (the mycobiont) and an alga (the phytobiont). Effectively, the fungi farm the algae, but both organisms benefit from the association. During this project I used electron microscopy to study the ultrastructure of a range of different species of the major algal partner in the lichen association, Trebouxia, grown in culture.
Then, for my PhD, I studied mosses. When moss spores germinate, they initially produce a filamentous, tip-growing growth stage called the protonema. In my project I used the moss protonema, grown in sterile culture in petri dishes, as a model system to look at the effect of plant hormones on the cytoskeleton. I also became interested in protonemal morphology (the specific way the protonema of different species grow) and as a side-line I cultured a range of different species, a bit like a Victorian botanist, but on a smaller scale. It was great fun. They’re very beautiful organisms.