Ricciocarpos natans, a seldom liverwort (part II)

[ralfwagner]

Hello,

as promised, part II:

- Leaf, cross section. Air chambers and oil-bodies (white corns), darkfield



- Leaf, cross section. Oil-body



- Elongated ventral scale of the floating form



Have fun!

[BJ]

Ralf,

Another interesting subject and instructive photos. I have never knowingly seen this liverwort - but I wonder if i have just overlooked it.

I particularly like the photo of the scale - it is strange that all the red pigment is confined to the "spines".

The oil body looks unusual as it has an irregular rather "lumpy" outline. In most cells/organisms oil bodies have a rounded outline. In this case could the oil actually be solid fat ?

Thanks for the photos,

BrianO

[ralfwagner]

Ralf,

The oil body looks unusual as it has an irregular rather "lumpy" outline. In most cells/organisms oil bodies have a rounded outline. In this case could the oil actually be solid fat ?

BrianO

Brian,

oil bodies are unique with liverworts and must not be confused with oil-droplets that are common to many protists. An oil body of a liverwort posseses an outer membrane that encapsules the oil in it. This is the reason why you described it as "lumpy". The shapes of these oil bodies are different with different species.

Oil droplets in a diatom for example have no membrane, they are just like a drop of oil in water and therefore of circular shape.

Oil bodies of a liverwort can be observed only with fresh material. When the moss dries, the oil bodies disappear.

It is very easy to oversee this moss because it often grows together with all kinds duckweeds. But now you are knowing what to look for and I'm sure you will find this one, soon.

[BJ]

Ralf,

Your reply stimulated further thought and a web search. It seemed to me that physics would still "demand" that a liquid oil body even with a membrane would assume a rounded shape. On the web, I came across a great reference " Bryophyte Biology" by Shaw and Goffinet (2000). it is possible to read many of the pages in Google Books - luckily including the pages and photos on Oil Bodies. I think that my concern is addressed as what is special about liverwort oil bodies apart from the membrane is that they are not just storage bodies but also the sites where the oil is synthesised. They contain therefore as well as the oil, enzymes, perhaps other proteins, and carbohydrates. Presumably these other molecules give the more complex structure.

Thanks for stimulating both the eyes and brain with your photos and insight. The next liverwort I see (not that common here in southern Portugal) will not escape my attention or my razor!

Regards
Brian

[rjlittlefield]

Ralf, congratulations on your selection for Administrators Appreciation Award for July -- this is a very interesting and well-shot series!

--Rik