Tag Archives: stomatal prints

When is a hole not a hole?

I’d been harboring a secret dread of stomatal counts since the very first day in UCD. The idea of manicuring a leaf and plucking off the varnish looking for tiny holes just seemed, well, a bit tedious, a bit fiddly and destined for failure. Amanda, yet another super-friendly and helpful Ph.D. (must be something in the water), brought us some beautiful Ginkgo leaves, which we subsequently butchered with a backed-blade (sorry Ginkgos). Obtaining the prints was blissfully easy. Paint, dry, lift with tape and onto a slide. What can I say, all those days spent, to quote my mother, “wasting your time putting on that stupid nail varnish” paid off. After a brief discussion on how to count stomata, (not the 1, 2, 3 bit!), we headed with nervous anticipation into the microscopy room. Slides focused and primed for action, we added our little counting boxes and off we went. Amanda’s infectious laughter, reminiscent of a kid who’s just discovered bubbles, provided the perfect backdrop to our little stomata counting party. Wow, there they were as clear as day and all you had to do was count ’em up, scale ’em up and you could tell how much carbon dioxide was present in the atmosphere. The images are astounding, like really pretty, flowery wallpaper.


My little fluorescent flowers (stomata to the uninitiated)

We take a glance at some triassic leaves. Two things are obvious. There’s a lot of holes of unknown origin and its very difficult to discern which ones are stomata. We leave this count to Amanda’s superior experience. Amanda gives us the counts for the fossils and added to our own data, we can now determine that the carbon dioxide level was approximately 200 ppm above present values. I am immediately struck by how accessible and relatively simple this technique is, although I can envisage many debates about statistics and sampling.

http://www.denison.edu/sustainability/duarb-253.html All about Ginkgos

At lunch Amanda pulls out a cup decorated in Ginkgo leaves. Now that’s dedication! After lunch, having passed our leaf grinding initiation yesterday, we move up a level. Isotope analysis. Another relatively simple method (except for the scary equations) to indirectly determine carbon dioxide levels based on how heavy isotopes of carbon are incorporated into plants. Today we get to grind in glass. Tomorrow, grinding with one hand while hopping on a pogo stick. Filtering our tiny pile into grindings into a 2cm wide glass vial turns out to be a little challenging, particularly while being observed. I’m doing oh so well and then boom crumbled leaf everywhere. I look pityingly at Amanda. This will be her life for the foreseeable future. Earlier on we were regaled with tales of fastest stomatal counts, Aidan is top of the leader board by Amanda’s tally. This job definitely wasn’t designed for speed. Amanda shows us the isotope analysis ‘boats’, teeny-weeny containers (like the ends of fuses) into which individual leaf grindings must be poured. Where’s Tinkerbell when you need her…..

I take off to the local library, realising the time has come to tackle an actual paleobotany book. I find the Science section. Dinosaurs, dinosaurs, dinosaurs, fossils, fossils, fossils, geology. Huh? Where’s the plant fossils? I consider complaining, especially since the pathway to the library is lined with fossil-impregnated limestone paving (Talk about false advertising). I settle on a generic fossil tome, remembering that Jenny has promised us a look at her own book. Towards the end, I find 8 pages in a 255 page book, dedicated to plants. I’m glad Jenny is around, making sure our humble producers aren’t consigned to a dusty shelf.

http://www.ucd.ie/plantpalaeo/porter.html Amanda’s bio

Our ultra clean high tech bench

Ginkgo biloba (or Rocky Balboa as I call it, mainly due to its comeback kid nature. See reference above)

Plastosaurus Rex, a victim of the late Cretaceous peak oil crisis