Tag Archives: gs value

You can’t have promise without compromise

Not happy with the boiling we got down in Wexford, we’re back in a super hot greenhouse again today. This time in Rosemount. I really feel for the plants. Sure they evolved clever little pores that could cope with the demands of life on land, but they can’t exactly go looking for shelter when the temperatures rising. Today we are looking at how the temperature of leaves correlates to stomatal conductance. The simple version? Stomata close, plant gets hot. We have a particularly cool toy, a thermal camera, which produces images like the ones shown below. If you’re an 80’s movie buff, you’ll remember these from the movie Predator.


I get very red-faced when people take my picture….


Predator…never got to test the cold mud theory..

Our host for today is the very erudite Dr. Charilaos Yiotis (from here on he will be referred to as Harry). Harry knows stuff. A lot of stuff. It’s ridiculous. Every question, every topic, he has some pertinent piece of information to impart. I can see why stomatal conductance is his baby. It is at a perfect juncture between Physics, Biology, Chemistry and Maths. I’d imagine knowing a lot of stuff helps. Apart from learning about stomatal conductance, photosynthesis strategies and plant defences, we get a run down on Greek cooking, politics and classical history and of course, language.
We test leaf conductance in the morning on a range of plants of differing evolutionary provenance using the Cirras ( I now know what it’s called and how it works!). Using the thermal camera, following some movie recreations of course!, we check leaf temperatures from reference and test leaves. Harry shows us how to use our temperature data to produce figures for leaf conductance. Our figures don’t match exactly match up to our conductance values, but we can see why snapshots with a camera is infinitely preferable to watching a graph readout for hours. We hope it works for Harry!

http://www.ucd.ie/plantpalaeo/yiotis.html Harry’s bio.


Cirras a.k.a evil machine that won’t behave itself..

After another lively chat at lunch, Breda and Aidan adding to the banter, we head over to Péac. I get straight into the million and one questions about Péac. How can you be sure what temperature to use? Why pick this group of plants? How do you match the light conditions of a relatively young planet? Harry is a patient guy. He explains the compromises that must be made. Without a time machine, it is very difficult to match all of the prevailing environmental conditions of the Devonian, Silurian or whatever period you’re looking at. There’s a lot of educated guessing. There is a need to keep a happy medium for the mixed community of plants present. It’s all about compromising on ideal experimental conditions to be able to produce data that is useful. A dead plant doesn’t tell you much.

http://www.ucmp.berkeley.edu/devonian/devonian.php Life during the Devonian


Chamber protective gear…also doubles as zombie apocalypse protection

We’ve discussed the dangers of working in mini worlds with various group members over the weeks. Harry explains the effect of low oxygen. It’s similar to the effects of altitude sickness, hallucinations and dizziness followed by coma. It sounds ok till you get to the coma part. I’m thinking Jenny needs to add Sherpa to the job requirements. High oxygen carries the danger of becoming a human torch. But hey, danger just adds to the excitement.


Stuck for BBQ ideas? Flaming Brachiosaurus anyone?


Cooling off in the greenhouse

http://www.co2science.org/subject/s/summaries/stomataltrees.php a summary of stomatal conductance