Asymmetry measurement ponderings

Dear flogophiles:

I’m trying to devise ways of measuring FA (see previous post) on our plants. Ideally, we would want measurements on several different organs or parts because if, for example, inbred plants are more developmentally unstable, it would be more convincing if they were more asymmetric in both leaves and inflorescences.

Colin is designing (and hopefully testing) the picture-taking rig for flowering heads. But, I think that it can also be used to take pics of leaves. The trick is getting the leaf to lie flat on the backing of the rig. I was thinking of buying a hand-held scanner to scan leaves in the field, but that takes 4-8 seconds per leaf, and it seems easier and quicker to just snap a picture. Also, I am not sure where measurement error would come from if you scanned the actual leaf.

My biggest concern is getting the inflorescence to lie flat on the rig backing. It is important to get the ray florets nice and flat against the backing or else you could be mis-measuring things pretty easily. I almost think it may be easier to actual measure the ray florets using calipers in the field — it would certainly be more accurate but would also take a bit longer, and you couldn’t really measure ALL the ray florets per head — it would take WAY too long.

If the rig doesn’t work, we could have three people go out with calipers, one after another, measuring the same heads and leaves per plant. You could only measure perhaps 4 ray florets per head, but this is probably OK. This could probably be done in one day! If we could get a pendragon form for this measurement, it would be great, too. So, then you would have the measurements, as well as error that could be assigned to individual observers.

One more thing: We can measure asymmetry in the actual inflorescence by measuring the length of the ray florets, but we could also measure asymmetry WITHIN each ray floret, by measuring the L-R sides. This is what has to be done for the leaves becuase they are naturally asymmetric about the stem of the plant anyway due to differences in leaf age.

OK, my thoughts for now. Things are very exciting here, I hope to get my batteries in the next 2 days so that we can get the cameras up and running by Sunday. Science is happening!

Andy McCall


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