measuring stomatal frequency, depth, etc.
Pedro J. Aphalo
pedro.aphalo at metla.fi
Mon Jul 25 01:54:07 EST 1994
In article <9407230010.AA13135 at m66-080-1.MIT.EDU>, kearns at MIT.EDU (Ellen
V Kearns) says:
>In response to Frank Berninger's request for information about how to
>the diffusion process for birch leaves, stomatal frequency can be
>by looking at epidermal peels under microscope magnification of about
>The open width can also be measured by microscopy with a special eye
>which has an etched ruler on it. As for depth of cavity, I have seen
>of this in a review, but I am not sure how to measure it.
>I'll send some refs. about these measurements on Monday. Sounds like an
>kearns at mit.edu
What you say is true only if you do not want to validate the model or
estimate gs under a given environmental condition because using epidermal
peels does not allow one to measure the stomatal dimensions as they
were in the leaf before peeling. If one floats the peels in an adequate
medium and light conditions one might be able to measure the dimensions
under maximum aperture. Of course, peels (or cyanoacrylate cement,
Loctite, replicas) are very good for measuring frequency and density.
The Loctite replicas may be good enough for measuring stomatal
pore width, but that would have to be validated with a method known
to work, such as using SEM on frozen samples.
This is why I suggested the use of SEM in my previuos posting to
bionet.plants. Peels or even whole leaves measured using light
microscopy normally do not yield measurements that reflect the in
planta stomatal aperture before disturbance (see Weyers and Meidner1990).
I agree that Frank's project is very interesting, but as with any model,
he will need to validate the estimates against actual gs measurements
made simultaneously with measurements of stomatal dimensions.
Pedro J. Aphalo
FINNISH FOREST RESEARCH INSTITUTE
Internet: pedro.aphalo at metla.fi
fax: +358 79 513 068 ,,,^..^,,,
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