Opening and closure Stoma

[cmug]

I work as a science/biology technician at a school in The Netherlands. I want to show my pupils the opening and closure of a Stoma. Theoretical is good described and shown in great pictures for example at wikipedia .
But seen this in practice is much more difficult. I can make good microscope slide from the Tulip. The Stoma are good visible.
But not an open and going closed stoma. I start with the cel in distilled water and later change the water for 10% NaCl solution.

What can I do to get best results in seen open and closed stoma in the same slide ?

Here a picture made with my smartphone through the microscope, that what I see in plain water, but with 10% NaCl it's nearly the same.

[MichaelG.]

Interesting question !!

From what little I remember, there are a number of triggers involved ... but I think you might experiment with Carbon Dioxide.

Update: I just found this page, which looks helpful
http://www.saps.org.uk/saps-associates/ ... and-a/1101

MichaelG.

[cmug]

Thanks !
Very interesting literature! I am going to try to find the plants that they use.
The CO2 method also seems useful to me. That's I'am going to try also

Today I bought the advised Bergenia and made some slides. sadly ; this is not an good plant for seen stoma. I get very difficult an epidermis from the leaf, and under the microscope it was a 'mess' . I don't post a picture, because is really difficult to find a stoma at all.
The Tulip I used before I find 10x better. Sadly the garden-shop here on the corner has not the Kniphofia , to late they said. I have to wait till spring for that plant.
On a school I prefer plants that are year through good available. The subject stoma is now educated not 5 months later.