After reading the post by KAVITHA (https://microcosmos.foldscope.com/?p=160084) about stomata, I had a question: Do all stomata look the same? So over the weekend, while visiting my sister and parents, we went on a Stomata Expedition! We collected a several different sorts of leaves, placing them in a plastic tub to keep them from drying out, and took them inside to examine them with the Foldscope!
The leaf is too thick and contains too many layers of cells to clearly see the stomata on the lower surface of the leaf, so we must peel the lower surface off of the leaf. We found the best way to do this was to fold the leaf so that the bottom surface of the leaf is on the outside of the fold.
The next step is to pinch the edge of the fold between your fingernails and try to peel the bottom layer of the leaf down, away from the fold.
I used my thumbnail to lightly scrape the green mesophyll off the inner side of the peel and then placed the thin, single cell thick, layer of leaf epidermis on a slide with a little water, then covered it with a cover slip.
We had a variety of plants that we collected from the side of the road and around the house. And made peels of each. I will add picture of each plant in the field and what the stomata look like.
So the answer to my question was, at this magnification, the stomata look fairly similar between the plants, but they are arranged very differently in different larger groups of plants and between species within these large groups of plants. There seemed to be some leaves with MANY stomata and some with not so many. And the shapes and arrangement of epidermal cells seem to be particular to whether the plant was a monocot or a eudicot. What questions do you have about these observation? What would you look at next?
I found this great fun. A few things that I learned were, scraping the mesophyll cells off helps, they are thick and can make focusing tricky. I also learned that the focus can shift a bit when I go from viewing with my eye to taking a picture with the phone, so that takes a few tries, and toss out the poorly focus images. Cropping out the out-of-focus parts around the edge is helpful, but it is hard to get a sense of how big things are relative to each other if different images are cropped differently.
For this project I was using glass slides and coverslips, the Foldscope LED illuminator directed straight through the lens, and an iPhone 6, mostly at full frame for photographing, then cropped. I used a knife to trim the leaf material so the piece that was left was just a thin piece of epidermis.