This past week in lab we got up close and personal with some familiar foods to learn about why they look and feel the way they do. The first plant we examined was the red cabbage. We were given cabbage leaves pretreated with digestive enzymes, which we then washed, filtered, and centrifuged. All of this was done in order to remove the cell wall leaving the protoplast behind. By removing the cell walls of the cabbage cells we were able to see them in a whole new light. While normally the cell wall would cause cells to be rigid and rectangular, these cells were circular. The outward pressure that is exerted by vacuoles is easy to see once the counterbalance of the cell wall is removed! Speaking of vacuoles, the vacuoles of the red cabbage are what gives it its distinctive color. As can be seen in the picture many of the smaller vacuoles are filled with blue and purple anthocyanin pigments. These pigments have been shown to have benefits for human health and may even help to prevent cancer. (On a personal note, over the summer I worked on a farm and was able to take home a lot of produce. One evening I made a stir fry with possibly the most potent and powerful purple cabbage in the world and immediately after had the first migraine I've had in years. I don't know that it was the anthocyanins but after that I definitely believe in the power of cabbages.) After we got a good look at the insides of a cell, and watched the cytoplasm move around for a while, we exposed our protoplasts to several different types of solution to see how they would react. Normally a plant cell, unlike an animal cell, has the cell wall to shield them so they can be a bit more resistant to things like changes in the concentration of solutes around them. However, because protoplasts don't have a cell wall, we thought that they would react more along the lines of animal cells. Our predictions were right, and the protoplasts reacted visibly to the different solutions that we tried. Pictured about is how they shriveled up after being treated with salt, but we also exposed them to pure water (some of them exploded) and detergent (membranes were basically melted away, but not very quickly or anything). As well as looking at the insides of cabbages, last week we also covered the insides of other edible plants. Specifically we looked at the ground tissue of pears and avocados. We observed their sclerenchyma cells, which are what gives these fruits their texture. We stained both the pear and the avocado with TBO, which stained the lignified cell walls of the sclerenchyma blue so they were easy to see. When we looked at the pear, it was easy to see that there were a lot of sclerenchyma cells as basically the whole sample was tinted blue. These are the brachysclereids or "stone cells" that you can feel when you eat pears. It was neat to be able to see the pit canals that went through the cell walls, especially when we looked at 400x magnification. It definitely explained why pears have the texture that they do! We also stained avocado with TBO in order to look at its sclerenchyma cells. Like the pear, it had brachysclereids, but it had fewer of them and they were more sprinkled throughout the tissue. In the images above, the brachysclereids are the dark blue dots. Overall the avocado cells seemed a lot softer and blobbier looking, while the pear cells had more clearly defined borders. Avocados are much creamier and softer than pears in general so this makes sense. In fact I would rarely describe an avocado as gritty at all and previously wouldn't have compared it to a pear in any way.
All in all, it was very cool to get to look at some common fruits and veggies under the scope! I really like looking at things that I actually eat because it's knowledge that is directly connected to my life outside of class. Out of everything that we looked at last week, I think I was most interested in the avocado slide because it wasn't what I expected an avocado to look like. I definitely didn't think an avocado would be a great candidate for staining, or that avocado fruits had any particular structure besides just mush. I was happily surprised to be proved wrong! -Ally Kershner
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Amateur Botanist Explores Microscopic Magic Crystals, Extra-Hairy Plants, and Alien Spores1/15/2017 I am a house plant addict. As in, turn-my-apartment-into-a-jungle-and-call-it-home kind of addict. I could use the phrase ‘house plant enthusiast’, but it doesn’t quite capture the depth of my affection for these organisms. So imagine my excitement upon seeing a table full of some of my favorites placed at the front of the lab room. Imagine again my slight adrenaline rush in in learning that we were going to study them under microscopes - exploring their cells, traveling to far off places unreachable by the naked eye. I was stoked. For starters, I had a quick *heart eyes* moment with one of the specimens, a majestic (and I do mean majestic) Begonia before diving in to the task at hand: trichome collection and examination. Trichomes are hair-like structures that cover the leaves and stem of the plant; they come in many shapes and sizes and serve a variety of functions. In some plants, trichomes are coated in sticky substances capable of trapping insects, preparing them for chemical digestion. In others, the hairs prevent herbivory by means of painful chemical injection. Begonias are more ‘sunshine and daisies’ when it comes to their epidermal hairs, most likely serving to collect moisture from the air or prevent herbivory by having an unpleasing texture. After producing a wet mount slide, I was surprised to see a difference in the cellular shape of the trichome relative to the those of the leaf it was attached to. Where leaf cells were circular in shape, cells of the trichomes were rectangular. Furthermore, fuzzy deep red pigments were mixed with slight pockets of green – an act of Christmas regurgitating its holiday sprinkles all over this plant or anthocyanins masking chlorophyll pigments? I’ll let you decide. Next up: examining raphide crystals found within Tradescantia zebrina (aka “Inchplant”) and druse crystals formed in an unknown species of Begonia via wet mount slides. These structures are products of excess inorganic particles (most often calcium salts) being deposited into the vacuole in crystalline form. The raphide crystals were easy enough to find, often found in clusters mixed with cell matter. However, searching for druse crystals felt like searching for Waldo in a sea of cartoon people; you find him once, painstakingly, and then you can’t find him again. My favorite part of this lab reminded me of one of my all-time favorite films, The Fifth Element, which revolves around the “untraditional hero saves planet” trope. Bruce Willis plays Korben Dallas, an ex-galactic special forces operative turned cab driver of the 23rd century, who attempts to save the world from a giant ball of talking fire in space. I can't make this stuff up, guys - its cinematic gold. That giant ball of talking fire, who calls himself "Mr. Shadow", looked pretty similar to the Ceratopteris richardii spore under my microscope (in my humble opinion). Under 400x magnification, the surface ridges on this tiny sphere give it the look of some far off planet in outer space. In reality, it comes from an aquatic fern found on Planet Earth, dubbed the “C-Fern”. Our mission: examine the spores under a microscope and sow into prepared culture plates containing agar and mineral nutrients, where it will be examined further in the coming weeks. Author: Amy KHouse plant addict. Believer in Himalayan Salt lamps. Enjoys the little things in life like popcorn and vegan marshmallows. |
AuthorContent is created by students participating in the Plant Structure course at Oregon State University for Winter 2017. Archives
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