Research Update
May 10, 2021
Discovering the patterns of Phalaenopsis amabilis
Microscope research project depicts structural elements of leaf and flower of the plant.
Project Dates: April 2021 - May 2021
40X objective capture of the outside layer of a leaf from a Phalaenopsis amabilis pant.
Over the course of MCB 68: Cell Biology Through the Microscope, I was able to cultivate skills in preparing and imaging samples of a wide variety. For my capstone project, I set out to image parts of the Phalaenopsis amabilis plant.
The leaf
I isolated the sample from a Phalaenopsis amabilis plant. Orchids are monocots, and thus I was expecting laterally aligned cellular patterns. I tried imagining a non-refrigerated leaf, but it was quite hard to get single layers out of the leaf, because the juices of the leaf were making different layers of the leaf stick together. Therefore, I refrigerated a second leaf for one week to allow the leaf juices to settle and the layers to separate.
10X objective capture of the outside layer of a leaf from a Phalaenopsis amabilis plant using the phase ring.
I also wanted to take a look at the stomata, so I imaged with the 40X objective. Interestingly, one can easily detect the chloroplasts in the stomata. I did not use the phase ring to prevent oversaturation, over-contrasting and having to over-expose. You can read technical details in the report linked in the Resources section.
40X objective capture of the outside layer of a leaf from a Phalaenopsis amabilis plant showing the chloroplasts.
The flower
The physical structure of the Phalaenopsis flower was quite interesting to me. I started with imaging one of the petals. The petals are quite thick and have a very thick white layer on the back. The thickness of the petals depends on the age, and since I wanted to image the “freshest” petal, I successfully removed the white layer using a small razor blade and placed the upper petal layer on a glass slide and added water and a glass coverslip. It is important to note that this is the only layer that is colored in the plant. I started imagining to take a general view of the petals.
Left: diagram with main parts of the flower I imaged. Right: 10X objective capture of the Phalaenopsis flower.
The image showed that the petal cells have no distinct structure, as their main purpose is to color the petal and attract pollinators. I observed that there were more transparent areas in the image where the petal was not colored. I took a closer image to investigate the cell structure.
40X objective capture of the Phalaenopsis flower.
In the picture you can still observe the transparent spots that create the white spots, which are scattered around the petal. This mimics the macroscopic color pattern of the petal. The pigment is quite dense and therefore obscures the inner structure of the cells. There was extreme brightness at the top of the image, as those parts were the almost transparent cells that gave the white color to the petal in real life, due to the thick white cell layers that were separated from below the upper layer. I hypothesize that the pigment color is anthocyanin, which is water soluble. That could explain why when I submerged the flowers in water for a week, the flowers started discoloring.
The labellum
The labellum in Phalaenopsis has distinct white and yellow markings, and I wanted to see if the cell structure in those was different from the petals. The function of the labellum is for pollinators to land so they can pollinate the flower. Again, I separated the white dense layers from the pigmented top cell layer before imaging. The cells in the labellum are quite large and do not show a specific pattern. The cell walls are quite thin, compared to a leaf cell, and it almost looks like an animal cell. You can easily observe the cell nuclei and the white transparent cells and pink and yellow pigmentation of other cells. Again, there was no way to avoid some extreme brightness, as those parts were the almost transparent cells that gave the white color to the labellum in real life, due to the thick white cell layers that were separated from below the upper layer.
40X objective capture of the Phalaenopsis labellum.
