PIGMENTATION AND CELL STRUCTURE: DIFFERENCES BETWEEN BODY AND STEM OF PLANTS THROUGH THE ANALYSIS OF APPLES AND FLOWERS

Objective: analyze the difference in cell pigmentation between different parts of a plant 

Method: 

1. Obtain samples of different parts of a plant from one fruit and one flower. 
   1. Fruit sample- apple peel and apple stem
   2. Flower sample- matthiola incana flower petal and leaf 
2. Analyze each sample and compare any noticeable differences between pigmentation or structure

• All samples were prepared on glass slides, dry mounted, and placed with the clear stickers provided in the kit
• All photos were taken with an iPhone camera using the portrait mode setting, and seen using the lighting attachment provided in the kit
• Origin of samples are not directly known; samples were obtained from outside vendors (second or third party) and were prepared some time after purchase. 

image of all collected sample slides


Process: 

Apple sample- 

The first sample obtained was the apple samples. Firstly, we bought apples from a local market nearby and washed them before peeling them. To peel the skin, we used a peeler and a knife, and cut down the peel to a small and thin sample. This sample was then slightly dried out with a paper issue before being put on a glass slide. 

process of peeling the apple

While there were many pieces of the apple that could have been used for this experiment, a thin slice of the apple peel was chosen as the pigment is more dominant on the surface/peel of the apple. It was necessary to make sure that our sample was thinly sliced as the cell structure and pigmentation would be easier to see through the foldscope if the sample was thinner. 

The photo below is the apple peel sample through the lense of the foldscope. As you can see, there are mainly green, red, and black pigments showing. Although the lense or photo is somewhat blurry, it can be inferred that specific parts of the cell contribute more than other parts to the color of the apple. This can be seen from the different colors in different areas of the sample, as well as, the lack of color in certain areas of the sample. 



The apple that we have observed was predominantly red with slight yellowing in some areas. After observing the sample, we can see that although there are areas with green pigmentation, the apple was ultimately red in color. Knowing that apples often go through color changes when growing, we can conclude that changes in the apple during it growing process and the genetic composition of the apple influence how its cells and pigment develop. Thus, the sample above (and other outside research) supports the idea that the pigment in apples are found in certain parts of the cell, and that this pigmentation occurs naturally as a result of the apple’s genetic composition. 



The next sample taken from the apple was a part of the stem. For this sample, there was difficulty in obtaining a thin flat piece of the stem that would have been more ideal to use as a slide. The side used included a small piece of apple stem that was slightly thick and not flat on the glass slide. This has caused the images obtained to be less accurate, and lacking view of the sample on a cellular level. Although the following image is not the best representation of what the stem would look like, I have included it for a brief comparison. 



The apple stem was rough and rigid in physical texture, while brown and orange under lighting. After a closer look with the foldscope, the structure can somewhat be seen as bark-like, and some verticals type of streaks/structure can be seen. From these brief observations, the pigment in stems does not seem to come directly as a result of it being an apple (genetically), but rather a result of functionality of being an apple. Similar to the flower leaf sample (mentioned later), the stem has a use to be sturdy so that the apple can grow. Compared to the apple peel, the pigment from apples can also allude to the genetic differences that causes different tastes between different types of apples. 

Flower sample- 


The next sample we collected was from flowers that were purchased from an outside street vendor. Both leaf and petal samples were collected by cutting the piece off of the original flower. While I do not know the exact species of flower this is, some sources point to it being a matthiola incana. 


The above foldscope image is the sample of the flower petal. As you can see the cells are more in a circular composition, with a stronger and more evident structure. Compared to the apple peel, the image does not seem to capture any strong pigments. While the flower on the outside was slightly purple in color, the image shows more monotone. From this we could conclude that the pigment in the petal may not be strong enough to be seen with the foldscope. This concept is supported as the less pigments something has, the lighter in color it typically is. In this instance the flower used is perhaps too light in color, therefore the pigments are not as evident or not enough to be noticeable in the cell. It could be possible that with a different microscope or technique, the pigment could be seen on a cellular level. Furthermore, aside from pigmentation, the cell structure of the petals, as seen in the image, can also contribute to the shape and style of the flower petals themselves. 



The next slide prepared was the sample of the flower’s leaf. When the leaf sample was first obtained it was slightly thicker and stronger than expected. The initial findings of the leaf were unclear in cellular structure, but evident of the strong green pigment in the leaves. The sample above is a thinner version of the leaf that was obtained by cutting the original leaf sample even thinner. This part of the leaf was more moist, and seemed to expose more cell structure than what was located on the outside of the leaf (without cutting thinly). As a result, the image has a more clear structure, but not as strong green color. Similar to the flower petal, the leaf structure also resembles a circular pattern, however less strict and less compact. The green pigment shown in the image indicates that there is strong pigments in the leaf cells. Unlike the petals, the leaves could show this color due to excessive amounts of pigments located in these parts of the plants. As we know, plant cells have organelles called chloroplasts that exhibit this green color. These organelles are necessary for plants as they help plants in their process of  photosynthesis. Therefore, pigmentation in the leaves is stronger compared to that in the petals since the leaves and stem contribute heavily to the photosynthesis process. While the flower petal color seems more dependent on the genetic and species of flower, the green pigment of the leaves seems more heavily related to the functionality and identity belonging to plants. 


Findings summary- 

Overall, the observations made between the apple/flower peel/petal and stem/leaf are comparable as the peel and petal’s pigment and cell structure seem to be because of the plant’s genetic makeup, rather than a cellular function. The pigments found in the peel and petal directly affect the outside appearance of the plant just like the stem and leaf do, however, the peel and petal appearance is more varied between species of flowers or fruits, compared to how leaves and stems typically are similar across different species. While the pigmentation is comparable as mentioned above, the structure between samples was noticeably different. This shows how the structure of the cells and the genetic makeup of cells manifest in different ways. 


Technical details- 

Although these are my personal findings, it should be mentioned that differences in outside influences such as the development of the plant during its growing stages and anything that could modify the cell’s structure will impact the results. For instance, chemical substances like pesticides, breeding, and artificial components (like flower dye), will affect what is seen through the microscope. Most of the background information used in my assumptions regarding pigments and plant cells comes from quick Google searches and previous background knowledge from school.