Caffeine Bulbs Experiment

For this experiment, there were four onion bulbs labeled A, B, C, and D. Bulbs B, C, and D were each immersed in a different concentration of coffee. Bulb A acted as the control because it was not immersed in any concentration of coffee; instead, the onion roots grew in water. The following is a list, in order, of the concentration of caffeine bulbs B, C, and D were in: 0.1%, 0.3%, and 0.5%. Four test tubes were gathered to set up the experiment, each holding an onion bulb. After each day, every individual bulb’s roots were counted and the average length was recorded. After recording this information for six days, an onion root tip from each bulb was taken and squashed under a coverslip. These root tips were then looked at under a microscope.
This tells us bulb D, the onion immersed in the highest caffeine concentration, had the hardest time growing. With that said, one would expect to see the most mitosis in bulb A. This is because mitosis increases cell growth and number. However, after recording the number of mitotic phases in each treatment bulb B had the most cells in mitosis and bulb A had the least. This could’ve been due to the experimental problems in the next paragraph. Bulb A’s roots grew the most because this onion only ever came in contact with water, which all plants need to survive. Bulb D did not grow as much because of the high concentration of coffee. These results were as expected. On the contrary, bulb b had the most cells in mitosis, followed by bulb d, bulb c, and then bulb d. These results were not as expected because, as discussed previously, one should’ve seen the most mitosis in the onion with the most growth. What experimenters should have seen was bulb A with the most growth followed by bulb B, bulb C, and then bulb D. Similarly (On the same note?), bulb A should have had the most cells in mitosis followed by bulb B, bulb C, and then bulb
Take the chemical caffeine for example. The more coffee concentration plants are exposed to the less growth, number of roots, and mitosis in each cell. Other things in nature that might affect the growth rate of plant cells are sunlight, water, space, temperature, nutrients, bacteria, weeds, allelopathy, insects, soil, etc. In areas where there are very few plants growing, the following abiotic factors may be affecting the plant's ability to thrive as well as the rate of mitosis: light, water, soil, nutrients, space and temperature. The few plants living are competing for sunlight, water, and nutrients a plant needs to perform photosynthesis. If this scarce number of plants is competing for sunlight then they are additionally competing for space as well. Drastically changing temperatures can also negatively affect plant growth and mitosis because the plant will have to adapt quickly to both hot and cold temperature conditions. When comparing paved areas like the cracks in a sidewalk to soil areas, there is a clear difference in which would benefit cell growth and mitosis rate and which would negatively benefit cell growth and mitosis rate. Plants in soil areas wouldn’t have as much to compete for as paved areas (Franco). Additionally, the following biotic factors may affect both the rate of mitosis and the growth rate: