The Effects of Light Exposure on Brassica rapa Jess Moore, Bri Cervantes, Erin Axeman, & Jason Seagraves
Introduction Plants require energy in order to grow and reproduce. Various types of plants need light energy to promote growth and absorb nutrients and do this by the process of photosynthesis. 2
Introduction (cont.) However various “environmental stressors” can impact the development and growth of the plants overall but some are able to withstand the stressors for long periods of time (Bergmann, 2018).
Introduction (continued) Light has the ability to activate or signal hormones within the plant to begin working. Light “is the main environmental factor that regulates the pathway of chlorophyll biosynthesis”( Liu, 2013).
Introduction (cont.) Too much light can also impact the development of photosynthetic organisms. In Ruban’s experiment that tested a mechanism (light harvesting antenna) that controlled light availability in order to prevent plants from being photodamaged (Ruban, 2018).
Hypothesis: Plants that are exposed to less light exposure would be negatively impacted in height, leaves, and color. 9
Methods Styrofoam Blocks Water apparatus Styrofoam blocks placed on bowls and was built using filled with wicks, soil, bowls, lids, and cells labeled a, b , c , fertilizer, and seeds. fleece. and d. Every 7 days, examined Bowls placed in and measured appropriate spots -24/7 heating lamp -Height (cm ruler) -1 2 hour timed Thinned 5 days later -Color heating lamp -# of leaves -Cabinet w/ no light
Results Figure 1: The effect of different amounts of light on plant height. Plants were subjected to different light environments, 24 hours of light, no light, or 12 hours of light. The plants that grew in no light grew faster than the other two. There was no statistically significant difference 11 between the control and 12-hour light to determine which grew better.
Table 2: The effect of different amounts of light on plant color. Plants were subjected to the different light environment, 24 hours of light, no light, or 12 hours of light. The plants that were yellow in color were the ones in an environment that had no light and the ones that were dark green were the control and 12-hour light.
Table 1: Number of Leaves Grown on Plants Exposed to Different Amounts of Light. Plants were subjected to the different light environment, 24 hours of light, no light, or 12 hours of light. The plants that had the environment that had no light grew the least amount of leaves and died quicker than the other two groups that were tested.
Discussion Our data has supported our hypothesis that low light exposure would negatively impact the plants. This was demonstrated by the height of the plant, the number of leaves, and the color of the plant. The treatment group with no light ended up all dying while the other two groups exposed to light survived and continued to grow. This experiment illustrated the importance of light on plant growth and how detrimental it can be on a plant if it is not exposed to light. 14
Discussion Light is one of the most important factors in plant growth, and it even comes before nutrients. As seen in seagrass, “Light was more important than the nutrient ratio of fertilization for the successful development of the young seedlings” (Alexandre, et al. 2018). Another study done with seagrass showed that excess shade damaged the morphology of the plant the most when tested alongside different salinity levels (Suykerbuyk, et al. 2018). 15
Discussion Different kinds of lighting, such as far-red, LED, or metal halide, all have different effects on plant development. One experiment came to the conclusion that a mixture of different light sources provided the best results in plant growth in tomato seedlings, while certain types alone caused damage (Wei, et al. 2018). 16
Discussion 17
Works Cited Suykerbuyk, et al. “Wild seaweed harvesting: strategic environmental assessment - environmental report”. Marine Scotland. 2018. Alexandre, et al. “Light Is More Important Than Nutrient Ratios of Fertilization for Cymodocea nodosa Seedling Development”. Frontiers in Plant Science. 2018. Wei, et al. “Effect of Supplementary Light Source on Quality of Grafted Tomato Seedlings and Expression of Two Photosynthetic Genes”. Agronomy. 2018. Liu, Xiaoqin, et al. “Interplay between Light and Plant Hormones in the Control of Arabidopsis Seedling Chlorophyll Biosynthesis.” Frontiers in Plant Science. 2017 Bergmann, B & Dole, John & McCall, Ingram. Postharvest Performance of Poinsettia Plants Exposed to Low Light Levels, Low Temperatures, and Low Substrate Moisture. HortTechnology. 2018 Ruban, Alexander V. “Light Harvesting Control in Plants.” FEBS Letters , vol. 592, no. 18, 2018, pp. 3030–3039. 18
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