Comparative Growth in Brassica rapa Full Light vs. Shade Western State Colorado University Jennifer Morgan, Jalen Stohlgren, Damien Parsons Abstract This experiment looked growth length and stem width of the Brassica rapa. 24 plants under full light and 24 under shade. Measurements were taken every seven days. Though the results from the data did not support the hypothesis that both the length and stem width would be greater in the control group. The data created more questions. In week four both groups received full light. Differing color and size of leaves as well as healthy overall look and survival rate were distinct between the two groups by week three. Although the average length was less, the shaded group had on average superior health and vitality by week three and in week four. Measuring specific light intensities may lend to a testable hypothesis to what level of light Brassica rapa prefer and thrive. Based on conditions and data collected, the results from this experiment were inconclusive . Methods The Brassica rapa were grown from seeds. 4 trays (6 pods each) under full light and four trays under shaded light. Light was continuous for both groups for the entire experiment. For the experimental group with shade, a plastic see through fixture was set over the plants with a single layer of black screen set on top. The first measurement was of length from soil level to tip of plant in (mm). The second measurement was width of the stem at soil level in (mm) with a caliper. Measurements taken every 7 days for 28 days. Fig. 1 Materials Brassica rapa seed, soil and fertilizer pellet for each tray pod 8 plastic trays (6 pods each) – 2 watering trays - 2 grow lights 1 plastic see through elevation platform - 1 layer of screen 1 caliper - 1 ruler Fig. 2 Questions Will a greater amount of light increase plant length and stem width? Will the plants that receive more light be healthier? Will the plants that receive more light complete their growth cycle before the plants that receive less light? Key Findings 1. More light increased plant length by week three 2. Less light increased stem width by week three and four 3. The shaded plants seemed much healthier by week three and four 4. The plants under full light may have completed their growth cycle before the shaded plants 5. Results were inconclusive. Fig. 3 Fig. 4