1. The Effects of Colored Light on the Species Vinca rosea Introduction Questions over whether different wavelengths of light affect the growth and or the physiological structure of a plant is one of which that has been speculated for many centuries. (Popp, 1926) It is without a doubt that numerous experiments have been conducted to prove this hypothesis, some dating back as late as 1783. Researchers have found that plants do in fact react and respond chemically as well as physiologically to certain wavelengths of light and light intensities, particularly blue and red light. (Dougher and Bugbee, 2001) While there are numerous environmental factors that partake in successful growth of plants, light intensity and light quality are the most important aspects in plant life. (Assmann, 1992) Plants have various spectral properties such as ultraviolet, visible, and infrared frequencies, when exposed, they either react positively or negatively to the light. (Gates, Keegan, Schleter, and Weidner, 1965) When under the effects of blue light, plants have proven to respond positively through chemical reactions. (Kasperbauer, 1971) Given the findings of previous researchers, I predict that a blue wavelength of light will be most beneficial to this particular thriving plant species. The goal of this experiment is to investigate whether different wavelengths of light do in fact affect the growth and or the environment of the species Vinca rosea. Results Figure1. The species Vinca rosea before entering the light simulator Table 1. Growth and physical change of Vinca rosea over a 72 hour period. Figure 2. Growth pattern of Vinca rosea over a 72 hour period. YOUR NAME HERE Juan Diego Academy Discussion The results from Table 1 and Figure 1 summarize the physiological effects of how the species Vinca rosea responds and reacts to simulated colored light. Vinca rosea proved to favor simulated blue light as opposed to yellow and white light. Red light also appears to be favored but results remained constant. According to (Popp, 1926), the reason as to why the blue light appeared to be successful compared to the others is proved in his investigation, in which he stated “the removal of blue-violet wavelengths was detrimental to the plants.” Having only observed the species for a short 72 hours, and based on the results from this investigation does not make them entirely conclusive. Many other factors such as whether or not growth rate is affected and if non-observable, chemical reactions are taking place due to the specific color of light that is being imposed may be taken into account if and when further research is conducted. Another factor that may have contaminated results is the fact that the simulated colored light that was imposed on the Vinca rosea may not have been spectroscopically pure, transmitting the entire visible spectrum to the plants rather than just one wavelength (Popp, 1926) The results of this experiment are evident that even though the light may not have been spectroscopically pure, the species Vinca rosea proved to favor a particular color of light over the rest.” Biological Writing Poster Session Methods Preparing the light simulator In order to observe the effects that colored light has on plants, four plants of the species Vinca rosea, were obtained from my garden in Mission, Texas the summer of 2012. The four plants were then transplanted from the soil to individual, 8-inch terracotta pots. Each plant was to be examined underneath four different colors of light, which included red, green, blue and white light over a period of 72 hours. The contraption used to simulate different wavelengths of light consisted of a cardboard banker’s box in which two 3 x 5 squares were cut on each side and then covered with a transparent, colored folder divider. Once each plant was placed in its simulator, the cardboard box was covered, leaving enough ventilation for oxygen flow, and a desk lamp was placed directly in front of the transparent cutout, recreating light from the sun. Maintaining the environment Plants, like any other species, require an environment that is providing in vital essentials. Each plant received exactly 6 hours of direct simulated sunlight throughout the course of three days as well as 1.5 hours of indirect “sunlight”. Each plant was also given exactly 2 cups of distilled water twice a day at 8:00 am and at 8:00 pm. The temperature of the habitat remained at a constant 72° Fahrenheit. It is extremely imperative to maintain the environment of the species in order to obtain relative results. Measuring and Recording Progression Measuring of growth and/or recordings of any physiological changes in the plants were documented every 12 hours beginning from August 4, 2012 through August 6, 2012. I observed any changes in growth, loss or gain of leaves, loss or gain of flower buds, as well as withering. These physical changes can be significant in pertaining to the effects that colored light has on the species Vinca rosea. Summary The purpose of this investigation was to observe the effects that different wavelengths of light have on the species Vinca rosea. The experiment was conducted over a period of 72 hours, using a light simulator that created the effects of blue, red, yellow and white light. Each plant responded individually to its assigned color, blue light being the most successful and yellow light being the least successful. This experiment showed to be a successful technique for identifying and observing physiological responses in plants to colored light. References Popp, H. W. 1926. A Physiological Study of the effect of Light of Various Ranges of Wavelength on the growth of plants. American Journal of Botany. 13. (10): 706 – 736 Dougher, A. O. and B. Bugbee. 2001. Evidence for Yellow light Supression of Lettuce Growth. American Society for Photobiology. 73 (2): (208 – 211) Kasperbauer, M. J. 1971. Spectral Distribution of Light in a Tobacco Canopy and Effects of End-of-Day Light Quality on Growth and Development. Plant Physiology. 47(6): 775–778 Gates, D. M., H. J. Keegan, J. C. Schleter, and V. R. Weidner. 1965. Spectral Properties of Plants. 4 (1): 11 – 20. Burkholder, P. R. 1936. The role of light in the life of plants. The Botanical Review. 2 (1): 1 – 52 Assmann, S. M. 1992, Effects of light quantity and quality during developmemt on the morphology and stomata physiology of Commelina cummis. Oecoligia. 92: 188 – 195. Date/ TimeA - RedB – BlueC - YellowD- White Aug. 4: 8 AM 4.32 in.4.54 in.4.48 in.4.37 in. Aug. 4: 8 PM 4.32 in.4.54 in.4.46 in. (slight withering) 4.36 in. (slight withering) Aug. 5: 8 AM 4.32 in.4.56 in.4.43 in. (flower loss) 4.36 in. Aug. 5: 8 PM 4.33 in4.56 in.4.42 in. (withered) 4.36 in. Aug. 6: 8 AM 4.33 in4.57 in. (Bud Bloomed) 4.42 in. (withered) 4.35 in. (slight withering) Aug. 6: 8 PM 4.33 in4.57 in.4.40 in. (withered) 4.33 in. (flower loss)