Effects of Light Type on Tagetes patula Growth

1. Effects of Light Type on Tagetes patula Growth Amber D. Jones Zoology Major, Biology Dept. TTU Cookeville, TN 38501

2. Introduction • “Light…supplies the energy upon which plant life is based…” “The effects of light quality on plant life are manifold (Wassink & Stolwijk)” • Plants need light to survive. My experiment examines which light type yields better growth in Tagetespatula.

3. “The importance of light in plant development cannot be overestimated.(Chory et al.)” • “Plants use light not only as an energy source for photosynthesis but also as an environmental signal and respond to its intensity, wavelength, and direction. (Takemiya et al.)” • “Removal of all of the near-UV or half of the green radiation from white light increased the fresh and dry weight, height of the plants….(Klein et al.)”

4. “Effects of light quality on various phases of growth and develpoment have been studied in almost every major group of plants. (Wassink & Stolwijk)” • “…light controls development and gene expression…(Chory et al.)” • Some plants have photoreceptors that “….control such responses as germination, stem elongation, flowering, gene expression, and chloroplast and leaf development. (Reed et al.)”

5. Objective and Hypothesis • Objective: To determine if light type has an effect on Tagetespatulagrowth. • Hypothesis: Tagetespatulawill grow better in sunlight. • Null: There will be no difference in growth.

6. Methods and Materials

7. Methods and Materials • Plants were grown in peat pellets for two weeks before being harvested. • They were measured after being harvested. (Weiner et al.) • Measurements taken were the height of stems and were statistically evaluated by averaging the heights. (Brown 2007)

8. Results • There was a difference in plant growth. • Table 1: • *Some seeds did not sprout at all and some sprouts died before harvesting so the averages were not of the total number planted but of the number that survived to be harvested which still turned out to be the same for each seed group; 3s, 5s and 8s.

9. Figure 1 • *1 is the 3s groups, 2 the 5s and 3 the 8s.

10. Discussion • Null Hypothesis rejected. There definitely was a difference in plant growth. • Results agree with published literature that quality of light effects development of plants. (Wassink & Stolwijk)

11. Conclusion • Results rejected the null hypothesis. • Due to results accept the hypothesis that Tagetespatulagrow better in sunlight. • Could compare more light types

12. Literature Cited • Chory, J., M. Chatterjee, R.K. Cook, T. Elich, C. Fankhauser, J. Li, M. Neff, A. Pepper, D. Poole, J. Reed, and V. Vitart. 1996. from seed germination to flowering, light controls plant development via the pigment phytochrome. Proc. Natl. Acad. Sci. USA 93: 12066-12071. • Klein, R.M., P. C. Edsall, and A.C. Gentile. 1965. Effects of Near Ultraviolet and Green Radiations on Plant Growth. Plant Physiology 40:903-906. • Reed, J.W., P. Nagpal, D.S. Poole, M. Furuya, and J. Chory. 1993. Mutations in the Gene for the Red/Far-Red Light Receptor Phytochrome B Alter Cell Elongation and Physiological Responses throughtout Arabidopsis Development. The Plant Cell 5: 147-157. • Takemiya, A., S. Inoue, M. Doi, T. Kinoshita, and K. Shimazaki. 2005. Phototropins Promote Plant Growth in Response to Blue Light in Low Light Environments. The Plant Cell 17:1120-1127. • Wassink, E.C., and J.A.J. Stolwiljk. 1956. Effects of Light Quality on Plant Growth. Annual Review of Plant Physiology 7: 373-400. • Weiner, J., E.B. Mallory, and C. Kennedy. 1989. Growth and Variablity in Crowded and Uncrowded Populations of Dwarf Marigolds. Annals of Botany 65:513-524.