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)” “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 Tagetes patula. Plants need light to survive. My experiment examines which light type yields better growth in Tagetes patula.

3. “The importance of light in plant development cannot be overestimated.(Chory et al.)” “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.)” “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.)” “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)” “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.)” “…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.)” 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 Tagetes patula growth. Objective: To determine if light type has an effect on Tagetes patula growth. Hypothesis: Tagetes patula will grow better in sunlight. Hypothesis: Tagetes patula will grow better in sunlight. Null: There will be no difference in growth. Null: There will be no difference in growth.

6. Methods and Materials Group A4 pots w/ 3 seeds (3s) 4 pots w/ 5 seeds (5s) 4 pots w/ 8 seeds (8s) 12 pots/ group Group B4 pots w/ 3 seeds (3s) 4 pots w/ 5 seeds (5s) 4 pots w/ 8 seeds (8s) 12 pots / group

7. Methods and Materials Plants were grown in peat pellets for two weeks before being harvested. Plants were grown in peat pellets for two weeks before being harvested. They were measured after being harvested. (Weiner et al.) 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) 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. There was a difference in plant growth. Table 1: 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. *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. Group AAvg. HeightGroup BAvg. Height 3s19.43s17.8 5s15.65s13.1 8s12.18s10.8

9. Figure 1 *1 is the 3s groups, 2 the 5s and 3 the 8s. *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. 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) Results agree with published literature that quality of light effects development of plants. (Wassink & Stolwijk)

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