Effects of Light Type on Effects of Light Type on Tagetes patulaTagetes patula Growth Growth

Amber D. JonesAmber D. Jones

Zoology Major, Biology Dept. TTUZoology Major, Biology Dept. TTU

Cookeville, TN 38501Cookeville, TN 38501

IntroductionIntroduction

““Light…supplies the energy upon Light…supplies the energy upon which plant life is based…” “The which plant life is based…” “The effects of light quality on plant life are effects of light quality on plant life are manifold (Wassink & Stolwijk)”manifold (Wassink & Stolwijk)”

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

““The importance of light in plant development The importance of light in plant development cannot be overestimated.(Chory et al.)”cannot be overestimated.(Chory et al.)”

““Plants use light not only as an energy source for Plants use light not only as an energy source for photosynthesis but also as an environmental photosynthesis but also as an environmental signal and respond to its intensity, wavelength, signal and respond to its intensity, wavelength, and direction. (Takemiya et al.)”and direction. (Takemiya et al.)”

““Removal of all of the near-UV or half of the green Removal of all of the near-UV or half of the green radiation from white light increased the fresh and radiation from white light increased the fresh and dry weight, height of the plants….(Klein et al.)”dry weight, height of the plants….(Klein et al.)”

““Effects of light quality on various phases of growth Effects of light quality on various phases of growth and develpoment have been studied in almost and develpoment have been studied in almost every major group of plants. (Wassink & Stolwijk)”every major group of plants. (Wassink & Stolwijk)”

“…“…light controls development and gene light controls development and gene expression…(Chory et al.)”expression…(Chory et al.)”

Some plants have photoreceptors that “….control Some plants have photoreceptors that “….control such responses as germination, stem elongation, such responses as germination, stem elongation, flowering, gene expression, and chloroplast and flowering, gene expression, and chloroplast and leaf development. (Reed et al.)”leaf development. (Reed et al.)”

Objective and Objective and HypothesisHypothesis Objective: To determine if light type has Objective: To determine if light type has

an effect on an effect on Tagetes patula Tagetes patula growth.growth.

Hypothesis: Hypothesis: Tagetes patula Tagetes patula will grow will grow better in sunlight.better in sunlight.

Null: There will be no difference in Null: There will be no difference in growth.growth.

Methods and MaterialsMethods and Materials

Group A 4 pots w/ 3 seeds (3s)

4 pots w/ 5 seeds(5s)

4 pots w/ 8 seeds(8s)

12 pots/ group

Group B 4 pots w/ 3 seeds(3s)

4 pots w/ 5 seeds(5s)

4 pots w/ 8 seeds(8s)

12 pots / group

Methods and MaterialsMethods and Materials

Plants were grown in peat pellets for two Plants were grown in peat pellets for two weeks before being harvested.weeks before being harvested.

They were measured after being harvested. They were measured after being harvested. (Weiner et al.)(Weiner et al.)

Measurements taken were the height of Measurements taken were the height of stems and were statistically evaluated by stems and were statistically evaluated by averaging the heights. (Brown 2007)averaging the heights. (Brown 2007)

ResultsResults

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 *Some seeds did not sprout at all and some sprouts died before harvesting so the averages were not of the total number planted but 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 of the number that survived to be harvested which still turned out to be the same for each seed group; 3s, 5s and 8s.be the same for each seed group; 3s, 5s and 8s.

Group A Avg. Height

Group B Avg. Height

3s 19.4 3s 17.8

5s 15.6 5s 13.1

8s 12.1 8s 10.8

Figure 1Figure 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.

Average Plant Heights per Group

0

5

10

15

20

25

1 2 3

Heig

hts

(c

m)

Sunlight

Incandescent

DiscussionDiscussion

Null Hypothesis rejected. There Null Hypothesis rejected. There definitely was a difference in definitely was a difference in plant growth.plant growth.

Results agree with published Results agree with published literature that quality of light literature that quality of light effects development of plants. effects development of plants. (Wassink & Stolwijk)(Wassink & Stolwijk)

ConclusionConclusion

Results rejected the null Results rejected the null hypothesis.hypothesis.

Due to results accept the Due to results accept the hypothesis that hypothesis that Tagetes patula Tagetes patula grow better in sunlight.grow better in sunlight.

Could compare more light typesCould compare more light types

Literature CitedLiterature Cited

Chory, J., M. Chatterjee, R.K. Cook, T. Elich, C. Fankhauser, J. Li, M. Neff, A. 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 Pepper, D. Poole, J. Reed, and V. Vitart. 1996. from seed germination to flowering, light controls plant development via the pigment phytochrome. flowering, light controls plant development via the pigment phytochrome. Proc. Natl. Acad. Sci. USA 93: 12066-12071.Proc. Natl. Acad. Sci. USA 93: 12066-12071.

Klein, R.M., P. C. Edsall, and A.C. Gentile. 1965. Effects of Near Ultraviolet and 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.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 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 the Gene for the Red/Far-Red Light Receptor Phytochrome B Alter Cell Elongation and Physiological Responses throughtout Arabidopsis Elongation and Physiological Responses throughtout Arabidopsis Development. The Plant Cell 5: 147-157.Development. The Plant Cell 5: 147-157.

Takemiya, A., S. Inoue, M. Doi, T. Kinoshita, and K. Shimazaki. 2005. Takemiya, A., S. Inoue, M. Doi, T. Kinoshita, and K. Shimazaki. 2005. Phototropins Promote Plant Growth in Response to Blue Light in Low Light Phototropins Promote Plant Growth in Response to Blue Light in Low Light Environments. The Plant Cell 17:1120-1127.Environments. The Plant Cell 17:1120-1127.

Wassink, E.C., and J.A.J. Stolwiljk. 1956. Effects of Light Quality on Plant Wassink, E.C., and J.A.J. Stolwiljk. 1956. Effects of Light Quality on Plant Growth. Annual Review of Plant Physiology 7: 373-400.Growth. Annual Review of Plant Physiology 7: 373-400.

Weiner, J., E.B. Mallory, and C. Kennedy. 1989. Growth and Variablity in Weiner, J., E.B. Mallory, and C. Kennedy. 1989. Growth and Variablity in Crowded and Uncrowded Populations of Dwarf Marigolds. Annals of Botany Crowded and Uncrowded Populations of Dwarf Marigolds. Annals of Botany 6565:513-524.:513-524.