Transcript Effects of Light Type on Tagetes patula Growth

Effects of Light Type on
Tagetes patula Growth
Amber D. Jones
Zoology Major, Biology Dept. TTU
Cookeville, TN 38501
Introduction
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“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.
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“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.)”
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“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.)”
Objective and Hypothesis
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Objective: To determine if light type has an
effect on Tagetes patula growth.
Hypothesis: Tagetes patula will grow better
in sunlight.
Null: There will be no difference in growth.
Methods 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 Materials
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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)
Results
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There was a difference in plant growth.
Table 1:
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
*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.
Figure 1
Average Plant Heights per Group
Heights (cm)
25
20
15
Sunlight
10
Incandescent
5
0
1
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2
3
*1 is the 3s groups, 2 the 5s and 3 the 8s.
Discussion
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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)
Conclusion
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Results rejected the null hypothesis.
Due to results accept the hypothesis
that Tagetes patula grow better in
sunlight.
Could compare more light types
Literature Cited
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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: 1206612071.
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: 147157.
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.