caffeine’s effect on mung bean germination and growth todd oravitz 9 th grade central catholic
TRANSCRIPT
CAFFEINE’S EFFECT ON MUNG BEAN GERMINATION AND GROWTH
TODD ORAVITZ
9TH GRADE
CENTRAL CATHOLIC
INSPIRATION
CAFFEINE• Naturally occurring substance
• Bitter, white purine compound• Similar chemical structure to
adenine and guanine
CAFFEINE EFFECTS
• Blocks adenosine receptors, leading to calcium loss in plant cells
• Low calcium can cause problems with
• Cell membrane permeability• Cell plate formation
CAFFEINE EFFECTS
• Interferes with plant cytokinesis• Stops Golgi vesicles from fusing
with membranes by decreasing ATP activity
• Has been shown to inhibit cell division in plants
CAFFEINE IN NATURE
• Pesticide-like protection to plants containing it
• Germination of competing seedlings may be slowed by plants depositing caffeine in nearby soil
GUARANA PLANT
• Effective natural stimulant
• Seeds contain about twice the caffeine concentration as those from coffee
GUARANA PLANT
• Naturally alters one’s perception of fullness, leading to weight loss
• FDA recognizes it as “generally safe”
PURPOSE
• To determine if caffeine has an effect on germination and growth of mung beans
HYPOTHESES
• Null
• Caffeine will not have a significant effect on mung bean germination and growth
• Alternative
• Caffeine will have a significant effect on mung bean germination and growth
MATERIALS
• Seed starter trays
• Potting soil
• Mung beans
• Guarana – caffeine source
• Sunlight via window
• Room lights
• Tap water
• Pyrex 500mL measuring cup (to make test solution)
• 10mL measuring cup (for watering)
• Ruler
• Scientific scale
(no continuous, dedicated light source)
PROCEDURE• Planted mung beans
• 72 plants each in test and control groups
• 5 mL caffeine solution [200mg/L] given every other day to test group
• 5 mL tap water given every other day to control group
PROCEDURE• Main shoot height of mung beans
measured daily for 28 days
• Mung bean mass measured on day 28:• Plant removed, rinsed with tap water and
cut at ground level• Above and below ground wet masses
measured, then added for total• Procedure repeated after air drying for
three hours to obtain dry mass
CAFFEINE CONTROL
DAY28
GERMINATION ANALYSISNo growth Growth Total
Caffeine 51 21 72
Control 19 53 72
Total 70 74 144
Χ2 = 28.466, p < 0.00001
CONCLUSIONS• Null hypothesis rejected
• Alternative hypothesis accepted – caffeine had a significant effect on mung bean germination and growth
• Specifically, it significantly decreased the number of mung beans that germinated
QUESTION
• When caffeine group mung beans did germinate, did they exhibit similar growth characteristics to control?
avg
sh
oo
t h
eig
ht
(mm
)
day
blue-caffeinegreen-control
CAFFEINE EFFECT ON SHOOT HEIGHT
generallinearmodeling,p = 0.812
HEIGHT ANALYSIS• Daily average mung bean shoot
height compared• Only plants that germinated• No significant difference between
caffeine and control average daily shoot heights
above ground below ground total0
0.1
0.2
0.3
0.4
0.5
0.6caffeinecontrol
AVG MASS/PLANT – WET
wet mass above ground below ground total
caffeine, g 0.297 0.261 0.558
control, g 0.259 0.308 0.567
p value 0.052 0.035 0.785
significant? no yes no
mas
s (g
)
above ground below ground total0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
caffeinecontrol
mas
s (g
)AVG MASS/PLANT – DRY
dry mass above ground below ground total
caffeine, g 0.224 0.129 0.353
control, g 0.176 0.142 0.318
p value 0.009 0.262 0.125
significant? yes no no
ABOVE/BELOW GROUND WET MASS RATIO
mass ratio0
0.2
0.4
0.6
0.8
1
1.2
Caffeine 0.297/0.261 = 1.138
Control 0.259/0.308 = 0.841
MASS ANALYSIS
• T-test done for all 6 subgroups• Significant difference seen in 2
• Below wet (p=0.035) and above dry (p=0.009)
• No significant difference in the other 4
• Above wet, total wet, below dry and total dry
HEIGHT, WET MASS CORRELATION
hei
gh
t (m
m)
total wet mass (g)
blue – caffeine;R=0.963green – control;R=0.807
p<0.001
HEIGHT, DRY MASS CORRELATION
hei
gh
t (m
m)
total dry mass (g)
blue – caffeine;R=0.941green – control;R=0.815
p<0.001
HEIGHT VS MASSANALYSIS
• Height vs total wet and dry mass• Only plants that germinated• Pearson correlation coefficient• Height correlated with mass in both
wet and dry groups
CONCLUSIONS
• Null hypothesis rejected
• Alternative hypothesis accepted – caffeine had a significant effect on mung bean germination and growth• Specifically, it reduced the
number of plants that germinated
CONCLUSIONS
• Mung beans in the caffeine group that did germinate, however, showed similar growth to control
• No significant differences in• Average daily shoot height• Average total wet mass• Average total dry mass
LIMITATIONS AND EXTENSIONS• Limitations
• Did not control soil content• Short drying time• Inconsistent lighting
• Extensions
• Different caffeine concentrations• Correlate pre-planting mung bean mass
with germination• Defined non-sunlight source
BIBLIOGRAPHY• ag.arizona.edu/pubs/garden/mg/soils/types.html
• Arnaud, M.J. 1987. The pharmacology of caffeine. Prog. Drug Res. 31: 273-313.
• Bonsignore, C.L, and Hepler, P.K. “Caffeine Inhibition of Cytokinesis: Dynamics of Cell Plate Formation-Deformation in vivo.” Protoplasma. 129, 28-35; 1985.
• en.wikipedia.org/wiki/guarana
• Etherdon, G.M., and M.S. Kochar. 1993. Coffee: Facts and controversies. Arch. Fam. Med. 2(3):317-322.
• extension.oregonstate.edu/lane/sites/default/files/documents/cffee07.pdf
• Hazardous Substances Data Bank. 1997. Caffeine. HSDB number 36. Bethesda, MD: National Library of Medicine.
BIBLIOGRAPHY• Hepler, P.K. “Calcium: A Central Regulator of Plant Growth
and Development.” Plant Cell 2005; 17; 2142-55.
• Kabagambe, Edmond K. "Benefits and Risks of Caffeine and Caffeinated Beverages." UpToDate. Wolters Kluwer Health, 27 Feb 2013.
• Lopez-Saez, J.F. et al. “ATP level and caffeine efficiency on cytokinesis inhibition in plants.” Eur J Cell Biol. 1982 Jun; 27(2): 185-90.
• Nathanson, J.A. “Caffeine and related methylxanthines: possible naturally occurring pesticides.” Science. 226 (4671), 184-7; 1984.
• www.hort.purdue/edu/ext/groundsforgardening.html
• www.hort.purdue.edu/newcrop/afcm/mungbean.html
ACKNOWLEDGEMENTS
• Thanks to Mr. Krotec for support and guidance throughout the experiment.
• Thanks to James Ibinson, MD, PhD, for help with statistical analysis.
• Thanks to my parents for helping me with ideas and suggestions, as well as supply of materials.
ANOVA TESTING – ABOVE/BELOW WET MASS
Anova: Single Factor
SUMMARY
Groups Count Sum Average Variance
Column 1 21 6.233 0.29681 0.004239
Column 2 21 5.489 0.261381 0.006237
Column 3 53 13.718 0.25883 0.008701
Column 4 53 16.345 0.308396 0.007563
ANOVA
Source of Variation SS df MS F P-value F crit
Between Groups 0.078898 3 0.026299 3.588881 0.015321 2.667443
Within Groups 1.055238 144 0.007328
Total 1.134137 147
ANOVA TESTING – ABOVE/BELOW DRY MASSAnova: Single Factor
SUMMARY
Groups Count Sum Average Variance
Column 1 21 4.701 0.223857 0.004027
Column 2 21 2.71 0.129048 0.001461
Column 3 53 9.332 0.176075 0.005073
Column 4 53 7.547 0.142396 0.002345
ANOVA
Source of Variation SS df MS F P-value F crit
Between Groups 0.133358 3 0.044453 12.91884 1.6E-07 2.667443
Within Groups 0.495492 144 0.003441
Total 0.62885 147
ABOVE/BELOW GROUND DRY MASS RATIO
mass ratio0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Caffeine 0.224/0.129 = 1.736
Control 0.176/0.142 = 1.239