TODD ORAVITZ
9 TH GRADE
CENTRAL CATHOLIC

• Naturally occurring substance
• Bitter, white purine compound
• Similar chemical structure to adenine and guanine

• Blocks adenosine receptors, leading to calcium loss in plant cells
• Low calcium can cause problems with
• Cell membrane permeability
• Cell plate formation

• Interferes with plant cytokinesis
• Stops Golgi vesicles from fusing with membranes by decreasing
ATP activity
• Has been shown to inhibit cell division in plants

• Pesticide-like protection to plants containing it
• Germination of competing seedlings may be slowed by plants depositing caffeine in nearby soil

• Effective natural stimulant
• Seeds contain about twice the caffeine concentration as those from coffee

• Naturally alters one’s perception of fullness, leading to weight loss
• FDA recognizes it as “generally safe”

• To determine if caffeine has an effect on germination and growth of mung beans

• 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)

• 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

• 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
DAY
28

No growth Growth Total
Caffeine 51 21 72
Control
Total
19 53
70 74
Χ 2 = 28.466, p < 0.00001
72
144

• 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

• When caffeine group mung beans did germinate, did they exhibit similar growth characteristics to control?

CAFFEINE EFFECT ON SHOOT HEIGHT day bluecaffeine greencontrol general linear modeling, p = 0.812

• Daily average mung bean shoot height compared
• Only plants that germinated
• No significant difference between caffeine and control average daily shoot heights

0,6
AVG MASS/PLANT – WET caffeine
0,5 control
0,4
0,3
0,2
0,1
0 wet mass caffeine, g control, g p value significant?
0.297
0.259
0.052
no
0.261
0.308
0.035
yes
0.558
0.567
0.785
no

0,4
AVG MASS/PLANT – DRY
0,35 caffeine control
0,3
0,25
0,2
0,15
0,1
0,05
0 dry mass caffeine, g control, g p value significant?
0.224
0.176
0.009
yes
0.129
0.142
0.262
no
0.353
0.318
0.125
no

1,2
1
0,8
Caffeine
0.297/0.261 = 1.138
0,6
0,4
Control
0.259/0.308 = 0.841
0,2
0 mass ratio

• 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 blue – caffeine;
R=0.963
green – control;
R=0.807
p<0.001
total wet mass (g)

HEIGHT, DRY MASS CORRELATION blue – caffeine;
R=0.941
green – control;
R=0.815
p<0.001
total dry mass (g)

• Height vs total wet and dry mass
• Only plants that germinated
• Pearson correlation coefficient
• Height correlated with mass in both wet and dry groups

• 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

• 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
• 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

• 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/docume nts/cffee07.pdf
• Hazardous Substances Data Bank. 1997. Caffeine. HSDB number 36. Bethesda, MD: National Library of Medicine.

• 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

• 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: Single Factor
SUMMARY
Groups
Column 1
Column 2
Column 3
Column 4
Count
21
21
53
53
Sum
6.233
5.489
13.718
16.345
Average
0.29681
0.261381
0.25883
0.308396
Variance
0.004239
0.006237
0.008701
0.007563
ANOVA
Source of Variation
Between Groups
Within Groups
Total
SS
0.078898
1.055238
1.134137
df
3
144
147
MS
0.026299
0.007328
F
3.588881
P-value
0.015321
F crit
2.667443

Anova: Single Factor
SUMMARY
Groups
Column 1
Column 2
Column 3
Column 4
Count
21
21
53
53
Sum
4.701
2.71
9.332
7.547
Average
0.223857
0.129048
0.176075
0.142396
Variance
0.004027
0.001461
0.005073
0.002345
ANOVA
Source of Variation
Between Groups
Within Groups
Total
SS
0.133358
0.495492
0.62885
df
3
144
147
MS
0.044453
0.003441
F
12.91884
P-value
1.6E-07
F crit
2.667443

2
1,8
1,6
1,4
1,2
1
0,8
0,6
0,4
0,2
0
Caffeine
0.224/0.129 = 1.736
Control
0.176/0.142 = 1.239
mass ratio