DEMONSTRATION C-3: Localization of response to light by the pigment in 
tomato skin, 
Materials: 
1. Use the same materials as in demonstration C-2, 
2. In addition, two small sheets of aluminum foil, enough to completely 
cover a tomato fruit. 
Procedure: 
1. Carefully select three uniform green-mature fruits. 
2. Completely and tightly wrap one of the tomato fruits with a sheet of 
aluminum foil (dark control). 
3. Remove a 5-millimeter-diameter section from the center of another 
sheet of aluminum foil. Completely and tightly wrap another tomato 
fruit, being careful that the perforation exposes an area of skin on the 
side of the fruit. 
4, Leave the remaining tomato fruit unwrapped (light control). 
5. Place all tomato fruits, both wrapped and unwrapped, in the light and 
allow 10 to 14 days for ripening, keeping the temperature at 70° F. 
6. When the unwrapped fruit is ripe (soft and red), unwrap all fruits and 
note any differences in skin color. 
7. Remove and process sections of the skin asin demonstration C-2, being 
careful to include the area exposed to the light through the perforation 
in the foil. 
Observations: 
Skins of the unwrapped fruit shouldbe bright yellow; skins of the completely 
wrapped fruits should be colorless; skins from the wrapped fruit with the 
small area exposed should be colorless except for the small exposed area 
which will be yellow. Anovelty canbe produced by tightly wrapping a green- 
mature fruit with a sheet of aluminum foil having a number of small 
perforations. 
Supplementary Reading: 
Hicks, C. B. You can make a plant do tricks. Pop. Mech. 108: 81-85, 
232=236.4 195i: 
DEMONSTRATION C-4: Effect of light on coloration of apples. 
Materials: 
Les 
Early harvested (green) Jonathan, Rome Beauty, or Arkansas apples. 
Jonathan variety is preferred, Store the apples at 32° F. in bags of 0.38- 
millimeter polyethylene plastic. 
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