Procedure: 
1, Cut two to four layers of blotter to fit each dish and presoak overnight 
(about 16 hours) by putting enough tapwater into the dishes to flood the 
blotters. 
2. After the blotters are thoroughly soaked pour off excess water and 
evenly distribute 100 seeds over the surface of the blotters in each dish. 
3. Immediately place the dishes with lids in the black cloth bags. 
4, Allow the seeds to imbibe water in the darkness of the black cloth bags 
for a period of 16 to 24 hours, then begin treatments. 
5. Treatments: 
(a) In the dimmest light possible, preferably complete darkness, remove 
dishes 1 and 2 from their black cloth bags and wrap each dish with 
two layers of red cellophane. 
(b) Place both the cellophane-wrapped dishes under the fluorescent 
lights for a period of 5 minutes. 
(c) Return dish 1 to its black cloth bag without further exposure to light. 
If no dark room is available during this transfer, place the dish in | 
the black cloth bag without removing it from the red-cellophane 
wrapping. 
(d) Dish 2 is wrapped in blue cellophane so that the seeds are now 
covered with two layers of red and two layers of blue cellophane, 
(e) Dish 2 is now exposed to light from the incandescent lamps for a 
period of 15 minutes. 
(f) Place dish 2 in the black cloth, either in complete darkness or if 
necessary still enclosed in the red- and blue-cellophane wrapping. 
6. The three dishes of seeds have now received their treatments. Dish 3 
has remained in the black cloth bag and serves as a dark control. Dish 
1 has been exposed to red radiant energy for 5 minutes and dish 2 has 
been exposed to red for 5 minutes and to far-red for 15 minutes. 
7. Allow 3 to 4 days to elapse, then remove the dishes from their black 
cloth bags and count and record the number of germinated seeds. 
Temperatures should be held as close to 70° F. as possible. 
Observations: 
When counting the number of seeds germinated in each dish, record as 
percentage of germination. These data can be presented in either tabular 
form or ina bar graph, using the bars for treatments and the height of the 
bars as percentage of germination, Those seeds that remained in darkness 
will probably germinate 0 percent if peppergrass seeds were used, or 5 to 
25 percent if seeds of Grand Rapids lettuce were used. Those seeds receiv- 
ing red light will probably germinate 90 to 100 percent for both species, 
whereas those receiving red followed by far-red might germinate 5 to 10 
percent for peppergrass, and 5 to 25 percent for lettuce. Evidence has now 
been obtained to show that these seeds require light (red) for germination, 
and that the potential germination induced by the exposure to red can be 
reversed by a subsequent exposure to far-red radiant energy. 
Supplementary Reading: 
See Demonstration A-l, 
14 
