Re: what scientists have performed seed germination experiments?

I think your teacher intended that you find the results of three seed 
germination experiments yourself so I'll suggest some places to look. 

Try the University of W. Virginia library given that you live in Morgantown, 
WV. They will have either biological or horticultural abstracts or online 
databases, such as Agricola or BIOSIS, to locate articles on seed germination. 
Ask the librarian for help in locating them.

Check out the books listed in references below. They are loaded with info on 
seed germination experiments.

Find out if your state has a seed testing laboratory and contact them for 
experiments they conduct.

Introductory college textbooks on biology and botany sometimes have some info 
on phytochrome experiments on seed germination and possibly others.

References

Hartmann, H.T. and Kester, D.E. 1983. Plant Propagation: Principles and 
Practices. Englewood Cliffs, NJ: Prentice-Hall.

USDA Forest Service. 1974. Seeds of Woody Plants in the United States. 
Washington, DC: USDA Forest Service.