Re: What type of grass to use for tropism experiment?

Lawn grass seed or grass seed in canary bird seed would probably be
satisfactory. They germinate fast and are very responsive to light when just a
few cm tall. Corn is a grass that is also used in many school experiments.
Charles Darwin did some of the first experiments on phototropism, and he used
annual canarygrass (Phalaris canariensis) and oat (Avena sativa). Annual
canarygrass is used mainly as birdseed.

To see if gravitropism or phototropism is stronger, take a potted plant and
place it upside down with continuous fluorescent light coming from below. That
way if the shoot continues to grow straight down, phototropism would be
stronger. If the shoot bends upright again, then gravitropism would be stronger. 

You will need to hold the soil in the pot possibly by securing plastic mesh over
the top of the pot prior to sowing the seed.

If you use a turntable, place a potted plant in the center and provide light on
one side only. See if the plant exhibits phototropism.


References



Darwin, C. 1880. The Power of Movement in Plants. John Murray, London. 


Annual Canarygrass (Phalaris canariensis)


Re: Phototropism experiment--best way to grow and place plants