You want to obtain the strongest phototropic response from a shoot. Which wavelength of light should you use?
A) Less than 500 nm
B) 660 nm
C) 730 nm
D) 800 nm
E) More than 800 nm

Question

Quizplus · Accepted Answer

Phototropic responses in plants are strongest under blue light, which has wavelengths less than 500 nm. This is because blue light is most effectively absorbed by phototropins, the photoreceptors that mediate phototropism.

You Want to Obtain the Strongest Phototropic Response from a Shoot