释义 |
pho·tot·ro·pism \fōˈtä.trəˌpizəm\ noun Etymology: International Scientific Vocabulary phot- + -tropism 1. : a tropism in which light is the orienting stimulus (as in the turning toward a light of a plant shoot or a tube worm and in the creeping away from a light of a blowfly larva) — compare heliotropism 2. : the reversible change in color of a substance produced by the formation of an isomeric modification when exposed to radiant energy (as light) |