CK-12 Foundation
Ck 12: Third Grade: Life Science: Plant Adaptations to Environmental Changes
[Free Registration/Login may be required to access all resource tools.] Discuses how plants respond to changes in their environment and some special adaptations in plants.
CK-12 Foundation
Ck 12: Life Science: 7.13 Tropisms
Learn how plants respond to different environmental stimuli.
Other
Kenyon College: Thigmotropism in Tendrils
What is thigmotropism? Do plants have a sense of touch? What causes plants to curve toward the stimulus? Animated illustrations help to provide these answers and more. Hint: highlighting the text makes it easier to read.
University of Hamburg
University of Hamburg: Photoperiodism and Stimulation
A good summary of the photoperiodic effects of plants. Discussion of the way that the length of the day effects the growth of plants.