This activity explores images of plant cells and structures, which serve as phenomena for learning about how plants respond to stimuli.

Plants, like animals, respond to stimuli in their environments. These images show the responses of plant roots and stomata to several common stimuli. The roots are particularly affected by gravity and water levels. These stimuli affect the timing of cell division and root elongation, which helps roots grow down into the soil. The stomata, pores on the surfaces of leaves, are affected by water and carbon dioxide levels. Plants regulate the opening and closing of their stomata to control carbon dioxide intake and water loss.

The “Educator Materials” document includes background information and implementation suggestions for using the images as phenomena. The “Student Handout” includes the images and background information. The “Root Movement animation” is a short time-lapse video that follows the growing root tip from the “Root Movement” image.

“Root Movement” image by Daniel von Wangenheim, Institute of Science and Technology, Austria

“Super Stoma” image by Dominique Bergmann, Stanford University