Plant Hormones, Nutrition, and Transport
In previous parts of this unit, we examined how a plant is constructed. We also looked at how plants reproduce, both sexually and asexually. Plants must have energy to grow and reproduce. Photosynthesis provides a plant with a basic energy resource, glucose. However, plants need to move this food to non-photosynthetic areas, such as the roots. How plants coordinate their responses to both internal and external stimuli, as well as how they transport essential food and minerals, makes for an interesting story.
Plant Movements and Responses to the Environment
Plants move. Doubt it? Place a houseplant next to a window, and in a few days, the leaves will turn toward the window. Plants don’t move as rapidly as animals do since they lack the muscles and nerves that animals use for motion. But plants move in response to chemical and especially hormonal control.
Plants exhibit two basic types of movements: tropisms and nastic movements. Tropisms are plant movements that involve the plant moving by growing toward or away from a stimulus. The stimulus might be light, gravity, or touch. Nastic movements are plant movements independent of the direction of the stimulus. A plant’s circadian movements of opening and closing leaves are an example of nastic movements.
Journal: Plants in Motion
Visit http://www.pbslearningmedia.org/resource/lsps07.sci.life.reg.plantmovies/plants-in-motion/ and examine at least three of the movies showing plant motion. Describe what you see in each.
Please submit your journal entry to the Journal: Plants in Motion assignment link. For information on how this assignment will be graded, please visit the Course Information section.