Plant Response to Stimuli Mechanisms plants have to respond to environmental stimuli
How do plants respond to stimuli! They don’t get up and run away! They do: Have tropisms in response to: Light, Gravity, Touch Have defense against pathogens Have hormones that initiate signal transduction pathways to send messages long-distance.
Responses to light Phytochromes: Phototropism: Phytochromes can initiate hormones that promote growth toward light (more later…) Circadium rhythm(daily) 4 o’clock flowers = to sleep cycle in animals Photoperiodism (seaonally) Season for flowering: Short day plants vs. long day plants…when would be the best time to flower in New England if…
Circadian Rhythm
Photoperiodism
Plant hormone experimental presentation! Find an experiment involving your plant hormone: Introduction —What is your hormone used for? Hypothesis —What was the researchers hypothesis? Methods —How did the researcher collect data. Data —Find a picture or graph to analyze results and explain a verbal trend. Conclusion —What did the experimenters learn about the plant hormones.
Hormones to be familiar with: Auxin Abscisic acid Cytokinins Ethylene Gibberellins