1. How Plants Respond to Their Environment

3. How is the dodder able to perceive the tomato plant? A bit about dodder… –Parasitic plant –One of USDA’s Top Ten Weeds –Little photosynthetic capability –Seedling will only survive for a few days without host What are possible explanations for what you observed?

4. In this case a plant is responding to volatiles in its environment. What are volatiles?

5. What other environmental cues can plants respond to?

6. At the cellular level, how is dodder able to respond to volatiles?

7. Discussion You are in the lab studying this phenomenon. What would you do next? Discuss the questions below in your group. –Hypothesize what is happening in the surface cell of the dodder plant. How could a plant detect the tomato “scent”? –What needs to happen for the plant to move toward the tomato at the cellular level? –What cell organelles and molecules might be involved? –Model your hypothesis through the structures of the cell from the initial detection of the tomato to the dodder movement. –Is this process happening in just one cell?

8. Examples of plant receptors Photoreceptors Hormone receptors Surface receptors for pathogens

9. Examples of signaling MAP Kinase cascade Ca 2+ Reactive Oxygen Ion fluxes

10. What are the results of signaling? Transcription –Activation –Repression Translation...Simply put, the information is copied from one molecule of DNA to a molecule of RNA. Why do we need so many signals and signal cascades?

11. Responses What types of responses would be needed to make the dodder move?

12. Pathways of other environmental cues