1 / 7

Plant Responses

Plant Responses. 3.3 pages 70-73. Plants Respond?. Stimulus: Plant stimuli: Tropism:. something that incites to action. Light, gravity, and changing seasons. Growth in response to a stimulus. Phototropism. Phototropism: How does the plant bend?.

guri
Download Presentation

Plant Responses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plant Responses 3.3 pages 70-73

  2. Plants Respond? • Stimulus: • Plant stimuli: • Tropism: something that incites to action Light, gravity, and changing seasons. Growth in response to a stimulus.

  3. Phototropism • Phototropism: • How does the plant bend? A change in the direction a plant grows that is caused by light. Cells on one side grow longer than cells on the other side, causing the plant to bend.

  4. Gravitropism • Gravitropism: • Positive gravitropism: • Negative gravitropism: A change in the direction a plant grows that is caused by gravity. Tendency to grow with the pull of gravity – grow down like the roots of plants. Tendency to grow against the pull of gravity – grow up like the shoots of plants.

  5. Seasonal Responses • Why don’t plants flower in the winter? • How do plants know what season it is? • How do they know? Too cold for tender tissues, not enough nutrients. They know because they can tell how long the days are. They have a chemical that acts like a timer! This chemical builds up at night and disappears at the first rays of light. So the more chemical that builds up… the longer the night must be!

  6. Seasons and leaf loss • Deciduous: • Evergreen: • Why lose leaves? Trees that lose their leaves all at one time. Trees that lose their leaves gradually over the whole year. Helps deciduous trees survive the cold or dry seasons.

  7. Leaf Color changes • What really happens? As the day lengths get shorter the chlorophyll begins to die and no more is made to replace it. The colors you see are colors that were there all long but covered up by all the chlorophyll. Red is the only color that is made in the fall… the rest were there all along.

More Related