Plant Responses and Adaptations.

What is a tropism?

Tropism : a response of a plant to an environmental

stimulus.

What is phototropism?

Phototropism: a tendency of plants to grow toward a source

of light.

What is thigmotropism?

Thigmotropism : the response of plants to

touch.

Venus Fly Trap

Bean Plant

What is gravitropism/geotropism?

Gravitropism/geotropism: a tendency of a plant to

grow in a direction in response to the force of

gravity.

What is negatively and positively geotropic mean?

Negatively geotropic means that the plant fights gravity and grow upward.

Positively geotropic means that the plants don’t fight against gravity and grow downward.

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Now for your viewing pleasure!

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Turgor Pressure

• Definition: Turgor Pressure: also called turgidity, is the main pressure of the cell contents against the cell wall in plant cells. Turgid plant cells contain more water than flaccid cells and exert a greater pressure on its cell walls.

• Turgor is a force exerted outward on a plant cell wall by the water contained in the cell. This force gives the plant rigidity, and may help to keep it erect. Turgor can result in the bursting of a cell.

When material such as water, leaves the cell the pressure on the inside cell wall decreases. This means the turgor pressure on the cell wall is decreased.

When material such as water leaves and enters the cell at the same rate, the pressure on the inside cell wall stays the same. This means the turgor pressure on the cell wall is not changed.

When material such as water enters the cell, the pressure on the inside cell wall increases. This means the turgor pressure on the cell wall is increased.

For your viewing pleasure!

• ://video.search.yahoo.com/video/play;_ylt=A0S00Mmni11RPnUAl3r7w8QF;_ylu=X3oDMTBrc3VyamVwBHNlYwNzcgRzbGsDdmlkBHZ0aWQD?p=turgor+pressure+in+plants&vid=979b8bec64d1e1a9e0907442cf69093e&l=00%3A18&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DV.470242322101