Plant tropism and other movements

a) growth response to amount of light

b) plants have grown in low light or dark

• a) leaves less green
• b) stems longer
• c) smaller leaves

• a) affects amount of auxin. Makes stems longer
• b) no chlorophyll formed

*auxin could be interacting with (GA) Gibberellic-acid

• a) growth response from one direction
• b) permanent, unless they change direction

• a) light from one direction
• b) internal factor is Auxin (IAA)

• a) auxin moves away from light
• b) more auxin, larger cells

a) growth response due to gravity

b) internal factors; auxin, GA, and others?

roots grow downward, along with gravity

a) growth response to touch

b) internal factors: ethylene and Auxin

1.) direct: touch, vine touching a stem

2.) indirect: wind, stems shorter, wider

• a) nondirectional
• b) reversible
• c) changes in turgor pressure

doesnt come from one direction

• a) plants parts moved when touched
• b) rapid changes
• c) internal factors: turgor pressure

ex) venus fly trap

a) leaves and flowers open and close

b) internal factors: internal clock and turgor pressure

• a) plants respond to seasonal changes
• b) daylength and red or red far light
• c) internal factors: Phytochrome
• d) photoperiodism can effect flowering time or session (some plants)

• -plants bloom when days are shorter
• *in fall or winter

-need a minimum # if hours of light, less than 8 hours

• -plant bloom when day are longer
• *in summer

need a max # of hours of light, +16

-flowering time not determined by day