Plant Transport and Tropisms

advertisement
Plant Transport
• Water Transport
– 1. Enters root by osmosis
– 2. Passes through cortex
(parenchyma) tissue by
osmosis
– 3. Passes through
endodermis
• One way only
• Combination of active
transport and osmosis
Plant Transport
• Water Transport (cont)
4. Enters xylem
• Cohesion– The attraction of
water molecules to
each other
• Transpiration– The evaporation of
water from the
leaves of plants
Plant Transport
• Water Transport (cont)
– 5. Transpiration Pull• The force that pulls water
upward.
• Cohesion holds the water
column together as it
moves upward through
the xylem
Plant Transport
• Food Transport
– Requires energy (active
transport)
– Translocation• Movement of food
through the phloem
– Pressure Flow
Hypothesis (source-sink)
• Food moves from an area
of high pressure to low
pressure
Plant Transport
• Food transport
– High Pressure (Source)• Could be leaves when
food is formed
• Could be areas of food
storage (root, stem, etc)
– Low Pressure (Sink)• Could be where food is
used for growth.
• Could be where food is
stored.
Plant Motions
•
Auxins–
Plant hormones
•
•
–
Stimulate or inhibit
cells to grow
Depends on the target
organ
Stem growth•
–
Auxins stimulate stem
cell growth
Root growth•
Auxins inhibit root cell
growth
Plant Motions
•
Tropism– Response of a plant to
environmental stimuli
– Positive•
Respond toward the
stimulus
– Negative•
Respond away from the
stimulus
Plant Motions
•
Phototropism–
Response of plants to
light
•
Stem- positive
Plant Motions
• Gravitropism or
geotropism– Response of plants to
gravity
• Stem- negative
• Root- positive
Plant Motions
• Thigmotropism– Response of plants to
touch
• Tendril- positive
Flowering
•
Photoperiodicity–
•
Response of flowering
plants to different light
conditions
Short day plants–
–
Flower when time
exposed to light is short
ex. chrysanthemums &
poinsettias
Flowering
• Long day plants– Flower when the
amount of time exposed
to light is long
– ex. clover, petunias, &
hollyhocks
Flowering
• Day-neutral plants– Length of light has no
effect on flowering
– ex. corn & tomato
• Actually the amount of
darkness, not light, that
stimulates these plants
Download
Related flashcards
Microbiology

34 Cards

Antiseptics

79 Cards

Disinfectants

40 Cards

Protista

20 Cards

Antimicrobials

22 Cards

Create flashcards