CH28: External factors Flashcards
Phototopism of a shoot is caused by ____ of cell ____ on the shaded side of the tip.
stimulation; elongation
The statoliths in roots and stems are:
amyloplasts
Thigmotropism is the response to:
contact with a solid
A plant’s photoperiodic response depends on ____.
Temperature
The number of required _____ cycles varies with the species.
induction
Some plant spacies can measure period durations of only ____ minutes
20 minutes
The plant’s photoperiodic response may vary with ____.
Age
Lettuce seeds will germinate if exposed to:
red light followed by far-red light followed by red light
Phytochrome can be detected only with a ______ __________.
sensitive spectrophotometer
Maryland mammoth tobacco flowers in the field by:
covering the plants in the afternoon to produce short days
To induce germination, some seeds are soaked in alcohol in order to:
remove substances that impede the entry of water
In the potato, bud dormancy is broken by:
dry storage
Thigmonastic movements are responses to:
marchanical stimulation
Define tropism
A growth response involving bending or curving of a plant part toward or away from an external stimulus that determines the direction of movement.
Define phototropism
Curving or growing shoot tips toward light
