Plant Responses
Growth responses made by plants to directional external stimuli
What is Tropism
Condition of arrested growth
An endogenous rhythm that is approximately 24 hours and is entrained by the light-dark cycle.
What is circadian rhythm
Plant hormone that promotes cell elongation and is activated by light.
What is Auxin
Bud burst and flowering following exposure to a cold period, in many flowering plants.
What is Vernalisation
An exogenous cue that synchronises (or resets) an organism's endogenous rhythms
What is Zeitgeber
Growth responses to light, particularly directional light.
What is Phototropism.
These plants flower when the photoperiod is greater than a critical day lenght
What is Long Day Plants
A rhythm that is repeated around 365 days.
What is Circannual
Responses in which the direction of the plant response is independent of the stimulus direction.
What is Nastic responses
Blue-green pigment that acts as a photoreceptor and has two forms Pr and Pfr.
What is phytochrome.
What advantages are organisms getting from these rhythms.
What is finding mates, finding food, avoiding predators.
Effect of gravity on the direction of root growth.
What is Gravitropism
When a long night is interrupted by a short period of light, these plants will not flower.
The period of an endogenous rhythm when given no external environmental cue