Plant Hormones Flashcards
(23 cards)
What is tropism?
Any growth response that results in plant organs curving towards or away from stimuli
What is phototropism
growth of shoot in response to light
what can be a result of phototropism
cells on the dark side of the plant stem elongate faster than other on the light side; bending
What are hormones?
a chemical signal
How does hormones travel?
produced in one part of the body then transported to other parts
What are the five major plant hormones?
Auxins
Cytokinins
Gibberellins
Abscisic acid
Ethylene
What is an Auxin?
any chemical substance that promotes seedling elongation
where is Auxin produced?
in the apical meristems at the tips of shoots
How do Auxins move in a plant?
Hormones move down the plant
What i the purpose of cytokinin?
to promote cell division (cytokinesis)
Where is Cytokinin produced?
in actively growing organs
How does Cytokinin move in the plant?
Up from the roots
What is the purpose of Gibberellins?
promote elongation and cell division in stems and leaves
What is the purpose of Abscisic acid?
inhibits growth
What do high concentrations of Abscisic acid do?
promote seed dormancy
What does the ratio of Abscisic acid to gibberellins do?
controlling germination
What is the purpose of Ethylene?
fruit rippening and programmed cell death
What is ethylene often a response to?
stressors such as drought, flooding, injury, or infection
How does a plant grow with positive tropism?
cause plants to grow towards a stimulus
How does a plant grow with negative tropism
cause plants to grow away from a stimuli
What are circadian rhythms influcenced by?
environmental cues such as light
What are circadian rhythms are controlled by?
biological clocks
What are herbivores?
animals that mainly eat plants
