Summary
Directional growth in response to gravity, with roots growing down and shoots growing up.
In depth
Statoliths (starch-filled amyloplasts) in root cap cells settle and trigger auxin redistribution. High auxin inhibits root elongation on the lower side so the root bends down; in shoots it promotes elongation, so they bend up.
Gravity sensing by statoliths leads to PIN protein repositioning and auxin redistribution. Roots show positive gravitropism and shoots negative.
Common mistake: plants do not 'know' up from down using a nervous system; it is a cellular response to sedimenting starch grains.
Frequently asked questions
What is Gravitropism?
Directional growth in response to gravity, with roots growing down and shoots growing up.
Which area of biology covers Gravitropism, and how advanced is it?
Gravitropism is one of the 56 topics in Plant Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Abscisic Acid and Drought, Plant Tissue Culture, Auxin and Phototropism.
Can you give an example of Gravitropism?
Plants grown in space show altered gravitropism.
What should I learn before Gravitropism?
Work through the Beginner topics in Plant Biology first, such as Plant Kingdom, Photosynthesis, Chlorophyll, then return to Gravitropism. Intermediate topics assume the Beginner vocabulary.
What topics are related to Gravitropism?
The closest topics to Gravitropism are Abscisic Acid and Drought, Plant Tissue Culture, Auxin and Phototropism, Plant Hormones. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Gravitropism?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Gravitropism. To practise the whole of Plant Biology, use the Plant Biology quiz.
How is Gravitropism different from Abscisic Acid and Drought?
Gravitropism: Directional growth in response to gravity, with roots growing down and shoots growing up. Abscisic Acid and Drought: ABA triggers guard cell closure and gene responses that help plants survive water stress. Read both side by side and note what each one explains.
What is a common mistake about Gravitropism?
Plants do not 'know' up from down using a nervous system; it is a cellular response to sedimenting starch grains.
How should I study Gravitropism step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Abscisic Acid and Drought and explain the difference aloud. Finally, take the Plant Biology quiz and come back to this page for any question you miss.