This definitions covers Key Definitions within Plant Hormones for GCSE Biology. Topic 11: Plant Hormones It is section 6 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Topic position
Section 6 of 12
Practice
15 questions
Recall
20 flashcards
Key Definitions
Auxin: A plant hormone produced in shoot and root tips that controls cell elongation; causes shoots to grow towards light and roots to grow downwards.
Phototropism: The growth of a plant in response to light; shoots show positive phototropism (grow towards light), roots show negative phototropism.
Gravitropism (geotropism): The growth of a plant in response to gravity; roots show positive gravitropism (grow downward), shoots show negative gravitropism (grow upward).
Cell elongation: The process by which plant cells increase in length; controlled by auxin through changes in cell wall flexibility.
Gibberellin: A plant hormone that promotes seed germination, stem elongation, and fruit development; used commercially to increase fruit size and improve crop yields.
Ethylene (ethene): A plant hormone in the form of a gas that promotes fruit ripening; used commercially to ripen fruit after harvesting during transport.
Plant hormone: A chemical substance produced in small amounts that regulates growth and development in plants; transported to target cells where it causes a response.