Short answerModerate1 mark
1(h)
The diagram given below represents a plant movement. Answer the following questions: The diagram given below represents a plant movement. Answer the following questions:
Name the tropic movement shown in the diagram.
Topic: Chemotropism
Previous-year question practice database
Answer
Exam answer
CHEMOTROPISM.
Explanation
The diagram shows a POLLEN TUBE growing down the style towards the ovule. It is directed by CHEMICALS secreted by the ovule, and a directional growth movement in response to a chemical stimulus is CHEMOTROPISM.
The prefix always names the stimulus: PHOTO light, GEO gravity, HYDRO water, CHEMO chemicals, THIGMO touch. Read the prefix and the answer follows.
This is the standard example of chemotropism in the syllabus, because it is how fertilisation is achieved in a flowering plant — the male gametes cannot swim, so the tube must grow to them.
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P. Thigmotropism — Touch
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S. Phototropism — Gravity
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