A plant shows normal phototropism but the pollen tube does not grow towards the ovule. Which mechanism may be specifically affected?
Answer and explanation
Correct answer: Chemotropism
The governing concept is stimulus-specific tropic growth. Phototropism is growth in response to light, so normal phototropism shows that the light-response pathway is functioning. A pollen tube is guided toward the ovule by chemical signals released in the reproductive tissues; this is chemotropism. Therefore A is correct. Geotropism responds to gravity and hydrotropism to water, so neither directly explains the stated defect.
Frequently asked questions
What is the correct answer to this question?
Chemotropism
Why is this the correct answer?
The governing concept is stimulus-specific tropic growth. Phototropism is growth in response to light, so normal phototropism shows that the light-response pathway is functioning. A pollen tube is guided toward the ovule by chemical signals released in the reproductive tissues; this is chemotropism. Therefore A is correct. Geotropism responds to gravity and hydrotropism to water, so neither directly explains the stated defect.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Control and Coordination.
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