From the given situations, identify 'Chemotropic' and 'Geotropic' movements in parts of plants, respectively:
(i) Growth of pollen tube towards ovule.
(ii) Movement of sunflower towards sunlight.
(iii) Movement of root towards Earth/Gravity.
(iv) Movement of leaves due to breeze.
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Tropic movements in plants:
Chemotropism \(\Rightarrow\) Chemical stimulus (e.g., pollen tube growth)
To solve this question, we need to understand the concepts of 'chemotropic' and 'geotropic' movements:
Chemotropic Movement: This type of movement occurs in response to a chemical stimulus. A classic example is the growth of a pollen tube towards an ovule, as it is attracted by chemicals released from the ovule.
Geotropic Movement: Also known as gravitropism, this refers to the movement or growth of a plant in response to gravity. Roots growing towards the Earth or in the direction of gravitational pull demonstrate geotropic movement.
Now, let's analyze the given options:
(i) Growth of pollen tube towards ovule: This is a chemotropic movement because the pollen tube grows towards the ovule due to chemical signals.
(ii) Movement of sunflower towards sunlight: This describes phototropism, a plant's response to light, not chemotropism or geotropism.
(iii) Movement of root towards Earth/Gravity: This represents geotropic movement, where roots grow in the direction of gravity.
(iv) Movement of leaves due to breeze: This is neither chemotropic nor geotropic. It is a mechanical response to wind stimulation, often described as thigmotropism or simple passive movement due to external force.
Based on the analysis above, the correct answer is:
