Question

The growth of pollen tube toward the ovule is an example of

• A. Phototropism
• B. Hydrotropism
• C. Thigmotropism
• D. Chemotropism

Answer 1

The correct option is D Chemotropism

• Tropic moments can be defined as the growth moments in plants which the direction of the external stimulus(light, heat, chemical, etc) is a factor.
• Chemotropism is a type of tropic movement in which the growth or movement of a plant or plant part in response to a chemical stimulus.
• The growth of the pollen tube towards the ovule occurs in response to the presence of sugars in the style. Hence it is an example for chemotropism.
  
• So, the correct answer is 'Chemotropism'.