Question

Growth of pollen tube towards the ovule is due to:

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

Answer 1

The correct option is D Chemotropism

Tropic movements are directional movements of the parts of a plant in response to a specific stimulus. These movements can be towards or away from the stimulus.​
The growth of the pollen tube towards the ovule is due to the chemicals released by the ovary, and this movement is called chemotropism.​
Depending upon the nature of the stimulus these movements are of the following types:

$\begin{array}{cc}\text{Tropic movement}& \text{Stimulus}\\ \text{Hydropism}& \text{Water}\\ \text{Phototropism}& \text{Light}\\ \text{Geotropism}& \text{Gravity}\\ \text{Chemotropism}& \text{Chemicals}\end{array}$