Question

Question 18
The growth of pollen tubes towards ovules is due to

(a) hydrotropism
(b) chemotropism
(c) geotropism
(d) phototropism

Answer 1

(b) chemotropism

Chemotropism is defined as the growth or movement of a plant or plant part in response to a chemical stimulus. The growth of the pollen tube down the style, for fertilisation to occur, is due to the presence of sugars (chemicals) in the style.