Chemotropism is growth of organisms (or parts of organism) such as bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 and plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, navigated by chemical stimulus

Stimulus (physiology)

In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....

 from outside of the organism.
The response by the plant is termed ‘positive’ if the growth is towards the stimulus or ‘negative’ if the growth is away from the stimulus.

An example of chemotropic movement can be seen during the growth of the pollen tube

Pollen tube

The pollen tubes is the male gametophyte of seed plants that acts as a conduit to transport the male sperm cells from the pollen grain, either from the stigma to the ovules at the base of the pistil, or directly through ovule tissue in some gymnosperms .After pollination, the pollen tube...

, where growth is always towards the ovules. It can be also written that conversion of flower into fruit is the example of chemotropism.

Fertilization of flowers by pollen is achieved because the ovary

Ovary (plants)

In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...

releases chemicals that produce a positive chemotropic response from the developing pollen tube.