What is the name of the growth of the root and other plant organs in the direction of the chemicals they need?

Plants are able to adapt to certain environmental conditions, grow in the direction where there are more chemical compounds. When the root grows more where the soil contains a large amount of minerals, this process is called chemotropism. There is also a similar concept – geotropism. But the root grows strictly down to the center of the Earth, and not to certain substances. Also, plants are able to direct the shoots upward. Some gardeners are able to use this property to create trees of an unusual shape, when the branches are drawn to the soil.