How do roots work?

A plant’s leaves use the energy from sunlight to make sugar. Water is drawn up through the roots and sugary sap moves down from the leaves, powering the plant’s growth.

Leaf ❯

Most plants have roots, which anchor the plant in the ground. Roots soak up vital water from the soil, along with the dissolved minerals that the plant uses to grow. Grasses have tufts of fibrous roots, but most other plants grow at least one taproot, which then sprouts smaller lateral (side) roots that spread outward.

❯ As a seed starts to grow, one or more strong roots push down into the soil. This is the plant’s taproot, and it grows only at its tip, forcing soil particles aside with a tough root cap as it grows deeper into the ground. Taproot

❯ These spindly roots branch out Lateral root from the main taproots to form a complex, tangled network of roots. Root hair ❯ Tiny root hairs sprout from just above the growing tip of each root. They grow between soil particles and absorb the water and minerals that the plant needs to grow.

Root hairs grow from the root’s skin cells (seen here in pink).

Types of roots

Mangroves growing on muddy tidal seashores are swept by waves at high tide. Many mangrove trees have stiltlike roots that arch down from their trunks to help support them in the moving water.

Stilt

Rooted in waterlogged, Pneumatophore airless mud, these mangrove trees grow in swampy, subtropical brackish (salty) water. Some have roots that grow upwards into the air to gather oxygen.

Many tropical rain forest trees are supported by roots that spread out partly above the ground. This is because most rain forest soil is not very deep and these surface roots help anchor the tree.

Buttress

Some plants, typically in tropical forests, grow in the treetops with roots that cling to the tree bark for support. The American pearl laceleaf grows roots that hang in the moist air to absorb essential water.