The main parts of a plant are the roots, stems, and leaves. Each part has its own function. The structure of each part enables it to perform its function.
A plant has different parts and characteristics that differentiate it from an animal. Most plants are green. They contain the substance called chlorophyll, so they can make their own food, something no animal can do. Unlike most animals, most plants are rooted to the soil, so they cannot move from place to place. However, their parts can move slowly to get the plants need from the environment.
Roots anchor the plant to the ground and absorb water. The stem supports the leaves and flowers; they also conduct water and food to various parts of the plant. The leaves make food. Modified roots, stems and leaves perform many other functions.
Roots. Roots are the parts of the plant that usually grow below the surface of the ground. They anchor the plant to the ground. They also absorb water with dissolved nutrients from the soil. These are the two main functions of roots to the plant. The taproot system has a bigger primary root and finer secondary roots arising from it. These roots can reach deeper sources of water in the soil. In contrast, the fibrous root system has a fine roots arising from the base of the stem. These roots often spread out close to the surface of the ground. They can readily absorb rainwater.
Inside the roots are tube-like parts called vascular bundles. Those that transport water are called xylem tissue. Those that transport dissolved food are called phloem tissue. In some plants, the structure of the root is modified to perform other functions. The special roots of corn that grow above the ground provide additional support to the plant. The enlarged root of sweet potato stores food. The clinging roots of the creeping fig enable the plant to cling to the wall.
Stems. Stems are part of the plant that usually grows above the ground. They support the leaves, flowers and fruits. Like roots, stems also have tissues for conducting water and dissolved food. Some stems are woody, while others are soft. A rose has a woody stem while a mayana has soft stem. Some stems grow very long but cannot stand upright. They have to cling to something for support. Vines are like that.
In some plants, the structure of the stem and also its functions are modified or changed. The enlarged stem of cactus is a modified stem. It stores food and water. The tendrils of cucumber are also modified stems. They support the vine. And the rhizomes of ginger are also modified stems. They are for reproduction and for storage of reserved food.