In this topic you will learn how parts of a plant help it to survive.

You and a plant have similar needs, but there is a big difference. You can move around to get things. A plant can't move around. Most plants have roots that hold them in the ground. Roots draw up water and minerals from the soil. Roots also store food for the plant.

A root gets its start early in the life of a plant. Roots bore deeper and deeper into the soil as the plant grows. The structure of a root helps it absorb water and minerals, sending them to other parts of the plant. The tip of the root is protected by a thin covering, or root cap, made up of cells that protect the root as it grows into the soil. The epidermis is the outermost layer of roots, stems, and leaves. The cortex is the layer just inside the epidermis of roots and stems.

The xylem is a tissue through which water and minerals move up through a plant. Phloem is a tissue through which food from the leaves moves down through the plant. Many plants also have a cambium. A cambium is a layer that separates the xylem from the phloem. A tough outer layer of tissue, called bark, protects woody stems.

All stems have certain things in common. All stems support leaves. Stems help leaves reach open spaces where the leaves can be in sunlight. Stems also help the transportation system for the plants. This system lets water and minerals move from the roots to all parts of the plant. It also moves food made in the leaves to other parts of the plant.

The parts of a leaf work together to help keep the plant alive. The leaf makes food in cells between the layers of epidermis. These cells contain chloroplasts. A chloroplast is a part of a plant cell containing chlorophyll, the green substance that enables a plant to make food. In addition to sunlight, chloroplasts need water, minerals, and carbon dioxide from air to make food.

Leaves are far from roots, yet they help roots take in water from the soil. When water evaporates from the leaves, more water moves up through the plant to replace the lost water. This process is called transpiration.

All living things need plants, so it is important to know how they survive. Part of a plant's ability to survive depends on how well its roots, stems, and leaves work together to move water and minerals in one direction and food in the other direction.