Section 3: The Basic Parts of a Plant

Glossary

Lesson 2: The Roots

 
 
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The root is an organ of the plant that is typically underground and functions primarily for the following purposes:

The roots attach the plants to the soil and enable it to hold the stem upright.
The roots act like straws that suck up water, from the soil, with nutrients dissolved in it. The plant uses water to "feed" itself by combining it with carbon dioxide from the air.
The root stores food in the roots, for future use.  A good example of this is a carrot plant; the carrot itself is a large orange root with lots of food stored in it.

    When a new plant begins to grow, the first root formed is known as the primary root. It develops from a part of the seed embryo known as the radicle.

    There are different types of root systems. They can be classified into three general categories as follows:

      • consist of numerous, long, branching roots,  of about the same size, that grow from the stem.
      • are also known as lateral roots.
      • are the opposite of a taproot.
      • are usually concentrated near the surface of the soil.
      • of a plant are good at controlling erosion
      • belong to such plants as grasses, wheat, rice and marigolds.
      • consist of one main root, with smaller side roots
      • grow straight down, rather than along the surface
      • can grow to enormous depths
      • are associated with carrots, beetroot, dandelions, and turnips.
      • arise from other plant organs, such as stems and leaves.
      • are especially numerous on underground stems.
      • make is possible to vegetatively propagate many plants from leaf and stem cuttings.
      • increase the plant's chance of survival
      • enable an ivy plant, for example, to cling to other plants or buildings for support

     Â©iStock

     Â©iStock

    The edible, orange part of the carrot is its taproot (above right).
                                    Wheat has a fibrous root system (above left).
     For all root systems, plant roots also develop root hairs. The function of root hairs is to increase the surface area for nutrient absorption, which is vital for plant survival. The root hairs absorb the nutrients and water, from the soil, and carry these to the rest of the plant.

     

    A Strawberry Plant


    Notice the green stem, usually called a "runner", coming from the right side of the picture; it's coming from the parent strawberry plant.

    The roots you see have developed from that runner, and are therefore adventitious roots. The plant you see is a new plant that developed from these roots.