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Biology
Plant Structure and Growth
Plant Structure
The plant body is divided into two main parts:
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Roots: The structure that anchors the plant to the ground and
absorbs water and minerals from the surrounding environment
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Shoots: The aboveground plant structure that includes the
stem, which is a framework for leaves, flowers, and fruits
Basic Plant Structure
Roots
Roots are the descending portion of the plant body, generally located
below ground. Roots anchor the plant and are responsible for the absorption of
water, minerals, and other important materials. Root systems come in two forms:
taproot systems and fibrous root systems.
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Taproot systems: Composed of a large central root, or
primary root, off of which smaller roots and root hairs grow, taproot
systems have a relatively small surface area and so are not as effective at
absorbing water and nutrients from the soil. However, the large taproot can
store nutrients and water—an advantage to plants that grow in regions of
minimal water or little sunlight for photosynthesis. Carrots and oak trees
are examples of plants with taproot systems.
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Fibrous root systems: Composed of a diffuse system of
roots and root hairs, with no single major root, fibrous roots systems have
a greater surface area and can extend away from the plant, allowing the
plant to absorb more water and nutrients. Ferns, grasses, and chives are
examples of plants with fibrous root systems.
EXAMPLE:
Most trees use a taproot system early in their development. This
allows the young tree to establish itself in the ground, setting the stage
for greater growth to come.
Features of a Root System
The features of a root system are summarized in the table below.
The Stem
The stem acts as the structural support for the plant and provides the
framework for leaves, flowers, and fruits. The features of a plant stem are
summarized in the table below.
The Structure of Leaves
Leaves extend from a plant’s apical shoot meristem. From
species to species, leaves can take a variety of forms, sizes, and
arrangements and can vary greatly in internal structure. All leaves serve
the primary function as the principal sites of photosynthetic reactions.
However, this variation from plant to plant is largely responsible for the
enormous diversity and adaptability of the plant kingdom.
In spite of their great variety, most leaves share the basic features
summarized in the table on the following page.
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