The structure of a bean plant is not unlike most other vascular plants and even bears a vague resemblance to aspects of human anatomy. Each part performs its assigned duty ensuring the plant will thrive and reach maturity. The sole purpose is to achieve reproduction which ensures survival of the species.
Beans are the seeds for new bean plants. They actually contain a plant embryo or baby plant inside them waiting for just the right conditions to spring them to life. When the bean is exposed to warm temperatures and receives enough moisture, the seed coat begins to loosen and the various plant parts inside begin to do their jobs. Inside the bean seed are the radicle, plumule, cotyledons, hypocotyls and epicotyls.
Roots develop from the radicle. As the parts of the plant emerge from the seed, the radicle grows downward and becomes the tap root. The tap root of the bean plant not only holds the plant in place but it is the main structural support for the other roots. The roots' function is to take in nutrients and water from the surrounding soil.
The hypocotyl pushes upward and develops into the stem or spine of the bean plant. The stem houses the phloem and xylem or the equivalent of the arteries and veins of the plant which carry water and nutrients from the roots to the leaves and other parts of the bean plant. Depending on the variety of bean, the stem may be short and stout or long and winding in the case of pole type beans.
The first leaves that emerge have the shape and size of the bean seed itself. That is because they are actually the cotyledons or seed leaves. Their purpose is to provide food for the plant until it grows enough to develop leaves. The epicotyl houses the first true leaves or the plumule. The leaves will then take over the food-making duties. The job of the leaves is to absorb sunshine and transform it into food for the plant. Leaves are attached to the stem by the petiole or leaf stem. Phloem and xylem are inside the petiole and continue on through the veins of the leaves.
Flowers are the reproductive mechanism of the bean plant. Bean plants have "perfect" flowers which mean they contain both female and male reproductive parts. They are also self-pollinating which means they do not require pollination from another variety of beans. Pollination occurs when the pollen from anther at the top of the stamen is transferred by a pollinator such as a bee to the pistil. The pollen enters the stigma and travels down the style to the ovaries where it fertilizes the ovule.
The fruit of the bean plant is the bean. Once the flower has been pollinated, the petals fall away and a small sprout begins to develop. The sprout continues to elongate. Its purpose is to house the growing seeds within. When the pod reaches maturity, it dries out, splits open and releases a new batch of seeds so that the cycle continues.