Describe the Organization of the Vascular Plant Body?
A typical plant body consists of two distinct systems: a root system and a shoot system. The root system is usually below the ground and functions to 1.) anchor and support the plant; 2.) absorb and conduct water, minerals and nutrients to the other systems; and 3.) store energy. The shoot system is usually the above the ground portion, which functions to support and bear vegetative leaf organs, and the reproductive organs--flowers. We will look at these two systems in more detail below.
Root System
There are two basic types of root systems: taproot and fibrous. Taproot systems consist of a large central root that is best typified by carrots, beets, and turnips. This main root grows deep into the soil, and sends out smaller lateral root branches. this provides a sturdy anchor and support for the shoot above ground. Turnip, carrot, and sugar beet taproots have been modified to store large quantities of energy in the form of sugar and starch. These reserves are then drawn upon by the plant when it develops flowers and fruit.
Taproots characteristically are found in the group of angiosperms known as the Dicots. Dicots are those flowering plants that also have two cotyledons (seed leaves) in the seed--thus named Dicots, a netted pattern of venation, stems with vascular bundle arrangement in a ring, and flower parts in multiples of four or five.
A fibrous root system, on the other hand, consists of a network of divided root branches that spread out under the ground. The secondary root branches divide as they grow, permeating the available soil so that they can interface with as much soil water, minerals and nutrients as possible. This enables them to get the maximize amount of absorption of soil nutrients and water by exposing the maximum amount of root surface area. Most of the absorption occurs in the tiny root hairs that extend from the tips of the roots. Fibrous root systems because fo their extensive network also provide good anchorage and support for the upright shoots.
Fibrous root systems are characteristically found in the group of Angiosperms known as the Monocots. Monocots, as opposed to the Dicots, have only a single cotyledon, or seed leaf in their seeds. Monocots have a parallel pattern of venation, a scattered pattern of vascular bundles in the stem, and floral parts occur in multiples of three.