Complex Plant Tissue

The complex tissues in a plant deal with moving nutrients and water to the leaves, while removing the products of photosynthesis from the leaves. Photosynthesis produces sugar glucose. Modified and bound to other 6-carbon sugars, the substance becomes sucrose or a variety of other disaccharides. In this form, it can be moved with small amounts of water and can be transported efficiently throughout the plant. The complex tissues of the plant aid in this overall effort to supply the roots with food as they supply the leaves with water and nutrients.

The two main forms of plant tissue used in this process are xylem and phloem. Xylem is a plant tissue specially designed for transporting water and nutrients.

This plant tissue can come in several forms, depending on the species. Sometimes, the xylem plant tissue is made up of a long chain of small tubes, called vessels, which interconnect and allow water to travel through unimpeded.

This main tube is supported by other cells, which help pull nutrients from the water and transport it to the cells within the leaves. Starting at the roots, the water is driven by pressure at the bottom and transpiration at the leaves, which sucks the water through the xylem like straw. It is estimated that up to 95% of the water used by plants is transpired, rather than used in photosynthesis or in the metabolism. This is thought to be necessary to concentrate nutrients found in the soil, an At certain places, the xylem extends small tubes into the other type of complex plant tissue, the phloem. Like the xylem, the phloem consists of a variety of different cell types which work together to produce a continual interconnected passageway connecting cells of the plant. The phloem, rather than bringing water up from the roots, needs to carry sugar down to the roots and stems. With a little water from the xylem, it can complete this process. It is further aided by companion cells, which surround the actual sieve-tube. The whole structure is then supported by phloem fibers, which give the tube shape and structure.