veresoonkonnakude

Veresoonkonnakude, also known as vascular tissue, is a complex tissue found in vascular plants that is responsible for the transport of water and nutrients throughout the plant. It consists of two primary types of conducting tissues: xylem and phloem. Xylem is responsible for transporting water and dissolved minerals from the roots to the rest of the plant, and it also provides structural support. Phloem, on the other hand, transports sugars produced during photosynthesis from the leaves to other parts of the plant where they are needed for growth or storage.

Xylem is composed of several cell types, including tracheids, vessel elements, xylem parenchyma, and xylem fibers. Tracheids and vessel elements are the main water-conducting cells; vessel elements are generally wider and shorter and form continuous vessels. Phloem is made up of sieve elements (sieve cells and sieve-tube elements), companion cells, phloem parenchyma, and phloem fibers. Sieve-tube elements, along with companion cells, are the primary conducting units of the phloem.

The arrangement and development of vascular tissue are crucial for plant survival and growth. In young stems and roots, vascular tissues are often arranged in distinct vascular bundles. As the plant matures, secondary growth can occur in woody plants, leading to the formation of secondary xylem (wood) and secondary phloem, which significantly increases the diameter of stems and roots. This continuous system of transport allows plants to reach large sizes and adapt to diverse environments by efficiently distributing resources. The presence of vascular tissue is a defining characteristic of vascular plants, distinguishing them from non-vascular plants like mosses.