vedvæv

Vedvæv, also known as vascular tissue, is a complex tissue found in vascular plants that is responsible for the transport of water, minerals, and sugars. It is composed of two main types of conducting cells: xylem and phloem. Xylem primarily transports water and dissolved minerals from the roots to the rest of the plant, while phloem transports sugars produced during photosynthesis from the leaves to other parts of the plant where they are needed for growth or storage.

Xylem consists of tracheary elements, which include tracheids and vessel elements. These cells are typically dead at maturity and form continuous tubes. Tracheids are elongated, tapered cells, while vessel elements are wider and shorter, forming more efficient conducting channels. Xylem also contains parenchyma cells for storage and fibers for structural support.

Phloem is composed of sieve elements, which are living cells. These include sieve cells and sieve-tube elements, which are arranged end to end. The end walls of sieve-tube elements have sieve plates, which allow for the passage of phloem sap, a sugary solution. Phloem also contains companion cells, which are metabolically active and support the sieve-tube elements, as well as phloem parenchyma and fibers. Together, xylem and phloem form the vascular bundles, which are distributed throughout the plant, providing a vital system for nutrient and water movement essential for plant survival and growth.