Barkvävnader

Barkvävnader, also known as secondary phloem, is the living tissue in woody plants that is responsible for transporting sugars produced during photosynthesis from the leaves to other parts of the plant where they are needed for growth or storage. This tissue is located just inside the bark of trees and shrubs. It is part of the vascular cambium, a layer of actively dividing cells that is responsible for secondary growth, leading to an increase in stem diameter. Barkvävnader is composed of several cell types, including sieve elements, companion cells, phloem parenchyma, and phloem fibers. Sieve elements are the primary conducting cells, forming sieve tubes that transport sugars. Companion cells are closely associated with sieve elements and provide metabolic support. Phloem parenchyma cells store food reserves, and phloem fibers provide structural support. The outer layers of barkvävnader are sloughed off and replaced by new growth from the vascular cambium. This continuous production of new phloem is essential for the long-term survival and development of woody perennial plants. The removal or damage to this tissue can significantly impair a plant's ability to transport nutrients, potentially leading to its decline or death.