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English: xylem (blue) carries water from the roots upwards phloem (orange) carries products of photosynthesis from the place of their origin (source) to organs where they are needed (roots, storage organs, flowers, fruits – sink); note that e.g. the storage organs may be source and leaves may be sink at the beginning of the growing season
File talk: Xylem and phloem diagram.svg. ... Print/export Download as PDF; Printable version; In other projects ...
Xylem also contains two other type of cells: parenchyma and fibers. [7] Xylem can be found: in vascular bundles, present in non-woody plants and non-woody parts of woody plants; in secondary xylem, laid down by a meristem called the vascular cambium in woody plants; as part of a stelar arrangement not divided into bundles, as in many ferns.
The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue: the vascular cambium and the cork cambium. All the vascular tissues within a particular plant together constitute the vascular tissue system of that plant.
Parenchyma is a versatile ground tissue that generally constitutes the "filler" tissue in soft parts of plants. It forms, among other things, the cortex (outer region) and pith (central region) of stems, the cortex of roots, the mesophyll of leaves, the pulp of fruits, and the endosperm of seeds.
Most of these cells transform into xylem and phloem. But certain cells don't transform into xylem and phloem and remain as such. [clarification needed] These cells cut out by the cambium towards the periphery are phloem parenchyma while those towards the pith are xylem parenchyma. Both of these cells together work as secondary medullary rays.
[2] Since the valuable fibres are located in the phloem, they must often be separated from the woody core, the xylem , and sometimes also from the epidermis . The process for this is retting , and can be performed by micro-organisms either on land (nowadays the most important) or in water, or by chemicals (for instance high pH and chelating ...
Xylem fibers or Xylem sclerenchyma; Xylem parenchyma; Cross section of 2-year-old Tilia americana, highlighting xylem ray shape and orientation. Xylem tissue is organised in a tube-like fashion along the main axes of stems and roots. It consists of a combination of parenchyma cells, fibers, vessels, tracheids, and ray cells.