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The basic function of the xylem is to transport water upward from the roots to parts of the plants such as stems and leaves, but it also transports nutrients. [ 1 ] [ 2 ] The word xylem is derived from the Ancient Greek word, ξύλον ( xylon ), meaning " wood "; the best-known xylem tissue is wood, though it is found throughout a plant. [ 3 ]
The presence of vessels in xylem has been considered to be one of the key innovations that led to the success of the flowering plants. It was once thought that vessel elements were an evolutionary innovation of flowering plants, but their absence from some basal angiosperms and their presence in some members of the Gnetales suggest that this hypothesis must be re-examined; vessel elements in ...
Parenchyma cells have a variety of functions: In leaves, they form two layers of mesophyll cells immediately beneath the epidermis of the leaf, that are responsible for photosynthesis and the exchange of gases. [2] These layers are called the palisade parenchyma and spongy mesophyll. Palisade parenchyma cells can be either cuboidal or elongated.
The cells in vascular tissue are typically long and slender. Since the xylem and phloem function in the conduction of water, minerals, and nutrients throughout the plant, it is not surprising that their form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the sections of a pipe might be.
It is used mainly for the transport of water, along with some small nutrients. The meristem of the stem creates cells which make up the cambium and pro-cambium. These cells then produce a highly branched poly-phenolic protein, called lignin, in a very high concentration. The cells then perform apoptosis, and the actual xylem tube begins to form ...
Xylem consists of four kinds of cells: Tracheids; Vessels (or tracheae) 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.
The xylem tissue arises from the cell facing inside and transports water by the action of transpiration pull, capillary action, and root pressure. The phloem tissue arises from the cell facing outside and consists of sieve tubes and their companion cells. The function of phloem tissue is to distribute food from photosynthetic tissue to other ...
It is a type of conductive cell called a tracheary element. Angiosperms also use another type of conductive cell, called vessel elements, to transport water through the xylem. The main functions of tracheid cells are to transport water and inorganic salts, and to provide structural support for trees.