Search results
Results from the WOW.Com Content Network
The fibers of the xylem are always lignified, while those of the phloem are cellulosic. Reliable evidence for the fibre cells' evolutionary origin from tracheids exists. [ 10 ] During evolution the strength of the tracheid cell walls was enhanced, the ability to conduct water was lost and the size of the pits was reduced.
Cross section of celery stalk, showing vascular bundles, which include both phloem and xylem Detail of the vasculature of a bramble leaf Translocation in vascular plants. Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem ...
In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Ancient Greek word φλοιός (phloiós), meaning "bark". [3] [4] The term was introduced by Carl Nägeli in 1858. [5] [6] Different types of phloem can be distinguished. The early phloem formed in the growth apices is called protophloem.
Xylem is one of the two types of transport tissue in vascular plants, the other being phloem; both of these are part of the vascular bundle. 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 .
Xylem and Phloem. A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, engages in photosynthesis, stores nutrients, and produces new living tissue. [1]
For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. [1] [2] [3] This provides them with the ability to extract resources from the host.
Xylem is the water-conducting tissue, and the secondary xylem provides the raw material for the forest products industry. [26] Xylem and phloem tissues each play a part in the conduction processes within plants. Sugars are conveyed throughout the plant in the phloem; water and other nutrients pass through the xylem.
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 agents ...