Noun:

மரவியம்,

xylem தமிழ் அர்த்தத்தின் உதாரணம்:

None

xylem's Usage Examples:

A point of anatomical interest is the occurrence in the vascular bundles of the cotyledons, scale-leaves, and elsewhere of a few centripetally developed tracheids, which give to the xylem-strands a mesarch structure such as characterizes the foliar bundles of cycads.

The tracheids or vessels, indifferently called tracheal elements, together with the immediately associated cells (usually amylom in Pteridophytes) constitute the xylem of the plant.

) xylem and phloem are developed pd, Periderm in leaf-bases.

In the stems of many water-plants various stages of reduction of the vascular system, especially of the xylem, are met with, and very often this reduction leads to the formation of a compact stele in which the individuality of the separate Reduced bundles may be suppressed, so that a closed cylinder lmpbost~h1c of xylem surrounds a pith.

When the protoxylems have an intermediate position the stele is inesarch (many Pteridophytes and some of the more primitive Phanerogams).

insigne, has scalariform tracheides, and is traversed by regular medullary rays, but in the forms from later ' horizons the tracheides are reticulately pitted, and the rays are for the most part replaced by a network of xylem-parenchyma.

"The xylem and phloem parenchyma consist of living cells, fundamentally similar in most respects to the medullary ray cells, which sometimes replace them altogether.

13, 23), the xylem of which is usually wedgeshaped in cross-section with the protoxylem elements at the inner extremity, while the phloem forms a band on the outer side of the xylem, and separated from it by a band of conjunctive tissue (mesodesm).

In others a central parenchyma or primetive pith a new region of the primitive stelar conjunctiveappears in the centre of the xylem.

metu starchy xylem-parenchyma, which, when the xylem is bulky, usually appear among the tracheids, the phloem also often being penetrated by similar bands of phloem-parenchyma.

When there is a single protoxylem strand in the centre of the stele, or when, as is more commonly the case, there are several protoxylem strands situated at the internal limit of the xylem,, the centre of the stem being occupied by parenchyma, the stele is endarch.

When the pith is large celled, the xylems of the bundles are separated from it by a distinct layer of conjunctive tissue called the endocycle, and a similar layer, the pericycle, separates the phloem from the cortex.

In other species, however, the centripetal primary xylem is represented.