pith


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pith,

in botany, core of the stemstem,
supporting structure of a plant, serving also to conduct and to store food materials. The stems of herbaceous and of woody plants differ: those of herbaceous plants are usually green and pliant and are covered by a thin epidermis instead of by the bark of woody plants.
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 of most plants. Pith is composed of large, loosely packed food-storage cells. As the stem grows older the pith usually dries out, and in some it disintegrates and the stem becomes hollow. In trees the pith becomes much reduced as the woody tissue (xylem) grows. In East Asia, rice paper is made from the pith of some shrubs. Candlewicks are made of the pith of certain rushes.

Pith

The central zone of tissue of an axis in which the vascular tissue is arranged as a hollow cylinder. Pith is present in most stems and in some roots. Stems without pith rarely occur in angiosperms but are characteristic of psilopsids, lycopsids, Sphenophyllum, and some ferns. Roots of some ferns, many monocotyledons, and some dicotyledons include a pith, although most roots have xylem tissue in the center.

Pith is composed usually of parenchyma cells often arranged in longitudinal files. This arrangement results from predominantly transverse division of pith mother cells near the apical meristem. See Parenchyma, Root (botany), Stem

Pith

 

the central portion of a plant stem, consisting of loose parenchymatous tissue. The internal part of the pith sometimes ruptures with age, forming one large air cavity (Labiatae, Um-belliferae, some Gramineae) or several cavities (grape). Roots have no typical pith. Pith usually consists mainly of thin-walled cells, among which there may be lignified thick-walled cells (apple), latex vessels (Campanulaceae, Convulvulaceae), mucous cells (linden), or canals with volatile oils (Compositae, Umbel-liferae). The parenchymatous cells contain reserve starch, which in woody plants is concentrated mainly in external small-celled layers of the pith—the perimedullary zone. Druses or single crystals of calcium oxalate are often found in the pith.

pith

[pith]
(botany)
A central zone of parenchymatous tissue that occurs in most vascular plants and is surrounded by vascular tissue.

pith

pith
The soft central core of a log.

pith

1. the soft fibrous tissue lining the inside of the rind in fruits such as the orange and grapefruit
2. Botany the central core of unspecialized cells surrounded by conducting tissue in stems
3. the soft central part of a bone, feather, etc.
References in periodicals archive ?
Among different corn stover fractions, the effective degradability of DM in rumen was the highest in leaf blade and stem pith, followed by ear husk and whole plant.
The NDF of corn stover fractions was similar to that of DM, the effective degradability of NDF in rumen was the highest in stem pith and leaf blade, followed by ear husk and whole plant.
Steam treatment may be caused to partial or complete hydrolysis of hemicellulose fraction of raw pith and decrease of NDF, changing it into more soluble components (Toussaint et al.
The result of this study showed that treating acidified sugarcane pith with low temperature (121degC for 120 min.
The Cheng Mei pictures may have been produced for the personal pleasure of the Qianlong Emperor in the seclusion of the Forbidden City but they must have had a wider circulation in some form since variants on the theme appear on pith a century later.
Here, "center" is the position including the pith or part thereof, "outer" is the outermost position of the log, and "inner" is a position between the two.
The objective of this study was to investigate the influence of pith location on warp in lumber sawn from small-diameter loblolly pine trees.
In this context, the objective of our study is to evaluate the drying quality of green baby-squares from second-growth mixed coastal forests of hemlock, under the influence of juvenile wood presence shown with a pith location at least on one of their end-surfaces, the tree harvesting season and dry target MC.
The flitches were planed to a thickness of 3/8 inch, keeping the pith approximately centered between opposite faces of each flitch.
This warp and checking may be attributed to juvenile wood, growth stresses, and differential shrinkage due to a centered pith or undesirable orientation of the growth rings in pieces cut near the pith (7).
It is a well-known fact that lumber sawn near the pith, either as boxed-in pith studs or with pith on the wide face, will almost always twist when dried to a low moisture content (MC), e.