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The region at the base of the nucellus of an ovule; gives rise to the integuments.
(cell and molecular biology)
One of the paired, spiral, albuminous bands in a bird's egg that attach the yolk to the shell lining membrane at the ends of the egg.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the basal part of the ovule where the seed stalk attaches the ovule to the placenta.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Hypostase development in Ornithogalum caudatum (Liliaceae), and notes on the other types of modifications in chalaza of Angiosperm ovules.
Microbes could bypass the tedious process of decomposing the seed coat if they could gain access directly via pre-designed weak spots, such as hilum, strophiole, chalaza, or micropyle, or via entrances created by cracks, nicks or wrinkles in the seed coat.
According to Werker (1997), the pachychalaza is formed from the enlargement of the chalaza, forming a large portion of the seed involucrum.
Microdiptera (in the broadest sense) is morphologically and anatomically similar to Decodon, sharing the following characteristics: anatropous ovules, bitegmic seeds with inner lignified layers typical of the Lythraceae, a germination valve on one side of the seed, and extensive spongy tissue through which the raphe runs from near the hilum to the chalaza. When considered as three distinct genera, Microdiptera, Diclidocarya, and Mneme, one to three co-occur with Decodon in Miocene lacustrine habitats in Europe, Asia and North America (Friis, 1980; Mai, 1987, 1995, 2001; Matthews & Ovenden, 1990; KvaCek & Teodoridis, 2007).
chalaza is recognized as the region where the integument and nucellus
Confusion between chalaza and nucellus originates from the general practise of referring to the (proximal) part of the nucellus nearest the chalaza as the "chalazal region of the nucellus," or "chalazal nucellus." Other confusion stems inevitably from literature in different languages.
Seed anatomy of Artabotrys odoratissimus with a discussion on chalaza, integumentary bundles and ruminate endosperm.
During storage, changes may occur in seed-coat permeability of hard seeds (Egley, 1989; Egley et al., 1985; Kolattukudy, 1980a, 1980b, 1981, 1984; Werker, 1980-1981) as well as the opening of the hilum valve (Hyde, 1954), the micropyle or chalaza (Marchaim et al., 1974), or the strophiale (lens) zone (Hagon & Ballard, 1970; Kelly & van Staden, 1987; Manning & van Staden, 1987).
Capsula cefalica color cafe, mas claro en cuernos y detras de ellos; cubierta de pelos; granulos, y con pequenas concavidades redondas en toda la cabeza, excepto el frontoclipeo; epicraneo con dos prominentes cuernos redondos; protuberancias conicas con una seta en sus apices (chalazas) de diferentes tamanos en cuernos y en zona media frontal, lateral y posterior de la cabeza.
Al respecto, la Norma NMX-FF-079-SCFI-2004 (productos avicolas huevo fresco de gallina especificaciones y metodos de prueba) [20] define al huevo de gallina como el producto ovoide, proveniente de la oviposicion de la gallina (Gallus galli), constituido por cascaron, membranas, camara de aire, clara, chalazas, yema y germen.