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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.



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

References in periodicals archive ?
Hypostase development in Ornithogalum caudatum (Liliaceae), and notes on the other types of modifications in chalaza of Angiosperm ovules.
Dalechampia stipulacea presents the basal part of the tegmen which develops by intercalary growth, with few vascular bundles extend from the chalaza by postchalazal branching.
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.
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.
Seed anatomy of Artabotrys odoratissimus with a discussion on chalaza, integumentary bundles and ruminate endosperm.
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.
Coloracion de capsula cefalica similar a instar dos; epicraneo con cuernos muy pronunciados casi redondos; con chalazas dispuestas de igual forma que instar anterior; mantiene concavidades y granulos.
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.
Instar 5: Capsula cefalica y cuerpo similar a instar 4; el tono del cuerpo se oscurece aun mas; se observa menos densa la superficie de setas secundarias, se mantienen las chalazas amarillas con las largas setas blancas (Figura 8).