chalaza


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cha·la·za

(kă-lā'ză),
1. Synonym(s): chalazion
2. Suspensory ligament of the yolk in a bird's egg.
[G. hail; a small tubercle, a sty (Galen)]

chalaza

(kə-lā′zə, -lăz′ə)
n. pl. chala·zae (-zē) or chala·zas
1. Biology One of two spiral bands of tissue in an egg that connect the yolk to the lining membrane at either end of the shell.
2. Botany The region of an ovule that is opposite the micropyle, where the integuments and nucellus are joined.

cha·la′zal adj.

chalaza

  1. the basal part of the OVULE of a flowering plant to which the FUNICLE is attached, and through which the pollen tube sometimes enters the ovule prior to fertilization.
  2. one of an opposite pair of spiral bands in the white of a bird's egg which suspend the yolk within the shell to prevent it from being damaged.
References in periodicals archive ?
5 mm, from anatropous ovules, have a chalaza at the broad end of the seed and hilum at the narrow end.
The chalaza is the region of the ovule where the nucellus, integuments, and funicle merge, and therefore usually encompasses a vascular bundle.
The structure of the proximal end of the nucellus, adjacent to the chalaza, is variable and often includes modifications such as a hypostase or enlarged dermal cells.
The commonest condition for Lilianae (Rudall, 1994) is one where the proximal nucellus is short and broad, without enlarged dermal cells, but often with a hypostase and a fairly extensive subdermal region at the proximal ends around the sides of the embryo sac, but not towards the chalaza.
It forms a barrier between the ovular vascular strand and the embryo sac, inhibiting the growth of the embryo sac into the chalaza (van Tieghem, 1901; Dahlgren, 1940).
Boesewinkel (1989) also considered these central cells in Drosera to be conductive, since they apparently form a conductive strand from the chalaza to the embryo sac.
Capsula cefalica color cafe oscuro, mas claro detras de los cuernos y parte inferior del frontoclipeo; prominentes cuernos casi redondos en vertice y protuberancias tuberculadas (chalazas); mantiene disposicion de chalazas, concavidades y granulos.
Capsula cefalica color cafe oscuro a negro, con una delgada banda mas clara detras de los cuernos; mantiene chalazas, granulos y concavidades; epicraneo con cuernos redondos muy pronunciados.
La presencia de protuberancias conicas o chalazas (Imagen 8) en la capsula cefalica en algunos instares, son referenciadas en los estados inmaduros de: Magneuptychia libye (KAMINSKI & FREITAS, 2008); Yphthimoides cipoensis (FREITAS, 2004); Manataria maculata (MURILLO & NISHiDa, 2003); Haetera Piera (CONSTANTINO, 1993); Taygetis andromeda (YOUNG, 1984); y algunas especies del genero Mycalesis (VAN DER POORTEN & VAN DER POORTEN, 2012) de Sri Lanka.