sporopollenin


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sporopollenin

[¦spȯr·ō′päl·ə·nən]
(biochemistry)
A substance related to suberin and cutin but more resistant to decay that is found in the exine of pollen grains.
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References in periodicals archive ?
Since mature orbicules consist of sporopollenin they are well represented in the fossil record.
1998), the patterned sporopollenin polymerisation in the anther mediated by 'white lines' and a glycocalyx, and the possible contribution of in vivo self-assembly of sporopollenin in the development of the sporoderm (Gabarayeva & Hemsley, 2006).
It has been reported that [11] orbicules originate in the cytoplasm of the tapetal cells as lipoidal pro-orbicular bodies that accumulate below the membrane and eventually extrude to the cell surface (facing the locule) where they provide sporopollenin precursors for exine formation.
At the free microspore stage, a material with a similar electron density to sporopollenin fills the whole locule and deposits over the pollen grain wall.
TRMX-3 (Supreme Edition), the company's sporopollenin based toxins extractor, was approved by Health Canada in Canada and in Europe by European Medical Device Agency.
A distinctly patterned multilayered spore wall containing sporopollenin develops around each spore/microspore.
Perforations and small sporopollenin granules may occur on the surface.
The tapetum and the microspores contain homologous, nearly identical genetic information for the production, release, and accumulation of sporopollenin (Hesse, 1986; Pacini et al.
Thus it is uncertain whether it is composed of sporopollenin, like those in the Asclepiadoideae, or of elastoviscin, which Dannenbaum and Schill (1991) found covering the tetrads in Raphionacme (P eriplocoideae).
The secretory tapetum is composed of cells usually with large nuclei [ILLUSTRATION FOR FIGURES 1, 64, 67 OMITTED], and it stains dark due to the cytoplasmic contents of lipids, proteins, and sporopollenin precursors [ILLUSTRATION FOR FIGURES 4, 5, 38, 42, 45, 47-50, 54, 62, 63, 65, 66 OMITTED].
Up to now these minute structures, covering the inner surface of most secretory tapeta, remained enigmatic and therefore highly attractive to botanists concerned with anther structure, pollen development, and sporopollenin synthesis.