Pollen Wall and Sporopollenin

Wiermann, R.; Gubatz, Sabine

doi:10.1016/s0074-7696(08)61093-1

Cited by 125 publications

(73 citation statements)

References 125 publications

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“…At the late tetrad stage, sporopollenin precursors, fatty acids (Wilmesmeier & Wiermann, 1995;Wiermann et al, 2001), and phenylpropanoids, probably p-coumaric acid (Rittscher & Wiermann, 1988;Wiermann & Gubatz, 1992;Gubatz et al, 1993;Niester-Nyveld et al, 1997), seem to appear in the periplasmic space, and the chemical composition of the medium in the periplasmic space changes: it shifts from a hydrophilic to a hydrophobic state. As a consequence, normal micelles turn inside out and reverse micelles emerge with hydrophilic cores and hydrophobic shells.…”

Section: Ectexine Development and Its Underlying Causementioning

confidence: 99%

Sporoderm development inSwida alba(Cornaceae), interpreted as a self-assembling colloidal system

Gabarayeva

Grigorjeva

2011

Grana

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Section: Ectexine Development and Its Underlying Causementioning

confidence: 99%

Sporoderm development inSwida alba(Cornaceae), interpreted as a self-assembling colloidal system

Gabarayeva

Grigorjeva

2011

Grana

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“…These results revealed that distinctly different flavonoid compounds accumulated in gentian anthers and petals, namely flavonols and flavones as unpigmented compounds. Pollen grains of higher plants accumulate mostly flavonol derivatives, which are frequently 3-diglycosides and 3-triglycosides of kaempferol, quercetin and isorhamnetin (Wiermann and Gubatz 1992). Major flavonoids of petunia pollen grains are quercetin and kaempferol 2-O-(2Ј-O-b -D-glucopyranosyl)-b -galactropyranoside (Zerback et al 1989).…”

Section: The Accumulation Of Flavonol Derivatives In Gentian Anthersmentioning

confidence: 99%

“…The exine wall is also composed primarily of sporopollenin, which is extremely resistant to decay and is formed from a series of related polymers derived from long-chain fatty acids and modest amounts of oxygenated aromatic rings and phenylpropanoids, including flavonoids (Piffanelli et al 1998). The principal site of flavonoid synthesis in the anther is the tapetum, from which the pigments are transported into the locule and incorporated in the outer surface of the pollen grain (Wiermann and Gubatz 1992). At later stages of anther development, flavonoids are distributed throughout the anther, and it is thought that transport of flavonoids may occur not only into the locule, but also further into the anther.…”

mentioning

confidence: 99%

“…Flavonols also have stimulatory effects on pollen development, germination and tube growth in tobacco (Ylstra et al 1992). Flavonoid diversity in pollen grains is often high (Wiermann and Gubatz 1992). The principal flavonoids in pollen are frequently 3-diglycosides and 3-triglycosides of kaempferol, quercetin, and isorhamnetin (Deboo et al 1995;Wiermann and Gubatz 1992;Zerback et al 1989).…”

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confidence: 99%

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A flavonol synthase gene GtFLS defines anther-specific flavonol accumulation in gentian

Kimura

Nakatsuka

Yamada

et al. 2010

Plant Biotechnology

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Flavonoids are important for male gametophyte development. Here we report on the flavonoid components and their biosynthetic regulation in gentian anthers. Among flavonoids, flavonols, including kaempferol, quercetin and isorhamnetin derivatives, accumulated abundantly in gentian anthers. However, flavones and anthocyanins, which are the main flavonoids accumulating in petals, were not detected. Northern blot analysis of nine flavonoid biosynthetic genes showed that the 'early' flavonoid biosynthetic genes were expressed in both anthers and petals, and that flavonol synthase (FLS) transcripts were restricted to anthers. In contrast, flavone synthase II (FNSII) and 'late' flavonoid biosynthetic genes were expressed specifically in gentian petals. To confirm anther-specific expression of FLS, the 5Ј-upstream region of FLS (GtFLSpro) was cloned by inverse PCR and fused to the uidA (GUS) reporter gene. Tobacco, Arabidopsis and gentian plants, transformed with the GtFLSproGUS construct, exhibited anther-specific GUS expression. Expression was observed in the tapetum and in pollen at late stages of anther development in transgenic plants. These results revealed that flavonol accumulation in gentian anthers was regulated by the spatial expression of GtFLS. Our results also suggest that antherspecific regulation of FLS is conserved among higher plants and the GtFLS promoter is useful for induction of specific gene expression in anthers.Key words: Anther, flavonol synthase, gentian, promoter, transgenic plants. Plant Biotechnology28, 211-221 (2010) DOI: 10.5511/plantbiotechnology.10.1109c Original PaperAbbreviations: ANS, anthocyanidin synthase; CHI, chalcone isomerase; CHS, chalcone synthase; DFR, dihydroflavonol 4-reductase; F3H, flavanone 3-hydroxylase; F3ЈH, flavonoid 3Ј-hydroxylase; F3Ј5ЈH, flavonoid 3Ј,5Ј-hydroxylase; FLS, flavonol synthase; FNSII, flavone synthase II; HPLC, high performance liquid chromatography; RACE, rapid amplification of cDNA ends The nucleotide sequences reported in this paper have been submitted to DDBJ under accession numbers AB587658 and AB587659. † The authors contributed equally to this work. This article can be found at

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“…Pollen grains carry male gametes for plant reproduction, and they comprise an inner intine layer surrounded by a hard outer exine layer [16,17]. The exine, composed of a substance called sporopollenin, is highly crosslinked and consists of fatty acid, phenylpropanoid, and phenolic substances.…”

Section: Introductionmentioning

confidence: 99%

Pollen fillers for reinforcing and strengthening of epoxy composites

2018

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Pollen grains have the potential to be effective plant-based biorenewable fillers in polymer matrices due to their high modulus, strength, chemical stability, and unique nanoscale architectures. In this work, we present evidence for the effectiveness of pollen as a reinforcing filler in epoxy matrices, characterized as a function of pollen loading and surface treatment. Composites prepared with unmodified native defatted ragweed pollen (D) displayed decreased mechanical properties and increasing glass transition temperatures (T g ) with increasing pollen loading. A soft interphase was observed to form around native pollen that is likely due to incompletely cured epoxy, resulting in decreased mechanical properties. However, pollen treated via a common base-acid (BA) surface preparation was a load-bearing, toughening filler in epoxy composites, displaying simultaneously increased tensile strength (by 47%) and strain at break (by 70%), improving interfacial morphology (absence of soft interphase), and increasing T g at 10 wt% pollen loading. Elastic modulus improves by 14% with 10 wt% BA pollen loading, and fitting of the modulus with the Halpin-Tsai and Counto models results in an estimated pollen exine modulus of 8 GPa, the first reported pollen modulus measurement from composite studies. Improvements in mechanical properties in BA pollen versus D pollen likely result due to crosslinks with the epoxy matrix due to the presence of protic functional groups (hydroxyls or carboxyls) on the BA surface. BAtreated ragweed pollen shows promise as a toughening filler for imparting higher strength to polymers without increasing mass.

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Pollen Wall and Sporopollenin

Cited by 125 publications

References 125 publications

Sporoderm development inSwida alba(Cornaceae), interpreted as a self-assembling colloidal system

Sporoderm development inSwida alba(Cornaceae), interpreted as a self-assembling colloidal system

A flavonol synthase gene GtFLS defines anther-specific flavonol accumulation in gentian

Pollen fillers for reinforcing and strengthening of epoxy composites

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