Pollen Diversity in Some Modern Magnoliids

Sampson, F. B.

doi:10.1086/317573

Cited by 101 publications

(94 citation statements)

References 75 publications

(90 reference statements)

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“…6A, C, D) and presumably triploid endosperm; an orthotropous ovule with cup-shaped outer integument (Endress and Igersheim 2000; Yamada et al 2001); and successive microsporogenesis (Furness et al 2002). These and other morphological characters (Doyle and Endress 2000;Sampson 2000;Endress 2001;Hesse 2001) indicate that monotypic Amborellaceae may be highly apomorphic, an obvious reminder that basal taxa need not be plesiomorphic taxa.…”

Section: The Distribution Of Female Gametophyte Types In Anitagrade Amentioning

confidence: 98%

Modularity of the Angiosperm Female Gametophyte and Its Bearing on the Early Evolution of Endosperm in Flowering Plants

Friedman

Williams

2003

Evolution

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Abstract. The monosporic seven-celled/eight-nucleate Polygonum-type female gametophyte has long served as a focal point for discussion of the origin and subsequent evolution of the angiosperm female gametophyte. In Polygonumtype female gametophytes, two haploid female nuclei are incorporated into the central cell, and fusion of a sperm cell with the binucleate central cell produces a triploid endosperm with a complement of two maternal and one paternal genomes, characteristic of most angiosperms. We document the development of a four-celled/four-nucleate female gametophyte in Nuphar polysepala (Engelm.) and infer its presence in many other ancient lineages of angiosperms. The central cell of the female gametophyte in these taxa contains only one haploid nucleus; thus endosperm is diploid and has a ratio of one maternal to one paternal genome. Based on comparisons among flowering plants, we conclude that the angiosperm female gametophyte is constructed of modular developmental subunits. Each module is characterized by a common developmental pattern: (1) positioning of a single nucleus within a cytoplasmic domain (pole) of the female gametophyte; (2) two free-nuclear mitoses to yield four nuclei within that domain; and (3) partitioning of three uninucleate cells adjacent to the pole such that the fourth nucleus is confined to the central region of the female gametophyte (central cell). Within the basal angiosperm lineages Nymphaeales and Illiciales, female gametophytes are characterized by a single developmental module that produces a four-celled/four-nucleate structure with a haploid uninucleate central cell. A second pattern, typical of Amborella and the overwhelming majority of eumagnoliids, monocots, and eudicots, involves the early establishment of two developmental modules that produce a sevencelled/eight-nucleate female gametophyte with two haploid nuclei in the central cell. Comparative analysis of ontogenetic sequences suggests that the seven-celled female gametophyte (two modules) evolved by duplication and ectopic expression of an ancestral Nuphar-like developmental module within the chalazal domain of the female gametophyte. These analyses indicate that the first angiosperm female gametophytes were composed of a single developmental module, which upon double fertilization yielded a diploid endosperm. Early in angiosperm history this basic module was duplicated, and resulted in a seven-celled/eight-nucleate female gametophyte, which yielded a triploid endosperm with the characteristic 2:1 maternal to paternal genome ratio.

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Section: The Distribution Of Female Gametophyte Types In Anitagrade Amentioning

confidence: 98%

Modularity of the Angiosperm Female Gametophyte and Its Bearing on the Early Evolution of Endosperm in Flowering Plants

Friedman

Williams

2003

Evolution

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“…Sampson and Foreman (1988) describe the two elongated apertures being centred and widest at the poles and tapering at their ends, to terminate, without meeting, near the equator of the grain. As well as having disulcate pollen with the above type of aperture, Doryphora sassafras can have meridionosulcate pollen where there is a median encircling aperture that narrows markedly or slightly in two regions opposite one another near the equator of the grain (Sampson 2000). See also Erdtman (1966, p. 271), and a synopsis of pollen of Monimiaceae s. lat.…”

Section: Doryphora Sassafrasmentioning

confidence: 99%

“…See also Erdtman (1966, p. 271), and a synopsis of pollen of Monimiaceae s. lat. by Sampson (2000). Doryphora is sometimes placed in the family Atherospermataceae.…”

Section: Doryphora Sassafrasmentioning

confidence: 99%

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Pollen morphology of some rainforest taxa occurring in the Illawarra region of New South Wales, Australia

Kodela¹

2006

Telopea

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Pollen morphological descriptions and photographic illustrations based on light microscope analyses are provided for over 60 angiosperm taxa that occur in rainforest and wet sclerophyll forest communities in the Illawarra region of New South Wales. The resulting pollen taxonomy contributes to the study of Holocene mesotherm rainforest floras in coastal and tableland New South Wales and, because many species are or will have been shared with other vegetation types in the past, also to the floras of other botanical regions. Taxonomic relationships assessed on pollen morphology are discussed for several taxa.

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“…The availability of detailed pollen data and phylogeny (1979 ) and Sampson (2000 a). From these it is evident that hypotheses now makes evaluating pollen evolution a meanWinteraceae is a stenopalynous family.…”

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confidence: 99%