Mode of Pollination, Pollen Germination, and Seed Set in Smooth Cordgrass (<i>Spartina alterniflora</i>, Poaceae)

Fang, Xiaobing; Subudhi, Prasanta K.; Venuto, Bradley C.; Harrison, Stephen A.

doi:10.1086/382810

Cited by 29 publications

(22 citation statements)

References 25 publications

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“…Self-incompatible grasses in general have a two-locus gametophytic incompatibility system in which the genotype of the pollen grain interacts with the genotype of the stigma and style to prevent pollen germination and growth of pollen tubes from self-produced pollen (Baumann et al 2000). However, careful observations of S. alterniflora by Fang et al (2004) showed that both self and non-self pollen was able to germinate on stigmas, grow pollen tubes, and penetrate micropiles in fairly equal numbers, suggesting that the selfincompatibility mechanisms in this case were not strong. Inbreeding depression can act in concert with self-incompatibility to reduce seed set, and it seemed reasonable that both would affect self-pollinated Spartina species and hybrids.…”

Section: Introductionmentioning

confidence: 99%

The rapid evolution of self-fertility in Spartina hybrids (Spartina alterniflora × foliosa) invading San Francisco Bay, CA

2008

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Plant hybridization can lead to the evolution of invasiveness. We wished to determine whether hybrids between the largely self-sterile Atlantic Spartina alterniflora and California native S. foliosa had evolved self-fertility during their ca 30 year existence in San Francisco Bay, CA. In pollination experiments we found that neither of the parental species was self-fertile, nor were early generation hybrids. A large fraction of later generation hybrids were profusely self-fertile. Inbreeding depression was high in the parental species and early generation hybrids, but was much reduced in later generation hybrids-some even showed outbreeding depression. We found that populations of later generation hybrids and their seedling progeny were almost two-fold more homozygous than early generation hybrids, consistent with the evidence of increased selfing shown by our parentage analyses based upon 17 microsatellite markers. We posit that evolved self-fertility has contributed substantially to the rapid spread of hybrid Spartina in San Francisco Bay.

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Section: Introductionmentioning

confidence: 99%

The rapid evolution of self-fertility in Spartina hybrids (Spartina alterniflora × foliosa) invading San Francisco Bay, CA

2008

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“…Entretanto, a produção de cariopses por S. alterniflora é irregular, com uma grande variabilidade interanual e local (Daehler & Strong 1994). Intensificação de fatores inibitórios dos processos de polinização anemófila e de fecundação cruzada (característicos de S. alterniflora; Fang et al 2004), como chuvas excessivas no período de polinização, poderiam explicar o grande número de estruturas florais que não geram cariopses. Esta variação na produção de cariopses pode estar também relacionada à predação de inflorescências por insetos e aves (Bertness & Shumway 1992), bem como variações nas populações de polinizadores e ocorrência de processos abortivos como mecanismo de defesa contra a autofecundação (Daehler & Strong 1994).…”

Section: Figs4 A-dunclassified

“…A biologia reprodutiva das espécies de Spartina ainda é pouco conhecida (Fang et al 2004). A densidade total de colmos de Spartina densiflora Brongn.…”

Section: Introductionunclassified

Variação na altura e na abundância de colmos e estruturas reprodutivas em populações pioneiras e maduras de Spartina alterniflora Loisel. e S. densiflora Brongn. (Poaceae) do sul do Brasil

Caetano¹,

Greis²,

Azevedo³

et al. 2017

Iheringia Ser Bot

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Variação na altura e na abundância de colmos e estruturas reprodutivas em populações pioneiras e maduras de, enquanto a população madura não fl oresceu. Palavras-chave: densidade, fecundidade, gradientes ambientais, ocupação espacialABSTRACT -Variation of the tiller height and abundance of tillers and reproductive structures in pioneer and mature populations of Spartina alternifl ora Loisel. and S. densifl ora Brongn. (Poaceae) in southern Brazil. This study aimed to quantify and elucidate the spatial variability of plant height and abundance of tillers and reproductive structures of the salt marsh grasses Spartina alternifl ora Loisel. and Spartina densifl ora Brongn. within and between pioneer (<10 years of colonization) and mature stands (>50 years of colonization) in southern Brazil. Both pioneer populations had taller tillers (p<0.01) than mature populations. Pioneer populations of S. densifl ora also showed massive investment on tiller density (10,084 m -2 ), more infl orescences (557 m -2 ) and higher fecundity (16,258 seeds m -2 ) than the mature population (131 infl orescence m -2; 2,199 seeds m -2 ). High redox and reduction of phosphorus availability in the sediment away from the water line seem to explain decreasing densities of tiller and infl orescences inside S. densifl ora mature populations. Fourteen percent of pioneer S. alternifl ora tillers fl owered and, on average, produced only 0.4 seeds per infl orescence and 76 seeds m -2 , whereas mature population did not fl ower.

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“…In the few such taxa that have been studied in detail, however, outcross pollen leads to higher seed set and germinability than self pollen (Fang et al 2004;Kettenring et al 2011). Even though barriers to self-pollination are rarely absolute, estimated rates of outcrossing are strongly bimodal, with self-incompatible species generally above 80 % outcrossing and self-compatible ones mostly well under 15 % (Connor 1987;Raduski et al 2012).…”

Section: Self-pollination and Self-incompatibility Systemsmentioning

confidence: 99%

Reproductive Systems

Kellogg¹

2015

Flowering Plants. Monocots

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Reproductive systems in the grasses are diverse. This section begins by describing the morphological variation in placement of the stamens and pistils, and then follows with discussion of outcrossing, self-pollination and apomixis. UNISEXUAL VS. BISEXUAL FLOWERSGrasses may have unisexual or bisexual flowers. Because of the distribution of the unisexual versus bisexual condition in the immediate outgroups and early diverging taxa, attempts to determine the ancestral condition for the family are highly sensitive to analytical method and assumptions (Malcomber and Kellogg 2006). Among the graminid Poales, flowers of Flagellariaceae are bisexual, whereas those of Restionaceae, Centrolepidaceae and Anarthriaceae are unisexual. The two immediate outgroups of the grasses, Ecdeiocoleaceae and Joinvilleaceae, have unisexual and bisexual flowers, respectively. In the grasses, flowers in Anomochlooideae are bisexual, but those in Pharoideae are unisexual, and Puelioideae are bisexual. This distribution of character states indicates either that unisexual flowers have arisen repeatedly, or that reversion from unisexual to bisexual is fairly easy over evolutionary time, or both.Virtually all possible arrangements of unisexual flowers on the plant are known in the grasses (Connor 1981(Connor , 1987. Monoecy is widespread, appearing in all Pharoideae, tribe Olyreae of Bambusoideae, many members of Chloridoideae and Panicoideae, and some Ehrhartoideae. Among monoecious grasses, sex expression may vary between flowers within a spikelet (e.g., Lecomtella, Ixophorus), between spikelets within an inflorescence (e.g., Pharus, Hypogynium, Zizania), or between inflorescences within a plant (e. g., Zea, many Olyreae).Andromonoecy is common, particularly in the Panicoideae, in which spikelets are conventionally two-flowered, with the lower flower often producing stamens and the upper one being bisexual. Additional variations on this theme occur in the tribe Andropogoneae, with sex expression varying between the flowers in each of the two spikelets of the spikelet pair. For example, in many species of Andropogon, the sessile spikelet has a sterile lower flower and bisexual upper flower, while the pedicellate spikelet has a sterile lower flower and staminate upper one; this produces an inflorescence of bisexual and staminate flowers in a 1:1 ratio. In other Andropogoneae (e.g., Elymandra), the most proximal spikelet pairs on the inflorescence consist entirely of staminate flowers, thus increasing the ratio of staminate to bisexual flowers.In contrast to andromonoecy, gynomonoecy is rare in the grasses as a whole. Connor (1981) reports only eight genera with this distribution of flower types. In two of these, the bambusoids Diandrolyra and Piresia, the apparently bisexual flowers are in fact staminate with the gynoecium non-functional; thus, the plants are actually monoecious. In the chloridoid genus Munroa, pistillate flowers are proximal to bisexual ones in the spikelets of most species, but in M. squarrosa, pistillate spikelets occur only...

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Mode of Pollination, Pollen Germination, and Seed Set in Smooth Cordgrass (Spartina alterniflora, Poaceae)

Cited by 29 publications

References 25 publications

The rapid evolution of self-fertility in Spartina hybrids (Spartina alterniflora × foliosa) invading San Francisco Bay, CA

The rapid evolution of self-fertility in Spartina hybrids (Spartina alterniflora × foliosa) invading San Francisco Bay, CA

Variação na altura e na abundância de colmos e estruturas reprodutivas em populações pioneiras e maduras de Spartina alterniflora Loisel. e S. densiflora Brongn. (Poaceae) do sul do Brasil

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