Ecology and seed morphology of endemic species from Kerguelen Phytogeographic Zone

Hennion, Françoise; Walton, David W.H.

doi:10.1007/s003000050182

Cited by 24 publications

(37 citation statements)

References 6 publications

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“…, 2005). This provincialism supports the hypothesis that the subantarctic flora survived in glacial refugia, and is also supported by the presence of five endemic phanerogams in the SIOP ( Pringlea antiscorbutica , Colobanthus kerguelensis , Ranunculus moseleyi , Poa kerguelensis and Poa cookii ) that have probably persisted in that archipelago for several millions of years (Hennion & Walton, 1997), and with the four endemic species that are currently found ( Puccinellia macquariensis , Azorella macquariensis , Nematoceras dienema and Nematoceras sulcatum ) on Macquarie Island (Clements et al. , 2007).…”

Section: Discussionsupporting

confidence: 74%

“…For South Georgia, data on Table 1 The subantarctic islands studied, together with the phytogeographical provinces (in italic) and their general geographical, geological and botanical characteristics. Data taken from Chown et al (1998) together with data from: South Georgia, Clapperton (1971) and Headland (1984); Marion Island, McDougall et al (2001); Îles Crozet, Giret et al (2003a); Îles Kerguelen, Hennion & Walton (1997) and Giret et al (2003b); Heard Island, Scott & Bergstrom (2005); McDonald Island, Jenkin (1997); Macquarie Island, Adamson et al (1996). pollen as well as on macroremains exist, which makes it possible to work on a higher taxonomic level.…”

Section: Palaeoecological and Palaeoenvironmental Datamentioning

confidence: 99%

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Subantarctic flowering plants: pre‐glacial survivors or post‐glacial immigrants?

Putten

Verbruggen

Ochyra

et al. 2010

Journal of Biogeography

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Aim The aim here was to assess whether the present-day assemblage of subantarctic flowering plants is the result of a rapid post-Last Glacial Maximum (LGM) colonization or whether subantarctic flowering plants survived on the islands in glacial refugia throughout the LGM. Location The circumpolar subantarctic region, comprising six remote islands and island groups between latitudes 46° and 55° S, including South Georgia in the South Atlantic Ocean, the Prince Edward Islands, Îles Crozet, Îles Kerguelen, the Heard Island group in the South Indian Ocean and Macquarie Island in the South Pacific Ocean. Methods Floristic affinities between the subantarctic islands were assessed by cluster analysis applied to an up-to-date dataset of the phanerogamic flora in order to test for the existence of provincialism within the subantarctic. A review of the primary literature on the palaeobotany, geology and glacial history of the subantarctic islands was carried out and supplemented with additional palaeobotanical data and new field observations from South Georgia, Île de la Possession (Îles Crozet) and Îles Kerguelen. Results First, a strong regionalism was observed, with different floras characterizing the islands in each of the ocean basins, and endemic species being present in the South Indian Ocean and South Pacific Ocean provinces. Second, the majority of the plant species were present at the onset of accumulation of post-glacial organic sediment and there is no evidence for the natural arrival of new immigrants during the subsequent period. Third, a review of geomorphological data suggested that the ice cover was incomplete during the LGM on the majority of the islands, and ice-free biological refugia were probably present even on the most glaciated islands. Main conclusions Several independent lines of evidence favour the survival of a native subantarctic phanerogamic flora in local refugia during the LGM rather than a post-LGM colonization from more distant temperate landmasses in the Southern Hemisphere

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Section: Discussionsupporting

confidence: 74%

Section: Palaeoecological and Palaeoenvironmental Datamentioning

confidence: 99%

Subantarctic flowering plants: pre‐glacial survivors or post‐glacial immigrants?

Putten

Verbruggen

Ochyra

et al. 2010

Journal of Biogeography

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“…The Kerguelen region is characterized by a permanently low temperature with an annual mean about +4°C and strong and perpetual wind (about 10 m s −1 ) (Frenot et al 1997). Pringlea antiscorbutica is abundant in plant communities and shows a broad altitudinal distribution from the shore to 1000 m (Hennion and Walton 1997a). This species can thus tolerate a wide range of adverse conditions, such as permanent low temperatures, frequent freeze–thaw cycles or salt spray.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐dependent changes of amine levels during early seedling development of the cold‐adapted subantarctic crucifer Pringlea antiscorbutica

Dufeu

Martin-Tanguy

Hennion

2003

Physiologia Plantarum

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Pringlea antiscorbutica R. Br., an endemic crucifer from the Kerguelen Archipelago in the subantarctic, has been previously shown to be unable to acclimatize to 25°C when transferred after several months cultivation under cold conditions. Furthermore, the polyamine composition was greatly modified in such high‐temperature‐treated plants. The development of seedlings of this species was investigated under a regime mimicking the subantarctic summer thermoperiod (5/10°C night/day) and a regime with high temperatures (22/25°C night/day). In parallel, the associated changes in polyamine composition that occurred during the first 6 days of seedling life were determined. Marked acceleration of seedling growth and intense cotyledon greening were observed at day 4 in 5/10°C‐grown seedlings but not in 22/25°C‐grown seedlings. Seedlings grown at high temperature accumulated agmatine and putrescine, whereas cold‐cultivated seedlings maintained high levels of spermidine. Cold‐cultivated seedlings accumulated the uncommon long‐chain polyamines norspermidine and homospermidine. These seedlings also accumulated free 1,3‐diaminopropane, cadaverine, N1‐acetylspermidine, N1‐acetylspermine and bound polyamines, whereas seedlings under high temperature accumulated N1‐acetylputrescine. Aromatic amine metabolism also appeared to be very responsive to temperature: seedlings under a cold regime accumulated free dopamine and bound phenylethylamine and tyramine, whereas seedlings grown at high temperature accumulated free tyramine. The possible relationships between the observed amine patterns and seedling growth under low and high temperature are discussed.

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“…The results of morphological and ecological studies of eight phanerogams growing on Kerguelen Islands (French Southern and Antarctic Lands) indicate that water plays an important role in seed dispersal (Hennion and Walton 1997). According to the above authors, seeds produced by other plant families, including Caryophyllaceae, are transported between Kerguelen Island by the sea, although this assumption has not been confirmed.…”

Section: Discussionmentioning

confidence: 97%

Generative reproduction of Antarctic grasses, the native species Deschampsia antarctica Desv. and the alien species Poa annua L.

Giełwanowska¹,

Kellmann−Sopyła²

2015

Polish Polar Research

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Abstract:The embryology of two species, Deschampsia antarctica, a native species, and Poa annua, an alien species in the Antarctic we studied. Flowering buds of plants growing in their natural habitats on King George Island and generative tissues of both plant species grown in a greenhouse were analyzed. Adaptations to autogamy and anemogamy were ob− served in the flower anatomy of both species. The microsporangia of the evaluated grasses produce a small number of three−celled pollen grains. Numerous pollen grains do not leave the microsporangium and germinate in the thecae. Deschampsia antarctica and P. annua plants harvested in Antarctica developed a particularly small number of microspores in pol− len chambers. In D. antarctica, male gametophytes were produced at a faster rate: genera− tive cells in pollen did not become detached from the wall of the pollen grain, they were not embedded in the cytoplasm of vegetative cells, and they divided into two sperm cells situ− ated close to the wall. The monosporous Polygonum type of embryo sac development was observed in the studied species. The egg apparatus had typical polarization, and the filiform apparatus did not develop in synergids. Large antipodals with polyploidal nuclei were formed in the embryo sacs of D. antarctica and P. annua. Poa annua was characterized by numerous antipodal cells which formed antipodal tissue in the chalazal region of the em− bryo sac. Three distinct antipodals with atypical, lateral position in the vicinity of the egg apparatus were observed in D. antarctica. The diaspores of the investigated grass species were characterized by small size, low weight and species−specific primary and secondary sculpture of the testa and caryopsis coat.

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Ecology and seed morphology of endemic species from Kerguelen Phytogeographic Zone

Cited by 24 publications

References 6 publications

Subantarctic flowering plants: pre‐glacial survivors or post‐glacial immigrants?

Subantarctic flowering plants: pre‐glacial survivors or post‐glacial immigrants?

Temperature‐dependent changes of amine levels during early seedling development of the cold‐adapted subantarctic crucifer Pringlea antiscorbutica

Generative reproduction of Antarctic grasses, the native species Deschampsia antarctica Desv. and the alien species Poa annua L.

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