ELECTRON‐MICROSCOPICAL STUDIES ON THE PHYCOBIONT <i>COCCOMYXA</i> SCHMIDLE

Peveling, Elisabeth; Galun, Margalith

doi:10.1111/j.1469-8137.1976.tb04665.x

Cited by 21 publications

(15 citation statements)

References 8 publications

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“…Early workers (Brown & Wilson, 1968;Webber & Webber, 1970;Jacobs & Ahmadjian, 1971;Peveling & Galun, 1976) made useful observations concerning the relative position and abundance of starch grains and pyrenoglobuli in algal cells of hydrated or desiccated thalli. However, potentially important correlations between these storage body patterns and photosynthetic rates were not investigated.…”

Section: Introductionmentioning

confidence: 99%

THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA

Scott

Larson

1986

New Phytologist

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SUMMARYThis paper describes the effects of transplantation on the ultrastructure and storage body distribution patterns in two saxicolous lichens which show a mutually exclusive distribution pattern. Umbilicaria vellea (L.) Ach., which grows in a snow-free microhabitat, was transplanted into an adjacent habitat which received a deep winter snow cover and which supported populations of Umbilicaria deusta (L.) Baum. The reverse was done for U. deusta in the [/. vellea habitat.Effects of transplantation on storage body distribution were evident for U. vellea, but not for U. deusta. At the ultrastructural level, thalli of U. vellea showed clear signs of disruption including senescence of the algal cells and an increase in the amount of stored starch which was negatively correlated with a decline in photosynthesis in the same replicates. Lipid deposits in U. vellea viere^ initially few in number and did not change as a result of transplantation. Changes were not observed for either species in the number of pyrenoglobuli in the pyrenoid body. Algal cells of U. deusta contained significantly larger amounts of starch and lipid than those of U. vellea and no overwintering treatment disrupted the fine structure of the plant. However, numbers of starch grains declined seasonally while thalli were under snow. Storage body distribution was found to be a stable feature of the algal cells and not dependent on short-term fluctuations in net photosynthesis. It is possible that U. deusta accumulates large amounts of photosynthetic products in the autumn and uses these to maintain low metabolic levels during the winter. It may be that U. vellea is excluded from snow-covered habitats because its thalli lack the ability to store photosynthetic products and have a pattern of gas exchange unsuited to overwintering under deep snow.

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Section: Introductionmentioning

confidence: 99%

THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA

Scott

Larson

1986

New Phytologist

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“…Moreover, TEM pictures showed numerous storage bodies, probably of lipid nature, in the cytoplasm of endosymbionts as well as in Ginkgo host cells (Trémouillaux-Guiller et al 2002). Similar storage bodies were observed in Coccomyxa phycobionts of ascolichens, while they were absent in cultured isolates (Peveling and Galun 1976). This suggests a possible involvement of the endosymbiont in metabolic pathways of its host.…”

Section: Discussionmentioning

confidence: 81%

A cryptic intracellular green alga in Ginkgo biloba: ribosomal DNA markers reveal worldwide distribution

Trémouillaux-Guiller

Huss

2007

Planta

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Intracellular symbioses involving eukaryotic microalgae and a variety of heterotrophic protists and invertebrates are widespread, but are unknown in higher plants. Recently, we reported the isolation and molecular identification of a Coccomyxa-like green alga from in vitro cell cultures of Ginkgo biloba L. This alga resides intracellularly in an immature "precursor" form with a nonfunctional chloroplast, implying that algal photosynthetic activity has no role in this endosymbiosis. In necrotizing Ginkgo cells, precursors evolved into mature algae, proliferated, and were liberated into the culture medium after host cell bursting. In the present paper we demonstrate by molecular methods a worldwide distribution of the alga in planta. Endosymbiont-specific sequences of ribosomal DNA could be traced in Ginkgo tissues of each specimen examined from different geographic locations in Europe, North America, and Asia. The Ginkgo/Coccomyca association represents a new kind of intracellular, vertically inherited symbiosis. Storage bodies, probably of lipid nature, present in the cytoplasm of each partner suggest a possible involvement of the endosymbiont in metabolic pathways of its host.

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“…In certain lichens, the type of symbiont contact may also be influenced by structural features of particular algal symbionts. For example, the lack of wall penetration in lichens containing the phycobiont Coccomyxa (Tschermak, 1941;Peveling and Galun, 1976) might be explained by the presence of degradation-resistant polymers in the algal cell wall (Brunner and Honegger, 1985;Honegger, 1988). In V. tavaresiae, the delamination of the algal wall near points of fungal penetration might be at least partly attributable to structural characteristics peculiar to the phaeophyte cell wall.…”

Section: Discussionmentioning

confidence: 95%

The intertidal marine lichen formed by the pyrenomycete fungus Verrucaria tavaresiae (Ascomycotina) and the brown alga Petroderma maculiforme (Phaeophyceae): thallus organization and symbiont interaction

Sanders

Moe

Ascaso

2004

American J of Botany

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The thallus formed by the marine pyrenomycete fungus Verrucaria tavaresiae and the phaeophycean alga Petroderma maculiforme was studied to elucidate the organization of the symbionts, determine the type of cellular contacts between them, and evaluate the status of the symbiosis as a lichen. Hand-sectioned and resin-embedded samples were examined with light and transmission electron microscopy. Within the uppermost portion of the cellular fungal tissue, separate algal filaments were arranged anticlinally. Protrusions of the fungal cell wall penetrated into adjacent algal walls but did not enter the cell lumen. A striking feature of these penetrations was the frequent separation of algal cell wall layers and insertion of fungal wall material between them. Algal filaments grew downward intrusively between fungal cells, often penetrating deeply into the fungal cell wall. Despite the exceptional nature of the phycobiont involved, the Verrucaria tavaresiae-Petroderma maculiforme symbiosis unequivocally fits the prevailing concept of a lichen. The distinctive interpenetrations observed between symbionts may be related to the integration of their different growth forms within a coherent tissue regularly subject to mechanical stresses. Periclinal cell divisions within and just below the algal layer may serve to replenish surface tissues lost to abrasion and herbivory.

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ELECTRON‐MICROSCOPICAL STUDIES ON THE PHYCOBIONT COCCOMYXA SCHMIDLE

Cited by 21 publications

References 8 publications

THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA

THE EFFECT OF WINTER FIELD CONDITIONS ON THE DISTRIBUTION OF TWO SPECIES OF UMBILICARIA

A cryptic intracellular green alga in Ginkgo biloba: ribosomal DNA markers reveal worldwide distribution

The intertidal marine lichen formed by the pyrenomycete fungus Verrucaria tavaresiae (Ascomycotina) and the brown alga Petroderma maculiforme (Phaeophyceae): thallus organization and symbiont interaction

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