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Cold hardiness in molluscs / Armelle Ansart ; Philippe Vernon in Acta Oecologica, Vol.24, n°2 ([01/01/2003])

Public ISBD [article]  inActa Oecologica > Vol.24, n°2 [01/01/2003] . - p.95-102 Titre : Cold hardiness in molluscs Type de document : Article Auteurs : Armelle Ansart ; Philippe Vernon Article en page(s) : p.95-102 Langues : Français (fre) Catégories : [Thesagri] froid Note de contenu : Molluscs inhabit all types of environments: seawater, intertidal zone, freshwater and land, and of course may have to deal with subzero temperatures. Ectotherm animals survive cold conditions by avoiding it by extensive supercooling (freezing avoidant species) or by bearing the freezing of their extracellular body fluids (freezing tolerant species). Although some studies on cold hardiness are available for intertidal molluscs, they are scarce for freshwater and terrestrial ones. Molluscs often exhibit intermediary levels of cold hardiness, with a moderate or low ability to supercool and a limited survival to the freezing of their tissues. Several factors could be involved: their dependence on water, their ability to enter dormancy, the probability of inoculative freezing in their environment, etc. Size is an important parameter in the development of cold hardiness abilities: it influences supercooling ability in land snails, which are rather freezing avoidant and survival to ice formation in intertidal organisms, which generally tolerate freezing. [article] Cold hardiness in molluscs [Article] / Armelle Ansart ; Philippe Vernon . - p.95-102. Langues : Français (fre) in Acta Oecologica > Vol.24, n°2 [01/01/2003] . - p.95-102 Catégories : [Thesagri] froid Note de contenu : Molluscs inhabit all types of environments: seawater, intertidal zone, freshwater and land, and of course may have to deal with subzero temperatures. Ectotherm animals survive cold conditions by avoiding it by extensive supercooling (freezing avoidant species) or by bearing the freezing of their extracellular body fluids (freezing tolerant species). Although some studies on cold hardiness are available for intertidal molluscs, they are scarce for freshwater and terrestrial ones. Molluscs often exhibit intermediary levels of cold hardiness, with a moderate or low ability to supercool and a limited survival to the freezing of their tissues. Several factors could be involved: their dependence on water, their ability to enter dormancy, the probability of inoculative freezing in their environment, etc. Size is an important parameter in the development of cold hardiness abilities: it influences supercooling ability in land snails, which are rather freezing avoidant and survival to ice formation in intertidal organisms, which generally tolerate freezing.

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
REV-00000759	Vol.24, n°2 - 01/01/2003	Revue	Archives sous-sol	Documentaires	Disponible

Plant biomass production and soil nitrogen in mixtures and monocultures of old field Mediterranean annuals / A. Gastine ; P.W. Leadley ; J. Roy in Acta Oecologica, Vol.24, n°2 ([01/01/2003])

Public ISBD [article]  inActa Oecologica > Vol.24, n°2 [01/01/2003] . - p.65-75 Titre : Plant biomass production and soil nitrogen in mixtures and monocultures of old field Mediterranean annuals Type de document : Article Auteurs : A. Gastine ; P.W. Leadley ; J. Roy Article en page(s) : p.65-75 Langues : Français (fre) Catégories : [Thesagri] biodiversité [Thesagri] nitrate [Thesagri] plante Note de contenu : We examine the relationship between plant diversity and ecosystem properties in a Mediterranean grassland. Five legumes, three grasses and two forb species are grown in monocultures and compared with mixtures that include these ten species. Trifolium angustifolium L. (a legume), Lolium rigidum Gaudin (a grass), and Centaurea solstitialis L. (a forb), are replicated in monocultures. Plant cover, root length and biomass, and concentrations of soil nitrate and ammonium are measured in all plots in March and May. Aboveground biomass is measured at a final harvest in late May to early June. Root biomass is significantly higher in the species mixtures than the average of the monocultures. Plant cover and root length are marginally significantly higher (0.05 < P 0.1) in the mixtures compared to the average of the monocultures. Soil inorganic nitrogen concentrations and aboveground biomass do not significantly differ between the average of the monocultures and the mixtures. Aboveground biomass in T. angustifolium monocultures is significantly higher than in the mixtures, and on average the legume monocultures do not differ significantly from the mixtures. Root length and biomass in L. rigidum monocultures are higher than in the mixtures in March. Nitrate concentrations (which are negatively correlated with root length and biomass) are the lowest in C. solstitialis in May. Thus, we have evidence that some of the measures of ecosystem performance decline in the average of the monocultures when compared with the mixtures, but mixtures never outperform or do more poorly than the best performing monocultures. [article] Plant biomass production and soil nitrogen in mixtures and monocultures of old field Mediterranean annuals [Article] / A. Gastine ; P.W. Leadley ; J. Roy . - p.65-75. Langues : Français (fre) in Acta Oecologica > Vol.24, n°2 [01/01/2003] . - p.65-75 Catégories : [Thesagri] biodiversité [Thesagri] nitrate [Thesagri] plante Note de contenu : We examine the relationship between plant diversity and ecosystem properties in a Mediterranean grassland. Five legumes, three grasses and two forb species are grown in monocultures and compared with mixtures that include these ten species. Trifolium angustifolium L. (a legume), Lolium rigidum Gaudin (a grass), and Centaurea solstitialis L. (a forb), are replicated in monocultures. Plant cover, root length and biomass, and concentrations of soil nitrate and ammonium are measured in all plots in March and May. Aboveground biomass is measured at a final harvest in late May to early June. Root biomass is significantly higher in the species mixtures than the average of the monocultures. Plant cover and root length are marginally significantly higher (0.05 < P 0.1) in the mixtures compared to the average of the monocultures. Soil inorganic nitrogen concentrations and aboveground biomass do not significantly differ between the average of the monocultures and the mixtures. Aboveground biomass in T. angustifolium monocultures is significantly higher than in the mixtures, and on average the legume monocultures do not differ significantly from the mixtures. Root length and biomass in L. rigidum monocultures are higher than in the mixtures in March. Nitrate concentrations (which are negatively correlated with root length and biomass) are the lowest in C. solstitialis in May. Thus, we have evidence that some of the measures of ecosystem performance decline in the average of the monocultures when compared with the mixtures, but mixtures never outperform or do more poorly than the best performing monocultures.

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
REV-00000759	Vol.24, n°2 - 01/01/2003	Revue	Archives sous-sol	Documentaires	Disponible