The Experts below are selected from a list of 6765 Experts worldwide ranked by ideXlab platform
Thomas D. Bruns - One of the best experts on this subject based on the ideXlab platform.
-
Evidence of a myco-heterotroph in the plant family Ericaceae that lacks mycorrhizal specificity
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Nicole A. Hynson, Thomas D. BrunsAbstract:Myco-Heterotrophy is one of the longest-studied aspects of the mycorrhizal symbiosis, but there remain many critical, unanswered questions regarding the ecology and physiology of myco-heterotrophic plants and their associated fungi. The vast majority of all myco-heterotrophs studied to date have exhibited specificity towards narrow lineages of fungi, but it is unclear whether the loss of photosynthesis in these plants is contingent upon fungal specialization. Here, we examine the fungal associates of the myco-heterotroph Pyrola aphylla (Ericaceae) and its closest green relative Pyrola picta to determine the pattern of mycorrhizal specialization. Our findings show that both plant species associate with a range of root-inhabiting fungi, the majority of which are ectomycorrhizal taxa. This study provides the first example of a eudicotyledonous myco-heterotroph that is a mycorrhizal generalist, indicating that the loss of photosynthesis in myco-heterotrophs is not contingent upon fungal specialization.
-
isotopic evidence of full and partial myco Heterotrophy in the plant tribe pyroleae ericaceae
New Phytologist, 2009Co-Authors: Nicole A. Hynson, Katja Preiss, Gerhard Gebauer, Thomas D. BrunsAbstract:Summary • Botanists and mycologists have long debated the potential for full myco-Heterotrophy in the achlorophyllous Pyrola aphylla (Ericaceae). Here we address the ecophysiology of this putative myco-heterotroph and two other closely related green species in the tribe Pyroleae (Pyrola picta and Chimaphila umbellata). The stable isotopes of carbon and nitrogen (δ 13 C and δ 15 N) were analysed from 10 populations of Pyroleae species in California and Oregon, USA. For all populations isotope signatures were tested for significant differences between P. aphylla, green pyroloids, surrounding autotrophs and obligate myco-heterotrophs. Throughout all populations P. aphylla was most similar to myco-heterotrophs that associate with ectomycorrhizal fungi in its 13 C signature (average enrichment e 13 C = 6.9 ± 0.9‰) and even more enriched in 15 N than many previously recorded myco-heterotrophic species (average enrichment e 15 N = 18.0 ± 2.2‰). The two green Pyroleae species were not enriched in 13 C compared with the autotrophic understory (C. umbellata average enrichment e 13 C =− 0.5 ± 1.0‰ and P. picta average e 13 C = 0.3 ± 1.4‰) and their 15 N signatures were similar to myco-heterotrophs that associate with ectomycorrhizal fungi (C. umbellata average enrichment e 15 N = 10.6 ± 1.6‰ and P. picta average e 15 N = 10.6 ± 1.9‰).
-
Isotopic evidence of full and partial myco‐Heterotrophy in the plant tribe Pyroleae (Ericaceae)
The New phytologist, 2009Co-Authors: Nicole A. Hynson, Katja Preiss, Gerhard Gebauer, Thomas D. BrunsAbstract:Summary • Botanists and mycologists have long debated the potential for full myco-Heterotrophy in the achlorophyllous Pyrola aphylla (Ericaceae). Here we address the ecophysiology of this putative myco-heterotroph and two other closely related green species in the tribe Pyroleae (Pyrola picta and Chimaphila umbellata). The stable isotopes of carbon and nitrogen (δ 13 C and δ 15 N) were analysed from 10 populations of Pyroleae species in California and Oregon, USA. For all populations isotope signatures were tested for significant differences between P. aphylla, green pyroloids, surrounding autotrophs and obligate myco-heterotrophs. Throughout all populations P. aphylla was most similar to myco-heterotrophs that associate with ectomycorrhizal fungi in its 13 C signature (average enrichment e 13 C = 6.9 ± 0.9‰) and even more enriched in 15 N than many previously recorded myco-heterotrophic species (average enrichment e 15 N = 18.0 ± 2.2‰). The two green Pyroleae species were not enriched in 13 C compared with the autotrophic understory (C. umbellata average enrichment e 13 C =− 0.5 ± 1.0‰ and P. picta average e 13 C = 0.3 ± 1.4‰) and their 15 N signatures were similar to myco-heterotrophs that associate with ectomycorrhizal fungi (C. umbellata average enrichment e 15 N = 10.6 ± 1.6‰ and P. picta average e 15 N = 10.6 ± 1.9‰).
Christine Ferrier-pagès - One of the best experts on this subject based on the ideXlab platform.
-
The relationship between heterotrophic feeding and inorganic nutrient availability in the scleractinian coral T. reniformis under a short‐term temperature increase
Limnology and Oceanography, 2015Co-Authors: Leila Ezzat, Erica K. Towle, Jean-olivier Irisson, Chris Langdon, Christine Ferrier-pagèsAbstract:Worldwide increase in seawater temperature represents one of the major threats affecting corals, which experience bleaching, and thereafter a significant decrease in photosynthesis and calcification. The impact of bleaching on coral physiology may be exacerbated when coupled with eutrophication, i.e., increasing plankton, inorganic nutrient concentrations, sedimentation and turbidity due to coastal urbanization. Whereas zooplankton provision (Heterotrophy) may alleviate the negative consequences of thermal stress, inorganic nutrient supply may exacerbate them, which creates a paradox. Our experimental study aims to disentangle the effects of these two components of eutrophication on the physiological response of Turbinaria reniformis subject to normal and to a short-term temperature increase. Additionally, three different inorganic nutrient ratios were tested to assess the influence of nutrient stoichiometry on coral physiology: control (ambient SW 0.5 μM N and 0.1 μM P), N only (ambient + 2 μM N) and N + P (ambient + 2 μM N and + 0.5 μM P). Our results show a deleterious effect of a 2 μM nitrate enrichment alone (N) on coral photosynthetic processes under thermal stress as well as on calcification rates when associated with Heterotrophy. On the contrary, a coupled nitrate and phosphorus enrichment (N + P) maintained coral metabolism and calcification during thermal stress and enhanced them when combined with Heterotrophy. Broadly, our results shed light on the tight relationship existing between inorganic nutrient availability and Heterotrophy. Moreover, it assesses the relevance of N: P stoichiometry as a determining factor for the health of the holobiont that may be adapted to specific nutrient ratios in its surrounding environment.
-
The Response of the Mediterranean Gorgonian Eunicella singularis to Thermal Stress Is Independent of Its Nutritional Regime
PLoS ONE, 2013Co-Authors: Leila Ezzat, Pierre Laurent Merle, Paola Furla, Alexandre Buttler, Christine Ferrier-pagèsAbstract:Over the last few decades, sessile benthic organisms from the Mediterranean Sea have suffered from the global warming of the world's oceans, and several mass mortality events were observed during warm summers. It has been hypothesized that mortality could have been due to a nutrient (food) shortage following the stratification of the water column. However, the symbiotic gorgonian Eunicella singularis has also presented a locally exceptional mortality, despite its autotrophic capacities through the photosynthesis of its dinoflagellate symbionts. Thus, this study has experimentally investigated the response of E. singularis to a thermal stress (temperature increase from 18 to 26 degrees C), with colonies maintained more than 2 months under four nutritional diets: autotrophy only (AO), autotrophy and inorganic nitrogen addition (AN), autotrophy and Heterotrophy (AH), Heterotrophy only (HO). At 18 degrees C, and contrary to many other anthozoans, supplementation of autotrophy with either inorganic nitrogen or food (Heterotrophy) had no effect on the rates of respiration, photosynthesis, as well as in the chlorophyll, lipid and protein content. In the dark, Heterotrophy maintained the gorgonian's metabolism, except a bleaching (loss of pigments), which did not affect the rates of photosynthesis. At 24 degrees C, rates of respiration, and photosynthesis significantly decreased in all treatments. At 26 degrees C, in addition to a decrease in the lipid content of all treatments, a bleaching was observed after 1 week in the AO treatment, while the AH and AN treatments resisted three weeks before bleaching. These last results suggest that, temperatures above 24 degrees C impair the energetic reserves of this species and might explain the mortality events in the Mediterranean.
-
Heterotrophy in tropical scleractinian corals.
Biological reviews of the Cambridge Philosophical Society, 2008Co-Authors: Fanny Houlbrèque, Christine Ferrier-pagèsAbstract:The dual character of corals, that they are both auto- and heterotrophs, was recognized early in the twentieth Century. It is generally accepted that the symbiotic association between corals and their endosymbiotic algae (called zooxanthellae) is fundamental to the development of coral reefs in oligotrophic tropical oceans because zooxanthellae transfer the major part of their photosynthates to the coral host (autotrophic nutrition). However, numerous studies have confirmed that many species of corals are also active heterotrophs, ingesting organisms ranging from bacteria to mesozooplankton. Heterotrophy accounts for between 0 and 66% of the fixed carbon incorporated into coral skeletons and can meet from 15 to 35% of daily metabolic requirements in healthy corals and up to 100% in bleached corals. Apart from this carbon input, feeding is likely to be important to most scleractinian corals, since nitrogen, phosphorus, and other nutrients that cannot be supplied from photosynthesis by the coral’s symbiotic algae must come from zooplankton capture, particulate matter or dissolved compounds. A recent study showed that during bleaching events some coral species, by increasing their feeding rates, are able to maintain and restore energy reserves. This review assesses the importance and effects of Heterotrophy in tropical scleractinian corals. We first provide background information on the different food sources (from dissolved organic matter to meso- and macrozooplankton). We then consider the nutritional inputs of feeding. Finally, we review feeding effects on the different physiological parameters of corals (tissue composition, photosynthesis and skeletal growth).
Leila Ezzat - One of the best experts on this subject based on the ideXlab platform.
-
The relationship between heterotrophic feeding and inorganic nutrient availability in the scleractinian coral T. reniformis under a short‐term temperature increase
Limnology and Oceanography, 2015Co-Authors: Leila Ezzat, Erica K. Towle, Jean-olivier Irisson, Chris Langdon, Christine Ferrier-pagèsAbstract:Worldwide increase in seawater temperature represents one of the major threats affecting corals, which experience bleaching, and thereafter a significant decrease in photosynthesis and calcification. The impact of bleaching on coral physiology may be exacerbated when coupled with eutrophication, i.e., increasing plankton, inorganic nutrient concentrations, sedimentation and turbidity due to coastal urbanization. Whereas zooplankton provision (Heterotrophy) may alleviate the negative consequences of thermal stress, inorganic nutrient supply may exacerbate them, which creates a paradox. Our experimental study aims to disentangle the effects of these two components of eutrophication on the physiological response of Turbinaria reniformis subject to normal and to a short-term temperature increase. Additionally, three different inorganic nutrient ratios were tested to assess the influence of nutrient stoichiometry on coral physiology: control (ambient SW 0.5 μM N and 0.1 μM P), N only (ambient + 2 μM N) and N + P (ambient + 2 μM N and + 0.5 μM P). Our results show a deleterious effect of a 2 μM nitrate enrichment alone (N) on coral photosynthetic processes under thermal stress as well as on calcification rates when associated with Heterotrophy. On the contrary, a coupled nitrate and phosphorus enrichment (N + P) maintained coral metabolism and calcification during thermal stress and enhanced them when combined with Heterotrophy. Broadly, our results shed light on the tight relationship existing between inorganic nutrient availability and Heterotrophy. Moreover, it assesses the relevance of N: P stoichiometry as a determining factor for the health of the holobiont that may be adapted to specific nutrient ratios in its surrounding environment.
-
the response of the mediterranean gorgonian eunicella singularis to thermal stress is independent of its nutritional regime
PLOS ONE, 2013Co-Authors: Leila Ezzat, Pierre Laurent Merle, Paola Furla, Alexandre Buttler, Christine FerrierpagesAbstract:Over the last few decades, sessile benthic organisms from the Mediterranean Sea have suffered from the global warming of the world's oceans, and several mass mortality events were observed during warm summers. It has been hypothesized that mortality could have been due to a nutrient (food) shortage following the stratification of the water column. However, the symbiotic gorgonian Eunicella singularis has also presented a locally exceptional mortality, despite its autotrophic capacities through the photosynthesis of its dinoflagellate symbionts. Thus, this study has experimentally investigated the response of E. singularis to a thermal stress (temperature increase from 18 to 26°C), with colonies maintained more than 2 months under four nutritional diets: autotrophy only (AO), autotrophy and inorganic nitrogen addition (AN), autotrophy and Heterotrophy (AH), Heterotrophy only (HO). At 18°C, and contrary to many other anthozoans, supplementation of autotrophy with either inorganic nitrogen or food (Heterotrophy) had no effect on the rates of respiration, photosynthesis, as well as in the chlorophyll, lipid and protein content. In the dark, Heterotrophy maintained the gorgonian's metabolism, except a bleaching (loss of pigments), which did not affect the rates of photosynthesis. At 24°C, rates of respiration, and photosynthesis significantly decreased in all treatments. At 26°C, in addition to a decrease in the lipid content of all treatments, a bleaching was observed after 1 week in the AO treatment, while the AH and AN treatments resisted three weeks before bleaching. These last results suggest that, temperatures above 24°C impair the energetic reserves of this species and might explain the mortality events in the Mediterranean.
-
The Response of the Mediterranean Gorgonian Eunicella singularis to Thermal Stress Is Independent of Its Nutritional Regime
PLoS ONE, 2013Co-Authors: Leila Ezzat, Pierre Laurent Merle, Paola Furla, Alexandre Buttler, Christine Ferrier-pagèsAbstract:Over the last few decades, sessile benthic organisms from the Mediterranean Sea have suffered from the global warming of the world's oceans, and several mass mortality events were observed during warm summers. It has been hypothesized that mortality could have been due to a nutrient (food) shortage following the stratification of the water column. However, the symbiotic gorgonian Eunicella singularis has also presented a locally exceptional mortality, despite its autotrophic capacities through the photosynthesis of its dinoflagellate symbionts. Thus, this study has experimentally investigated the response of E. singularis to a thermal stress (temperature increase from 18 to 26 degrees C), with colonies maintained more than 2 months under four nutritional diets: autotrophy only (AO), autotrophy and inorganic nitrogen addition (AN), autotrophy and Heterotrophy (AH), Heterotrophy only (HO). At 18 degrees C, and contrary to many other anthozoans, supplementation of autotrophy with either inorganic nitrogen or food (Heterotrophy) had no effect on the rates of respiration, photosynthesis, as well as in the chlorophyll, lipid and protein content. In the dark, Heterotrophy maintained the gorgonian's metabolism, except a bleaching (loss of pigments), which did not affect the rates of photosynthesis. At 24 degrees C, rates of respiration, and photosynthesis significantly decreased in all treatments. At 26 degrees C, in addition to a decrease in the lipid content of all treatments, a bleaching was observed after 1 week in the AO treatment, while the AH and AN treatments resisted three weeks before bleaching. These last results suggest that, temperatures above 24 degrees C impair the energetic reserves of this species and might explain the mortality events in the Mediterranean.
Nicole A. Hynson - One of the best experts on this subject based on the ideXlab platform.
-
Evidence of a myco-heterotroph in the plant family Ericaceae that lacks mycorrhizal specificity
Proceedings of The Royal Society B: Biological Sciences, 2009Co-Authors: Nicole A. Hynson, Thomas D. BrunsAbstract:Myco-Heterotrophy is one of the longest-studied aspects of the mycorrhizal symbiosis, but there remain many critical, unanswered questions regarding the ecology and physiology of myco-heterotrophic plants and their associated fungi. The vast majority of all myco-heterotrophs studied to date have exhibited specificity towards narrow lineages of fungi, but it is unclear whether the loss of photosynthesis in these plants is contingent upon fungal specialization. Here, we examine the fungal associates of the myco-heterotroph Pyrola aphylla (Ericaceae) and its closest green relative Pyrola picta to determine the pattern of mycorrhizal specialization. Our findings show that both plant species associate with a range of root-inhabiting fungi, the majority of which are ectomycorrhizal taxa. This study provides the first example of a eudicotyledonous myco-heterotroph that is a mycorrhizal generalist, indicating that the loss of photosynthesis in myco-heterotrophs is not contingent upon fungal specialization.
-
isotopic evidence of full and partial myco Heterotrophy in the plant tribe pyroleae ericaceae
New Phytologist, 2009Co-Authors: Nicole A. Hynson, Katja Preiss, Gerhard Gebauer, Thomas D. BrunsAbstract:Summary • Botanists and mycologists have long debated the potential for full myco-Heterotrophy in the achlorophyllous Pyrola aphylla (Ericaceae). Here we address the ecophysiology of this putative myco-heterotroph and two other closely related green species in the tribe Pyroleae (Pyrola picta and Chimaphila umbellata). The stable isotopes of carbon and nitrogen (δ 13 C and δ 15 N) were analysed from 10 populations of Pyroleae species in California and Oregon, USA. For all populations isotope signatures were tested for significant differences between P. aphylla, green pyroloids, surrounding autotrophs and obligate myco-heterotrophs. Throughout all populations P. aphylla was most similar to myco-heterotrophs that associate with ectomycorrhizal fungi in its 13 C signature (average enrichment e 13 C = 6.9 ± 0.9‰) and even more enriched in 15 N than many previously recorded myco-heterotrophic species (average enrichment e 15 N = 18.0 ± 2.2‰). The two green Pyroleae species were not enriched in 13 C compared with the autotrophic understory (C. umbellata average enrichment e 13 C =− 0.5 ± 1.0‰ and P. picta average e 13 C = 0.3 ± 1.4‰) and their 15 N signatures were similar to myco-heterotrophs that associate with ectomycorrhizal fungi (C. umbellata average enrichment e 15 N = 10.6 ± 1.6‰ and P. picta average e 15 N = 10.6 ± 1.9‰).
-
Isotopic evidence of full and partial myco‐Heterotrophy in the plant tribe Pyroleae (Ericaceae)
The New phytologist, 2009Co-Authors: Nicole A. Hynson, Katja Preiss, Gerhard Gebauer, Thomas D. BrunsAbstract:Summary • Botanists and mycologists have long debated the potential for full myco-Heterotrophy in the achlorophyllous Pyrola aphylla (Ericaceae). Here we address the ecophysiology of this putative myco-heterotroph and two other closely related green species in the tribe Pyroleae (Pyrola picta and Chimaphila umbellata). The stable isotopes of carbon and nitrogen (δ 13 C and δ 15 N) were analysed from 10 populations of Pyroleae species in California and Oregon, USA. For all populations isotope signatures were tested for significant differences between P. aphylla, green pyroloids, surrounding autotrophs and obligate myco-heterotrophs. Throughout all populations P. aphylla was most similar to myco-heterotrophs that associate with ectomycorrhizal fungi in its 13 C signature (average enrichment e 13 C = 6.9 ± 0.9‰) and even more enriched in 15 N than many previously recorded myco-heterotrophic species (average enrichment e 15 N = 18.0 ± 2.2‰). The two green Pyroleae species were not enriched in 13 C compared with the autotrophic understory (C. umbellata average enrichment e 13 C =− 0.5 ± 1.0‰ and P. picta average e 13 C = 0.3 ± 1.4‰) and their 15 N signatures were similar to myco-heterotrophs that associate with ectomycorrhizal fungi (C. umbellata average enrichment e 15 N = 10.6 ± 1.6‰ and P. picta average e 15 N = 10.6 ± 1.9‰).
Alexandre Buttler - One of the best experts on this subject based on the ideXlab platform.
-
the response of the mediterranean gorgonian eunicella singularis to thermal stress is independent of its nutritional regime
PLOS ONE, 2013Co-Authors: Leila Ezzat, Pierre Laurent Merle, Paola Furla, Alexandre Buttler, Christine FerrierpagesAbstract:Over the last few decades, sessile benthic organisms from the Mediterranean Sea have suffered from the global warming of the world's oceans, and several mass mortality events were observed during warm summers. It has been hypothesized that mortality could have been due to a nutrient (food) shortage following the stratification of the water column. However, the symbiotic gorgonian Eunicella singularis has also presented a locally exceptional mortality, despite its autotrophic capacities through the photosynthesis of its dinoflagellate symbionts. Thus, this study has experimentally investigated the response of E. singularis to a thermal stress (temperature increase from 18 to 26°C), with colonies maintained more than 2 months under four nutritional diets: autotrophy only (AO), autotrophy and inorganic nitrogen addition (AN), autotrophy and Heterotrophy (AH), Heterotrophy only (HO). At 18°C, and contrary to many other anthozoans, supplementation of autotrophy with either inorganic nitrogen or food (Heterotrophy) had no effect on the rates of respiration, photosynthesis, as well as in the chlorophyll, lipid and protein content. In the dark, Heterotrophy maintained the gorgonian's metabolism, except a bleaching (loss of pigments), which did not affect the rates of photosynthesis. At 24°C, rates of respiration, and photosynthesis significantly decreased in all treatments. At 26°C, in addition to a decrease in the lipid content of all treatments, a bleaching was observed after 1 week in the AO treatment, while the AH and AN treatments resisted three weeks before bleaching. These last results suggest that, temperatures above 24°C impair the energetic reserves of this species and might explain the mortality events in the Mediterranean.
-
The Response of the Mediterranean Gorgonian Eunicella singularis to Thermal Stress Is Independent of Its Nutritional Regime
PLoS ONE, 2013Co-Authors: Leila Ezzat, Pierre Laurent Merle, Paola Furla, Alexandre Buttler, Christine Ferrier-pagèsAbstract:Over the last few decades, sessile benthic organisms from the Mediterranean Sea have suffered from the global warming of the world's oceans, and several mass mortality events were observed during warm summers. It has been hypothesized that mortality could have been due to a nutrient (food) shortage following the stratification of the water column. However, the symbiotic gorgonian Eunicella singularis has also presented a locally exceptional mortality, despite its autotrophic capacities through the photosynthesis of its dinoflagellate symbionts. Thus, this study has experimentally investigated the response of E. singularis to a thermal stress (temperature increase from 18 to 26 degrees C), with colonies maintained more than 2 months under four nutritional diets: autotrophy only (AO), autotrophy and inorganic nitrogen addition (AN), autotrophy and Heterotrophy (AH), Heterotrophy only (HO). At 18 degrees C, and contrary to many other anthozoans, supplementation of autotrophy with either inorganic nitrogen or food (Heterotrophy) had no effect on the rates of respiration, photosynthesis, as well as in the chlorophyll, lipid and protein content. In the dark, Heterotrophy maintained the gorgonian's metabolism, except a bleaching (loss of pigments), which did not affect the rates of photosynthesis. At 24 degrees C, rates of respiration, and photosynthesis significantly decreased in all treatments. At 26 degrees C, in addition to a decrease in the lipid content of all treatments, a bleaching was observed after 1 week in the AO treatment, while the AH and AN treatments resisted three weeks before bleaching. These last results suggest that, temperatures above 24 degrees C impair the energetic reserves of this species and might explain the mortality events in the Mediterranean.