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Ibsen PC, Santiago LS, Shiflett SA, Chandler M, Jenerette GD. Irrigated urban trees exhibit greater functional trait plasticity compared to natural stands. Biol Lett 2023; 19:20220448. [PMID: 36596464 PMCID: PMC9810417 DOI: 10.1098/rsbl.2022.0448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Urbanization creates novel ecosystems comprised of species assemblages and environments with no natural analogue. Moreover, irrigation can alter plant function compared to non-irrigated systems. However, the capacity of irrigation to alter functional trait patterns across multiple species is unknown but may be important for the dynamics of urban ecosystems. We evaluated the hypothesis that urban irrigation influences plasticity in functional traits by measuring carbon-gain and water-use traits of 30 tree species planted in Southern California, USA spanning a coastal-to-desert gradient. Tree species respond to irrigation through increasing the carbon-gain trait relationship of leaf nitrogen per specific leaf area compared to their native habitat. Moreover, most species shift to a water-use strategy of greater water loss through stomata when planted in irrigated desert-like environments compared to coastal environments, implying that irrigated species capitalize on increased water availability to cool their leaves in extreme heat and high evaporative demand conditions. Therefore, irrigated urban environments increase the plasticity of trait responses compared to native ecosystems, allowing for novel response to climatic variation. Our results indicate that trees grown in water-resource-rich urban ecosystems can alter their functional traits plasticity beyond those measured in native ecosystems, which can lead to plant trait dynamics with no natural analogue.
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Affiliation(s)
- Peter C. Ibsen
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA,Geosciences and Environmental Change Science Center, United States Geological Survey, Denver, CO 80225, USA
| | - Louis S. Santiago
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Sheri A. Shiflett
- Department of Environmental Sciences, University of North Carolina Wilmington, Wilmington, NC 28403, USA
| | | | - G. Darrel Jenerette
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
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Gemal EL, Green TGA, Cary SC, Colesie C. High Resilience and Fast Acclimation Processes Allow the Antarctic Moss Bryum argenteum to Increase Its Carbon Gain in Warmer Growing Conditions. Biology (Basel) 2022; 11:biology11121773. [PMID: 36552282 PMCID: PMC9775354 DOI: 10.3390/biology11121773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Climate warming in Antarctica involves major shifts in plant distribution and productivity. This study aims to unravel the plasticity and acclimation potential of Bryum argenteum var. muticum, a cosmopolitan moss species found in Antarctica. By comparing short-term, closed-top chamber warming experiments which mimic heatwaves, with in situ seasonal physiological rates from Cape Hallett, Northern Victoria Land, we provide insights into the general inherent resilience of this important Antarctic moss and into its adaptability to longer-term threats and stressors associated with climate change. Our findings show that B. argenteum can thermally acclimate to mitigate the effects of increased temperature under both seasonal changes and short-term pulse warming events. Following pulse warming, this species dramatically increased its carbon uptake, measured as net photosynthesis, while reductions in carbon losses, measured as dark respiration, were not observed. Rapid growth of new shoots may have confounded the effects on respiration. These results demonstrate the high physiological plasticity of this species, with acclimation occurring within only 7 days. We show that this Antarctic moss species appears to have a high level of resilience and that fast acclimation processes allow it to potentially benefit from both short-term and long-term climatic changes.
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Affiliation(s)
- Emma L. Gemal
- Global Change Research Institute, School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE, UK
- Department of Physical Geography, Stockholm University, SE-106 91 Stockholm, Sweden
| | - T. G. Allan Green
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton 3240, New Zealand
- Unidad de Botánica, Facultad de Farmacia, Universidad Complutense, E-28040 Madrid, Spain
| | - S. Craig Cary
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton 3240, New Zealand
| | - Claudia Colesie
- Global Change Research Institute, School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE, UK
- Correspondence:
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Wang Y, Sperry JS, Anderegg WRL, Venturas MD, Trugman AT. A theoretical and empirical assessment of stomatal optimization modeling. New Phytol 2020; 227:311-325. [PMID: 32248532 DOI: 10.1111/nph.16572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/09/2020] [Indexed: 05/13/2023]
Abstract
Optimal stomatal control models have shown great potential in predicting stomatal behavior and improving carbon cycle modeling. Basic stomatal optimality theory posits that stomatal regulation maximizes the carbon gain relative to a penalty of stomatal opening. All models take a similar approach to calculate instantaneous carbon gain from stomatal opening (the gain function). Where the models diverge is in how they calculate the corresponding penalty (the penalty function). In this review, we compare and evaluate 10 different optimization models in how they quantify the penalty and how well they predict stomatal responses to the environment. We evaluate models in two ways. First, we compare their penalty functions against seven criteria that ensure a unique and qualitatively realistic solution. Second, we quantitatively test model against multiple leaf gas-exchange datasets. The optimization models with better predictive skills have penalty functions that meet our seven criteria and use fitting parameters that are both few in number and physiology based. The most skilled models are those with a penalty function based on stress-induced hydraulic failure. We conclude by proposing a new model that has a hydraulics-based penalty function that meets all seven criteria and demonstrates a highly predictive skill against our test datasets.
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Affiliation(s)
- Yujie Wang
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Martin D Venturas
- School of Biological Sciences, University of Utah, Salt Lake City, UT, 84112, USA
| | - Anna T Trugman
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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Singh SK, Reddy VR, Fleisher DH, Timlin DJ. Phosphorus Nutrition Affects Temperature Response of Soybean Growth and Canopy Photosynthesis. Front Plant Sci 2018; 9:1116. [PMID: 30127794 PMCID: PMC6088274 DOI: 10.3389/fpls.2018.01116] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 07/11/2018] [Indexed: 05/15/2023]
Abstract
In nature, crops such as soybean are concurrently exposed to temperature (T) stress and phosphorus (P) deficiency. However, there is a lack of reports regarding soybean response to T × P interaction. To fill in this knowledge-gap, soybean was grown at four daily mean T of 22, 26, 30, and 34°C (moderately low, optimum, moderately high, and high temperature, respectively) each under sufficient (0.5 mM) and deficient (0.08 mM) P nutrition for the entire season. Phosphorus deficiency exacerbated the low temperature stress, with further restrictions on growth and net photosynthesis. For P deficient soybean at above optimum temperature (OT) regimes, growth, and photosynthesis was maintained at levels close to those of P sufficient plants, despite a lower tissue P concentration. P deficiency consistently decreased plant tissue P concentration ≈55% across temperatures while increasing intrinsic P utilization efficiency of canopy photosynthesis up to 147%, indicating a better utilization of tissue P. Warmer than OTs delayed the time to anthesis by 8-14 days and pod development similarly across P levels. However, biomass partitioning to pods was greater under P deficiency. There were significant T × P interactions for traits such as plant growth rates, total leaf area, biomass partitioning, and dry matter production, which resulted a distinct T response of soybean growth between sufficient and deficient P nutrition. Under sufficient P level, both lower and higher than optimum T tended to decrease total dry matter production and canopy photosynthesis. However, under P-deficient condition, this decrease was primarily observed at the low T. Thus, warmer than optimum T of this study appeared to compensate for decreases in soybean canopy photosynthesis and dry matter accumulation resulting from P deficiency. However, warmer than OT appeared to adversely affect reproductive structures, such as pod development, across P fertilization. This occurred despite adaptations, especially the increased P utilization efficiency and biomass partitioning to pods, shown by soybean under P deficiency.
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Affiliation(s)
- Shardendu K. Singh
- Adaptive Cropping Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, United States
- School of Environmental and Forest Science, University of Washington, Seattle, WA, United States
| | - Vangimalla R. Reddy
- Adaptive Cropping Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, United States
| | - David H. Fleisher
- Adaptive Cropping Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, United States
| | - Dennis J. Timlin
- Adaptive Cropping Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, United States
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Johnson DM, Domec JC, Carter Berry Z, Schwantes AM, McCulloh KA, Woodruff DR, Wayne Polley H, Wortemann R, Swenson JJ, Scott Mackay D, McDowell NG, Jackson RB. Co-occurring woody species have diverse hydraulic strategies and mortality rates during an extreme drought. Plant Cell Environ 2018; 41:576-588. [PMID: 29314069 DOI: 10.1111/pce.13121] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 12/01/2017] [Indexed: 05/25/2023]
Abstract
From 2011 to 2013, Texas experienced its worst drought in recorded history. This event provided a unique natural experiment to assess species-specific responses to extreme drought and mortality of four co-occurring woody species: Quercus fusiformis, Diospyros texana, Prosopis glandulosa, and Juniperus ashei. We examined hypothesized mechanisms that could promote these species' diverse mortality patterns using postdrought measurements on surviving trees coupled to retrospective process modelling. The species exhibited a wide range of gas exchange responses, hydraulic strategies, and mortality rates. Multiple proposed indices of mortality mechanisms were inconsistent with the observed mortality patterns across species, including measures of the degree of iso/anisohydry, photosynthesis, carbohydrate depletion, and hydraulic safety margins. Large losses of spring and summer whole-tree conductance (driven by belowground losses of conductance) and shallower rooting depths were associated with species that exhibited greater mortality. Based on this retrospective analysis, we suggest that species more vulnerable to drought were more likely to have succumbed to hydraulic failure belowground.
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Affiliation(s)
- Daniel M Johnson
- College of Natural Resources, University of Idaho, Moscow, ID, 83844, USA
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, UMR INRA-ISPA 1391, Gradignan, 33195, France
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Z Carter Berry
- College of Natural Resources, University of Idaho, Moscow, ID, 83844, USA
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, 03824, USA
| | - Amanda M Schwantes
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | | | - David R Woodruff
- US Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
| | - H Wayne Polley
- Grassland, Soil & Water Research Laboratory USDA-Agricultural Research Service, Temple, TX, 76502, USA
| | - Remí Wortemann
- INRA Nancy, UMR INRA-UL 1137 Ecologie et Ecophysiologie Forestières, Champenoux, 54280, France
| | - Jennifer J Swenson
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - D Scott Mackay
- Department of Geography, State University of New York, Buffalo, NY, 14261, USA
| | - Nate G McDowell
- Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Robert B Jackson
- Department of Earth System Science, Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University, Stanford, CA, 94305, USA
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6
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Wohlfahrt G, Cremonese E, Hammerle A, Hörtnagl L, Galvagno M, Gianelle D, Marcolla B, di Cella UM. Tradeoffs between global warming and day length on the start of the carbon uptake period in seasonally cold ecosystems. Geophys Res Lett 2013; 40:6136-6142. [PMID: 24587563 PMCID: PMC3935172 DOI: 10.1002/2013gl058182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 11/12/2013] [Accepted: 11/14/2013] [Indexed: 05/31/2023]
Abstract
It is well established that warming leads to longer growing seasons in seasonally cold ecosystems. Whether this goes along with an increase in the net ecosystem carbon dioxide (CO2) uptake is much more controversial. We studied the effects of warming on the start of the carbon uptake period (CUP) of three mountain grasslands situated along an elevational gradient in the Alps. To this end we used a simple empirical model of the net ecosystem CO2 exchange, calibrated and forced with multi-year empirical data from each site. We show that reductions in the quantity and duration of daylight associated with earlier snowmelts were responsible for diminishing returns, in terms of carbon gain, from longer growing seasons caused by reductions in daytime photosynthetic uptake and increases in nighttime losses of CO2. This effect was less pronounced at high, compared to low, elevations, where the start of the CUP occurred closer to the summer solstice when changes in day length and incident radiation are minimal.
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Affiliation(s)
- Georg Wohlfahrt
- Institute of Ecology, University of Innsbruck, Innsbruck, AUSTRIA
| | - Edoardo Cremonese
- Environmental Protection Agency of Aosta Valley, ARPA VdA, Climate Change Unit, Aosta, ITALY
| | - Albin Hammerle
- Institute of Ecology, University of Innsbruck, Innsbruck, AUSTRIA
| | - Lukas Hörtnagl
- Institute of Ecology, University of Innsbruck, Innsbruck, AUSTRIA
| | - Marta Galvagno
- Environmental Protection Agency of Aosta Valley, ARPA VdA, Climate Change Unit, Aosta, ITALY
| | - Damiano Gianelle
- Sustainable Agro-ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, ITALY ; Foxlab, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, ITALY
| | - Barbara Marcolla
- Sustainable Agro-ecosystems and Bioresources Department, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, ITALY
| | - Umberto Morra di Cella
- Environmental Protection Agency of Aosta Valley, ARPA VdA, Climate Change Unit, Aosta, ITALY
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7
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Preiss K, Adam IKU, Gebauer G. Irradiance governs exploitation of fungi: fine-tuning of carbon gain by two partially myco-heterotrophic orchids. Proc Biol Sci 2010; 277:1333-6. [PMID: 20053652 PMCID: PMC2871938 DOI: 10.1098/rspb.2009.1966] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 12/09/2009] [Indexed: 11/12/2022] Open
Abstract
While all members of the Orchidaceae are fully dependent on mycorrhizal fungi during their achlorophyllous juvenile stages, mature plants may remain fully myco-heterotrophic, become fully autotrophic or develop a nutritional mode where the carbon gain through photosynthesis is complemented by organic carbon from fungal partners. This so-called partial myco-heterotrophy is intriguingly complex. Current knowledge indicates a large range in the proportion of fungus-derived carbon between and within partially myco-heterotrophic plant species. However, the driving factors for this variation are so far mostly unknown. Here we show for two green species of the orchid genus Cephalanthera that light availability is the major determinant of the degree of myco-heterotrophy. Using leaf stable isotope natural abundance analysis together with time-integrated microscale light climate monitoring we could demonstrate that there is a sensitive reaction to varying light availability within forests. Low light levels result in strong myco-heterotrophy while higher irradiances successively drive the orchids towards autotrophy. Our results demonstrate that partial myco-heterotrophy in these species is not a static nutritional mode but a flexible mechanism driven by light availability which allows a balanced usage of carbon resources available in nature.
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Affiliation(s)
| | | | - Gerhard Gebauer
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany
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Wieser G, Matyssek R, Luzian R, Zwerger P, Pindur P, Oberhuber W, Gruber A. Effects of atmospheric and climate change at the timberline of the Central European Alps. Ann For Sci 2009; 66:402. [PMID: 21379395 PMCID: PMC3047780 DOI: 10.1051/forest/2009023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This review considers potential effects of atmospheric change and climate warming within the timberline ecotone of the Central European Alps. After focusing on the impacts of ozone (O(3)) and rising atmospheric CO(2) concentration, effects of climate warming on the carbon and water balance of timberline trees and forests will be outlined towards conclusions about changes in tree growth and treeline dynamics.Presently, ambient ground-level O(3) concentrations do not exert crucial stress on adult conifers at the timberline of the Central European Alps. In response to elevated atmospheric CO(2)Larix decidua showed growth increase, whereas no such response was found in Pinus uncinata. Overall climate warming appears as the factor responsible for the observed growth stimulation of timberline trees.Increased seedling re-establishment in the Central European Alps however, resulted from invasion into potential habitats rather than upward migration due to climate change, although seedlings will only reach tree size upon successful coupling with the atmosphere and thus loosing the beneficial microclimate of low stature vegetation.In conclusion, future climate extremes are more likely than the gradual temperature increase to control treeline dynamics in the Central European Alps.
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Affiliation(s)
- Gerhard Wieser
- Dept. Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Rennweg 1, 6020 Innsbruck, Austria
| | - Rainer Matyssek
- Dept. of Ecology/Ecophysiology of Plants, Technische Universität München/Weihenstephan, Am Hochanger 13, 85354 Freising, Germany
| | - Roland Luzian
- Dept. Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Rennweg 1, 6020 Innsbruck, Austria
| | - Peter Zwerger
- Dept. Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Rennweg 1, 6020 Innsbruck, Austria
| | - Peter Pindur
- Institut für Stadt- und Regionalforschung, Österreichische Akademie der Wissenschaften, Postgasse 7, 1010 Wien, Austria
| | - Walter Oberhuber
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andreas Gruber
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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Osunkoya OO, Daud SD, Wimmer FL. Longevity, lignin content and construction cost of the assimilatory organs of Nepenthes species. Ann Bot 2008; 102:845-53. [PMID: 18757449 PMCID: PMC2712385 DOI: 10.1093/aob/mcn162] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/08/2008] [Accepted: 07/29/2008] [Indexed: 05/04/2023]
Abstract
BACKGROUND AND AIMS This study examined level of causal relationships amongst functional traits in leaves and conjoint pitcher cups of the carnivorous Nepenthes species. METHODS Physico-chemical properties, especially lignin content, construction costs, and longevity of the assimilatory organs (leaf and pitcher) of a guild of lowland Nepenthes species inhabiting heath and/or peat swamp forests of Brunei, northern Borneo were determined. KEY RESULTS Longevity of these assimilatory organs was linked significantly to construction cost, lignin content and structural trait of tissue density, but these effects are non-additive. Nitrogen and phosphorus contents (indicators of Rubisco and other photosynthetic proteins), were poor predictors of organ longevity and construction cost, suggesting that a substantial allocation of biomass of the assimilatory organs in Nepenthes is to structural material optimized for prey capture, rigidity and escape from biotic and abiotic stresses rather than to light interception. Leaf payback time - a measure of net carbon revenue - was estimated to be 48-60 d. This is in line with the onset of substantial mortality by 2-3 months of tagged leaves in many of the Nepenthes species examined. However, this is a high ratio (i.e. a longer minimum payback time) compared with what is known for terrestrial, non-carnivorous plants in general (5-30 d). CONCLUSIONS It is concluded that the leaf trait bivariate relationships within the Nepenthes genus, as in other carnivorous species (e.g. Sarraceniaceae), is substantially different from the global relationship documented in the Global Plant Trait Network.
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Affiliation(s)
- Olusegun O Osunkoya
- Department of Biology, University of Brunei Darussalam, Jalan Tungku Link, Bandar Seri Begawan, Brunei Darussalam.
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Miller RM, Miller SP, Jastrow JD, Rivetta CB. Mycorrhizal mediated feedbacks influence net carbon gain and nutrient uptake in Andropogon gerardii. New Phytol 2002; 155:149-162. [PMID: 33873302 DOI: 10.1046/j.1469-8137.2002.00429.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• The carbon sink strength of arbuscular mycorrhizal fungi (AMF) was investigated by comparing the growth dynamics of mycorrhizal and nonmycorrhizal Andropogon gerardii plants over a wide range of equivalent tissue phosphorus : nitrogen (P : N) ratios. • Host growth, apparent photosynthesis (Anet ), net C gain (Cn ) and P and N uptake were evaluated in sequential harvests of mycorrhizal and nonmycorrhizal A. gerardii plants. Response curves were used to assess the effect of assimilate supply on the mycorrhizal symbiosis in relation to the association of C with N and P. • Mycorrhizal plants had higher Cn than nonmycorrhizal plants at equivalent shoot P : N ratios even though colonization did not affect plant dry mass. The higher Cn in mycorrhizal plants was related to both an increase in specific leaf area and enhanced photosynthesis. The additional carbon gain associated with the mycorrhizal condition was not allocated to root biomass. The Cn in the mycorrhizal plants was positively related to the proportion of active colonization in the roots. • The calculated difference between Cn values in mycorrhizal and nonmycorrhizal plants, Cdiff , appeared to correspond to the sink strength of the AMF and was not an indirect result of enhanced nutrition in mycorrhizal plants.
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Affiliation(s)
- R M Miller
- Environmental Research Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - S P Miller
- Department of Agronomy, University of Kentucky, N-122 Agricultural Sciences North, Lexington, KY 40506-0091, USA
| | - J D Jastrow
- Environmental Research Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
| | - C B Rivetta
- Environmental Research Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA
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