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1.
Nature ; 570(7759): E25, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31101908

RESUMO

We thank reader Joseph Craine for pointing out three inadvertent errors in this Letter. First, 4 of the 71 divergence dates extracted from ref. 1 of this Amendment and used in Fig. 1b of the original Letter were overestimated. The correct values are 45 million years ago (Ma) for Apocynaceae, 51 Ma for Anacardiaceae, 40 Ma for Primulaceae, and 53 Ma for Amaryllidaceae. These errors had little influence on the overall trend of Fig. 1b (r2 is now 0.48 rather than 0.54, with no change to P < 0.001) and do not change our conclusion and inferences. Second, we neglected to note that since refs. 1 and 2 of this Amendment considered only angiosperms, our Fig. 1b necessarily did not include gymnosperm taxa. The in-text reference to Fig. 1b should therefore read "all major angiosperm plant families in our dataset" rather than "all major vascular plant families in our dataset". Third, in Fig. 1c the trait value of mycorrhizal colonization for Machilus kwangtungensis was erroneously given the value 0.25 instead of 1.0. This error had little influence on the overall Fig. 1c trend, reducing r2 from 0.64 to 0.63 (with no change to P < 0.001).

2.
Glob Chang Biol ; 30(7): e17405, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38973563

RESUMO

Anthropogenic activities have raised nitrogen (N) input worldwide with profound implications for soil carbon (C) cycling in ecosystems. The specific impacts of N input on soil organic matter (SOM) pools differing in microbial availability remain debatable. For the first time, we used a much-improved approach by effectively combining the 13C natural abundance in SOM with 21 years of C3-C4 vegetation conversion and long-term incubation. This allows to distinguish the impact of N input on SOM pools with various turnover times. We found that N input reduced the mineralization of all SOM pools, with labile pools having greater sensitivity to N than stable ones. The suppression in SOM mineralization was notably higher in the very labile pool (18%-52%) than the labile and stable (11%-47%) and the very stable pool (3%-21%) compared to that in the unfertilized control soil. The very labile C pool made a strong contribution (up to 60%) to total CO2 release and also contributed to 74%-96% of suppressed CO2 with N input. This suppression of SOM mineralization by N was initially attributed to the decreased microbial biomass and soil functions. Over the long-term, the shift in bacterial community toward Proteobacteria and reduction in functional genes for labile C degradation were the primary drivers. In conclusion, the higher the availability of the SOM pools, the stronger the suppression of their mineralization by N input. Labile SOM pools are highly sensitive to N availability and may hold a greater potential for C sequestration under N input at global scale.


Assuntos
Carbono , Nitrogênio , Microbiologia do Solo , Solo , Solo/química , Nitrogênio/metabolismo , Nitrogênio/análise , Carbono/metabolismo , Carbono/análise , Ciclo do Carbono , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Isótopos de Carbono/análise , Biomassa
3.
Ecol Appl ; 34(1): e2807, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36691856

RESUMO

Many terrestrial ecosystems are co-invaded by multiple exotic species. The "invasional meltdown" hypothesis predicts that an initial invasive species will facilitate secondary invasions. In the plant kingdom, the potential underlying mechanisms of this hypothesis may be that modification of the soil properties by the initial invaders benefits for the subsequent exotic species invasion. In this study, we analyzed the composition of soil microbial communities and soil chemical properties from sites invaded by woody Rhus typhina, as well as uninvaded sites, to assess the impact of R. typhina invasion. Furthermore, we conducted a greenhouse experiment with multiple native-invasive pairs of herbaceous species to test whether R. typhina invasion facilitates subsequent exotic herb invasion. Our results showed that R. typhina invasion significantly altered the composition of soil fungal communities, especially pathogenic, endophytic, and arbuscular mycorrhizal fungi. However, this change in microbial composition led to neither direction nor magnitude changes in negative plant-soil feedback effects on both native and invasive species. This indicates that initial R. typhina invasion does not facilitate subsequent herb invasion, which does not support the "invasional meltdown" hypothesis. Additionally, R. typhina invasion significantly decreased soil total nitrogen and organic carbon contents, which may explain the significantly lower biomass of herbaceous roots grown in invaded soils compared with uninvaded soils. Alternately, although invasive herb growth was significantly more inhibited by soil microbiota compared with native herb growth, such inhibition cannot completely eliminate the risk of exotic herb invasion because of their innate growth advantages. Therefore, microbial biocontrol agents for plant invasion management should be combined with another approach to suppress the innate growth advantages of exotic species.


Assuntos
Microbiota , Micorrizas , Solo/química , Micorrizas/fisiologia , Madeira , Biomassa , Espécies Introduzidas , Microbiologia do Solo
4.
Nature ; 555(7694): 94-97, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29466331

RESUMO

Plant roots have greatly diversified in form and function since the emergence of the first land plants, but the global organization of functional traits in roots remains poorly understood. Here we analyse a global dataset of 10 functionally important root traits in metabolically active first-order roots, collected from 369 species distributed across the natural plant communities of 7 biomes. Our results identify a high degree of organization of root traits across species and biomes, and reveal a pattern that differs from expectations based on previous studies of leaf traits. Root diameter exerts the strongest influence on root trait variation across plant species, growth forms and biomes. Our analysis suggests that plants have evolved thinner roots since they first emerged in land ecosystems, which has enabled them to markedly improve their efficiency of soil exploration per unit of carbon invested and to reduce their dependence on symbiotic mycorrhizal fungi. We also found that diversity in root morphological traits is greatest in the tropics, where plant diversity is highest and many ancestral phylogenetic groups are preserved. Diversity in root morphology declines sharply across the sequence of tropical, temperate and desert biomes, presumably owing to changes in resource supply caused by seasonally inhospitable abiotic conditions. Our results suggest that root traits have evolved along a spectrum bounded by two contrasting strategies of root life: an ancestral 'conservative' strategy in which plants with thick roots depend on symbiosis with mycorrhizal fungi for soil resources and a more-derived 'opportunistic' strategy in which thin roots enable plants to more efficiently leverage photosynthetic carbon for soil exploration. These findings imply that innovations of belowground traits have had an important role in preparing plants to colonize new habitats, and in generating biodiversity within and across biomes.


Assuntos
Evolução Biológica , Ecossistema , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/fisiologia , Biodiversidade , Carbono/metabolismo , Bases de Dados Factuais , Clima Desértico , Micorrizas/fisiologia , Fotossíntese , Filogenia , Raízes de Plantas/classificação , Raízes de Plantas/microbiologia , Estações do Ano , Solo/química , Especificidade da Espécie , Simbiose , Clima Tropical
5.
Nature ; 556(7699): 135, 2018 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-29620725

RESUMO

This corrects the article DOI: 10.1038/nature25783.

6.
J Environ Manage ; 354: 120498, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38417361

RESUMO

Liming, as a common amelioration practice worldwide, has the potential to alleviate soil acidification and ensure crop production. However, the impacts of long-term liming on the temperature sensitivity (Q10) of soil organic carbon (SOC) mineralization and its response to labile C input remain unclear. To fill the knowledge gap, soil samples were collected from a long-term (∼10 years) field trial with unlimed and limed (CaO) plots. These soil samples were incubated at 15 °C and 25 °C for 42 days, amended without and with 13C-labeled glucose. Results showed that compared to the unlimed soil (3.6-8.6 mg C g-1 SOC), liming increased SOC mineralization (6.1-11.2 mg C g-1 SOC). However, liming significantly mitigated the positive response of SOC mineralization to warming, resulting in a lower Q10. Long-term liming increased bacterial richness and Shannon diversity as well as their response to warming which were associated with the decreased Q10. Furthermore, the decreased Q10 due to liming was attributed to the decreased response of bacterial oligotrophs/copiotrophs ratio, ß-glucosidase and xylosidase activities to warming. Labile C addition had a strong impact on Q10 in the unlimed soil, but only a marginal influence in the limed soil. Overall, our research highlights that acidification amelioration by long-term liming has the potential to alleviate the positive response of SOC mineralization to warming and labile C input, thereby facilitating SOC stability in agroecosystems, especially for acidic soils in subtropical regions.


Assuntos
Compostos de Cálcio , Carbono , Solo , Microbiologia do Solo , Óxidos
7.
Plant Cell Environ ; 44(4): 1231-1242, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33175402

RESUMO

Plant roots interact with rhizosphere microorganisms to accelerate soil organic matter (SOM) mineralization for nutrient acquisition. Root-mediated changes in SOM mineralization largely depend on root-derived carbon (root-C) input and soil nutrient status. Hence, intraspecific competition over plant development and spatiotemporal variability in the root-C input and nutrients uptake may modify SOM mineralization. To investigate the effect of intraspecific competition on SOM mineralization at three growth stages (heading, flowering, and ripening), we grew maize (C4 plant) under three planting densities on a C3 soil and determined in situ soil C- and N-mineralization by 13 C-natural abundance and 15 N-pool dilution approaches. From heading to ripening, soil C- and N-mineralization rates exhibit similar unimodal trends and were tightly coupled. The C-to-N-mineralization ratio (0.6 to 2.6) increased with N availability, indicating that an increase in N-mineralization with N depletion was driven by microorganisms mining N-rich SOM. With the intraspecific competition, plants increased specific root lengths as an efficient strategy to compete for resources. Root morphologic traits rather than root biomass per se were positively related to C- and N-mineralization. Overall, plant phenology and intraspecific competition controlled the intensity and mechanisms of soil C- and N- mineralization by the adaptation of root traits and nutrient mining.


Assuntos
Carbono/metabolismo , Nitrogênio/metabolismo , Desenvolvimento Vegetal/fisiologia , Rizosfera , Ecologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Zea mays/fisiologia
8.
Chemistry ; 27(49): 12659-12666, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111323

RESUMO

Both one-pot catalytic conversion of furfural (FAL) to isopropyl levulinate (PL) and carbonization of by-product (humins) for electromagnetic wave absorption are discussed, which provides inspiration that humins can be applied to electromagnetic wave absorption. In the former, phosphotungstic acid (PW) is employed as a homogeneous catalyst to convert FAL to PL via a tandem reaction in one pot, with the formation of a vast amount of humins. With FAL and various intermediates as substrates, it was found that humins was a polymerization product of FAL, furfuryl alcohol (FOL) and furfuryl ester (FE) with furan rings. In addition, the in situ attenuated total reflection infrared (ATR-IR) spectra also provided a basis for the proposed reaction route. In the latter, with the humins as raw material, P species and WO3 doped nano-porous carbon (Humins-700) platform formed after high-temperature annealing is used for electromagnetic wave absorption and manifests desirable absorption performance. The minimum reflection loss (RLmin ) value is -47.3 dB at 13.0 GHz with a thickness of 2.0 mm and the effective absorption bandwidth reaches 4.5 GHz (11.2-5.7 GHz).

9.
Glob Chang Biol ; 26(2): 931-943, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31554024

RESUMO

Nitrous oxide (N2 O) emissions from soil contribute to global warming and are in turn substantially affected by climate change. However, climate change impacts on N2 O production across terrestrial ecosystems remain poorly understood. Here, we synthesized 46 published studies of N2 O fluxes and relevant soil functional genes (SFGs, that is, archaeal amoA, bacterial amoA, nosZ, narG, nirK and nirS) to assess their responses to increased temperature, increased or decreased precipitation amounts, and prolonged drought (no change in total precipitation but increase in precipitation intervals) in terrestrial ecosystem (i.e. grasslands, forests, shrublands, tundra and croplands). Across the data set, temperature increased N2 O emissions by 33%. However, the effects were highly variable across biomes, with strongest temperature responses in shrublands, variable responses in forests and negative responses in tundra. The warming methods employed also influenced the effects of temperature on N2 O emissions (most effectively induced by open-top chambers). Whole-day or whole-year warming treatment significantly enhanced N2 O emissions, but daytime, nighttime or short-season warming did not have significant effects. Regardless of biome, treatment method and season, increased precipitation promoted N2 O emission by an average of 55%, while decreased precipitation suppressed N2 O emission by 31%, predominantly driven by changes in soil moisture. The effect size of precipitation changes on nirS and nosZ showed a U-shape relationship with soil moisture; further insight into biotic mechanisms underlying N2 O emission response to climate change remain limited by data availability, underlying a need for studies that report SFG. Our findings indicate that climate change substantially affects N2 O emission and highlights the urgent need to incorporate this strong feedback into most climate models for convincing projection of future climate change.


Assuntos
Mudança Climática , Ecossistema , Óxido Nitroso , Solo , Tundra
11.
Oecologia ; 188(2): 441-450, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29974246

RESUMO

Plant invasions are a major component of global change, but they may be affected by other global change components. Here we used a mesocosm-pot experiment to test whether high water availability, nitrogen (N) enrichment and their interaction promote performance of three invasive alien plants (Lepidium virginicum, Lolium perenne and Medicago sativa) when competing with a native Chinese grassland species (Agropyron cristatum). Single plants of the three invasive and the one native species were grown in the center of pots with a matrix of the native A. cristatum under low, intermediate or high water availability and low or high N availability. The invasive species L. virginicum and M. sativa grew larger, and produced a higher biomass relative to competitors than the native species A. cristatum did. Increasing water availability promoted biomass production of all species, but water availability did not change the biomass of the central plants relative to that of the competitors. Nitrogen addition also increased biomass production of all species, and it increased the biomass of the central plants more so than that of the competitors. The positive effect of N addition on the biomass of the central plants relative to that of the competitors increased with increasing water availability. However, compared to central plants of the native species, the positive effect of N addition on the relative biomass of L. virginicum decreased when water availability increased. These interactions indicate that future changes in water availability and N enrichment may affect the invasion success of different alien species differently.


Assuntos
Nitrogênio , Água , Biomassa , Pradaria , Espécies Introduzidas
12.
J Environ Sci (China) ; 66: 20-30, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29628088

RESUMO

Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen (N) dynamics and nitrous oxide (N2O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N2O emissions by field experiments in Hulunber in northern China. Soil (0-10cm), nitrate (NO3-), ammonium (NH4+), and microbial N were measured in plots in a temperate steppe (Leymus chinensis grassland) and two managed grasslands (Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M. sativa or B. inermis grasslands decreased concentrations of NO3--N, but did not change NH4+-N. Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M. sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa (i.e., a legume grass) increased N2O emissions by 26.2%, while the conversion to the B. inermis (i.e., a non-legume grass) reduced N2O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO3--N and NH4+-N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N2O emissions.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Pradaria , Dióxido de Nitrogênio/análise , China , Nitrificação , Ciclo do Nitrogênio , Estações do Ano , Solo
13.
Glob Chang Biol ; 23(8): 3363-3370, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-27888560

RESUMO

Invasive alien plant species threaten native biodiversity, disrupt ecosystem functions and can cause large economic damage. Plant invasions have been predicted to further increase under ongoing global environmental change. Numerous case studies have compared the performance of invasive and native plant species in response to global environmental change components (i.e. changes in mean levels of precipitation, temperature, atmospheric CO2 concentration or nitrogen deposition). Individually, these studies usually involve low numbers of species and therefore the results cannot be generalized. Therefore, we performed a phylogenetically controlled meta-analysis to assess whether there is a general pattern of differences in invasive and native plant performance under each component of global environmental change. We compiled a database of studies that reported performance measures for 74 invasive alien plant species and 117 native plant species in response to one of the above-mentioned global environmental change components. We found that elevated temperature and CO2 enrichment increased the performance of invasive alien plants more strongly than was the case for native plants. Invasive alien plants tended to also have a slightly stronger positive response to increased N deposition and increased precipitation than native plants, but these differences were not significant (N deposition: P = 0.051; increased precipitation: P = 0.679). Invasive alien plants tended to have a slightly stronger negative response to decreased precipitation than native plants, although this difference was also not significant (P = 0.060). So while drought could potentially reduce plant invasion, increases in the four other components of global environmental change considered, particularly global warming and atmospheric CO2 enrichment, may further increase the spread of invasive plants in the future.


Assuntos
Biodiversidade , Aquecimento Global , Espécies Introduzidas , Desenvolvimento Vegetal , Ecossistema , Temperatura
14.
Ann Bot ; 116(1): 113-22, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26050068

RESUMO

BACKGROUND AND AIMS: The advantage of clonal integration (resource sharing between connected ramets of clonal plants) varies and a higher degree of integration is expected in more stressful and/or more heterogeneous habitats. Clonal facultative epiphytes occur in both forest canopies (epiphytic habitats) and forest understories (terrestrial habitats). Because environmental conditions, especially water and nutrients, are more stressful and heterogeneous in the canopy than in the understorey, this study hypothesizes that clonal integration is more important for facultative epiphytes in epiphytic habitats than in terrestrial habitats. METHODS: In a field experiment, an examination was made of the effects of rhizome connection (connected vs. disconnected, i.e. with vs. without clonal integration) on survival and growth of single ramets, both young and old, of the facultative epiphytic rhizomatous fern Selliguea griffithiana (Polypodiaceae) in both epiphytic and terrestrial habitats. In another field experiment, the effects of rhizome connection on performance of ramets were tested in small (10 × 10 cm(2)) and large (20 × 20 cm(2)) plots in both epiphytic and terrestrial habitats. KEY RESULTS: Rhizome disconnection significantly decreased survival and growth of S. griffithiana in both experiments. The effects of rhizome disconnection on survival of single ramets and on ramet number and growth in plots were greater in epiphytic habitats than in terrestrial habitats. CONCLUSIONS: Clonal integration contributes greatly to performance of facultative epiphytic ferns, and the effects were more important in forest canopies than in forest understories. The results therefore support the hypothesis that natural selection favours genotypes with a higher degree of integration in more stressful and heterogeneous environments.


Assuntos
Gleiquênias/citologia , Gleiquênias/crescimento & desenvolvimento , Florestas , Análise de Variância , Biomassa , Células Clonais , Ecossistema
15.
Glob Chang Biol ; 20(6): 1943-54, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24293210

RESUMO

Increase of belowground C allocation by plants under global warming or elevated CO2 may promote decomposition of soil organic carbon (SOC) by priming and strongly affects SOC dynamics. The specific effects by priming of SOC depend on the amount and frequency of C inputs. Most previous priming studies have investigated single C additions, but they are not very representative for litterfall and root exudation in many terrestrial ecosystems. We evaluated effects of (13)C-labeled glucose added to soil in three temporal patterns: single, repeated, and continuous on dynamics of CO2 and priming of SOC decomposition over 6 months. Total and (13)C labeled CO2 were monitored to analyze priming dynamics and net C balance between SOC loss caused by priming and the retention of added glucose-C. Cumulative priming ranged from 1.3 to 5.5 mg C g(-1) SOC in the subtropical, and from -0.6 to 5.5 mg C g(-1) SOC in the tropical soils. Single addition induced more priming than repeated and continuous inputs. Therefore, single additions of high substrate amounts may overestimate priming effects over the short term. The amount of added glucose C remaining in soil after 6 months (subtropical: 8.1-11.2 mg C g(-1) SOC or 41-56% of added glucose; tropical: 8.7-15.0 mg C g(-1) SOC or 43-75% of glucose) was substantially higher than the net C loss due to SOC decomposition including priming effect. This overcompensation of C losses was highest with continuous inputs and lowest with single inputs. Therefore, raised labile organic C input to soils by higher plant productivity will increase SOC content even though priming accelerates decomposition of native SOC. Consequently, higher continuous input of C belowground by plants under warming or elevated CO2 can increase C stocks in soil despite accelerated C cycling by priming in soils.


Assuntos
Ciclo do Carbono , Dióxido de Carbono/metabolismo , Florestas , Solo/química , China , Glucose/metabolismo , Clima Tropical
16.
Tree Physiol ; 44(1)2024 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-37672222

RESUMO

Increased soil nutrient availability can promote tree growth while drought impairs metabolic functioning and induces tree mortality. However, limited information is available about the role of nutrients in the drought responses of trees. A greenhouse experiment was conducted with sessile oak (Quercus petraea (Matt.) Liebl) and Scots pine (Pinus sylvestris L.) seedlings, which were subjected to three fertilization treatments in the first year and two water regimes in the second year. Old and newly fixed carbon (C) and nitrogen (N) allocation were traced by dual labeling with 13C and 15N tracers, respectively, at two time points. Leaf gas exchange, biomass, as well as N and nonstructural carbohydrate (NSC) concentrations of all organs were measured. Fertilization predisposed sessile oak to drought-induced mortality, mainly by prioritizing aboveground growth, C and N allocation, reducing root NSC concentrations and decreasing old C contribution to new growth of leaves. In contrast, fertilization did not additionally predispose Scots pine to drought, with minor effects of fertilization and drought on newly fixed and old C allocation, tissues N and NSC concentrations. The role of nutrients for drought responses of trees seems to be species-specific. Therefore, we suggest nutrient availability and species identity to be considered in the framework of physiological mechanisms affecting drought-induced mortality.


Assuntos
Pinus sylvestris , Quercus , Plântula/fisiologia , Isótopos de Carbono/metabolismo , Quercus/fisiologia , Pinus sylvestris/fisiologia , Secas , Isótopos de Nitrogênio , Árvores/fisiologia , Nutrientes
17.
New Phytol ; 198(3): 656-669, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23521345

RESUMO

Demand of all living organisms on the same nutrients forms the basis for interspecific competition between plants and microorganisms in soils. This competition is especially strong in the rhizosphere. To evaluate competitive and mutualistic interactions between plants and microorganisms and to analyse ecological consequences of these interactions, we analysed 424 data pairs from 41 (15)N-labelling studies that investigated (15)N redistribution between roots and microorganisms. Calculated Michaelis-Menten kinetics based on K(m) (Michaelis constant) and V(max) (maximum uptake capacity) values from 77 studies on the uptake of nitrate, ammonia, and amino acids by roots and microorganisms clearly showed that, shortly after nitrogen (N) mobilization from soil organic matter and litter, microorganisms take up most N. Lower K(m) values of microorganisms suggest that they are especially efficient at low N concentrations, but can also acquire more N at higher N concentrations (V(max)) compared with roots. Because of the unidirectional flow of nutrients from soil to roots, plants are the winners for N acquisition in the long run. Therefore, despite strong competition between roots and microorganisms for N, a temporal niche differentiation reflecting their generation times leads to mutualistic relationships in the rhizosphere. This temporal niche differentiation is highly relevant ecologically because it: protects ecosystems from N losses by leaching during periods of slow or no root uptake; continuously provides roots with available N according to plant demand; and contributes to the evolutionary development of mutualistic interactions between roots and microorganisms.


Assuntos
Nitrogênio/metabolismo , Raízes de Plantas/metabolismo , Microbiologia do Solo , Aminoácidos/metabolismo , Aminoácidos/farmacocinética , Amônia/metabolismo , Amônia/farmacocinética , Carbono/metabolismo , Ecossistema , Nitratos/metabolismo , Nitratos/farmacocinética , Isótopos de Nitrogênio , Raízes de Plantas/microbiologia , Rizosfera , Simbiose
18.
Ann Bot ; 111(6): 1181-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23532045

RESUMO

BACKGROUND AND AIMS: Orchid mycorrhizas exhibit a unique type of mycorrhizal symbiosis that occurs between fungi and plants of the family Orchidaceae. In general, the roots of orchids are typically coarse compared with those of other plant species, leading to a considerably low surface area to volume ratio. As a result, orchids are often ill-adapted for direct nutrient acquisition from the soil and so mycorrhizal associations are important. However, the role of the fungal partners in the acquisition of inorganic and organic N by terrestrial orchids has yet to be clarified. METHODS: Inorganic and amino acid N uptake by non-mycorrhizal and mycorrhizal Cymbidium goeringii seedlings, which were grown in pots in a greenhouse, was investigated using a (15)N-labelling technique in which the tracer was injected at two different soil depths, 2·5 cm or 7·5 cm. Mycorrhizal C. goeringii seedlings were obtained by inoculation with three different mycorrhizal strains isolated from the roots of wild terrestrial orchids (two C. goeringii and one C. sinense). KEY RESULTS: Non-mycorrhizal C. goeringii primarily took up NO3(-) from tracers injected at 2·5-cm soil depth, whereas C. goeringii inoculated with all three mycorrhiza primarily took up NH4(+) injected at the same depth. Inoculation of the mycorrhizal strain MLX102 (isolated from adult C. sinense) on C. goeringii roots only significantly increased the below-ground biomass of the C. goeringii; however, it enhanced (15)NH4(+) uptake by C. goeringii at 2·5-cm soil depth. Compared to the uptake of tracers injected at 2·5-cm soil depth, the MLX102 fungal strain strongly enhanced glycine-N uptake by C. goeringii from tracers injected at 7·5-cm soil depth. Cymbidium goeringii inoculated with CLB113 and MLX102 fungal strains demonstrated a similar N uptake pattern to tracers injected at 2·5-cm soil depth. CONCLUSIONS: These findings demonstrate that mycorrhizal fungi are able to switch the primary N source uptake of a terrestrial orchid, in this case C. goeringii, from NO3(-) to NH4(+). The reasons for variation in N uptake in the different soil layers may be due to possible differentiation in the mycorrhizal hyphae of the C. goeringii fungal partner.


Assuntos
Micorrizas/fisiologia , Nitrogênio/metabolismo , Orchidaceae/metabolismo , Biomassa , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/microbiologia
19.
Nanomaterials (Basel) ; 13(4)2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36839098

RESUMO

Dandelion-like CuCo2O4 nanoflowers (CCO NFs) with ultrathin NiMn layered double hydroxide (LDH) shells were fabricated via a two-step hydrothermal method. The prepared CuCo2O4@NiMn LDH core/shell nanoflowers (CCO@NM LDH NFs) possessed a high specific surface area (~181 m2·g-1) with an average pore size of ~256 nm. Herein, the CCO@NM LDH NFs exhibited the typical battery-type electrode material with a specific capacity of 2156.53 F·g-1 at a current density of 1 A·g-1. With the increase in current density, the rate capability retention was 68.3% at a current density of 10 A·g-1. In particular, the 94.6% capacity of CCO@NM LDH NFs remains after 2500 cycles at 5 A·g-1. An asymmetric supercapacitor (ASC) with CCO@NM LDH NFs//activated carbon (AC) demonstrates a remarkable capacitance of 303.11 F·g-1 at 1 A·g-1 with excellent cycling stability. The coupling and synergistic effects of multi-valence transition metals provide a convenient channel for the electrochemical process, which is beneficial to spread widely within the realm of electrochemical energy storage.

20.
Chem Commun (Camb) ; 59(22): 3301-3304, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36846958

RESUMO

Herein, we report a simple and highly efficient approach for simultaneous in situ synthesis of Cu nanoparticles on Mg-Al-LDH (in situ reduced CuMgAl-LDH) from Cu-Mg-Al ternary LDH and catalytic transfer hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) using isopropanol (2-PrOH) as a reducing agent and hydrogen source. The in situ reduced CuMgAl-LDH, especially Cu1.5Mg1.5Al1-LDH as a precursor, offered excellent performance for the catalytic transfer hydrogenation of FAL to FOL (achieving almost full conversion with 98.2% selectivity of FOL). Strikingly, the in situ reduced catalyst was robust and stable with a wide scope in the transfer hydrogenation of various biomass-derived carbonyl compounds.

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