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1.
Mar Environ Res ; 196: 106436, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38479293

RESUMO

Coastal land reclamation has become a primary strategy for alleviating conflicts between human development and land resource utilization. However, anthropogenic activities associated with land reclamation inevitably result in significant changes to coastal wetland ecosystems. Previous studies have mainly focused on the ecological consequences of land reclamation on above-ground vegetation, while overlooking the distinctions between different reclamation patterns and the critical role of soil seed bank in maintaining ecosystem stability. In this study, the responses of soil seed bank and vegetation to various reclamation patterns, as well as the factors influencing changes in seed bank characteristics, were analyzed in a natural coastal wetland (NCW), a reclaimed wetland with sea embankments constructed on native wetland (SEW), and another reclaimed wetland formed through land reclamation from the sea (LRW). These findings suggest that seed banks and their vegetation adopt different adaptation strategies under various reclamation patterns. In the NCW, the proportion of non-halophytes (1.39%), diversity, and density of the seed bank were at their lowest levels, whereas the species compositions derived from the seed bank and vegetation were very similar (similarity coefficient = 0.67). Conversely, the seed bank in the SEW demonstrated the highest species diversity, which differed significantly from the species composition of its above-ground vegetation (similarity coefficient = 0.21). However, the highest proportion of non-halophytes (36.60%), vegetation diversity, and seed bank density occurred in LRW. Furthermore, differences in seed bank characteristics under different reclamation patterns may be related to changes in soil salinity and plant reproductive strategies after reclamation. Adjusting reclamation patterns and restoring soil properties could potentially optimize the types of local plant species and their distribution in reclaimed areas.


Assuntos
Ecossistema , Solo , Humanos , Banco de Sementes , Sementes/fisiologia , Plantas
2.
Ying Yong Sheng Tai Xue Bao ; 35(1): 95-101, 2024 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-38511445

RESUMO

Long-term occupation of coal gangue dumping sites (CGDS) may destroy ecological environment of nearby area. However, how the CGDS affects the distribution pattern of soil seed banks and vegetation in the nearby area is not clear. In this study, we investigated soil seed bank and vegetation at different distances from the second CGDS of Yangchangwan in Ningdong mining area, Lingwu, Ningxia. The results showed that soil seed bank was mainly distributed in 0-10 cm layer and decreased with increasing soil depth. Species richness of soil seed bank and vegetation first increased and then tended to be stable with increasing distance to the CGDS. The influence range of CGDS on soil seed banks was 300-500 m and was 100-300 m on aboveground vegetation. The CGDS did not affect the vertical distribution pattern of soil seed bank, but significantly affected the horizontal distribution pattern of soil seed banks and aboveground vegetation. The key area of vegetation restoration around the CGDS was between 100 m and 300 m.


Assuntos
Banco de Sementes , Solo , Carvão Mineral , Mineração , Instalações de Eliminação de Resíduos
3.
Pest Manag Sci ; 80(3): 1446-1453, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37946692

RESUMO

BACKGROUND: Soil seedbanks have been recognized as one of the crucial components of agricultural ecosystems. However, studies on the shift in structure and biodiversity of soil seedbanks in herbicide-resistant crop systems are limited, and a functional trait perspective of the soil seedbank is often overlooked. RESULTS: A 6 years experiment was conducted to investigate the roles of region, crop system, and weed management strategy on species richness, functional trait diversity, and composition of the weed seedbank. Species richness was different across the interaction of region and crop system, while functional trait diversity only showed difference across regions. Species and functional trait compositions were affected by the interaction of region and crop system. Specifically, the compositional difference among crop systems was mainly determined by the significant heterogeneity of group dispersion. CONCLUSION: Growers and practitioners should consider weed functional traits in developing lasting agricultural management strategies. Long-term weed research should draw attention to the impact of transgenic crop systems and specific management tactics on weed dispersal, functional composition, and resistance evolution of weed species in such agroecosystems. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Herbicidas , Estados Unidos , Herbicidas/farmacologia , Controle de Plantas Daninhas , Banco de Sementes , Plantas Daninhas , Ecossistema , Produtos Agrícolas , Resistência a Herbicidas , Solo
4.
J Phycol ; 60(1): 195-202, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37864777

RESUMO

To examine the potential for the autogenic ecosystem engineers, crustose coralline algae (CCA), to serve as seed banks or refugia for life stages of other species, it is critical to develop sampling protocols that reflect the diversity of life present. In this pilot study on two shallow water species of CCA collected from Raoul Island (Kermadec Islands; Rangitahua) New Zealand, we investigated two preservation methods (ethanol vs. silica gel), sampled inner and outer regions of the crusts, and used DNA metabarcoding and seven genes/gene regions (16S rRNA, 18S rRNA, 23S rRNA, cox1, rbcL, and tufA genes and the ITS rRNA region) to develop a protocol for taxa identification. The results revealed immense diversity, with typically more taxa identified within the inner layers than the outer layers. As highlighted in other metabarcoding studies and in earlier work on rhodoliths (nodose coralline algae), reference databases are incomplete, and to some extent, the use of multiple markers mitigates this issue. Specifically, the 23S rRNA and rbcL genes are currently more suitable for identifying algae, while the cox1 gene fares better at capturing the diversity present inclusive of algae. Further investigation of these autogenic ecosystem engineers that likely act as marine seed banks is needed.


Assuntos
Ecossistema , Rodófitas , Rodófitas/genética , RNA Ribossômico 16S , Código de Barras de DNA Taxonômico , Projetos Piloto , RNA Ribossômico 23S , Banco de Sementes
5.
Plant Biol (Stuttg) ; 25(7): 1035-1045, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37703520

RESUMO

In many landscapes, successful re-establisment of plant populations depends on the presence of diaspores, either near or directly beneath sites to be restored. The soil seed bank is, therefore, an important part of ecosystem resilience and a vital pillar for regeneration of genetic diversity in many plant populations. However, regeneration from the soil seed bank and the siubsequent restoration can only be considered successful when genetic diversity of restored populations is not eroded nor genetic differentiation inflated. We compared genetic variation within and among soil seed bank and aboveground populations of Origanum vulgare, to test whether genetically variable populations can be restored from the soil seed bank. We explored levels of genetic diversity within aboveground populations and the corresponding soil seed banks. Furthermore, we assessed the extent to which the soil seed bank differs genetically from the aboveground population. Levels of genetic diversity were to generally similar in aboveground populations and the corresponding soil seed banks. Only levels of inbreeding were slightly higher in the lower layer of the soil seed bank compared to the aboveground populations, probably because of selection processes acting against homozygotes accumulating in the seed bank. Furthermore, significant genetic differentiation between the aboveground population and the corresponding seed banks was completely absent. Across all sites, genetic differentiation between the soil seed bank was similar to that between aboveground populations, probably due to the absence of severe climate conditions, strong bottlenecks or disturbance events. Our conclusions support the possibility of successful re-establishment of healthy, genetically variable plant populations after aboveground destruction or following soil re-allocation from persistent seed banks.


Assuntos
Ecossistema , Solo , Banco de Sementes , Sementes/genética , Plantas , Variação Genética
6.
PLoS One ; 18(8): e0288804, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37603554

RESUMO

This study aimed to understand the impact of shrub encroachment on native species in the Guassa Community Conservation Area in Ethiopia. We assessed the soil seed bank composition and density across different elevations and aspects, and management systems within the area. The vegetation was stratified and eight blocks were selected across a range of elevation (<3350 m and >3350 m) and aspect (northeast, northwest, southeast, southwest). Within each block we established twenty 5m x 5m plots for a total of 160. We then collected soil samples from five subplots (1 m x 1 m) at three depths (0-3 cm, 3-6 cm and 6-9 cm) for a total of 480 samples, which were established in pots in greenhouse. We calculated species abundance by totaling the number of seedlings that emerged from each sample. To determine the variability in the abundance of Festuca macrophylla and Helichrysum splendidum in the soil seed bank along altitudinal gradient, we used two-way ANOVA using SAS statistical software version 9.0.1. Shannon diversity index was used to determine species diversity in the soil seedbank. After counting all the seeds, we identified 74 plant species represented in the soil seedbank which belong to 55 genera and 23 families. Eleven species are endemic to Ethiopia. At the lower elevation range, the effects of aspect (P <0.0088) and soil depth (P <0.005) are not significant to determine the abundance of seeds of H. splendidum and F. macrophylla. But when the factors are segregated, both aspect and soil depth play a significant role (p<0.0001) regarding the abundance of the seeds of the competing species at lower elevation. At higher elevation, only the effect of soil depth is significant (P<0.0001) for determining the abundance of H. splendidum. Soil depth and aspect have no significant effects on soil seed bank abundance at this elevation.


Assuntos
Banco de Sementes , Análise de Variância , Etiópia , Solo
7.
J Evol Biol ; 36(9): 1282-1294, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37551039

RESUMO

Seed banking (or dormancy) is a widespread bet-hedging strategy, generating a form of population overlap, which decreases the magnitude of genetic drift. The methodological complexity of integrating this trait implies it is ignored when developing tools to detect selective sweeps. But, as dormancy lengthens the ancestral recombination graph (ARG), increasing times to fixation, it can change the genomic signatures of selection. To detect genes under positive selection in seed banking species it is important to (1) determine whether the efficacy of selection is affected, and (2) predict the patterns of nucleotide diversity at and around positively selected alleles. We present the first tree sequence-based simulation program integrating a weak seed bank to examine the dynamics and genomic footprints of beneficial alleles in a finite population. We find that seed banking does not affect the probability of fixation and confirm expectations of increased times to fixation. We also confirm earlier findings that, for strong selection, the times to fixation are not scaled by the inbreeding effective population size in the presence of seed banks, but are shorter than would be expected. As seed banking increases the effective recombination rate, footprints of sweeps appear narrower around the selected sites and due to the scaling of the ARG are detectable for longer periods of time. The developed simulation tool can be used to predict the footprints of selection and draw statistical inference of past evolutionary events in plants, invertebrates, or fungi with seed banks.


Assuntos
Deriva Genética , Banco de Sementes , Evolução Biológica , Plantas/genética , Sementes/genética , Seleção Genética , Modelos Genéticos
8.
Sci Rep ; 13(1): 11269, 2023 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-37438408

RESUMO

Progressive habitat fragmentation threatens plant species with narrow habitat requirements. While local environmental conditions define population growth rates and recruitment success at the patch level, dispersal is critical for population viability at the landscape scale. Identifying the dynamics of plant meta-populations is often confounded by the uncertainty about soil-stored population compartments. We combined a landscape-scale assessment of an amphibious plant's population structure with measurements of dispersal complexity in time to track dispersal and putative shifts in functional connectivity. Using 13 microsatellite markers, we analyzed the genetic structure of extant Oenanthe aquatica populations and their soil seed banks in a kettle hole system to uncover hidden connectivity among populations in time and space. Considerable spatial genetic structure and isolation-by-distance suggest limited gene flow between sites. Spatial isolation and patch size showed minor effects on genetic diversity. Genetic similarity found among extant populations and their seed banks suggests increased local recruitment, despite some evidence of migration and recent colonization. Results indicate stepping-stone dispersal across adjacent populations. Among permanent and ephemeral demes the resulting meta-population demography could be determined by source-sink dynamics. Overall, these spatiotemporal connectivity patterns support mainland-island dynamics in our system, highlighting the importance of persistent seed banks as enduring sources of genetic diversity.


Assuntos
Fluxo Gênico , Banco de Sementes , Repetições de Microssatélites/genética , Dinâmica Populacional , Solo
9.
Nat Commun ; 14(1): 3949, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37402739

RESUMO

Anthropogenic nutrient enrichment and shifts in herbivory can lead to dramatic changes in the composition and diversity of aboveground plant communities. In turn, this can alter seed banks in the soil, which are cryptic reservoirs of plant diversity. Here, we use data from seven Nutrient Network grassland sites on four continents, encompassing a range of climatic and environmental conditions, to test the joint effects of fertilization and aboveground mammalian herbivory on seed banks and on the similarity between aboveground plant communities and seed banks. We find that fertilization decreases plant species richness and diversity in seed banks, and homogenizes composition between aboveground and seed bank communities. Fertilization increases seed bank abundance especially in the presence of herbivores, while this effect is smaller in the absence of herbivores. Our findings highlight that nutrient enrichment can weaken a diversity maintaining mechanism in grasslands, and that herbivory needs to be considered when assessing nutrient enrichment effects on seed bank abundance.


Assuntos
Pradaria , Herbivoria , Animais , Banco de Sementes , Solo , Plantas , Nutrientes , Ecossistema , Mamíferos
10.
PLoS One ; 18(6): e0286760, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37267389

RESUMO

Rumex obtusifolius is a problematic weed in temperate grasslands worldwide as it decreases yield and nutritional value of forage. Because the species can recruit from the seed bank, we determined the effect of management and soil properties on the soil seed bank of R. obtusifolius in intensively managed, permanent grasslands in Switzerland (CH), Slovenia (SI), and United Kingdom (UK). Following a paired case-control design, soil cores were taken from the topsoil of grassland with a high density of R. obtusifolius plants (cases) and from nearby parcels with very low R. obtusifolius density (controls). Data on grassland management, soil nutrients, pH, soil texture, and density of R. obtusifolius plants were also collected. Seeds in the soil were germinated under optimal conditions in a glasshouse. The number of germinated seeds of R. obtusifolius in case parcels was 866 ±152 m-2 (CH, mean ±SE), 628 ±183 m-2 (SI), and 752 ±183 m-2 (UK), with no significant difference among countries. Densities in individual case parcels ranged from 0 up to approximately 3000 seeds m-2 (each country). Control parcels had significantly fewer seeds, with a mean of 51 ±18, 75 ±52, and 98 ±52 seeds m-2 in CH, SI, and UK, respectively, and a range between 0 and up to 1000 seeds m-2. Across countries, variables explaining variation in the soil seed bank of R. obtusifolius in case parcels were soil pH (negative relation), silt content (negative), land-use intensity (negative), and aboveground R. obtusifolius plant density (positive). Because a large soil seed bank can sustain grassland infestation with R. obtusifolius, management strategies to control the species should target the reduction in the density of mature plants, prevention of the species' seed production and dispersal, as well as the regulation of the soil pH to a range optimal for forage production.


Assuntos
Pradaria , Rumex , Solo/química , Banco de Sementes , Poaceae , Plantas , Sementes/fisiologia
11.
ISME J ; 17(8): 1315-1325, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37286738

RESUMO

Dormancy is an adaptation to living in fluctuating environments. It allows individuals to enter a reversible state of reduced metabolic activity when challenged by unfavorable conditions. Dormancy can also influence species interactions by providing organisms with a refuge from predators and parasites. Here we test the hypothesis that, by generating a seed bank of protected individuals, dormancy can modify the patterns and processes of antagonistic coevolution. We conducted a factorially designed experiment where we passaged a bacterial host (Bacillus subtilis) and its phage (SPO1) in the presence versus absence of a seed bank consisting of dormant endospores. Owing in part to the inability of phages to attach to spores, seed banks stabilized population dynamics and resulted in minimum host densities that were 30-fold higher compared to bacteria that were unable to engage in dormancy. By supplying a refuge to phage-sensitive strains, we show that seed banks retained phenotypic diversity that was otherwise lost to selection. Dormancy also stored genetic diversity. After characterizing allelic variation with pooled population sequencing, we found that seed banks retained twice as many host genes with mutations, whether phages were present or not. Based on mutational trajectories over the course of the experiment, we demonstrate that seed banks can dampen bacteria-phage coevolution. Not only does dormancy create structure and memory that buffers populations against environmental fluctuations, it also modifies species interactions in ways that can feed back onto the eco-evolutionary dynamics of microbial communities.


Assuntos
Bacteriófagos , Humanos , Bacteriófagos/genética , Banco de Sementes , Bactérias/genética , Esporos Bacterianos/genética , Mutação
12.
J Environ Manage ; 344: 118512, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37384992

RESUMO

Poor regeneration of natural vegetation is a major factor contributing to the degradation of tropical coral islands. Soil seed banks (SSB) are important for maintaining the resilience of plant communities. However, the community characteristics and spatial distribution of SSBs and the controlling factors along human disturbance on coral islands are unclear. To fill this gap, we measured the community structure and spatial distributions of forest SSBs on three coral islands in the South China Sea, with varying degrees of human disturbance. The results showed that strong human disturbance increased the diversity, richness, and density of SSBs, as well as increased the richness of invasive species. With increased human disturbance, the heterogeneity pattern of SSBs spatial distribution changed from difference between forest east and west to forest center and edge. The similarity between the SSBs and above-ground vegetation also increased, and the distribution of invasive species extended from the edge to the central area of the forests, demonstrating that human disturbance limited the outward dispersal of seeds of resident species but increased the inward dispersal of seeds of invasive species. Interaction between soil properties, plant characteristics, and human disturbance explained 23-45% of the spatial variation of forest SSBs on the coral islands. However, human disturbance reduced the correlations of plant communities and spatial distribution of SSBs with soil factors (i.e., available phosphorus and total nitrogen) and increased the correlations of the community characteristics of SSB with landscape heterogeneity index, road distance, and shrub and litter cover. Resident seed dispersal on tropical coral islands might be enhanced by reducing building height, constructing buildings in down-wind locations, and preserving corridors that support animal movement among forest fragments.


Assuntos
Antozoários , Ecossistema , Animais , Humanos , Solo/química , Banco de Sementes , Efeitos Antropogênicos , Ilhas , Florestas , Plantas , Sementes , Espécies Introduzidas
13.
Science ; 379(6634): eadd2889, 2023 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-36821678

RESUMO

Extinct in the Wild (EW) species are placed at the highest risk of extinction under the International Union for Conservation of Nature Red List, but the extent and variation in this risk have never been evaluated. Harnessing global databases of ex situ animal and plant holdings, we report on the perilous state of EW species. Most EW animal species-already compromised by their small number of founders-are maintained at population sizes far below the thresholds necessary to ensure demographic security. Most EW plant species depend on live propagation by a small number of botanic gardens, with a minority secured at seed bank institutions. Both extinctions and recoveries are possible fates for EW species. We urgently call for international effort to enable the latter.


Assuntos
Espécies em Perigo de Extinção , Extinção Biológica , Jardins , Banco de Sementes , Animais , Plantas , Dinâmica Populacional
15.
Ecol Appl ; 33(2): e2782, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36479756

RESUMO

Some research indicates that soil seed banks can promote species coexistence through storage effects. However, the seed bank mechanism that maintains plant assembly and its role in degraded grassland restoration are still not clear. We collected seed bank samples from early, mid and late secondary successional stages of an abandoned subalpine meadow on the Tibetan Plateau, and samples from each stage were exposed to full (i.e., natural), mid, and low light treatments in the field to represent light availability at the bottom/understory (soil surface) of a plant community in the early, mid and late stages of succession, respectively. Species richness, seed density, species composition, and community weighted mean values (CWMs) of seed mass of the species whose seeds germinated in soil samples were evaluated. In response to the light treatments, species richness increased significantly with increased light only for the late successional stage, seed density increased significantly with increased light only in the early and mid successional stages, and seed mass decreased significantly with increased light only in the mid and late successional stages. Species composition differed significantly among the light treatments only in the late successional stage. For the successional series, species richness and seed mass of the species that germinated increased significantly with succession only under mid and full light treatments. Seed density decreased significantly with succession in each light treatment. Species composition differed significantly between the early- and late stage and between the mid and late stage in each light treatment. Both the abiotic (light) and biotic (seed mass) factors influence seed bank recruitment to the plant community. Regeneration of small-seeded species in the seed bank was inhibited under low light in the late successional stage. The balance of stochastic and deterministic processes along a successional gradient was determined by regeneration from the seed bank depending on light intensity change. Differences in seed response to light intensity change largely determined plant community assembly. Our findings should help in the development of effective conservation and restoration strategies.


Assuntos
Ecossistema , Pradaria , Banco de Sementes , Plantas , Sementes , Solo
16.
Ecology ; 104(3): e3968, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36571436

RESUMO

A key challenge in ecology is understanding how multiple drivers interact to precipitate persistent vegetation state changes. These state changes may be both precipitated and maintained by disturbances, but predicting whether the state change will be fleeting or persistent requires an understanding of the mechanisms by which disturbance affects the alternative communities. In the sagebrush shrublands of the western United States, widespread annual grass invasion has increased fuel connectivity, which increases the size and spatial contiguity of fires, leading to postfire monocultures of introduced annual grasses (IAG). The novel grassland state can be persistent and is more likely to promote large fires than the shrubland it replaced. But the mechanisms by which prefire invasion and fire occurrence are linked to higher postfire flammability are not fully understood. A natural experiment to explore these interactions presented itself when we arrived in northern Nevada immediately after a 50,000 ha wildfire was extinguished. We hypothesized that the novel grassland state is maintained via a reinforcing feedback where higher fuel connectivity increases burn severity, which subsequently increases postfire IAG dispersal, seed survivorship, and fuel connectivity. We used a Bayesian joint species distribution model and structural equation model framework to assess the strength of the support for each element in this feedback pathway. We found that prefire fuel connectivity increased burn severity and that higher burn severity had mostly positive effects on the occurrence of IAG and another nonnative species and mostly negative or neutral relationships with all other species. Finally, we found that the abundance of IAG seeds in the seed bank immediately after a fire had a positive effect on the fuel connectivity 3 years after the fire, completing a positive feedback promoting IAG. These results demonstrate that the strength of the positive feedback is controlled by measurable characteristics of ecosystem structure, composition, and disturbance. Further, each node in the loop is affected independently by multiple global change drivers. It is possible that these characteristics can be modeled to predict threshold behavior and inform management actions to mitigate or slow the establishment of the grass-fire cycle, perhaps via targeted restoration applications or prefire fuel treatments.


Assuntos
Queimaduras , Incêndios , Ecossistema , Sobrevivência , Teorema de Bayes , Banco de Sementes , Poaceae
17.
Sci Total Environ ; 864: 161142, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36572295

RESUMO

The global increase in drought frequency and intensity in large areas has potentially important effects on soil seed banks (SSBs). However, a systematic evaluation of the impact of drought on SSBs at a global scale has not yet been well understood. We evaluated the effects of drought on SSBs and identified the association key drivers in the current meta-analysis. The overall effects of drought on soil seed density and richness were weak negative and positive, respectively. Drought significantly increased soil seed density by 11.94 % in forest ecosystem, whereas soil seed richness were significantly increased in vascular plants (7.39 %). Linear mixed-effect results showed that soil seed density and richness significantly reduced as increasing drought intensity. In addition, geography (altitude) has significance in controlling the lnRR of soil seed density by altering climate (mean annual precipitation, drought) and soil properties (pH, soil organic carbon, and clay content) in the structural equation model, whereas soil seed richness was controlled by geography (altitude, and latitude) via climate (mean annual precipitation). In summary, the results suggested the size of SSBs response to drought and its relationship with drought intensity in terrestrial ecosystems, it may shed light on ecosystem restoration, succession, and management using SSBs when estimating the future drought.


Assuntos
Ecossistema , Solo , Solo/química , Secas , Banco de Sementes , Carbono
18.
Ecology ; 104(4): e3948, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36495246

RESUMO

Plant population ecologists regularly study soil seed banks with seed bag burial and seed addition experiments. These experiments contribute crucial data to demographic models, but we lack standard methods to analyze them. Here, we propose statistical models to estimate seed mortality and germination with observations from these experiments. We develop these models following the principles of event history analysis, and analyze their identifiability and statistical properties by algebraic methods and simulation. We demonstrate that seed bag burial, but not seed addition experiments, can be used to make inferences about age-dependent mortality and germination. When mortality and germination do not change with seed age, both experiments produce unbiased estimates but seed bag burial experiments are more precise. However, seed mortality and germination estimates may be inaccurate when the statistical model that is fit makes incorrect assumptions about the age dependence of mortality and germination. The statistical models and simulations that we present here can be adopted and modified by plant population ecologists to strengthen inferences about seed mortality and germination in the soil seed bank.


Assuntos
Germinação , Banco de Sementes , Sementes , Plantas , Solo
19.
Ying Yong Sheng Tai Xue Bao ; 33(11): 2907-2914, 2022 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-36384824

RESUMO

We investigated the morphological characteristics of C. korshinskii seeds with three different sizes under plantations with different stand ages (6, 12, 18, 40 and 50 years old) in the typical sandy-hilly region of northwest Shanxi Province, to explore the restoration potential of artificial vegetation from the perspective of reproduction strategies. The results showed that seed production of C. korshinskii plantation increased with stand age, reaching the maximum (584 grain·plant-1) in 50-year-old stand. Seed length, seed width, and seed shape index decreased with stand age, reaching the minimum (5.09 mm, 2.76 mm and 0.05) in 50-year-old stand. Seed germination percentage showed an upward-downward-upward fluctuating trend, reaching the maximum (97.2%) at 12-year-old stand. Seed production was significantly negatively correlated with seed weight. Seed germination percentage was closely related to seed weight. Seeds with low weight had a low germination percentage and were easier to form a persistent seed bank. In addition, seed production was significantly positively correlated with the height of mother plant, aboveground biomass and belowground biomass, while the shape index of C. korshinskii seeds was significantly negatively correlated with number of new branches. It indicated that with the increases of stand age, the reproduction strategy of C. korshinskii changed from the K strategy with larger seeds in the early stage (6-12 year-old) to the r strategy of small seeds in the later stage (18-50 year-old). Specifically, C. korshinskii kept both the high number and high persistence of seeds by producing a larger number of small and round seeds.


Assuntos
Caragana , Germinação , Sementes , Biomassa , Banco de Sementes
20.
Int J Syst Evol Microbiol ; 72(10)2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36314898

RESUMO

As currently circumscribed, Acrogenospora (Acrogenosporaceae, Minutisphaerales, Dothideomycetes) is a genus of saprobic hyphomycetes with distinctive conidia. Although considered common and cosmopolitan, the genus is poorly represented by sequence data, and no neotropical representatives are present in public sequence databases. Consequently, Acrogenospora has been largely invisible to ecological studies that rely on sequence-based identification. As part of an effort to identify fungi collected during ecological studies, we identified strains of Acrogenospora isolated in culture from seeds in the soil seed bank of a lowland tropical forest in Panama. Here we describe Acrogenospora terricola sp. nov. based on morphological and phylogenetic analyses. We confirm that the genus has a pantropical distribution. The observation of Acrogenospora infecting seeds in a terrestrial environment contrasts with previously described species in the genus, most of which occur on decaying wood in freshwater environments. This work highlights the often hidden taxonomic value of collections derived from ecological studies of fungal communities and the ways in which rich sequence databases can shed light on the identity, distributions and diversity of cryptic microfungi.


Assuntos
Ascomicetos , Banco de Sementes , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Florestas , Filogenia , RNA Ribossômico 16S/genética , Sementes/microbiologia , Análise de Sequência de DNA , Solo , Clima Tropical , Panamá
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