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1.
Julie L. Commerford Kendra K. McLauchlan Thomas A. Minckley 《Ecology and evolution》2016,6(15):5273-5289
Grassland vegetation varies in composition across North America and has been historically influenced by multiple biotic and abiotic drivers, including fire, herbivory, and topography. Yet, the amount of temporal and spatial variability exhibited among grassland pollen assemblages, and the influence of these biotic and abiotic drivers on pollen assemblage composition and diversity has been relatively understudied. Here, we examine 4 years of modern pollen assemblages collected from a series of 28 traps at the Konza Prairie Long‐Term Ecological Research Area in the Flint Hills of Kansas, with the aim of evaluating the influence of these drivers, as well as quantifying the amount of spatial and temporal variability in the pollen signatures of the tallgrass prairie biome. We include all terrestrial pollen taxa in our analyses while calculating four summative metrics of pollen diversity and composition – beta‐diversity, Shannon index, nonarboreal pollen percentage, and Ambrosia:Artemisia – and find different roles of fire, herbivory, and topography variables in relation to these pollen metrics. In addition, we find significant annual differences in the means of three of these metrics, particularly the year 2013 which experienced high precipitation relative to the other 3 years of data. To quantify spatial and temporal dissimilarity among the samples over the 4‐year study, we calculate pairwise squared‐chord distances (SCD). The SCD values indicate higher compositional dissimilarity across the traps (0.38 mean) among all years than within a single trap from year to year (0.31 mean), suggesting that grassland vegetation can have different pollen signatures across finely sampled space and time, and emphasizing the need for additional long‐term annual monitoring of grassland pollen. 相似文献
2.
Symbiotic seed germination of Habenaria macroceratitis (Orchidaceae), a rare Florida terrestrial orchid 总被引:1,自引:0,他引:1
The rapid loss of native orchid habitat throughout ecologically important areas (e.g., Florida) has prompted researchers to develop appropriate plans for the propagation and reintroduction of many native orchid species. Ideally, symbiotic orchid seed germination methods are utilized in the production of orchid seedlings to be used in plant reintroduction programs. In the current study we (1) describe an efficient symbiotic seed germination protocol to germinate seeds of the rare sub-tropical terrestrial orchid Habenaria macroceratitis; (2) discuss the in vitro fungal specificity demonstrated by this species; and (3) describe the effects of three photoperiods (0/24 h, 16/8 h, 24/0 h L/D) on in vitro symbiotic seed germination of H. macroceratitis. Six fungal mycobionts were isolated from both vegetative and flowering plants of H. macroceratitis from two geographically distinct sites. Symbiotic seed germination percent was highest (65.7%) and protocorm development was most advanced (Stage 2) when seeds were cultured with fungal mycobiont Hmac-310. Seeds of H. macroceratitis demonstrated a degree of specificity toward fungal mycobionts isolated from plants originating from the same site where seed was collected. Continual darkness (0/24 h L/D) inhibited initial seed germination (Stage 1; 17.1%), but stimulated subsequent protocorm development (Stage 2; 53.5%). These findings will aid in developing an efficient symbiotic seed germination protocol for the conservation of this rare Florida terrestrial orchid, and may prove useful in the conservation of other sub-tropical terrestrial orchid species. 相似文献
3.
Questions: Most modern fire‐prone landscapes have experienced disruptions of their historic fire regimes. Are the primary tallgrass prairies of the Flint Hills reflective of a history of continuous fire occurrence? Did fire frequency, severity, size and seasonality change in connection with changes in land use? Has fire occurrence been related to drought conditions? Location: Edges of Cross Timbers forest stands at the Tallgrass Prairie Preserve (TGPP) in the Flint Hills of Osage County, Oklahoma, USA. Methods: Cross‐sections of 76 Quercus stellata were collected from Cross Timbers stands at or near the grassland edge in the TGPP. Dendrochronological methods were used to identify years of formation for tree rings and fire scars. Superposed epoch analysis was used to evaluate the effect of drought conditions on fire occurrence. Results: Fires were recorded in 46.6% of the years between 1729 and 2005. In 41 cross‐sections at one site, the mean fire interval between 1759 and 2003 was 2.59 years, with fire interval decreasing from a mean fire interval of 3.76 years in the early part of the record to 2.13 years in modern times. No extended periods without fire were recorded in the study area. Drought conditions had no significant effect on fire occurrence. Conclusions: In contrast with many fire‐prone landscapes worldwide, the prairies of the Flint Hills have experienced no recent fire suppression or exclusion. Changes in fire frequency mark transitions in land use, primarily from being traditionally used by Native Americans to being managed for cattle production. 相似文献
4.
Sergey Timofeev Alexander Tsarev Igor Senderskiy Eugene Rogozhin Galina Mitina Sergey Kozlov Viacheslav Dolgikh 《Mycoscience》2019,60(3):197-200
All experiments on genetic modifications of Lecanicillium species performed so far used laborious PEG-mediated protoplast transformation and Agrobacterium tumefaciens-mediated transformation. In this study we demonstrated that simple and effective method of electroporation of germinated conidia can be used for transformation of this fungus. Electroporation of L. muscarium (strain VL 72) germinated conidia by the pBARGPE1 vector harboring an eGFP gene, showed a transformation efficiency 65.7 ± 1.4 phosphinothricin-resistant colonies per 2.5 μg of linearized plasmid DNA and expression of fluorescent protein without affecting fungal growth and virulence. By analysis of GFP-expressing isolates by fluorescent microscopy and immunoblotting, we found that the Aspergillus nidulans PgpdA promoter and trpC terminator in the pBARGPE1 vector provide an effective synthesis of heterologous proteins in L. muscarium cells. 相似文献
5.
We induced basidioma formation of a fungus belonging to the Thelephoraceae that was isolated from the orchid Cephalanthera falcata. The mycobiont was isolated from root, cultured on modified Melin-Norkrans medium, and then inoculated onto fine roots of a Quercus serrata (Fagaceae) seedling. After observation of ectomycorrhiza formation, the Q. serrata seedling was grown in a pot. Thirty-six mo after ectomycorrhiza formation, basidioma formation was confirmed at the bottom of the pot. From comparisons in morphological characteristics between the mycobiont and known related Thelephoraceae species, and sequence similarities of internal transcribed spacer region in ribosomal DNA, we identified the mycobiont as Thelephora ellisii sensu lato in Thelephoraceae (Basidiomycota). Phylogenetic analysis indicated that the related sequences came from ectomycorrhizae of trees of the Salicaceae, Pinaceae, and Fagaceae distributed in East Asia, the USA, central Africa, and Europe. 相似文献
6.
Phyllis H. Pischl Sean V. Burke Elizabeth M. Bach Melvin R. Duvall 《Ecology and evolution》2020,10(14):7602-7615
Native grasslands are one of the most endangered ecosystems in North America. In this study, we examined the ecological and evolutionary roles of endangered and threatened (e/t) grasses by establishing robust evolutionary relationships with other nonthreatened native and introduced grass species of the community. We hypothesized that the phylogenomic distribution of e/t species of grasses in Illinois would be phylogenetically clustered because closely related species would be vulnerable to the same threats and have similar requirements for survival. This study presents the first time a phylogeny based on complete plastome DNA of Poaceae was analyzed by phylogenetic diversity analysis. To avoid the disturbance of e/t populations, DNA was extracted from herbarium specimens. Next‐generation sequencing (NGS) techniques were used to sequence DNA of plastid genomes (plastomes). The resulting phylogenomic tree was analyzed by phylogenetic diversity metrics. The extracted DNA successfully produced complete plastomes demonstrating that herbarium material is a practical source of DNA for genomic studies. The phylogenomic tree was strongly supported and defined Dichanthelium as a separate clade from Panicum. The phylogenetic metrics revealed phylogenetic clustering of e/t species, confirming our hypothesis. 相似文献
7.
Tetsuhiro Matsuzawa Paride Abliz Takashi Yaguchi Tohru Gonoi Yoshikazu Horie 《Mycoscience》2019,60(6):354-360
Aspergillus takadae is characterized by its heterothallic reproduction, pale yellow cleistothecia, broadly lenticular ascospores with two short equatorial crests and smooth convex surfaces, and broadly ellipsoidal to ovate conidia with a smooth wall. The validation of these novel species is supported further by the analyses of the β-tubulin, calmodulin, actin, and RPB2 sequences. In addition, the phylogenetic tree and DDBJ accession numbers of all the species of Aspergillus section Fumigati are presented. We report on the crossing of A. takadae species and the result of crossing A. takadae with a closely related species, A. spathulatus. 相似文献
8.
Andrea Garvetto Yacine Badis Marie-Mathilde Perrineau Cecilia Rad-Menéndez Eileen Bresnan Claire M.M. Gachon 《Fungal biology》2019,123(6):471-480
Chytrids have long been recognised as important parasites of microalgae in freshwater systems, able to shape the dynamics of blooms, the gene pool of their host and phytoplankton succession. In the sea however, where the presence of these organisms is erratic and ephemeral, studies concerning chytrids are sparse and confined to metabarcoding surveys or microscopy observations. Despite the scarcity of data, chytrid epidemics are supposed to play an important role in marine biogeochemical cycles, being one of the drivers of phytoplankton dynamics. Here we combine microscopy observations and in silico mining of a single-cell whole genome to molecularly and morphologically characterise a novel chytrid parasite of the dominant diatom genus Skeletonema. Morphological observations highlight features of the thallus and ascertain the parasitic nature of the interaction whilst the genetic markers obtained allows for a phylogenetic reconstruction, placing the new species in the order Rhizophydiales. Thanks to the molecular data obtained we are also able to provide a first investigation of the global distribution of this organism by screening the Ocean Sampling Day (OSD) dataset, highlighting a northern transatlantic dissemination. 相似文献
9.
J. K. Bush 《Plant Ecology》2006,183(2):215-225
This study evaluated the relationships among soil moisture, soil salinity, and soil oxygen on the growth of Helianthus paradoxus (Asteraceae), a threatened inland salt marsh species of western North America. The study was conducted in large growth boxes
(1×2×0.3 m) tilted at an angle to achieve a saturated to dry water gradient similar to that found in the marsh. This experimental
design allowed the evaluation of major abiotic factors (soil moisture and soil salinity) which have been shown to be potentially
important for this species, while removing major biotic factors, such as competition from other community dominants. Maximum
aboveground biomass occurred in the middle rows of the boxes, where surface soil water was reduced and subsurface soil water
was intermediate in the gradient. Regression analyses indicated that H. paradoxus would grow best where surface soil water is approximately 5%, subsurface soil water ranges from 20 to 30%, and where surface
soil salinity is less than 0.5 g kg−1. Edaphic variables, particularly soil moisture and soil salinity, affect the growth of H. paradoxus. Data presented here suggest that the survival of this species depends on maintenance of the hydrologic regime. 相似文献
10.
Kento Rammitsu Tomohisa Yukawa Yumi Yamashita Shiro Isshiki Yuki Ogura-Tsujita 《American journal of botany》2020,107(12):1654-1662
11.
Melanoderma boninense is described and illustrated as a new species from the Bonin Islands, Japan, on the basis of morphological and phylogenetic investigations. This species is characterized by sessile basidiocarps with an ungulate pileus, a black crust on the pileus surface, pores 4–6/mm, a dimitic hyphal system comprising clamped generative hyphae and cyanophilous skeletal binding hyphae with or without a dextrinoid reaction, cylindrical basidiospores measuring 5.5–7.5 × 2–3 μm, and cystidioles on the sides of tubes and near the pore surface. Morphological examination of authentic specimens of other Melanoderma species revealed that the genus is variable in terms of the shape and size of cystidioles. A black crust on the pileus surface composed of palisade and highly agglutinated hyphae is a distinctive diagnostic morphological feature of Melanoderma that differentiates it from allied genera. Melanoderma boninense, which is currently known from a restricted area of the Bonin Islands, is potentially threatened by environmental reduction of the type locality due to the invasive tree Bischofia javanica. 相似文献
12.
Mycodrosophila is a cosmopolitan genus of Drosophilidae that comprises approximately 130 species with mycophagous habitats. In this study, we described a new species of Mycodrosophila based on morphological traits and included details of the male terminalia. The holotype is from Eugênio Lefévre, locality in Campos do Jordão municipality, SP, Brazil, located in the Atlantic rainforest biome and was sampled in the 1930s. 相似文献
13.
Junli Yao Cornelis van Achterberg Michael J. Sharkey Eric G. Chapman Jiahua Chen 《Journal of Asia》2019,22(1):103-109
SenwotWharton 1983, is a small braconid genus with only two previously described species. The genus is revised using morphological characters and a phylogenetic analysis of COI sequence. Senwot Wharton is reported for the first time from Thailand and two new species: Senwot yinxianggaoae Yao n. sp. and Senwot jiyuanyaoi Yao n. sp. are described and illustrated. A key to species of the genus Senwot is presented.www.zoobank.org/urn:lsid:zoobank.org:pub:D7E79499-491E-4845-991B-0FE763A45162 相似文献
14.
Rhinoleucophenga pallida Hendel, 1917 (type species of the genus) is redescribed based on its female holotype and a male from a nearby locality, and Rhinoleucophenga obesa (Loew, 1872) on its two syntypes, which are designated as the male lectotype and a female paralectotype. Both are valid species. A proposal is made to establish the genus Pseudophortica Sturtevant, 1918 (type species R. obesa), a junior synonym of Rhinoleucophenga, to subgenus rank and include all species of Rhinoleucophenga described or redescribed from males except R. pallida, which is unique in having a remarkable pedunculate surstylus, among other differences. The North American R. obesa is compared to its closest sibling, the South American species Rhinoleucophenga gigantea (Thomson, 1869). The occurrence of R. obesa in Brazil is also questioned, as suggested long ago by Marshall R. Wheeler. The specimens from Brazil previously identified as such most probably belong to the new species described in the present paper as Rhinoleucophenga (Pseudophortica) cantareira sp. nov. (type locality: Parque Estadual da Cantareira, City of São Paulo, State of São Paulo, Brazil). Numerous photomicrographs of their habitus and male terminalia taken with a Smartphone's rear camera and digitally stacked to create images with greater depth of focus are provided. 相似文献
15.
André V.L. Freitas Luísa L. Mota Thamara Zacca Eduardo P. Barbosa 《Revista Brasileira de Entomologia》2019,63(3):254-261
A new genus and species of Euptychiina (Satyrinae), Cristalinaia vitoria Mota, Zacca & Freitas gen. et sp. nov., is described based on three specimens collected in the region of the Cristalino River, Alta Floresta, Mato Grosso, Brazil. This rare species is known only from this region, where it flies inside the dense bamboo patches typical of that area. The last instar larva and the pupa are described; the larva was observed feeding on mature leaves of the common bamboo Guadua aff. paniculata Munro.urn:lsid:zoobank.org:pub:D61EDE8D-CAE9-41C6-B24D-BB789873566E 相似文献
16.
《Fungal Ecology》2019
The ophiostomatoid fungus Leptographium abietinum is symbiotic with the North American spruce beetle Dendroctonus rufipennis; however, the ecology of these interactions are not understood. Multiple functional hypotheses regarding beetle-symbiont interactions pervade the literature, especially the view that symbionts may provide nutrition, competitively exclude antagonistic microbes, or detoxify host plant compounds. Here, these three hypotheses are tested in an effort to discern whether the ecological profile of L. abietinum is consistent with bark beetle-fungus mutualisms. Three important findings emerged: (1) by comparison with conifer phloem, L. abietinum mycelia contained considerable quantities of N, P, and protein; (2) L. abietinum outcompetes a ubiquitous entomopathogen for growing space in a resource-limited environment and can maintain captured space; and (3) inoculation with L. abietinum significantly reduced concentrations of a tree defensive compound, (+)-3-carene, in growth media. Collectively, these findings indicate that L. abietinum fulfills multiple ecological functions that are potentially consistent with bark beetle-fungus mutualism. 相似文献
17.
Balázs Tóth 《Journal of Asia》2019,22(2):437-442
The species Naarda postpallida de Joannis, 1929 is reported for the first time from mainland China. Naarda pectinata Sugi, 1982 is synonymised with N. postpallida on the basis of material from Vietnam. This species can immediately be recognised by its dark grey forewing, white hindwing and several genital characters. The female genitalia of N. postpallida, together with those of N. lingualis Tóth and Ronkay, 2015 are presented for the first time. Naarda macrostigma sp. n. is described. The hitherto known nine Chinese Naarda species are listed. With nineteen figures.www.zoobank.org/urn:lsid:zoobank.org:pub:092AE905-08AA-4818-BDA8-2B9EF150793A 相似文献
18.
The taxonomic status and phylogenetic affinities of Mymaridae and Scelionidae are controversial, based on similarities between these families in the characteristics of adults, larvae, and eggs. In this study, we sequenced the mitochondrial (mt) genomes of representatives from these two families and found that the derived secondary structure of tRNA-Arg was the same in each family due to the absence of the D-stem. The segment of “cox1 trnL2 cox2 trnK trnD atp8 atp6 cox3” in Gonatocerus sp. (Mymaridae) is conserved and distinct from those of four other species of Chalcidoidea but similar to that in Proctotrupoidea and Platygastroidea. However, phylogenetic analysis indicated that Gonatocerus sp. was sister group to other species of Chalcidoidea. Comparisons based on complete gene orders may be more useful in a phylogenetic and systematic context, as different branches may exhibit partially homoplastic gene orders. 相似文献
19.
Effect of irrigation from a point source (trickling) on oxygen flux and on root extension in the soil 总被引:2,自引:0,他引:2
A two-dimensional trickle-irrigated soil model was examined in order to determine its aeration regime. Oxygen diffusion rate (O.D.R.) was used as an index of the soil aeration regime, and its influence on the development of root systems was determined. Volumetric soil air content was calculated from soil water tension data, using a retention curve.The root system was markedly concentrated at the periphery of the trickle-irrigated soil volume, while in the center there were few roots. An exponential correlation was found between root distribution and O.D.R., in which 20×10–8g O2×cm–2×min–1 was the critical value for root growth. There was a linear correlation between O.D.R. and volumetric air content which was affected by diffusion distance. 相似文献
20.
Khalid A. Al-Gaadi Rangaswamy Madugundu ElKamil Tola 《Saudi Journal of Biological Sciences》2019,26(7):1392-1399
Based on the massive production of cow and poultry manures, farmers in Saudi Arabia are moving towards the application of organic fertilizers in their farms. Therefore, the present work was conducted to study the response of soil and selected vegetable crops to poultry and cow manures, using ground data and Landsat-8 and Hyperion images. The studied vegetable crops are cabbage, cauliflower, broccoli, and lettuce. A total of 100 t ha?1 organic manures were applied as a pre-planting treatment. A 12.5 ha field in Tawdeehiya Farms, 200 km southeast of Riyadh, was earmarked for this study. The field was divided into sectors cultivated with the above-mentioned vegetable crops. Soil characteristics, including the soil pH, the electric conductivity (EC), the nitrogen (N), the phosphorus (P) and the potassium (K), were examined before the application of manures and 25 days after the transplanting process. Observations on crops chlorophyll content, number of leaves, the diameter of merchantable products and yield were also investigated. Furthermore, the relationship between the crop performance and yield was investigated through the satellite images generated vegetation indices (VIs). This study revealed the better performance of poultry manure compared to cow manure in terms of development and production parameters of the experimental crops. Dynamics of the chlorophyll content across the crop growth period revealed that all the tested crops responded significantly (R2 = 0.69; P = 0.001) to the poultry manure treatments. Among the tested crops, the chlorophyll content, curd or head sizes and crop yields were quite better in poultry manure applied plots. The investigation of crop yield was significant with poultry manure (R2 = 0.64; P = 0.001) than cow manure (R2 = 0.57; P = 0.001) using the OSAVI and mNDVI, respectively. 相似文献