Epiphytic Communities Research Articles

What happens to epiphytic bromeliads in a windy spot?

Abstract Several studies of hurricane damage on epiphyte communities implied that epiphytes might be in danger of being blown off their host when subjected to strong wind. There is very limited knowledge about the mechanical impact that wind may have on epiphytes. Using a wind-triggered camera set-up, we observed how epiphytic tank bromeliads are affected by wind. Despite offering a relatively large area of ‘attack’ to the airflow, bromeliads moved relatively little themselves. Rather than being directly moved by wind, the bromeliads in the upper crown of tall trees moved with the sway of the branches. Only when the substrate did not move, bromeliads with long broad leaves showed considerable disturbance due to wind. Our observations underline the complexity of the system and emphasise that our current understanding of the mechanical aspects of the epiphyte–host system is still very limited.

Little time left. Microrefuges may fail in mitigating the effects of climate change on epiphytic lichens

Climate change is already causing considerable reductions in biodiversity in all terrestrial ecosystems. These consequences are expected to be exacerbated in biomes that are particularly exposed to change, such as those in the Mediterranean, and in certain groups of more sensitive organisms, such as epiphytic lichens. These poikylohydric organisms find suitable light and water conditions on trunks under the tree canopy. Despite their small size, epiphytic communities contribute significantly to the functionality of forest ecosystems.In this work, we surveyed epiphytic lichen communities in a Mediterranean area (Sardinia, Italy) and hypothesized that 1) the effect of microclimate on lichens at tree scale is mediated by the functional traits of these organisms and that 2) micro-refuge trees with certain morphological characteristics can mitigate the negative effects of future climate change.Results confirm the first hypothesis, while the second is only partially supported, suggesting that the capability of specific trees to host specific conditions may not be sufficient to maintain the diversity and ecosystem functionality of lichen communities in the Mediterranean.

Comparison studies of epiphytic microbial communities on four macroalgae and their rocky substrates

Macroalgae and their rocky substrates both support diverse and abundant microbiota, performing essential ecological functions in marine ecosystem. However, the differences in the epiphytic microbial communities on macroalgae and rocky substrate are still poorly understood. In this study, the epiphytic microbial communities on four macroalgae (Corallina officinalis, Rhodomela confervoides, Sargassum thunbergii, and Ulva linza) and their rocky substrates from Weihai coast zone were characterized using high-throughput sequencing technology. The results showed that the alpha diversity indices were greater in rocky substrates than that in macroalgae. The microbial similarities among macroalgae and rocky substrate groups tended to decrease from the high taxonomic ranks to lower ranks, only 22.69% of the total amplicon sequence variants (ASVs) were shared between them. The functional analysis revealed that the microbiotas were mainly involved in metabolic activities. This study would provide the theoretical foundation for macroalgal cultivation and algal reef applications.

Determination of Phylloplane Associated Bacteria of Lettuce from a Small-Scale Aquaponic System via 16S rRNA Gene Amplicon Sequence Analysis

Fresh vegetables harbour diverse bacterial populations on their surfaces which are important for plant health and growth. Information on epiphytic bacteria is limited to only a few types of vegetables and it is unknown how the lettuce epiphytic bacterial community structure may respond when a probiotic product is added to an aquaponic system. In this study, we evaluated lettuce growth and analysed epiphytic bacterial communities of lettuce based on metabarcoding analysis of the V3-V4 region of the 16S rRNA gene obtained from paired-end Illumina MiSeq reads. The addition of Bacillus probiotics resulted in a significant increase of nitrate and phosphate in the deep-water culture solution, as well as increased vegetative growth of lettuce. Metabarcoding analysis revealed that the most abundant phyla on lettuce leaf surfaces were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The in-depth bacterial composition analysis indicated that genera Chryseobacterium, Bacillus, Pantoea, Pseudoduganella, Flavobacterium, Paludibacter, and Cloacibacterium were dominant in leaf samples obtained from Bacillus-treated systems. Analysis of lettuce epiphytic bacterial communities of the fresh lettuce leaf surfaces also indicated the presence of food-borne pathogens belonging to the Shigella and Aeromonas genera, which were less abundant in the probiotic treated systems. This study provides the first characterization of the epiphytic bacterial community structure and how it can be modulated by the addition of a probiotic mixture to the nutrient solution of aquaponic systems.

Recolonization of epiphytic bryophytes after decades of air pollution in forest ecosystems in the Erzgebirge (Ore Mountains) shows the importance of deciduous trees for the diversity of this species group

In recent decades, great efforts have been made in Central Europe to convert homogeneous conifer stands into mixed stands. One major goal of this measure is to promote the biodiversity of forest ecosystems. Research on forest biodiversity is mostly limited to the spatial scale of the stand (alpha diversity), and only few studies focus on the landscape level (gamma diversity). In our study, we investigate the recolonization of epiphytic bryophytes after decades of air pollution on different host tree species. The study area is the Erzgebirge (Ore Mountains, eastern Germany), a low mountain range in which very high SO2 inputs from industrial emissions caused severe damage to the vegetation up to the end of the 20th century. We selected twelve plots each of the tree species Picea abies, Fagus sylvatica, Acer pseudoplatanus and Sorbus aucuparia and recorded the occurrence of all epiphytic bryophytes on trunk and branches at a height between approx. 0.5 and 2.0 m. We recorded a total of 84 species, finding a significantly higher species richness and number of species of conservation concern as well as a larger regional epiphytic species pool (RESP) on F. sylvatica, A. pseudoplatanus and S. aucuparia compared to P. abies. In contrast, there were only minor differences in epiphytic species diversity and composition between the studied deciduous tree species. The dominance of colonists in the current species composition shows that these epiphyte communities are still in the early stages of succession, supported by the observation that species with small range sizes are still very rare. Compared to other studies, the species pool of the examined tree species is relatively large. This is an indication of the much improved environmental conditions for epiphytes in the Erzgebirge. We also recorded Ulota drummondii in the stands, providing its first record in Germany since 1886. In general, we conclude that changing tree species composition from monospecific coniferous to broadleaved stands will lead to an increase in the epiphytic bryophyte diversity of forest ecosystems.

Olive Fungal Epiphytic Communities Are Affected by Their Maturation Stage.

The phyllosphere comprises the aerial parts of plants and is colonized by a great diversity of microorganisms, either growing inside (as endophytes) or on the surface (as epiphytes) of plant tissues. The factors that structure the diversity of epiphytes and the importance of these microorganisms for host plant protection have been less studied when compared to the case of endophytes. In this work, the epiphytic fungal communities from fruits of the olive tree (olives) in different maturation stages (green and semi-ripened), obtained from different olive orchard managements (integrated and organic production) and from distinct cultivars displaying different susceptibilities to olive anthracnose (Cobrançosa and Madural), are compared by using a metabarcoding approach. We discuss whether such differences in host resistance against anthracnose depend on both the fungal taxa or fungal community composition. A total of 1565 amplicon sequence variants (ASVs) were obtained, mainly belonging to the Ascomycota phylum and Saccharomycetes class. Although significant differences on epiphytic fungal richness were observed among olives obtained in different production systems and maturation stages, these factors in addition to host cultivar did not influence the composition of the epiphytes. Despite these results, a co-inertia analysis showed that Aureobasidium spp. and Sporocadaceae spp. were positively associated with the green olives of the cv. Madural produced under integrated production, while Saccharomycetales spp. (Kluyveromyces, Candida, Kazachstania and Saccharomyces) were positively associated with the semi-ripened olives of the cv. Cobrançosa obtained from organic production. The discriminant power of these fungi, some of them recognized as biocontrol agents, suggest that they might be important in conferring differences on host plant susceptibility to anthracnose.

Epiphytic fungal communities vary by substrate type and at submetre spatial scales.

Fungal species have numerous important environmental functions. Where these functions occur will depend on how fungi are spatially distributed, but the spatial structures of fungal communities are largely unknown, especially in understudied hyperdiverse tropical tree canopy systems. Here we explore fungal communities in a Costa Rican tropical rainforest canopy, with a focus on local-scale spatial structure and substrate specificity of fungi. Samples of ~1cm3 were collected from 135 points along five adjacent tree branches, with intersample distances from 1 to 800cm, and dissected into four substrates: outer host tree bark, inner bark, dead bryophytes and living bryophytes. We sequenced the ITS2 region to characterize total fungal communities. Fungal community composition and diversity varied among substrate types, even when multiple substrates were in direct contact. Fungi were most diverse in living bryophytes, with 39% of all operational taxonomic units (OTUs) found exclusively in this substrate, and the least diverse in inner bark. Fungal communities had significant positive spatial autocorrelation and distance decay of similarity only at distances less than 1m. Similarity among samples declined by half in less than 10cm, and even at these short distances, similarities were low with few OTUs shared among samples. These results indicate that community turnover is high and occurs at very small spatial scales, with any two locations sharing very few fungi in common. High heterogeneity of fungal communities in space and among substrates may have implications for the distributions, population dynamics and diversity of other tree canopy organisms, including epiphytic plants.

Diversity and Source of Airborne Microbial Communities at Differential Polluted Sites of Rome

Biogenic fraction of airborne PM10 which includes bacteria, viruses, fungi and pollens, has been proposed as one of the potential causes of the PM10 toxicity. The present study aimed to provide a comprehensive understanding of the microbial community variations associated to PM10, and their main local sources in the surrounding environment in three urban sites of Rome, characterized by differential pollution rate: green area, residential area and polluted area close to the traffic roads. We combined high-throughput amplicon sequencing of the bacterial 16S rRNA gene and the fungal internal transcribed spacer (ITS) region, with detailed chemical analysis of particulate matter sampled from air, paved road surfaces and leaf surfaces of Quercus ilex. Our results demonstrated that bacterial and fungal airborne communities were characterized by the highest alpha-diversity and grouped separately from epiphytic and road dust communities. The reconstruction of source-sink relationships revealed that the resuspension/deposition of road dust from traffic might contribute to the maximum magnitude of microbial exchanges. The relative abundance of extremotolerant microbes was found to be enhanced in epiphytic communities and was associated to a progressively increase of pollution levels as well as opportunistic human pathogenicity in fungal communities.

Maple and hickory leaf litter fungal communities reflect pre-senescent leaf communities.

Fungal communities are known to contribute to the functioning of living plant microbiomes as well as to the decay of dead plant material and affect vital ecosystem services, such as pathogen resistance and nutrient cycling. Yet, factors that drive structure and function of phyllosphere mycobiomes and their fate in leaf litter are often ignored. We sought to determine the factors contributing to the composition of communities in temperate forest substrates, with culture-independent amplicon sequencing of fungal communities of pre-senescent leaf surfaces, internal tissues, leaf litter, underlying humus soil of co-occurring red maple (Acer rubrum) and shagbark hickory (Carya ovata). Paired samples were taken at five sites within a temperate forest in southern Michigan, USA. Fungal communities were differentiable based on substrate, host species, and site, as well as all two-way and three-way interactions of these variables. PERMANOVA analyses and co-occurrence of taxa indicate that soil communities are unique from both phyllosphere and leaf litter communities. Correspondence of endophyte, epiphyte, and litter communities suggests dispersal plays an important role in structuring fungal communities. Future work will be needed to assess how this dispersal changes microbial community functioning in these niches.

Climate and epiphytic macrolichen communities in the Four Corners region of the U.S.A.

We used data on epiphytic lichen communities in 1215, 0.4-ha plots in the Southwest U.S.A. collected by the Forest Inventory and Analysis (FIA) program to analyze relationships with climate. We sought the climate variables most strongly associated with differences in epiphytic macrolichen communities and described the nature of those relationships, including diversity, community composition, and patterns in individual species. Five lichen community groups were strongly related to temperature and elevation gradients, overall moisture, and summer rain. Lichen abundance was highest in the wettest groups and lowest in the hottest and driest groups. Warm summer monsoonal climates supported the greatest number of species across all plots and within plots. The monsoonal pattern did not occupy a discrete geographic area, but instead formed a gradient, strongest in the southern part of our study area, diminishing to the north and west. In contrast, hot summer monsoonal climates had much lower within-plot richness. Hot, dry climates had the most variation in species composition among plots, but the fewest species within each plot and across all plots. Lichen community gradients had nonlinear relationships with combinations of climate variables rather than strong linear relationships with any single variable, including those derivative climate variables meant to have direct biological relevance. Relationships between air quality and community gradients were weak, potentially overwhelmed by regional climatic variation and complex topographic gradients. Richness of particular functional groups was more strongly related to climate than was overall species richness; functional groups have their own climatic tolerances, owing to the physiological consequences of growth form and photobiont. Presumably species in different functional groups have experienced their own evolutionary tradeoffs, developing peak performance in different climates. On the other hand, overall richness was driven by an even more complex combination of performances relative to climate and was in some functional groups more strongly related to geographic coordinates than to climate variables. Because climatic variables are themselves geographically structured, stronger model fit for geographic coordinates than for climate implies some influence of large-scale historical factors (i.e., factors not clearly expressed in modern climates, such as past climates, vegetation structure, or disturbance regimes).

Genetic variation in the symbiont partners in the endangered macrolichenSeirophora villosa(Teloschistaceae: Ascomycota)

AbstractThe decline observed in many populations of highly sensitive lichens has led to the inclusion of some species on regional Red Lists, but this has seldom been accompanied by an examination of the genetic variation of the fungal and algal symbiotic partners. Here, the red-listed epiphytic lichen Seirophora villosa was surveyed in 14 Mediterranean coastal populations to examine the genetic diversity of both partners. The geographical distribution of four-locus haplotypes followed the same trend in mycobiont and photobiont data sets, some being widespread and others restricted to single localities. The fungus showed a moderate selectivity in its photobiont choice, associating with two undescribed Trebouxia microalgae with a biased distribution across the western Mediterranean. One alga species occurred exclusively in the Italian Peninsula. This region also hosted the highest number of haplotypes for both symbionts. The use of 454-pyrosequencing revealed no clear signs of algal coexistence within selected thalli. The phylogenetic reconstruction for the mycobiont showed uncertain limits among Seirophora spp., stressing the need for further taxonomic evaluation. Additionally, we found that Ramalina lacera, a co-occurring epiphytic lichen in the studied area, shared photobiont genotypes with S. villosa. Our results thus suggest that the protection not only of the red-listed species S. villosa, but also of the whole epiphytic lichen community investigated here might be advisable.

Phyllosphere fungal communities of rubber trees exhibited biogeographical patterns, but not bacteria.

Phyllosphere microbiomes play an essential role in maintaining host health and productivity. Still, the diversity patterns and the drivers for the phyllosphere microbial community of the tropical cash crop Rubber tree (Hevea brasiliensis) - are poorly understood. We sampled the phyllosphere of field-grown rubber trees in South China. We examined the phyllosphere bacterial and fungal composition, diversity and main drivers of these microbes using the Illumina® sequencing and assembly. Fungal communities were distinctly different in different climatic regions (i.e. Xishuangbanna and Hainan Island) and climatic factors, especially mean annual temperature, and they were the main driving factors of foliar fungal communities, indicating fungal communities showed a geographical pattern. Significant differences of phyllosphere bacterial communities were detected in different habitats (i.e. endophytic and epiphytic). Most of the differences in taxa composition came from Firmicutes spp., which have been assigned as nitrogen-fixing bacteria. Since these bacteria cannot penetrate the cuticle like fungi, the abundant epiphytic Firmicutes spp. may supplement the deficiency of nitrogen acquisition. And the main factor influencing endophytic bacteria were internal factors, such as total nitrogen, total phosphorus and water content of leaves. External factors (i.e. climate) were the main driving force for epiphytic bacteria community assembly. Our work provides empirical evidence that the assembly of phyllosphere bacterial and fungal differed, which creates a precedent for preventing and controlling rubber tree diseases and pests and rubber tree yield improvement.

Temporal Succession of Bacterial Community Structure, Co-occurrence Patterns, and Community Assembly Process in Epiphytic Biofilms of Submerged Plants in a Plateau Lake.

In shallow macrophytic lakes, epiphytic biofilms are formed on the surface of submerged plant stems and leaves because of algae and bacterial accumulation. Epiphytic biofilms significantly impact the health of the host vegetation and the biogeochemical cycling of lake elements. However, community diversity, species interactions, and community assembly mechanisms in epiphytic bacterial communities (EBCs) of plants during different growth periods are not well understood. We investigated the successional dynamics, co-occurrence patterns, and community assembly processes of epiphytic biofilm bacterial communities of submerged plants, Najas marina and Potamogeton lucens, from July to November 2020. The results showed a significant seasonal variation in EBC diversity and richness. Community diversity and richness increased from July to November, and the temperature was the most important driving factor for predicting seasonal changes in EBC community structure. Co-occurrence network analysis revealed that the average degree and graph density of the network increased from July to November, indicating that the complexity of the EBC network increased. The bacterial community co-occurrence network was limited by temperature, pH, and transparency. The phylogeny-based null model analysis showed that deterministic processes dominated the microbial community assembly in different periods, increasing their contribution. In addition, we found that as the dominance of deterministic processes increased, the microbial co-occurrence links increased, and the potential interrelationships between species became stronger. Thus, the findings provide insights into the seasonal variability of EBC assemblage and co-occurrence patterns in lacustrine ecosystems.

Diversity and network structure of epiphytic bacterial communities on different submerged macrophytes

沉水植物叶表附着大量细菌,与沉水植物构成了复杂的共生体系.叶片附着细菌是水生态的重要组成部分,能影响沉水植物自身生长和水体物质循环过程.目前,对于沉水植物多样性对植物叶片附着细菌群落的影响知之甚少.本研究比较了不同沉水植物物种多样性对浮游细菌和叶片附着细菌群落的影响,同时探究不同植物——苦草(Vallisneria natans)、穗状狐尾藻(Myriophyllum spicatum)、微齿眼子菜(Potamogeton maackianus)和黑藻(Hydrilla verticillata)叶片附着细菌的群落结构和多样性特征.结果表明,浮游细菌和叶片附着细菌的群落α多样性和β多样性具有显著差异.与单一植物物种体系相比,高植物物种多样性体系中植物叶片附着细菌群落α多样性较高.在高植物物种多样性体系中,黑藻叶片附着细菌群落的α多样性显著较高而β多样性显著较低,苦草叶片附着细菌群落的α多样性较低.沉水植物叶片附着细菌群落优势菌群属于变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes).高植物物种多样性体系中苦草的物种共现网络最具模块性.嗜甲基菌(g_Methylophilus)、红杆菌(f_Rhodobacter)、黄杆菌(g_Flavobacterium)是物种共现网络的关键物种.本文研究植物物种多样性对淡水湖泊细菌群落结构的影响,并强调宿主植物对附着细菌群落的重要选择作用,加深对细菌群落在水生植物叶片定殖机制的理解.;Epiphytic bacteria, adhering to the leaf surface of aquatic submerged macrophytes, develop a complex symbiotic relationship with submerged macrophytes. Epiphytic bacteria are an important component of the aquatic ecosystem, which can affect not only the growth of submerged macrophytes but also the nutrient cycling in aquatic ecosystems. Currently, the effect of submerged macrophyte diversity on the epiphytic bacteria communities is far from well understood. This study compared the effects of submerged macrophyte on bacterioplankton and epiphytic bacterial communities, meanwhile explored the community structure and diversity of epiphytic bacterial communities on different macrophytes-Vallisneria natans,Myriophyllum spicatum, Potamogeton maackianus andHydrilla verticillata. The results showed that the α diversity and structure of planktonic bacterial communities were significantly different from those of the epiphytic bacterial communities. With the increase of submerged macrophyte diversity, the α diversity of epiphytic bacterial communities increased slightly. In the systems with high submerged macrophyte diversity, significantly higher α diversity and lower β diversity were found for the epiphytic bacterial community on H. verticillata. Bacteroidetes and Proteobacteria were dominant phyla on the submerged macrophyte leaves. Co-occurrence network analysis revealed that the modularity value of V. natans epiphytic bacterial network was relatively high. Methylophilus, Rhodobacter andFlavobacterium were core species in the co-occurrence networks. This study demonstrated the effect of submerged macrophytes on bacterial community structure in freshwater lakes, emphasizing the importance of host-specific selection for epiphytic bacterial communities, and deepening our understanding of the mechanism of bacterial colonization on submerged macrophytes.

Vallisneria Natans Decreased Ch4 Fluxes in Wetlands: Interactions Among Plant Activities, Nutrients and Epiphytic Bacterial Community

Vallisneria Natans Decreased Ch4 Fluxes in Wetlands: Interactions Among Plant Activities, Nutrients and Epiphytic Bacterial Community

The epiphytic bryophyte succession of Picea orientalis forests on the Kumbet High Plateau (Giresun-Turkey)

In this study, the epiphytic bryophyte succession of Picea orientalis forests on the K?mbet High Plateau (Giresun-Turkey) were studied. A total of 21 epiphytic bryophyte species were determined (16 mosses and 5 liverworts). The epiphytic bryophyte communities were sampled in 60 sample plots taken from the trunks of Picea orientalis, each of which was 20 ? 20 cm in size. The Index of Ecological Significance (IES), based on a combination of the relative frequency and mean cover of epiphytic bryophytes, was used to evaluate the abundance of bryophyte communities in epiphytic habitats on the tree trunks. In addition, multivariate classification techniques (TWINSPAN and DECORANA) were used to classify the community structures in successional stages. TWINSPAN divided the 60 sample plots into two main groups: a) the lower base communities (LB) and b) the middleupper zone communities (MU). Moreover, the middle-upper zone communities (MU) were divided into two sub-groups associated with the successional gradient (MU1 and MU2). DECORANA classified these communities along the ordination axes 1 and 3 related to the height gradient of Picea orientalis and the moisture (from mesic to xeric) gradient of the epiphytic habitat. While Exsertotheca crispa, Cynodontium fallax, Lewinskya striata, and Habrodon perpusillus were only found on old spruce trees, Drepanium fastigiatum was only found on young trees and Lophocolea heterophylla was only found on middle-aged trees.

Importance of Quercus spp. for diversity and biomass of vascular epiphytes in a managed pine-oak forest in Southern Mexico

Forestry management modifies the diversity, structure, and functioning of intervened forests. Timber extraction reduces tree density and basal area, leading to changes in the communities of vascular epiphytes. The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method (release cutting, and thinning) in comparison with an unharvested old-secondary forest in southern Mexico. For each treatment, richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated. We calculated the true diversity (Hill numbers) and beta diversity using the Jaccard coefficient of similarity, and generated rank abundance curves per taxonomic epiphyte group (bromeliads, orchids, ferns and others). For each treatment, the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models. We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks. The greatest species richness (0D) was recorded in the old-secondary forest. Fewer common (1D) and dominant (2D) species were recorded in the release cutting than in the other treatments. Epiphyte diversity and biomass were both slightly related to host tree basal area. Composition of epiphytes was similar (60%) among treatments, although orchids, bromeliads, and other families were more diverse in the old-secondary forest. Most bromeliad species were shared across all treatments, although orchids presented the most exclusive species in the unharvested forest. The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments, followed by the orchid Camaridium densum. Generalized linear models indicated that epiphyte diversity was significantly related to treatment, and epiphyte biomass to basal area of host trees. Although forest management affects diversity, composition, and abundance of vascular epiphytes, most of their diversity and biomass can be maintained despite timber harvesting. This requires sparing some mature oaks during logging, as they contribute to conservation, establishment, and development of epiphytic communities, and maintaining untreated areas as a source of propagules for these communities.

Importance of the Vertical Gradient in the Variation of Epiphyte Community Structure in the Brazilian Atlantic Forest

Importance of the Vertical Gradient in the Variation of Epiphyte Community Structure in the Brazilian Atlantic Forest

Neglected epiphytism: Accidental epiphytes dominate epiphytic communities on tree ferns in the Atlantic Forest

AbstractVascular epiphytes and tree ferns constitute an important part of the Atlantic Forest structure. We characterized vascular epiphyte communities on two tree fern species (Alsophila setosa Kaulf. and Cyathea phalerata Mart.) including accidental epiphytes (i.e., species that are usually terrestrial, without necessarily completing their life cycle as an epiphyte), which have been overlooked in many previous studies. We aimed to understand epiphytism in terms of distribution, diversity, community composition, and host attributes that affect the richness and abundance of accidental epiphytes. Despite the great species richness of accidental epiphytes, they were—in contrast to true epiphytes—generally low in abundance and heavily represented by singletons and doubletons. We did not identify a difference in accidental epiphytic diversity and composition between host species, implying that both host species provide similar habitats for accidental epiphytes—although some epiphytic species showed a preference for a specific host species and/or stratum. Epiphyte richness and abundance were positively associated with a codependence of host surface area and moisture content, but only for accidental epiphytes. Our study illustrates the importance of two tree fern species as epiphyte hosts in the rainforest understory. It also shows that, although frequently overlooked, accidental epiphytism can be common in the understory of tropical forests and a phenomenon that merits further study in this region.Abstract in Portuguese is available with online material.

Epiphytic Microbial Community and Post-Harvest Characteristics of Strawberry Fruits as Affected by Plant Nutritional Regime with Silicon

Despite being not essential to plants, Silicon (Si) has proven to have promoting effects on plants growth, yield, and resistance against biotic and abiotic stressors. The increase of concentration in specific minerals in plant tissues can also improve shelf-life, which, in fruits like strawberries, is also affected by the epiphytic microbial community. The present research was carried out to assess whether Si biofortification of strawberry plants, grown in soilless system, could affect plants yield and post-harvest feature of fruits during the storage period, carried out at three different temperatures (i.e., 1, 4 and 10 °C) for 7 and 14 days. Furthermore, we investigated whether the plant nutritional regime, specifically the Si fertilization, can impact the composition of microbial community. Our results showed that biofortification did not significantly affect fruits firmness, whereas, at the highest Si levels, an increase in titratable acidity was observed. The microbial community analysis highlighted for the first time the presence of probiotic bacteria, as Bacillus breve, which could present interesting technological features as strains adapted to the strawberry fruit-sphere. In addition, with the increasing levels of Si biofortification, the depletion of potentially pathogenic microorganisms, like Escherichia coli and Terrisporobacter glycolicus, was also observed. In conclusion, data here reported highlight for the first time the possible role played by the nutritional regimes of strawberry plants in shaping composition of the fruit epiphytic microbial community.