Evolution and expression of LEAFY genes in ferns and lycophytes

Background The LEAFY (LFY) transcription factors are present in algae and across land plants. The available expression and functional data of these genes in embryophytes suggest that LFY genes control a plethora of processes including the first zygotic cell division in bryophytes, shoot cell divisions of the gametophyte and sporophyte in ferns, cone differentiation in gymnosperms and floral meristem identity in flowering plants. However, their putative plesiomorphic role in plant reproductive transition in vascular plants remains untested. Results We perform Maximum Likelihood (ML) phylogenetic analyses for the LFY gene lineage in embryophytes with expanded sampling in lycophytes and ferns. We recover the previously identified seed plant duplication that results in LEAFY and NEEDLY paralogs. In addition, we recover multiple species-specific duplications in ferns and lycophytes and large-scale duplications possibly correlated with the occurrence of whole genome duplication (WGD) events in Equisetales and Salviniales. To test putative roles in diverse ferns and lycophytes we perform LFY expression analyses in Adiantum raddianum, Equisetum giganteum and Selaginella moellendorffii. Our results show that LFY genes are active in vegetative and reproductive tissues, with higher expression in early fertile developmental stages and during sporangia differentiation. Conclusions Our data point to previously unrecognized roles of LFY genes in sporangia differentiation in lycophytes and ferns and suggests that functions linked to reproductive structure development are not exclusive to seed plant LFY homologs.

Identifying cryptic fern gametophytes using DNA barcoding: A review

Ferns and lycophytes are unique among land plants for having sporophyte (diploid) and gametophyte (haploid) generations that can grow independently of each other. While most studies of fern ecology focus on the more obvious sporophytic stage, the gametophyte is critically important, as it is the sexual phase of the life cycle. Yet, fern gametophytes have long been neglected in field studies due to their small size and cryptic morphology. DNA barcoding is a powerful method that can be used to identify field-collected gametophytes to species and allow for detailed study of their ecology. Here, we review the state of DNA barcoding as applied to fern gametophytes. First, we trace the history of DNA barcoding and how it has come to be applied to fern gametophytes. Next, we summarize case studies that show how DNA barcoding has been used to better understand fern species distributions, gametophyte ecology, and community ecology. Finally, we propose avenues for future research using this powerful tool, including next-generation DNA sequencing for in-field identification of cryptic gametophytes.

Biogeographic analysis of ferns and lycophytes in Oaxaca: A Mexican beta-diverse area

Background: Spatial patterns related to richness and endemism of Mexican ferns and lycophytes are not well known, particularly in highly biodiverse areas; among these, Oaxaca is considered a highly biodiverse Mexican state. Questions: Where are located the centers of richness and endemism of lycophytes and ferns in Oaxaca? Both groups of plants support the idea of beta-diverse state condition for Oaxaca? Study site and research period: The study includes all territory of Oaxaca, between 2015 and 2019. Methods: We analyzed the species distribution using grid cells of 20’ × 20’ of latitude and longitude as study units. For this, we applied species richness, endemism indexes (weighted endemism and corrected weighted endemism), and components of biodiversity (a, b and g), associated with a complementarity index. The distributional data of the species were mainly obtained from herbarium specimens. Results: The richness areas are concentrated in the Sierra Norte and Istmo regions. Three important areas in richness and endemic species are suggested from the endemism indexes. Most of the grid-cell combinations resulted in high values from the complementarity analysis suggesting a high species turnover. Conclusions: The diversity analyses suggested that Oaxaca is a beta-diverse state. The NOM-059 needs a serious, urgent, and critical revision for ferns and different biological groups. The Areas Voluntarily Designated for Conservation in Oaxaca play a major role in relation to Natural Protected Areas for conservation of ferns and lycophytes.

Comparing trait syndromes between Taiwanese subtropical terrestrial and epiphytic ferns and lycophytes at the species and community level

While functional trait-trait and trait-environment relationships are well studied in angiosperms, it is less clear if similar relationships, such as the leaf economics spectrum (LES), hold for ferns and lycophytes. Similarly, studies exploring potential differences in trait-trait and trait-environment relationships between terrestrial and epiphytic fern communities in a given ecosystem are largely lacking. We measured nine leaf traits for 76 terrestrial and 43 epiphytic fern and lycophyte species across 59 vegetation plots along an elevation gradient in the subtropical forest of Northern Taiwan. We explored trait-trait and trait-environment relationships at both the species- and community level for both species groups. Epiphytes differed from terrestrial ferns and lycophytes in species- and community-level trait values, mainly reflecting responses to higher drought and nutrient stress. The angiosperm LES was reflected in the trait-trait correlations of terrestrial ferns, but not of epiphytes. This suggests that epiphytic trait patterns are mainly shaped by water, rather than nutrient availability. Trait-environment relationships were nonetheless more-or-less similar for several drought-related traits across both species' groups. This study illustrates that ferns and lycophyte trait patterns are not equivalent for epiphytic and terrestrial species or communities, and should not be extrapolated across species groups or between the species- and community-level.

Nowhere to escape – Diversity and community composition of ferns and lycophytes on the highest mountain in Honduras

IPCC predictions for Honduras indicate that temperature will increase by up to 3–6°C and precipitation will decrease by up to 7–13% by the year 2050. To better understand how fern and lycophyte communities might be affected by climate change, we comprehensively surveyed the community compositions of ferns and lycophytes at Celaque National Park, the highest mountain in Honduras. We surveyed a total of 80 20 × 20 m2 plots along an altitudinal gradient of 1249–2844 m a.s.l., identifying all species and estimating their abundances. We recorded a total of 11,098 individuals from 160 species and 61 genera. Community composition was strongly influenced by changes in altitude, precipitation and the abundance of bryophytes (a proxy for air humidity). Of the 160 species, 63 are expected, under a RCP2.6 scenario for the year 2050, to shift their range fully or partially above the maximum altitude of the mountain. Of these, 65.1% are epiphytes. We found that species with narrow altitudinal ranges at high altitudes were more at risk. Our study indicated that conservation efforts should prioritise higher altitudinal sites, focusing particularly on preserving the vulnerable epiphytic fern species, which are likely to be at greater risk.

Ferns and Lycophytes of Honduras: A new annotated checklist

For over two decades no attempt has been made to update the checklist of Ferns and Lycophytes (hereafter only referred to as pteridophytes) of Honduras. In 1996 Nelson-Sutherland and co-workers published the first fully annotated checklist for the country, which included 651 named species (680 taxa including varieties and hybrids). However, phylogenetic relationships have changed substantially since then. There have also been many taxonomic revisions for several groups and a considerable number of new records have since been published. Our work aimed to provide a comprehensive updated and fully annotated checklist of Honduran ferns. We undertook a comprehensive literature review of new records for Honduras and verified each individual record for the country. We followed PPGI for our taxonomic species revisions. We excluded a total of 81 taxa from the original 1996 checklist due to synonymy or lack of evidence of the species occurrence in Honduras. A total of 114 new species records were added, including four previously unpublished records. Our new updated checklist includes 713 taxa (including 8 varieties and 7 hybrids) which represents a 19% increase to the number of pteridophytes known from Honduras. Our work provides updated information regarding the pteridophytes diversity of Honduras. These data provide a crucial first step towards the first Honduran pteridophytes flora.

Ferns and Licophytes in Coal Mining Waste and Tailing Landfills

Mineral coal extraction in Santa Catarina State (Brazil) Carboniferous Basin has degraded the local ecosystem, restricting the use of its areas. One of the biggest environmental impacts in the mining areas is the uncontrolled disposal of waste and sterile mining with high concentrations of pyrite, which in the presence of air and water is oxidized promoting the formation of acid mine drainage (AMD). These contaminants can be leached into water resources, restrict the use of water, soil and cause threats to fauna and flora. This study aimed to characterize these areas as to the content of Cd, Pb, Ni and Zn metals in the tailings and waste resulting from coal mining and to survey the species of ferns and lycophytes present. Wastes and tailing samples and specimens of ferns and lycophytes were collected in 23 landfills in six municipalities in the region and in four underlying areas used as controls. Chemical and physical analyses (pH in water and pH in KCl, Ca, Mg, P, K, Na, Mn, Fe, Al, clay and OM contents) were carried out and the total contents of heavy metals Cd, Pb were determined, Ni and Zn. Sampling of ferns and lycophytes was carried out by walking. The levels of heavy metals, Cd, Ni and Zn were below the prevention concentrations established by CONAMA Resolution 420/2009. Pb levels were above prevention values ​​in four landfills. Sixteen species of ferns and one lycophyte were found, with hemicryptophytes the most frequent and helophytes the most adapted to the environment. Of the species found, Pteridium esculentum (G. Forst.) Cockayne, Pityrogramma calomelanos (L.) Link and Telmatoblechnum serrulatum (Rich.) Perrie, DJ Ohlsen & Brownsey demonstrated resistance to degraded and contaminated environments with Pb, which may constitute an alternative for projects monitoring and environmental recovery.

Ferns and lycophytes from Ferradura Park, Canela (RS), Brazil

A list of ferns and lycophytes from Ferradura Park, a private park located in Canela, Rio Grande do Sul, Brazil is presented. The park has an area of 400 ha with forest formations such as Araucaria Forest, Mixed Ombrophilous Forest and Seasonal Deciduous Forest, with transition zones and areas at different stages of regeneration. We found 56 species (five lycophytes and 51 ferns) in Ferradura Park. Lycophytes are represented by two families (Lycopodiaceae and Selaginellaceae) and four genera, while 11 families and 33 genera were recorded for ferns. Most of the species are exclusively terrestrial (39 spp.). The predominant life form is hemicriptophytic with rosulate growth (27 spp.). Phlegmariurus heterocarpon, Polytaenium lineatum and Vittaria lineata are considered locally rare. The area presents 15% of the species richness of the State of Rio Grande do Sul including rare species, which highlights the importance of implementing effective actions for the continuing Park conservation.