Heavy metals in different moss species in alpine ecosystems of Mountain Gongga, China: Geochemical characteristics and controlling factors

Terrestrial mosses are promising tracers for research concerning metal atmospheric deposition and pollution. Concentrations of Cr, Co, Ni, Zn, Sr, Cd, Ba, and Pb in different moss species from Mountain Gongga, China were analyzed to investigate the effects of growth substrates, geographic elevation, and type of moss species on the accumulation characteristics of heavy metals, as well as to identify heavy metal sources. The ability of heavy metals to accumulate in moss varied significantly, with low concentrations of Cd and Co; medium concentrations of Cr, Ni, and Pb; and high concentrations of Zn, Sr, and Ba. Elevation significantly influenced the accumulation characteristics of heavy metals, with high concentrations found at lower elevations due to proximal pollution. Growth substrate and moss species were found to have certain influence on the bioconcentration capacities of heavy metals in moss in this study. Correlation analysis showed similar sources for Sr, Zn, and Ba, as well as for Ni, Co, and Cr. The positive matrix factorization (PMF) model was consistent with atmospheric deposition of Pb and Cd; substrate sources of Cr, Co, and Ni; and anthropogenic sources of Ba, Sr, and Zn. This research characterized the accumulation characteristics of heavy metals and their influence factors in different mosses found in alpine ecosystems and provides a reference for future studies in similar areas.

Accumulation and influencing factors of novel brominated flame retardants in soil and vegetation from Fildes Peninsula, Antarctica

The concentrations and distributions of nine novel brominated flame retardants (NBFRs) were analyzed in soil, lichen (Usnea aurantiaco-atra), and moss (Sanionia uncinata) samples collected from the Chinese Antarctic Great Wall Station and surrounding Fildes Peninsula area in west Antarctica. Total NBFR concentrations ranged from 61.2-225 pg/g dry weight (dw) in soil, 283-1065 pg/g dw in moss, and 135-401 pg/g dw in lichen, respectively. Decabromodiphenyl ethane (DBDPE) was the dominant NBFR in all samples, accounting for 65.2%, 50.1%, and 72.4% of cumulative NBFR concentration in soil, moss, and lichen, respectively. The concentrations of NBFRs in plant samples were higher than those in soil, which may be related to plant bioaccumulation. Significant log/log-linear correlations (p < 0.05) were found between the concentrations of BEHTEBP and total organic carbon (TOC) in soil, and between DBDPE and lipid content in mosses, indicating that TOC and lipid content potentially affect certain NBFRs in Antarctic soil and moss. This study presents the first report on NBFR contamination in soil and various vegetation in Antarctica.

Cellulase and Macerozyme-PEG-mediated Transformation of Moss Protoplasts

This protocol describes the generation of protoplasts from protonemal tissue of the moss Physcomitrium patens (syn. Physcomitrella patens), using Cellulase ONOZUKA R10 and Macerozyme R10, followed by polyethylene glycol (PEG) mediated transformation. The protonemal tissue grown in liquid suspension was harvested and treated with enzyme cocktails mix of 1.5% Cellulase ONOZUKA R10 and 0.5% Macerozyme R10 to generate 1,8 million protoplasts within 3 h.

Multivariate assessment of atmospheric deposition studies in Bulgaria based on moss biomonitors: trends between the 2005/2006 and 2015/2016 surveys

This study aims to investigate the changes in atmospheric deposition trends in Bulgaria, studied using the moss biomonitoring technique since 1995. For the first time, a paired (site-wise) comparison was performed after a critical review of the sampling networks and adjusting for location, the distance between the sampling points, and moss species. Data from the 2005/2006 and 2015/2016 moss surveys were chosen as instrumental neutron activation analysis was employed in both to determine the content of 34 elements (Al, As, Ba, Br, Са, Ce, Cl, Со, Cr, Cs, Fe, Hf, I, K, La, Mn, Na, Nd, Ni, Rb, Sb, Sc, Se, Sr, Ta, Tb, Th, Ti, Tm, U, V, W, Yb, Zn). In addition, Cd, Cu, and Pb were determined using complementary analytical methods: inductively coupled plasma atomic emission spectroscopy in 2015/2016 and atomic absorption spectroscopy in 2005/2006. For the subset of 57 routinely sampled locations in Bulgaria, hierarchical clustering on principal components and multiple factor analysis (MFA) were applied to assess the spatial trends in the 10 years elapsed between the surveys, as well as to characterise the origin of the determined elements. Elevation and distance between the sampling points were used as additional variables in the multiple factor analysis plane to ascertain their effect on the overall variance in the datasets. Distribution maps were constructed to illustrate the deposition patterns for the pollutant Pb. The results were consistent with decreased industrial output in the country, increased coal combustion and transport pollution, and construction of roads.

Comprehensive analysis of the Ppatg3 mutant reveals that autophagy plays important roles in gametophore senescence in Physcomitrella patens

BACKGROUND

Autophagy is an evolutionarily conserved system for the degradation of intracellular components in eukaryotic organisms. Autophagy plays essential roles in preventing premature senescence and extending the longevity of vascular plants. However, the mechanisms and physiological roles of autophagy in preventing senescence in basal land plants are still obscure.

RESULTS

Here, we investigated the functional roles of the autophagy-related gene PpATG3 from Physcomitrella patens and demonstrated that its deletion prevents autophagy. In addition, Ppatg3 mutant showed premature gametophore senescence and reduced protonema formation compared to wild-type (WT) plants under normal growth conditions. The abundance of nitrogen (N) but not carbon (C) differed significantly between Ppatg3 mutant and WT plants, as did relative fatty acid levels. In vivo protein localization indicated that PpATG3 localizes to the cytoplasm, and in vitro Y2H assays confirmed that PpATG3 interacts with PpATG7 and PpATG12. Plastoglobuli (PGs) accumulated in Ppatg3, indicating that the process that degrades damaged chloroplasts in senescent gametophore cells was impaired in this mutant. RNA-Seq uncovered a detailed, comprehensive set of regulatory pathways that were affected by the autophagy mutation.

CONCLUSIONS

The autophagy-related gene PpATG3 is essential for autophagosome formation in P. patens. Our findings provide evidence that autophagy functions in N utilization, fatty acid metabolism and damaged chloroplast degradation under non-stress conditions. We identified differentially expressed genes in Ppatg3 involved in numerous biosynthetic and metabolic pathways, such as chlorophyll biosynthesis, lipid metabolism, reactive oxygen species removal and the recycling of unnecessary proteins that might have led to the premature senescence of this mutant due to defective autophagy. Our study provides new insights into the role of autophagy in preventing senescence to increase longevity in basal land plants.

Moss biomonitoring and air pollution modelling on a regional scale: delayed reflection of industrial pollution in moss in a heavily polluted region?

A passive biomonitoring survey using terrestrial mosses was performed in a heavily polluted industrial region on the border between Czechia and Poland in a regular grid of 41 sampling points. The concentrations of 38 elements were determined in the moss samples, using Neutron Activation Analysis (NAA). Simultaneously, air pollution modelling was performed using the Czech reference methodology Symos'97 for the year of the sampling (2015) and 3 years prior (2012) in order to compare the results of both the approaches and evaluate the credibility of the moss biomonitoring method. The NAA results were transformed according to the principles of compositional data analysis and assessed using hierarchical clustering on principal components. The resulting clusters were compared with the results of air pollution modelling using one-way analysis of variance. The association of determined clusters with the pollution from industrial sources was confirmed only for the results of the 2012 modelling. This validates the complementarity of the air pollution modelling and the moss biomonitoring, ascertains the moss biomonitoring as a valid method for long-term pollution assessment and confirms one of the fundamentals of moss biomonitoring, the reflection of the atmospheric conditions prevailing in the period before the sampling.

Biological soil crusts determine soil properties and salt dynamics under arid climatic condition in Qara Qir, Iran

Biological soil crusts are a thin layer within the soil system but strongly determine the infiltration, runoff and water and solute movement. Little is known about the role of biological soil crusts on soil solute dynamics in arid ecosystems and the objective of this paper is to determine in Qara Qir rangeland how biological soil crusts control the water and salt distribution along the soil profile. Rainfall simulation experiments were carried out at five locations, and measurements of the soil at 0-5, 5-10, 10-20, 20-30, 30-50 and 50-80 cm depth were done before, 48 h and 21 days after the rainfall simulations. Soil particle size distribution, bulk density, water content, organic carbon and electrical conductivity were measured at each of the 270 samples (3 seasons × 3 times × 5 sites × 6 depths). Biological soil crusts increased soil organic carbon, soil water content, and infiltration rate; and biological soil crusts decreased soil bulk density, clay fraction, electrical conductivity, and other saline-sodic properties, especially in the upper layers (0-10 cm). Large pores in soils covered by biological soil crusts enhanced the preferential flows, infiltration and solute transport. Biological soil crusts not only directly affected the soil surface, but also influenced soil properties, and consequently determined spatio-temporal soil salinity distribution. Biological soil crusts act as a soil salinity reducing agent and contribute to the soil quality improvement under arid climatic conditions. Biological soil crusts can be considered as a soil conservation strategy and actively used in soil rehabilitation and ecosystems restoration.

Functional redundancy and divergence of β-carbonic anhydrases in Physcomitrella patens

β-carbonic anhydrases, which function in regulating plant growth, C/N status, and stomata number, showed functional redundancy and divergence in Physcomitrella patens. Carbonic anhydrases (CAs) catalyze the interconversion of CO₂ and HCO₃^-. Plants have three evolutionarily unrelated CA families: α-, β-, and γ-CAs. βCAs are abundant in plants and are involved in CO₂ assimilation, stress responses, and stomata formation. Recent studies of βCAs have mainly examined C₃ or C₄ plants, whereas their functions in non-vascular plants are mostly unknown. In this study, phylogenetic analysis revealed that the evolution of βCAs were conserved between subaerial green algae and bryophytes after terrestrialization event, and βCAs from some cyanobacteria might begin evolving for the adaptation of terrestrial environment/habitat. In addition, we investigated the physiological roles of βCAs in the basal land plant Physcomitrella patens. High PpβCA expression levels in different tissues suggest that PpβCAs play important roles in development in P. patens. Plants treated with 1-10 mM NaHCO₃ had higher fresh and dry weight, PpβCA expression, total CA activity, and photosynthetic yield (Fv/Fm) compared with water-treated plants. However, treatment with 10 mM NaHCO₃ influenced the C/N status. Further study of six Ppβca single-gene mutants revealed that PpβCAs have functional redundancy and divergence in regulating the C/N ratio of plants and stomatal formation. This study provides new insight into the physiological roles of βCAs in basal land plants.

A critical review on plant biomonitors for determination of polycyclic aromatic hydrocarbons (PAHs) in air through solvent extraction techniques

Polycyclic aromatic hydrocarbons (PAHs) are hydrocarbons having two or more fused aromatic rings, released from natural (like forest fires and volcanic eruption) as well as man-made sources (like burning of fossil fuel & wood, automobile emission). They are persistent priority pollutants and continue to last for a long time in the environment causing severe damage to human health owing to their genotoxicity, mutagenicity and carcinogenicity. The study of PAHs in environment has therefore aroused a global concern. PAHs adsorption to plant cell wall is facilitated by transpiration and plant root lipids which help PAHs transfer from roots to leaves and stalks, causing more accumulation of contaminants with the increase in lipid content. Hence, these bioaccumulators can be utilized as biomonitors for indirect assessment of ambient air pollution. Efficacy of specific plants, lichens and mosses as useful biomonitors of airborne PAHs pollution has been discussed in this review along with prevalent classical and modified extraction techniques coupled with proper analytical procedures in order to gain an insight into the assessment of atmospheric PAHs concentrations. Different modern and modified solvent extraction techniques along with conventional Soxhlet method are identified for extraction of PAHs from accumulative bioindicators and analytical methods are also developed for accurate determination of PAHs. Process parameters like choice of solvent, temperature, time of extraction, pressure and matrix characteristics are usually checked. An approach of biomonitoring of PAHs using plants, lichens and mosses has been discussed here as they usually trap the atmospheric PAHs and mineralize them.

Influence of Pseudomonas japonica and organic amendments on the growth and metal tolerance of Celosia argentea L

In this study, a pot experiment was piloted in a greenhouse to evaluate the potential of Celosia argentea var. cristata L. for tolerating/accumulating heavy metals in synthetic wastewater in the presence of Pseudomonas japonica and organic amendment, i.e., moss and compost. Two-week-old seedlings were transferred to pots, and after 4 weeks, the bacterial strain was inoculated, then watered with synthetic wastewater for 5 weeks and harvested after 9 weeks. After harvesting, physiological and biochemical parameters, as well as metal contents of plants, were quantified. The results indicated highest growth and biomass production in moss- and compost-associated plants while highest metal uptake has been found in the presence of P. japonica and synthetic wastewater-irrigated plants. Synthetic wastewater-irrigated plants have shown highest Pb uptake of 2899 mg kg^-1 DW, while with P. japonica in soil those plants have shown highest Cd, Cu, Ni, and Cr uptake of 962, 1479, 1042, and 956 mg kg^-1 DW, respectively. The production of antioxidant enzymes, i.e., catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione-s-transferase (GST), was high in P. japonica-amended plants because of increased uptake of metals. It is concluded that moss and compost have improved growth while P. japonica improved metal accumulation and translocation to aerial parts with little involvement in plant growth.

Epiphytic bryophyte biomass estimation on tree trunks and upscaling in tropical montane cloud forests

Epiphytic bryophytes (EB) are some of the most commonly found plant species in tropical montane cloud forests, and they play a disproportionate role in influencing the terrestrial hydrological and nutrient cycles. However, it is difficult to estimate the abundance of EB due to the nature of their "epiphytic" habitat. This study proposes an allometric scaling approach implemented in twenty-one 30 × 30 m plots across an elevation range in 16,773 ha tropical montane cloud forests of northeastern Taiwan to measure EB biomass, a primary metric for indicating plant abundance and productivity. A general allometry was developed to estimate EB biomass of 100 cm² circular-shaped mats (n = 131) with their central depths. We developed a new point-intercept instrument to rapidly measure the depths of EB along tree trunks below 300 cm from the ground level (sampled stem surface area (SSA)) (n = 210). Biomass of EB of each point measure was derived using the general allometry and was aggregated across each SSA, and its performance was evaluated. Total EB biomass of a tree was estimated by referring to an in-situ conversion model and was interpolated for all trees in the plots (n = 1451). Finally, we assessed EB biomass density at the plot scale of the study region. The general EB biomass-depth allometry showed that the depth of an EB mat was a salient variable for biomass estimation (R ² = 0.72, p < 0.001). The performance of upscaling from mats to SSA was satisfactory, which allowed us to further estimate mean (±standard deviation) EB biomass of the 21 plots (272 ± 104 kg ha^-1). Since a significant relationship between tree size and EB abundance is commonly found, regional EB biomass may be mapped by integrating our method and three-dimensional remotely sensed airborne data.

Moss as a biomonitor for the atmospheric deposition of anthropogenic microfibres

Microplastics, which are plastic particles < 5 mm, have been found throughout the environment. However, few studies have focused on their transport via atmospheric deposition. Bryophytes have been used as biomonitors for the atmospheric deposition of trace elements, persistent organic pollutants and particulate matter, and may potentially be used to monitor the atmospheric deposition of microplastics or anthropogenic microfibres (mf). Hylocomium splendens was collected from three lake catchments, which are remote from anthropogenic disturbance and emissions sources. Anthropogenic mf were observed in all moss samples; the average number was 24 mf g^-1 dry weight (range: 15-30 mf g^-1) across the three study sites. The average length of mf was 1.02 mm (range: 0.83-1.20 mm). Plastic mf were identified using five rigorous visual criteria; 27% of the observed mf passed four criteria and 13% passed all five, suggesting at most a quarter of the mf may be plastic. Annual average atmospheric deposition of anthropogenic mf across the three lake catchments was estimated at ~47,700 mf m^-2 (~12,000 plastic mf m^-2), based on a moss biomass of 2 kg dry weight m^-2. These preliminary findings suggest that moss may be a useful biomonitor for the atmospheric deposition of mf (and microplastics).

Application of δ15N to trace the impact of penguin guano on terrestrial and aquatic nitrogen cycles in Victoria Land, Ross Sea region, Antarctica

Penguin colonies in Antarctica offer an ideal "natural laboratory" to investigate ecosystem function and the nitrogen (N) cycle. This study assessed the spatial distribution of penguin-derived N from guano and quantitatively assessed its impact on plant N utilization strategies in Victoria Land, Ross Sea region, Antarctica. Soil, moss, and aquatic microbial mats were collected inside and outside an active Adélie penguin (Pygoscelis adeliae) colony and analyzed for δ¹⁵N of total and inorganic nitrogen (NH₄⁺-N and NO₃^--N). The soil total nitrogen (TN), NH₄⁺-N, and NO₃^--N concentrations, as well as their δ¹⁵N values were significantly higher in guano-impacted areas than those in guano-free areas, verifying that guano is an important N source at and near penguin colonies. However, even far from the penguin colonies, soil δ¹⁵N values resembled those in penguin colonies, suggesting strong spatial impacts of penguin-derived N. The moss impacted by guano was more enriched in δ¹⁵N than in guano-free areas. The δ¹⁵N values of NH₄⁺-N and NO₃^--N in soils covered with moss revealed that the moss might prefer inorganic N in the absence of guano, while the dissolved organic N would become an important source for moss growing on ornithogenic soils. Aquatic microbial mat samples near penguin colonies were ¹⁵N-enriched, but ¹⁵N-depleted at upland sites.

The complete mitochondrial genome of a moss Korea Climacium dendroides (Hedw.) F. Weber & D. Mohr

The complete mitochondrial genome of Climacium dendroides (GenBank accession number MN942036 was 104,860 base pairs in length, containing 40 protein-coding genes, 3 ribosomal RNA (rRNA), and 24 transfer RNA (tRNA). The base composition was 29.6% A, 29.4% T, 21.0% G, and 19.8% C and its G + C content was 41.0%. The mitochondrial structure and gene order was similar to other Bryophytes. Phylogenetic tree based on the combined analysis of 33 protein-coding genes was well congruent with traditional species relationship of the moss order Hypnales.

Perspective of mitigating atmospheric heavy metal pollution: using mosses as biomonitoring and indicator organism

Mosses were proved as an ideal and reliable biomonitor as well as an indicator of atmospheric trace metal pollution. They are used as model indicator species of air pollution since long back due to their simple structure, genetic diversity, totipotency, rapid colony-forming ability, and high metal resistance behavior. Bryomonitoring technique is gradually being popularized as an economically viable procedure for estimating the degrees of environmental health and evaluating the toxic pollutants in biosphere. Thus, in the present scenario, many parts of the world use these organisms for monitoring the air pollution. This article describes an overview of the relationship of terrestrial mosses with trace metals with respect to their uptake, accumulation, and toxification as well as detoxification and tolerance mechanisms. The review article explicitly expresses the caliber of the cryptogamic mosses in establishing the pristine environment around the world. It also highlights the underpinning mechanisms and potential for future research directions. We have referred more than 250 articles, which deals with the assessment and impact of different heavy metals on 52 numbers of different moss species belongs to different climatic zones. The present review covers the research work in this area carried out worldwide since 1965.

Functional characterization of metallothionein-like genes from Physcomitrella patens: expression profiling, yeast heterologous expression, and disruption of PpMT1.2a gene

Physcomitrella patens contains four metallothionein-like genes. Three were shown to confer metal tolerance in yeast. Transcript profiling suggests their roles in senescence and reproductive development or cadmium and oxidative stress. Metallothioneins (MTs) have been suggested to play various roles including metal detoxification, nutrient remobilization, ROS scavenging, stress tolerance, and plant development. However, little is known about the forms and functions of MTs in bryophytes. The moss Physcomitrella patens genome was found to contain four MT-like genes. Amino acid sequence composition showed that the P. patens MTs (PpMTs) were clustered with Type 1 plant MTs, and could be further classified into two sub-types, herein referred to as sub-type 1: PpMT1.1a and PpMT1.1b and sub-type 2: PpMT1.2a and PpMT1.2b. Transcript abundance of PpMT1.1b and PpMT1.2b was upregulated in the gametophore compared to protonema, and all, except PpMT1.2a, were highly induced in senescing gametophytes. PpMT1.1a and PpMT1.1b transcripts were upregulated in protonema treated with cadmium and hydrogen peroxide. Unlike many higher plant MTs, the PpMT transcript abundance was not strongly induced in response to copper and zinc. These results suggest that PpMTs may play a role in protecting P. patens from cadmium and oxidative stress and may be involved in tissues senescence and reproductive development. The PpMTs, except PpMT1.2b, were also able to confer metal tolerance and accumulation when heterologously expressed in the ∆cup1 yeast. A P. patens mutant lacking PpMT1.2a through targeted gene disruption was generated. However, it did not show any alteration in growth phenotypes under senescence-induced conditions or hypersensitivity to cadmium, copper, zinc, H₂O₂, and NaCl stresses. Further characterization of additional P. patens mutants lacking single or multiple PpMTs may provide insight into the physiological roles of bryophytic MTs.

Soil amendments enhanced the growth of Nicotiana alata L. and Petunia hydrida L. by stabilizing heavy metals from wastewater

Due to the non-degradable nature of heavy metals (HMs), the industrial effluent, whether treated or untreated, carrying HMs, eventually end up into the water bodies, soil, and sediments. Numerous countermeasures were applied, but the use of ornamental plants for the stress mitigation associated with HMs on the environment is a neglected research domain. The composition of wastewater influences bioremediation strategies. As the wastewater is contaminated with multiple HMs, many lab studies, with the plants, failed in the industrial field. This work focuses on the potential of Nicotiana alata L. and Petunia hydrida L. against multiple HMs contaminated synthetic wastewater. To improve plant tolerance, soil amendments (biochar, compost, and moss, each at 5% v/v in soil) were used, individually and in combination. After 6 weeks of the exposure, plant physiological, biochemical and enzymatic parameters, as well as the distribution of HMs, (Cd, Cr, Cu, Pb, Mn, Ni, and Zn) in the plant (flower, leaves, root, and shoot) and soil, were measured. The HMs uptake positivity influenced the malondialdehyde content, hydrogen peroxide content and electrolyte leakage, while negatively to photosynthetic pigments, and resulted in increased catalase, guaiacol peroxidase, glutathione s-transferase, ascorbate peroxidase, while reduced superoxide dismutase activity. It was found that all amendments improved the plant growth by metal stabilization, and best results were obtained with the combined application of biochar + compost + moss. So, HMs stabilization can be achieved by growing ornamental plants, like Nicotiana alata L. and Petunia hydrida L. along with soil amendments.

Agrobacterium-mediated Tnt1 mutagenesis of moss protonemal filaments and generation of stable mutants with impaired gametophyte

The gametophyte of moss exhibits a simple body plan, yet its growth is regulated by complex developmental phenomena similar to angiosperms. Because moss can be easily maintained under laboratory conditions, amenable for gene targeting and the availability of genome sequence, P. patens has become an attractive model system for studying evolutionary traits. Until date, there has been no Agrobacterium-mediated Tnt1 mutagenesis protocol for haploid protonemal filaments of moss. Hence, we attempted to use the intact tobacco Tnt1 retrotransposon as a mutagen for P. patens. Bioinformatic analysis of initiator methionyl-tRNA (Met-tRNAi), a critical host factor for Tnt1 transposition process, suggested that it can be explored as a mutagen for bryophytes. Using protonemal filaments and Agrobacterium-mediated transformation, 75 Tnt1 mutants have been generated and cryopreserved. SSAP analysis and TAIL-PCR revealed that Tnt1 is functional in P. patens and has a high-preference for gene and GC-rich regions. In addition, LTR::GUS lines exhibited a basal but tissue-specific inducible expression pattern. Forward genetic screen resulted in 5 novel phenotypes related to hormonal and gravity response, phyllid, and gamete development. SSAP analysis suggests that the Tnt1 insertion pattern is stable under normal growth conditions and the high-frequency phenotypic deviations are possibly due to the combination of haploid explant (protonema) and the choice of mutagen (Tnt1). We demonstrate that Agrobacterium-mediated Tnt1 insertional mutagenesis could generate stable P. patens mutant populations for future forward genetic studies.

Ti and Zn Content in Moss Shoots After Exposure to TiO2 and ZnO Nanoparticles: Biomonitoring Possibilities

To assess the uptake of nanoparticles by moss shoots and the possibility of biomonitoring the moss of nanoparticle pollution, two moss species frequently used in biomonitoring surveys [Hylocomium splendens (Hedw.) Schimp. and Pleurozium schreberi (Brid.) Mitt.] were repeatedly exposed to known concentrations of either nano-TiO₂ or nano-ZnO suspensions. The interspecies differences were assessed by exposing both the species to 1 g L^-1 nano-ZnO suspension, H. splendens samples were also exposed to either 0.1 g L^-1 or 1 g L^-1 suspension of nano TiO₂. The exposed samples were analysed for Zn or Ti content using Inductively Coupled Plasma-Atomic Emission Spectroscopy. Both species showed a similar accumulation pattern, H. splendens being a slightly better accumulator. The washing suggests that Ti successfully penetrated the interior of the gametophyte. Since the relationship between the exposure and accumulation is linear, moss biomonitoring is, hereby, considered to be a viable, novel technique in nanoparticle pollution assessment.

Assays of Protonemal Growth Responses in Physcomitrella patens Under Blue- and Red-Light Stimuli

The non-seed land plant Physcomitrella patens is a model species for developmental, cellular, and molecular biology studies in mosses and also for performing genetic analyses. Previously, it was shown that wild-type P. patens displays a unique photomorphogenetic behavior, in which chloronemal filaments grow in the opposite direction to a blue-light source. Here, we describe bioassay systems that can be used to study light avoidance responses as well as other aspects of photomorphogenetic regulation in P. patens grown under red- and blue-light sources.

Direct and indirect effects of land use on bryophytes in grasslands

Land-use intensification is the major threat for biodiversity in agricultural grasslands, and fertilization has been suggested as the most important driver. A common explanation for the decline of bryophyte diversity with higher land-use intensity is an indirect negative effect via the increase in vascular plant productivity, which reduces light levels for bryophytes. However, direct negative effects of land-use intensification may also be important. Here, we disentangle direct and vascular plant biomass mediated indirect effects of land use on bryophytes. We analyzed two complementary datasets from agricultural grasslands, an observational study across 144 differently managed grasslands in Germany and an experimental fertilization and irrigation study of eleven grasslands in the Swiss Alps. We found that bryophyte richness and cover strongly declined with land-use intensity and in particular with fertilization. However, structural equation modelling revealed that although both direct and indirect effects were important, the direct negative effect of fertilization was even stronger than the indirect effect mediated by increased plant biomass. Thus, our results challenge the widespread view that the negative effects of fertilization are mostly indirect and mediated via increased light competition with vascular plants. Our study shows that land use intensification reduces bryophyte diversity through several different mechanisms. Therefore, only low-intensity management with limited fertilizer inputs will allow the maintenance of bryophyte-rich grasslands.

In vitro assessment of antimicrobial activity of aqueous and alcoholic extracts of moss Atrichum undulatum (Hedw.) P. Beauv

Bryophytes, the shade loving plants, have tremendous medicinal properties. The aqueous and alcoholic extracts of Atrichum undulatum (Hedw.) P. Beauv. were analysed for antimicrobial properties against the fungi Aspergillus fumigatus and Fusarium oxysporum and the bacteria Escherichia coli, Bacillus mycoides, Proteus mirabilis, Staphylococcus aureus and Salmonella typhi. The study is an attempt to investigate the medicinal properties of Atrichum undulatum (Hedw.) P. Beauv. using disc-diffusion method. No inhibition was observed against A. fumigatus and P. mirabilis. For bacteria S. typhi and E. coli (20 and 15 mm), aqueous and alcoholic extracts of Atrichum showed significant inhibition. However, alcoholic extract was found remarkably effective against bacteria rather than aqueous extract.

Nothotylenchus andrassy n. sp. (Nematoda: Anguinidae) from Northern Iran

Nothotylenchus andrassy n. sp. is described and illustrated from moss ( Sphagnum sp.) based on morphology and molecular analyses. Morphologically, this new species is characterized by a medium body size, six incisures in the lateral fields, and a delicate stylet (8-9 µm long) with clearly defined knobs. Pharynx with fusiform, valveless, non-muscular and sometimes indistinct median bulb. Basal pharyngeal bulb elongated and offset from the intestine; a long post-vulval uterine sac (55% of vulva to anus distance); and elongate, conical tail with pointed tip. Nothotylenchus andrassy n. sp. is morphologically similar to five known species of the genus, namely Nothotylenchus geraerti , Nothotylenchus medians , Nothotylenchus affinis , Nothotylenchus buckleyi , and Nothotylenchus persicus . The results of molecular analysis of rRNA gene sequences, including the D2-D3 expansion region of 28S rRNA, internal transcribed spacer (ITS) rRNA and partial 18S rRNA gene are provide for the new species.

Peristome as a potential tool for delimiting Bryum Hedw. (Bryaceae) from India

The peristome, an interesting and important taxonomic structure used in the systematics of mosses, is for the first time studied in detail for 21 taxa of Bryum, which constitute a fraction of Indian representatives. Macro- and micro-morphological characters including color, size and length of two components of peristome, tapering pattern, median line, and papillosity at upper part under light microscope; width of exostome border, number and inner surface of ventral trabeculae, presence or absence of longitudinal/oblique septae between ventral trabeculae, pattern of exostome surface and height of endostomial basal membrane, adherence, perforations, and surface of cilia under scanning electron microscope were examined to bring out submicroscopic differences. Detail surface structure of eight taxa, viz., B. apalodictyoides, B. evanidinerve, B. pachytheca, B. pseudotriquetrum var. subrotundum, B. reflexifolium, B. thomsonii, B. tuberosum, and B. turbinatum, under LM and nine species, namely, B. apalodictyoides, B. apiculatum, B. argenteum, B. billarderi, B. dichotomum, B. evanidinerve, B. recurvulum, B. turbinatum, and B. uliginosum, under SEM is being provided for the first time. Description of peristome surface and a key based on SEM and other taxonomical features is also being provided. The data obtained from the present study suggest that the species of this genus can easily be distinguished on the basis of peristomial surface pattern.

Source discrimination of atmospheric metal deposition by multi-metal isotopes in the Three Gorges Reservoir region, China

Concentrations of heavy metals, as well as isotopic compositions of mercury (Hg) and lead (Pb), in mosses (Bryum argenteum) from the Three Gorges Reservoir (TGR) region were investigated to decipher the sources of atmospheric metals in this region. Higher contents of metals (0.90 ± 0.65 mg/kg of Cd, 24.6 ± 27.4 mg/kg of Cu, and 36.1 ± 51.1 mg/kg of Pb) in the mosses from TGR were found compared with those from pollution-free regions. Principal component analysis (PCA) grouped the moss metals into four main components which were associated with both anthropogenic and natural sources. The ratios of Pb isotopes of the mosses (1.153-1.173 for ²⁰⁶Pb/²⁰⁷Pb and 2.094-2.129 for ²⁰⁸Pb/²⁰⁶Pb) fell between those of the traffic emissions and coals. Similarly, the compositions of δ²⁰²Hg (-4.29∼-2.33‰) and Δ¹⁹⁹Hg (within ±0.2‰) were comparable to those of the coals and coal combustion emissions from China and India. These joined results of Pb and Hg isotope data give solid evidences that the coal combustion and traffic emissions are the main causes of metal accumulation in the TGR region.