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This research aims to analyze the efficiency of processing liquid waste from the laundry industry using the Free Water Surface Constructed Wetland (FWS) system with Azolla microphylla plants. The research method used is experimental research by manipulating independent variables and controlling other relevant variables, as well as observing the effect on the dependent variable. Laundry waste samples were taken from Berkah Laundry, Puri Gading, Bekasi. The results showed that the biomass of Azolla microphylla plants increased significantly from day 0 to day 12, with a growth rate between 0.0289 - 0.0477 grams/day and plant density between 185.19 ind/m2 - 277.78 ind/m2. The influent BOD concentration of laundry liquid waste during the acclimatization stage ranged from 5.89 - 10.54 mg/L, while the effluent BOD ranged from 4.35 - 6.98 mg/L, with the highest efficiency reaching 33.8%. The constructed wetland system with Azolla microphylla plants has proven to be effective in reducing pollutant content in liquid waste, with a BOD removal efficiency of 11.1% - 17.7% and COD of 14.5% - 39%. The conclusion of this research is that the use of artificial wetlands with Azolla microphylla plants can be an effective and environmentally friendly alternative solution for processing liquid waste from the laundry industry. The implications of this research show the potential for applying constructed wetland technology in the clothes washing industry to reduce the negative impact of waste on the environment. [ABSTRACT FROM AUTHOR]

Highlights • Adaxial epidermis of floating fronds holds sunken stomata and multicellular trichomes. • The submerged leaves contain numerous filamentous trichomes. • The spore-bearing organs are represented by submerged sori. • The microsporangiate sori contain a number of small spherical microsporangia. • The megasporangiate sori include a small number of large ovoid-oval megasporangia. Abstract The article describes the growth and development of Salvinia natans (L.) All., a native aquatic fern found in Ukraine, collected from artificial water reservoirs in the Desnyansky district of Kyiv. Scanning electron microscopy was used to study the surface microstructure of its vegetative and reproductive organs. The success of the fern on the boundary of water and air is apparently supported by the specific microstructure of its floating leaves, the adaxial surface of which are characterised by the presence of a well-developed cuticle and sunken stomata. The stomatal density was found to be 142 per mm2, with an average stomatal pore diameter of 8.1 μm. The abaxial surface of both floating and submerged leaves was characterised by the presence of thin cell walls in the epidermis and of numerous filamentary appendages (trichomes). The structure of both the sori and the sporangia allows for an annual summer-green phenological pattern, whereby sori are produced near the bottom of the reservoir in autumn, and rise to the surface of water in spring. [ABSTRACT FROM AUTHOR]

Plant leaves occur in diverse shapes. Divarication patterns that develop during early growths are one of key factors that determine leaf shapes. We utilized leaves of Microsorum pteropus, a semi-aquatic fern, and closely related varieties to analyze a variation in the divarication patterns. The leaves exhibited three major types of divarication: no lobes, bifurcation, and trifurcation (i.e., monopodial branching). Our investigation of their developmental processes, using time-lapse imaging, revealed localized growths and dissections of blades near each leaf apex. Restricted cell divisions responsible for the apical growths were confirmed using a pulse-chase strategy for EdU labeling assays. [ABSTRACT FROM AUTHOR]

We report here two megaspores species related to the aquatic ferns of the order Salviniales from the Late Cretaceous Mata Amarilla Formation (Austral Basin), southern Santa Cruz Province, Argentina. We identified the species Arcellites disciformis and Balmeisporites cf. B. holodictyus. The presence of A. disciformis, in particular, is significant not only because it represents the first record for the Southern Hemisphere, indicating a bi-hemispheric distribution for the species, but also because it increases the diversity of this genus in Patagonia. The new findings of salvinialean megaspores highlight the importance of water ferns in the Late Cretaceous aquiferous enviroments of southern South America. The common occurrences of Arcellites and Balmeisporites, whether in shallow, fresh or brackish water facies, indicates aquatic paleoenvironment of the Mata Amarilla Formation, as was inferred also from the sedimentological evidence. Their presence also indicates that the lower and middle levels of the Mata Amarilla Formation can be attributed to the megaspore Zone M3 (Albian-Cenomanian) defined for the Cretaceous of Patagonia. [ABSTRACT FROM AUTHOR]

The world's largest green tide originated from the Jiangsu Shoal of the Yellow Sea was due to fast reproduction of floating green macroalgae ( Ulva prolifera ). It brought significant impacts on marine environment and ecosystem in the Yellow Sea. In this study, we examined the expansion of green tide from the Jiangsu Shoal during the period from 29 April to 25 June 2016. Using high-resolution satellite images, we revealed a declined growth rate during the northward drifting of early-stage green tide for the first time, i.e., the green tide had higher growth rate (up to 25% per day) in the turbid waters of the Jiangsu Shoal in May and a lower growth rate (low to 3% per day) in the relatively clear waters in the middle of the western Yellow Sea in June, which suggests that water clarity might not be the key factor controlling the growth rate of the floating macroalgae in the surface waters under natural conditions. The high growth rate led to shortened time windows for controlling the green tide by employing macroalgae collecting campaigns at the initial sites of the green tide, which was no more than 14 days in the 2016 case. [ABSTRACT FROM AUTHOR]

Abstract: Modern literature on plant dispersal by birds focuses mainly on the importance of frugivory and scatter‐hoarding, yet recent studies show that endozoochory by migratory waterbirds is an important mechanism of long‐distance dispersal for a broad range of plants. Nevertheless, there is a lack of empirical field studies that identify the plants dispersed by waterbirds in a comprehensive manner. In particular, so far there are no detailed studies of the level of spatial variation in the plant taxa dispersed by a waterbird vector, and no clear demonstration that aquatic ferns can be dispersed by endozoochory. Consequently, we remain ignorant of the networks of dispersal interactions between granivorous waterbirds and plants. Five sets of faecal samples (total n = 215) were collected from mallards Anas platyrhynchos on autumn migration in the Hevesi‐holm and Balaton regions in Hungary, central Europe. Intact diaspores were extracted, identified and their germinability assessed under standard conditions. The plant communities recorded at different sites were compared with PERMANOVA and other multivariate methods. Macrospores of the floating watermoss Salvinia natans were recorded in 32 samples, and a total of 16 macrospores germinated, providing the first field demonstration of endozoochory of ferns by birds. Of 21 angiosperm taxa recorded (of which eight germinated), 13 were terrestrial species, although the most abundant taxa were aquatic species such as the alkali bulrush Bolboschoenus maritimus and the sago pondweed Potamogeton pectinatus. Two naturalized alien species, the common fig Ficus carica and the hackberry Celtis occidentalis were also recorded. Only four of the taxa had an endozoochory syndrome. The plant taxa dispersed varied at two different spatial scales, with minor but significant differences between samples from sites separated by less than 1 km, and major differences between the two regions separated by c. 220 km. Synthesis. This is a unique study of the spatial variation in plants dispersed by endozoochory by a migratory waterfowl species, with a high taxonomic resolution and the first demonstration of avian endozoochory of ferns. We recorded eight taxa not previously reported as dispersed by mallards, showing how more empirical studies are essential, so we can understand which plants are dispersed by migratory birds. We found evidence that networks of interactions between granivorous waterbird vectors and dispersed plants vary spatially. [ABSTRACT FROM AUTHOR]

Premise of research. In the past two decades, numerous aquatic ferns related to Marsileaceae from the Upper Cretaceous have been described. Most fossils resembling Marsilea L. but lacking reproductive structures have been included in the fossil genus Marsileaceaephyllum. Here we describe a new species of the aquatic fern genus Marsilea from the Olmos Formation (upper Campanian), northern Mexico, that is represented by leaves, rhizomes, and a sporocarp. This new fossil represents the first unequivocal record of the extant genus Marsilea worldwide from the Late Cretaceous.Methodology. The fossils we describe in this article were collected from sediments of the Olmos Formation, Coahuila, Mexico. The samples were identified by direct comparison with fossils from other localities and extant species.Pivotal results. The aquatic fern described here consists of leaves that are composed of four opposite leaflets in a cruciform arrangement. The fossil leaflets can be sessile or attached to a short petiolule, and their base is straight to cuneate. The leaflet apex can be obtuse and/or round, and the margin is entire but is sometimes slightly wavy toward the apex of the leaflet. The leaflets have straight venation, dichotomous with anastomoses (reticulate) throughout the leaflet. The areoles are polygonals and fusiform, and they fuse to form a marginal vein. Small sporocarp without teeth, oblong in lateral view. The combination of the features discussed above supports the creation of a new species of Marsilea from the upper Campanian of northern Mexico.Conclusions. The new species of Marsilea reported here represents the first record of the genus from the Cretaceous and provides additional evidence that aquatic plants such as Marsilea—as well as Salvinia, Dorfiella, Pistia, Nymphaceae, and Nelumbonaceae—were an important element of the flora preserved in the Olmos Formation. [ABSTRACT FROM AUTHOR]

This study investigated the potential of Azolla pinnata (AP) in the removal of toxic methyl violet 2B (MV) dye wastewater using the phytoextraction approach with the inclusion of an Artificial Neural Network (ANN) modelling. Parameters examined included the effects of dye concentration, pH and plant dosage. The highest removal efficiency was 93% which was achieved at a plant dosage of 0.8 g (dye volume = 200 mL, initial pH = 6.0, initial dye concentration = 10 mg L−1). A significant decrease in relative frond number (RFN), a growth rate estimator, observed at a dye concentration of 20 mg L−1 MV indicated some toxicity, which coincided with the plant pigments studies where the chlorophyll a content was lower than the control. There were little differences in the plant pigment contents between the control and those in the presence of dye (5 to 15 mg L−1) indicating the tolerance of AP to MV at lower concentrations. A three-layer ANN model was optimized (6 neurons in the hidden layer) and successfully predicted the phytoextraction of MV (R = 0.9989, RMSE = 0.0098). In conclusion, AP proved to be a suitable plant that could be used for the phytoextraction of MV while the ANN modelling has shown to be a reliable method for the modelling of phytoextraction of MV using AP. [ABSTRACT FROM AUTHOR]

The data presented in this paper concern the occurrence of Salvinia natans (L.) All. in Wrocław area. Field research was conducted in the vegetation season (June-September) between 2013 and 2017 in water bodies (natural and artificial), in the main river beds of the Oława and the Odra Rivers and in the Odra canals in Wrocław. The study provided 32 S. natans locations in the city area. The studied species occurred in various plant communities accompanied by numerous species which were also under protection, increasing the ecological value of the habitats. Additionally, a stable S. natans site was confirmed by the study in a location where aquatic fern had previously been recorded in Wrocław. The research indicates numerous populations of the species along the Odra and the Oława and in many old river beds and artificial water bodies in Wrocław and the results confirm the visible trend of a growing number of S. natans sites in all of Poland. [ABSTRACT FROM AUTHOR]

Azolla (Azolla filiculoides) is a common aquatic fern that has been used successfully as a dual crop with lowland rice. It grows rapidly and has the ability to fix N2for rice paddy. However, its ecological significance especially on greenhouse gases emissions remains unclear. To investigate the effect of azolla cover on methane (CH4) and nitrous oxide (N2O) emissions from rice paddy, a pot experiment with two treatments, control (rice plant only) and azolla cover (rice plus azolla covering on the flooding water), was carried out in Tsuruoka, Yamagata, Japan, in 2016. The results showed that the rice growth parameters, like shoot height, maximum and productive tiller numbers, and plant biomass were not significantly different between the two treatments. Dual cropping of azolla with rice significantly suppressed CH4emissions, likely due to an increase in dissolved oxygen concentration and redox potential at the soil-water interface between flooding water and soil surface. There were significant (P < 0.05) positive correlations between CH4flux and night respiration (CO2emissions) between the two treatments. The cumulated CH4emissions during the growth period until 106 days after transplanting (DAT) was significantly lower at 36.2 g C m−2from azolla cover treatment than that from control treatment pot at 55.4 g C m−2. A prolonged nonsignificant N2O emission under the azolla cover treatment after the initial highest peak at 15 DAT was recorded due to denitrification of the nitrate in initial soil. No further N2O emissions were recorded thereafter from both treatments. Azolla cover did not affect N2O emissions from both treatments. [ABSTRACT FROM PUBLISHER]

We analyzed chloroplast ultrastructure, microstructure of fronds surfaces, pigment's content and efficient use of light by photosynthetic apparatus in floating and submerged fronds of water fern Salvinia natans at different stages of development. In parenchymal cells of floating fronds average chloroplast cross-section area at intensive growth stage (June) was 5.56 gm2. Well-developed system of thylakoid membranes formed numerous gram. Up to four starch grains occurred. In submerged fronds chloroplasts cross-section area was 2.16 gm2. Degradation of grana thylakoid membrane and disruption of intergranal connections were revealed in fronds in stage of sporocarp formation (September). Rows of plastoglobules were found in chloroplasts of floating frond. Starch grains were almost entirely absent in stroma. Adaxial surface of floating fronds had simple structure stomata. The abaxial surface had no stomata and the cuticle was not developed. Pigment's content in floating fronds was twice higher than that of submerged ones. During development of fern a content of pigments raised up in the floating leaves. At stage of sporocarps formation the chlorophyll and carotenoid content reduced. Floating fronds showed an effective operation of chloroplast photosynthetic electron-transport chain. Submerged fronds exposed to intensive light were characterized by decrease of efficiency of PSII and increase of nonphotochemical quenching of chlorophyll fluorescence. [ABSTRACT FROM AUTHOR]

Salvinia minima was assessed for its ability to accumulate lead (Pb) by exposing it to concentrations of 40 µM Pb(NO 3 ) 2 during 24 h. At the same time, the expression levels were quantified, of four genes coding for transporters: SmABCC (ABCC-MRP), SmATPase (ATPase-P3A), SmNhaD (Type-Na + /H + ) and SmABCG (ABCG-WBC). In the absence of lead, S. minima had very low expression of those genes, when plants were exposed to the metal however, those genes showed a rapid (in just three hours or less) and sharp increase (up to 60 times) in their expression, particularly the SmNhaD (Type-Na + /H + ) gene. This sharp increase in expression levels of the genes studied, occurred at the same time that the plant accumulated the highest content of lead in its tissues. The first two genes, are apparently implicated in detoxification and lead accumulation mechanisms, while the other two genes are apparently involved in maintaining cell balance (homeostatic control) and membrane integrity. Our results confirmed that S. minima is efficient for phytoremediation of water bodies contaminated by lead, as it is efficient in accumulating this metal in its tissues (bioconcentration factor; BCF) values greater than 1000, in short times of exposure. More importantly, our data on the expression profiles of four genes coding for transporters, represent a first sight scenario of the molecular basis for understanding the different mechanism of detoxification, apparently present in this aquatic fern. [ABSTRACT FROM AUTHOR]

We investigated the ability of the aquatic fern Azolla to take up ciprofloxacin (Cipro), as well as the effects of that antibiotic on the N-fixing process in plants grown in medium deprived (-N) or provided (+N) with nitrogen (N). Azolla was seen to accumulate Cipro at concentrations greater than 160 μg g −1 dry weight when cultivated in 3.05 mg Cipro l −1 , indicating it as a candidate for Cipro recovery from water. Although Cipro was not seen to interfere with the heterocyst/vegetative cell ratios, the antibiotic promoted changes with carbon and nitrogen metabolism in plants. Decreased photosynthesis and nitrogenase activity, and altered plant's amino acid profile, with decreases in cell N concentrations, were observed. The removal of N from the growth medium accentuated the deleterious effects of Cipro, resulting in lower photosynthesis, N-fixation, and assimilation rates, and increased hydrogen peroxide accumulation. Our results shown that Cipro may constrain the use of Azolla as a biofertilizer species due to its interference with nitrogen fixation processes. [ABSTRACT FROM AUTHOR]

Dangers of arsenic contamination are well known in human civilization. The threat increases when arsenic is accumulated in food and livestock through irrigated crops or animal food. Hence, it is important to mitigate the effects of arsenic as much as possible. This paper discusses a process for reducing the level of arsenic in different parts of rice plants with an aquatic fern, Marsilea minuta L. A pot experiment was done to study the possibility of using Marsilea minuta as a phytoremediator of arsenic. Rice and Marsilea minuta were allowed to grow together in soils. As a control, Marsilea minuta was also cultured alone in the presence and absence of arsenic (applied at 1 mg/L as irrigation water). We did not find any significant change in the growth of rice due to the association of Marsilea minuta, though it showed a reduction of approximately 58.64% arsenic accumulation in the roots of rice grown with the association of fern compared to that grown without fern. We measured a bioaccumulation factor (BF) of > 5.34, indicating that Marsilea minuta could be a good phytoremediator of arsenic in rice fields. [ABSTRACT FROM AUTHOR]

ABSTRACT The primitive land plant life cycle featured the production of spores of unimodal size, a condition called homospory. The evolution of bimodal size distributions with small male spores and large female spores, known as heterospory, was an innovation that occurred repeatedly in the history of land plants. The importance of desiccation-resistant spores for colonization of the land is well known, but the adaptive value of heterospory has never been well established. It was an addition to a sexual life cycle that already involved male and female gametes. Its role as a precursor to the evolution of seeds has received much attention, but this is an evolutionary consequence of heterospory that cannot explain the transition from homospory to heterospory (and the lack of evolutionary reversal from heterospory to homospory). Enforced outcrossing of gametophytes has often been mentioned in connection to heterospory, but we review the shortcomings of this argument as an explanation of the selective advantage of heterospory. Few alternative arguments concerning the selective forces favouring heterospory have been proposed, a paucity of attention that is surprising given the importance of this innovation in land plant evolution. In this review we highlight two ideas that may lead us to a better understanding of why heterospory evolved. First, models of optimal resource allocation - an approach that has been used for decades in evolutionary ecology to help understand parental investment and other life-history patterns - suggest that an evolutionary increase in spore size could reach a threshold at which small spores yielding small, sperm-producing gametophytes would return greater fitness per unit of resource investment than would large spores and bisexual gametophytes. With the advent of such microspores, megaspores would evolve under frequency-dependent selection. This argument can account for the appearance of heterospory in the Devonian, when increasingly tall and complex vegetative communities presented competitive conditions that made large spore size advantageous. Second, heterospory is analogous in many ways to anisogamy. Indeed, heterospory is a kind of re-invention of anisogamy within the context of a sporophyte-dominant land plant life cycle. The evolution of anisogamy has been the subject of important theoretical and empirical investigation. Recent work in this area suggests that mate-encounter dynamics set up selective forces that can drive the evolution of anisogamy. We suggest that similar dispersal and mating dynamics could have underlain spore size differentiation. The two approaches offer predictions that are consistent with currently available data but could be tested far more thoroughly. We hope to re-establish attention on this neglected aspect of plant evolutionary biology and suggest some paths for empirical investigation. [ABSTRACT FROM AUTHOR]

Severely infected water fern, Azolla microphylla Kaulf., has been observed in natural habitats in different districts in the lower Gangetic plain of West Bengal, India. The infected plants have turned dark brown and been rotted entirely within 5-7 days, causing loss of natural resource as the plant species has immense commercial value. Specific growing colonies with cottony white mycelium, yellow pigmentation on the cultured medium, macro- and micro- conidial features, and absence of chlamydospore indicate the causal pathogen to be Fusarium thapsinum Klittich., Lesile, Nelson, Marases. The identification of the causal pathogen has been authenticated by standard pathogenicity test (Koch's Postulates). Extensive literature survey reveals that this is a new record of brown rot disease in A. microphylla. [ABSTRACT FROM AUTHOR]

Azolla primaeva (Penhallow) Arnold fertile whole plants from the lower Eocene of Driftwood Creek, Canada have been examined using LM, SEM, TEM and SRXTM methods on hand specimens and sieved residues. The new data have resulted in an emended diagnosis. The megaspore is partly covered by filosum and the wall lacks excrescences. The exoperine is highly variable with nodular, to clavate, baculate and tabulate elements, which fuse to form a foveolate to reticulate megaspore surface, which is complex and contorted. Glochidia on the microspore massulae are sometimes septate and the flukes on their anchor-shaped tips are variable, some being long, narrow and wavy, others shorter and broad and a few are recurved. Hairs are lacking on the massula surface and glochidia. The organization of the float zone of the megaspore apparatus has always been controversial with 0, 1, 3 or 9 floats proposed. The new results show that there are no pseudovacuolate floats. By contrast, the ‘float’ zone consists of bundles of modified granular and filamentous endoperine elements surrounded by bundles of broader suprafilosum hairs. The absence of pseudovacuolate floats in A. primaeva is suggested to be an important character for phylogenetic analyses. The high variability in glochidia tips, glochidia septa and exoperine organisation is unusual within the genus Azolla . The new data on A. primaeva are compared with the other two whole plant Azolla species from Canada ( Azolla stanleyi and Azolla schopfii ) and with dispersed Azolla reproductive structures from Canada including the Arctic. This confirms that all are distinct species. [ABSTRACT FROM AUTHOR]

Pilularia globulifera is a subatlantic European fern threatened with extinction. In Poland, it reaches the eastern border of its continuous range. Up to the end of the 20th century, it was observed here in 21 stands; only 2 of them existed by the second half of the century, so the species was categorized as critically endangered. Five new locations have been found in western and northwestern Poland during the last 10 years. Abundant and permanent populations grow in 3 locations, while 2 stands were ephemeral. All the current stands are situated in anthropogenic habitats with spontaneous vegetation, in oligotrophic to eutrophic waters. One of the new localities is about 280 km distant from the eastern range of the limit known previously. Pilularia forms its own plant community Pilularietum globuliferae, enters plots of Ranunculo-Juncetum bulbosi and occurs in mesotrophic to eutrophic rushes of Eleocharis palustris, Phragmites australis, Typha angustifolia and Equisetum fluviatile. Specimens are vigorous and regularly produce sporocarps.

Azolla filiculoides has been an ephemeral plant in Poland since the end of the 20th century. In the last 15 years this species appeared in 5 locations in south-west Poland. Habitat and plants of two populations became destroyed, three other still exist. A. filiculoides occurs in eutrophic or even polluted water where it forms dense mats, up to 10 cm thick. It stays sterile and propagates only in a vegetative manner. Frost resistance of Lower Silesia populations is higher than reported so far; fern may winter and rebuild the population after frost reaching 22oC. Size of the populations is changeable during the vegetation season. A. filiculoides occurs in water habitats and plant communities in which it substitutes Lemna minor.

The present study investigated the effect of copper on photosynthesis, antioxidant potential, and anatomical response of aquatic fern, Salvinia cucullata, with a view to ascertain its phytoremediation potential. Plants were exposed in hydroponics for 21 days to different Cu concentrations (10, 15, 20, and 30 mg/L). Significant declines in chlorophyll, carotenoids, and soluble proteins, as a function of Cu proportion were observed. Lipid peroxidation was also evident, which implied reactive oxygen species (ROS) generation. However, both root and leaf tissues responded remarkably to the ROS produced, by inducing superoxide dismutase (1.6-6.5 times), catalase (1.5-5.4 times), guaicol peroxidase (1.5-7.2 times), and ascorbyl peroxidase (1.3-4.7 times) over the control. The plant showed best phytoremedial activity within Cu range of 10-15 mg/L, with maximum accumulation of 2956 ± 82.6 μg/g dw., at 15 mg Cu/L and showed efficient root to shoot translocation (translocation factor, TF > 1) at this range, which is the stipulated minimum requirement to be a hyperaccumulator. The capacity of metal extraction from environment to leaf (extraction coefficient, EC) was also high (EC = 73-197). However, at higher doses (20-30 mg/L), the plant resorted to an exclusion strategy, whereby, more metal accumulation was observed in root than in leaf. The plant conferred suitable remediation attributes by showing minimal root and leaf anatomical damages along with high Ca peaks in both the tissues, and rapid leaf stomatal closure, all of which probably helped in the Cu induced stress mitigation. Due to its widespread availability, fast growth, ability to grow in myriads of polluted environment, and having hardy physiology, this plant can be suggested for use as a suitable Cu phytoremediator. [ABSTRACT FROM AUTHOR]

Water ferns (Azolla spp., Azollaceae) are reported for the first time as host plants for the larvae of the small China-mark moth Cataclysta lemnata (Linnaeus) (Lepidoptera: Crambidae: Acentropinae) in rice fields and waterways of northern Iran. Cataclysta lemnata is a semi-aquatic species that has been recorded to feed on Lemnaceae and a few other aquatic plants. However, it has not been reported before on Azolla spp. Larvae use water fern as food source and shelter and, at high population density in the laboratory, they completely wiped water fern from the water surface. Feeding was confirmed after rearing more than eight continual generations of C. lemnata on water fern in the laboratory. Adults obtained this way are darker and have darker fuscous markings in both sexes compared with specimens previously reported and the pattern remains unchanged after several generations. [ABSTRACT FROM AUTHOR]

This paper analyses aquatic ferns from the genera Azolla Lam., Marsilea L. and Salvinia Séguier, which occur in the Danube Delta, Romania, and comprises a series of anatomical and histological observations of taxonomical, chorological and eco-morphological importance. The research conducted on specimens collected between 2005-2013 from the natural habitats of the Danube Delta, but also from the extra-deltaic artificial habitats have enabled: i) a reconsideration of some chorological aspects regarding the species of the genus Azolla in Romania; ii) a greater understanding of the adaptive plasticity relative to the factor water for the taxon Marsilea quadrifolia L. collected from natural and artificial habitats; iii) the enrichment of the data regarding the structural characteristics of the taxon Salvinia natans (L.) All., particularly around the adaptive elements associated with living on the surface of the water. [ABSTRACT FROM AUTHOR]

Habitat attributes of submerged aquatic vegetation and floating-leaved aquatic vegetation were analyzed from survey data collected in estuaries and coastal river systems of Mississippi and Mobile Bay, Alabama. The objectives were to: locate aquatic plant beds along tidally influenced areas and characterize landscape parameters of the sites; group the plant species into a manageable number of logical clusters; and characterize the landscape attributes indicative of the plant communities through Classification and Regression Tree (CART) analysis. Based on the cluster analyses, aquatic vegetation was categorized into three groups: (1) downstream estuarine/saline group, (2) brackish tolerant freshwater species group, and (3) upstream freshwater only group. Landscape features used for habitat characterization and plant classification were defined by long-term environmental conditions which would shape plant communities, rather than water quality parameters, such as water transparency and salinity, that exhibit higher variability and reflect the discrete conditions at time of sampling. The CART results suggest that salinity and “energy” (relative exposure to waves/currents) are the two most important abiotic factors that structure plant communities in the river deltas studied. [ABSTRACT FROM AUTHOR]

Salvinia molesta , an aquatic fern was observed to have a potential of degrading azo dye Rubine GFL up to 97% at a concentration of 100 mg/L within 72 h using 60±2 g of root biomass. Both root as well as stem tissues showed induction in activities of the enzymes such as lignin peroxidase, veratryl alcohol oxidase, laccase, tyrosinase, catalase, DCIP reductase and superoxide dismutase during decolorization of Rubine GFL. FTIR, GC-MS, HPLC and UV–visible spectrophotometric analysis confirmed phytotransformation of the model dye into smaller molecules. Analysis of metabolites revealed breakdown of an azo bond of Rubine GFL by the action of lignin peroxidase and laccase and formation of 2-methyl-4-nitroaniline and N-methylbenzene-1, 4-diamine. Anatomical tracing of dye in the stem of S. molesta confirmed the presence of dye in tissues and subsequent removal after 48 h of treatment. The concentration of chlorophyll pigments like chlorophyll a, chlorophyll b and carotenoid was observed during the treatment. Toxicity analysis on seeds of Triticum aestivum and Phaseolus mungo revealed the decreased toxicity of dye metabolites. In situ treatment of a real textile effluent was further monitored in a constructed lagoon of the dimensions of 7 m×5 m×2 m (total surface area 35 m 2 ) using S. molesta for 192 h. This large scale treatment was found to significantly reduce the values of COD, BOD 5 and ADMI by 76%, 82% and 81% considering initial values 1185, 1440 mg/L and 950 units, respectively. [ABSTRACT FROM AUTHOR]

The existence of long (>100 kpc) HI streams and small (<20 kpc) free-floating HI clouds is well known. While the formation of the streams has been investigated extensively, and the isolated clouds are often purported to be interaction debris, little research has been done on the formation of optically dark HI clouds that are not part of a larger stream. One possibility is that such features result from the fragmentation of more extended streams, while another idea is that they are primordial, optically dark galaxies. We test the validity of the fragmentation scenario (via harassment) using numerical simulations. In order to compare our numerical models with observations, we present catalogues of both the known long HI streams (42 objects) and free-floating HI clouds suggested as dark galaxy candidates (51 objects). In particular, we investigate whether it is possible to form compact features with high velocity widths (>100 km s-1), similar to observed clouds which are otherwise intriguing dark galaxy candidates. We find that producing such features is possible but extremely unlikely, occurring no more than 0.2% of the time in our simulations. In contrast, we find that genuine dark galaxies could be extremely stable to harassment and remain detectable even after 5 Gyr in the cluster environment (with the important caveat that our simulations only explore harassment and do not yet include the intracluster medium, heating and cooling, or star formation). We also discuss the possibility that such objects could be the progenitors of recently discovered ultra diffuse galaxies. [ABSTRACT FROM AUTHOR]

Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus concentrations should be taken into account in future studies dealing with competition between plants. [ABSTRACT FROM AUTHOR]

This study builds on previous investigations of paleomycological diversity within permineralized plants of a significant Eocene paleobotanical locality, the Princeton Chert. The fungal body fossils described here occur in decayed rhizomes of the extinct semi-aquatic fern Dennstaedtiopsis aerenchymata. Fungi include vegetative hyphae throughout the plant tissue, as well as a dense assemblage of .100 dematiaceous spores. The spores occur in a discrete zone surrounding two extraneous rootlets of other plants, which penetrated the fern tissue post-mortem. Spores are obovoid and muriform, composed of 8-12 cells with constricted septa and produced from hyaline or slightly pigmented hyphae. The spores are morphologically similar to both asexual reproductive dictyospores of phylogenetically disparate microfungi attributed to the morphogenus Monodictys and perennating dictyochlamydospores that occur in the anamorph genus Phoma. In addition to expanding the early Eocene fossil record for Ascomycota, these specimens also provide new insight into the rapidity of initial phases of the fossilization process in this important paleobotanical locality. [ABSTRACT FROM AUTHOR]

In 2016, the order Mononegavirales was emended through the addition of two new families ( Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status ( Pneumoviridae), the addition of five free-floating genera ( Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV). [ABSTRACT FROM AUTHOR]

Studies were conducted to undertake a physico-chemical analysis and to examine the bioavailability as well as the leachability of potential toxic elements during the rotary drum reactor composting of water fern with rice husk and cattle manure in different combinations. The highest temperature (54.2 °C) was measured in trial 3 (water fern, cattle manure and rice husk at a ratio of 6:3:1) during the process. The highest reductions of the moisture content and volatile solids were observed approximately 31.4 and 32.9%, respectively, in trial 3. The soluble biochemical oxygen demand (BOD) and the oxygen uptake rate of the compost in trial 3 indicated that the compost was stable after the process. The total concentrations of potential toxic elements (Zn, Cu, Mn, Fe, Ni} Pb, Cd and Cr) were increased in the process of composting. The total concentrations of the macronutrients in the final composts of different trials were increased by 1.4-2.0% for K, 1.1-1.3% for Ca and 0.76-0.82%. The highest reduction in the soluble BOD was found to be 82.4% in trial 3. Composting of water fern biomass with the appropriate ratio of cattle manure decreased the bioavailable and leachable forms of the potential toxic elements greatly. [ABSTRACT FROM AUTHOR]

rom the mid-19th century to the end of the 20th century, Salvinia natans (L.) All. occurred very rarely in the Vistula Delta (northern Poland), but from the beginning of the 21st century it was present in almost every watercourse and had formed very abundant populations. We examined the influence of temperature on the abundance of this plant and the efficiency of macrospore germination. Field work was carried out in 10 permanent plots every 14 days for 5 years. Macrospores germinate at water temperature of 12.4 ± 0.2°C or higher; at 20°C they develop more effectively than at 15°C. Usually, ice cover on the rivers melts in the second half of March. At this time, macro- and microspores emerge on the water surface and germinate in April. They occur in the water surface film at 15.1 ± 2.4°C and massively die during spring frost. After 1989, March and April mean temperature in the Vistula Delta rose by 1.6°C versus 1901-1988, and by 1.9°C versus 1851-1988. In 1951-1988, the mean temperature for March and April was +4.6°C and was characterized by considerable interannual variation (SD = 1.64), whereas in 1989-2009, it rose to +5.7°C and the variation range narrowed (SD = 1.24). We found that macrospores are active earlier during the warm and mild summers, germination is more effective, survival of young stages is higher, the growing season is longer, and the number of vegetative offsprings in a year is larger. [ABSTRACT FROM AUTHOR]

This study has investigated the potential of an Azolla-Anabaena symbiosis, a marriage between the cyanobacterium Anabaena azollae and the aquatic fern ( Azolla), to remove ammonia from freshwater fish breeding areas. Experiments were carried out under artificial light of 20, 70, and 140 μmol m s. We investigated three different water temperatures for the growing Azolla, ranging from sub-optimal to optimal temperatures (15, 22, and 28 °C). The capability of Azolla to remove ammonia from wastewater was demonstrated, and the highest ammonia concentration tolerated by the symbiosis between Azolla-anabaena without any toxic effect on the aquatic ferns was ascertained. The shortest time taken to remove ammonia from wastes, 2.5 cm deep and at 28 °C, was 40 min. The ammonia removal rate ( A) was both light and temperature dependent and the highest rate (6.394 h) was attained at light intensity of 140 μmol m s and at a temperature of 28 °C; the lowest (0.947 h) was achieved at 20 μmol m s and 15 °C. The depth of the fish-wastewater pool also affected the A with the relation between A and the depth being a hyperbolic function. [ABSTRACT FROM AUTHOR]

Aquatic pteridophyte ( Azolla sp.) was taken to assess its potential to synthesize the metal (Au) nanoparticles. The synthesized particles were characterized using X-ray, UV-visible, scanning and transmission electron microscopy analyses. Nanoparticles almost spherical in shape having the sizes of 5-17nm are found. UV-visible study revealed the surface plasmon resonance at 538nm. Responsible phytochemicals for the transformation were principally phenolics, tannins, anthraquinone glycosides and sugars present abundantly in the plant thereby bestowing it adaptive prodigality. Also, the use of Azolla sp. for the synthesis of gold nanoparticles offers the benefit of eco-friendliness. [ABSTRACT FROM AUTHOR]

During a survey at the Rice Research Institute of Iran (RRII, Rasht, Guilan) for potential biocontrol agents of water fern, Azolla filiculoides Lam. (Pteridophyta: Azollaceae), larvae of Diasemiopsis ramburialis (Duponchel) (Pyralidae s. l., Spilomelinae) were discovered feeding on water fern. Larvae were found to cause serious feeding damage on leaves of water fern in the laboratory. The biology, life cycle, and the morphology of all stages of this species are described and illustrated for the first time. This is also the first record of this cosmopolitan species in Iran. We report water fern as a host for Diasemiopsis ramburialis; until now the host plant of D. ramburialis was unknown. [ABSTRACT FROM AUTHOR]

The article discusses the use of living and powder salvinia natans for the removal of Crystal violet (CV). Particular focus is given to investigate the biosorption behavior and phytoextraction of living and powder Salvinia natans. Also included are determination of optimum phytoremediation conditions, thermodynamic parameters and analysis of equilibrium data.

Giant Salvinia ( Salvinia molesta Mitchell) is a floating aquatic fern introduced from South America whose rapid growth impairs health of plants and animals in lakes, rivers, and bayous in various southern U.S. states. To assist in development of long-term control strategies, we examined in 2009 the range of diversity at the whole-plant and molecular level within and across six populations of S. molesta in Louisiana and Texas. Significant variation was observed for all five morphological traits measured both within and across collection sites. Root length was moderately associated with colony width, rhizome length, and leaf width when averaged across sites, but not when each location was evaluated separately. Cluster analysis revealed that S. molesta could be grouped into three to five distinct groups depending on the trait under consideration. Fruiting bodies (sporocarps) were observed only at one south Louisiana location. The salvinia weevil, Cyrtobagous salviniae Calder & Sands, was not found at any location during this study. Analysis of Molecular Variance of AFLP markers and DNA sequence analysis of the gap C p gene showed that the majority of molecular variation was detected within populations (87–93%) compared to diversity among populations (7–13%). Location (environment) was considered to be the most important source of variation for all measured traits. Principal Component Analysis (PCA) of AFLP and gap C p data revealed distinct clusters comprised of members across different collection sites. Although substantial morphological and molecular variations were detected both within and among populations, all data from this study suggested that these six populations were derived originally from the same clonal or related populations. [ABSTRACT FROM AUTHOR]

The first description of the larva and pupa of Alluaudomyia amazonica Spinelli & Wirth and a detailed redescription of the larva and pupa of A. schnacki Spinelli are provided. Studied specimens were collected in the Corrientes and Buenos Aires provinces, Argentina, from habitats associated with aquatic ferns, those of A . amazonica with Salvinia biloba Raddi emend. De la Sota and A . schnacki with Azolla filiculoides Lam. The larvae were examined using a Scanning Electron Microscope (SEM) and a Compound Microscope (CM), while the pupae by the CM only. Data on the bionomics of both species are provided. [ABSTRACT FROM AUTHOR]

Herein, we report new fossil remains with marsileaceous affinity associated with dispersed microspores corresponding to Crybelosporites, different types of massulae of Salvianiaceae ( Paleoazolla patagonica and Azolla circinata), and a single megaspore assigned to the fossil genus Grapnelispora. These fossils were recovered from the Late Cretaceous Loncoche Formation, at the Calmu-Co section, Malargüe Group, Northern Neuquén Basin, Mendoza, Argentina. The macrofossils include scattered leaflets, rhizomes, roots, and a sporocarp-like structure. They share characters with members of the aquatic fern family Marsileaceae; however, based on the characters preserved, they could not be placed within any extant or fossil species; therefore, the fossils are better included within a new fossil-taxon, Mendozaphyllum loncochense. Dispersed spores of Crybelosporites pannuceus, also belonging to Marsileaceae, were recovered from the entire section. Additionally, abundant isolated massulae with affinity to the aquatic fern family Salviniaceae, and a single megaspore assigned to Grapnelispora loncochensis, were identified from the plant bearing layer. The presence of Marsileaceae fossils in the Campanian-Maastrichtian Loncoche Formation, Mendoza, extends towards the north the paleogeographical distribution of the family Marsileaceae in Argentina, since previous records are from Patagonia. A fluvial to deltaic environment with lacustrine episodes is suggested by the sedimentology of the lower and middle parts of the Calmu-Co section and supported by the abundant fresh water algae recovered from the palynological association. This was probably the optimum habitat for the growth of aquatic ferns related to Marsileaceae and Salviniaceae and explains its abundance in the studied sediments. [ABSTRACT FROM AUTHOR]

In order to conserve and multiply the aquatic fernMarsilea quadrifoliaL., in a long-termin vitroprocedure, the effects of different cytokinins, i.e., 6-benzylaminopurine, zeatine riboside, andN6-(2-isopentenyl)adenine, were investigated, varying their concentration and period of supplementation. No clear stimulatory effect on thede novonodes produced per explant was detected when compared with hormone-free (HF) condition. On the contrary, the rhizome explant micropropagation was inhibited, the inhibition decreasing with the decreasing strength of cytokinins, though without reaching any significant enhancement. Since, as a consequence of the tissue culture procedure, the occurrence of somaclonal variation may introduce genomic alterations, genetic stability was assessed by random amplified polymorphic DNA (RAPD) analysis by comparing eight randomly selected micropropagated plants derived from repeated subcultures, with donor plant. Eighteen different primers generated 189 bands ranging from 100 to 3250 bp, and the same banding profiles were exhibited. No genomic alterations were evidenced in any of the micropropagated plants. Well-developed micropropagated plants were also successfully acclimatized under greenhouse condition. These positive results suggest that thein vitroHF micropropagation could be useful in the development ofex situconservation programs ofM. quadrifolia, even in order to possibly reintroduce the plants in their natural environment. [ABSTRACT FROM AUTHOR]

Salvinia minima is a widely distributed floating fern that bioaccumulates high concentrations of heavy metals and is a promising species for Cr(VI) removal from polluted waters. Metal bioaccumulation efficiency of aquatic plants can be affected by different factors such as surrounding pH and metal concentration. In this study we investigated the effect of solution pH on the biosorption and reduction of Cr(VI) in living plants of S. minima under both pH-stat (buffered) and pH-shift (unbuffered) conditions. Plants were exposed to 0, 5 and 20 mg L −1 Cr(VI) concentrations for 7 days under controlled conditions at pH 4.0, 6.0 and 7.6. Cr(VI) was determined using 1,5-diphenylcarbazide in presence and absence of KMnO 4 . Cr(III) concentration was estimated as the difference between Cr total [Cr(VI) + Cr(III)] (with KMnO 4 ) and Cr(VI) (without KMnO 4 ) concentrations. Metal biosorption was significantly higher in acid buffered solution than in unbuffered solution, but the biosorption pattern was different indicating that solution pH could be a key factor controlling the removal of Cr(VI) by S. minima. The pH of acid unbuffered Cr(VI)-containing solutions was significantly increased during Salvinia growth. Contrarily no significant changes of pH were observed in unbuffered solutions without Cr(VI). Reduction of Cr(VI) to Cr(III) was significantly higher at lower pH. Visual symptoms of Cr(VI)-induced damage were less evident at lower pH. Results demonstrated that S. minima can survive and remove Cr(VI) at low pH values. This work indicates that selection of suitable aquatic macrophytes for potential application in heavy metal phytoremediation requires an additional focus regarding interactions among metal, solution pH, and plant performance. [ABSTRACT FROM AUTHOR]

The aquatic fern Marsilea quadrifolia L is a rare and threatened species in entire Europe due to wetland habitats destruction and changing agricultural practices. To protect it, in situ and ex situ conservation methods are approached in European Union an in other countries. The in vivo and in vitro collections that were developed in botanical gardens in the last two decades are used for reintroduction and for restoration of M. quadrifolia populations in natural sites as well as in agro ecosystems that are analogous to natural habitats. Natural establishment of several M. quadrifolia populations in its natural range is an evidence that it can colonize new suitable habitats, including anthropogenic habitats. Despite conservation strategies approached within the European Union, its area of occupancy has decreased, thereby this species has become vulnerable at European Union level. The main threats are the small size populations, low genetic diversity and genetic erosion of populations, habitat degradation and chemical pollutions of waters by herbicides and fertilizers used in modern agricultural practice. [ABSTRACT FROM AUTHOR]

Field studies evidence shifts between phytoplankton and free-floating plant regimes; yet, it is unclear what drives these shifts and if they are critical transitions (alternative stable states). In this review, we synthesized field and experimental data on free-floating plants (of varying size and phylogenies) and phytoplankton regimes, to assess the effects of these producers on the environment. Nutrient-rich environments promote free-floating plants dominance-regardless of life form-which causes dark and anoxic environments, and nutrient release from sediments. This reinforces free-floating plants dominance, but controls phytoplankton biomass by strong shading (despite high nutrients and low grazing). Phytoplankton dominance renders turbid and oxygen-rich (when producing) environments. We also searched for case studies of regime shifts for free-floating plants and phytoplankton dominance. Most studies showed that when free-floating plants dominance was interrupted, phytoplankton biomass (usually Cyanobacteria) rose steeply. Likewise, when phytoplankton-dominated, the development of dense mats of free-floating plants covers usually controlled phytoplankton. Field evidence that suggests critical transitions include abrupt regime transitions in time and space; yet, evidence including indoor controlled experiments and mathematical models is needed for conclusive evidence of alternative stable states to be drawn. [ABSTRACT FROM AUTHOR]

An experiment was designed to assess the capacity of Salvinia minima Baker to uptake and accumulate nickel in its tissues and to evaluate whether or not this uptake can affect its physiology. Our results suggest that S. minima plants are able to take up high amounts of nickel in its tissues, particularly in roots. In fact, our results support the idea that S. minima might be considered a hyper-accumulator of nickel, as it is able to accumulate 16.3 mg g-1 (whole plant DW basis). Our results also showed a two-steps uptake pattern of nickel, with a fast uptake of nickel at the first 6 to 12 h of being expose to the metal, followed by a slow take up phase until the end of the experiment at 144 h. S. minima thus, may be considered as a fern useful in the phytoremediation of residual water bodies contaminated with this metal. Also from our results, S. minima can tolerate fair concentrations of the metal; however, at concentrations higher than 80 µM Ni (1.5 mg g-1 internal nickel concentration), its physiological performance can be affected. For instance, the integrity of cell membranes was affected as the metal concentration and exposure time increased. The accumulation of high concentrations of internal nickel did also affect photosynthesis, the efficiency of PSII, and the concentration of photosynthetic pigments, although at a lower extent. [ABSTRACT FROM AUTHOR]

An aquatic fern leaf, Flabellariopteris mii Sun gen. et sp. nov. from the Late Triassic of Western Liaoning, China, is described and proposed as the type species of the new morphortaxon of the Marsileaceae. The fossil leaves are preserved as impression. No fertile and rhizomatic materials are found. The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement. The petiole is slender. The leaflet is fan-shaped or semi-circular, and commonly divided into four wedge-shaped lobes. Terminal margin of lobes is usually incised, incisions shallow or deep, with bluntly rounded or notched apex. The veins are conspicuously dichotomous, but anastomoses and marginal vein are absent. The unique morphological features, including two-parted thin leaflets, size, shape, veins and slender petiole, indicate that the present specimen represents an aquatic fern, which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is involved in versatile functions in plant growth and development as a signaling molecule. To date, plants have been reported to produce NO following exposure to nitrite (N O) the amino acid L-arginine, hydroxylamine, or polyamines. Here we demonstrate azide-dependent NO production in plants. The water fern Azolla pinnata emitted NO into air upon exposure to sodium azide (NaN). The NO production was dependent on azide concentration and was strongly inhibited by potassium cyanide (KCN). Incubation of A. pinnata with the catalase inhibitor 3-aminotriazole (3-AT) abolished the azide-dependent NO production. Although nitrite-dependent NO production was inhibited by sodium azide, azide-dependent NO production was not affected by nitrite. These results indicate that A. pinnata enzymatically produces NO using azide as a substrate. We suggest that plants are also capable of producing NO from azide by the action of catalase as previously reported in animals. [ABSTRACT FROM AUTHOR]

A new species of megaspores,Arcellites punctatussp. nov. and associated microspores, are described from the Early Cretaceous Torres Vedras, Catefica and Buarcos localities in Portugal. The new taxon is most abundant in the Torres Vedras plant assemblages where it co-occurs with several other types of megaspores, remains of aquatic and terrestrial angiosperms as well as other plant fossils. The megaspore body is smooth without appendages, finely perforated and with a rugose surface pattern. High resolution synchrotron radiation X-ray tomographic microscopy (SRXTM) analysis of the megaspore wall shows a three-layered structure. The outer layer is punctate-perforate. Perforations are densely spaced in the valleys between the ridges, while they are more scattered or lacking on the top of the ridges. The middle layer is granular-fibrous and of uneven thickness causing the rugose surface pattern. The inner layer is evenly thin and solid. The outer layer of the megaspore body continues into the elongated, six-parted and inverted cone-shaped acrolamella or neck. Lateral margins of acrolamella segments are laminar and crenulate. Microspores occur attached to the acrolamella of all specimens studied in scanning electon microscopy (SEM) and SRXTM. In general morphology, the megaspores are closely similar to megaspores ofArcellites rugosusfrom Canada that also lack body appendages, but the Portuguese megaspores are distinguished by their distinct punctate-perforate megaspore wall structure. [ABSTRACT FROM AUTHOR]

Highlights: [•] The aquatic fern S. minima was exposed to aqueous solution of Pb(NO3)2 for 12h. [•] TEM analysis revealed Pb accumulation in cells of both roots and leaves. [•] Analysis by EDS and HRTEM confirmed the formation of PbNPs by the plant. [ • ] Two types of PbNPs were found in cells: quasi-spherical and elongated. [•] S. minima has potential for biosynthesis of heavy metal nanostructures. [Copyright &y& Elsevier]

Highlights: [•] Cd induced ecophysiological responses of Ceratopteris pteridoides were studied. [•] Photosynthesis of C. pteridoides was greatly affected by Cd treatment. [•] Cd modified reactive oxygen species-related responses in C. pteridoides. [ • ] Cd influenced nitrogen metabolism in C. pteridoides. [ABSTRACT FROM AUTHOR]

Highlights: [•] Marsilea quadrifolia is a vulnerable species in W Europe based on IUCN categories. [•] AFLP analyses show low genetic variability among and within M. quadrifolia populations. [•] M. quadrifolia is sensitive to herbicides with different mechanisms of action. [•] The implementation of an action plan for species in agro-ecosystems is outlined. [Copyright &y& Elsevier]

Highlights: [•] Azolla pinnata, an exotic aquatic fern, is now in the northern Everglades. [•] Molecular/morphological tools indicate three A. pinnata subspecies. [•] These tools ID the exotic as A. pinnata subsp. pinnata, the Australian subspecies. [•] These tools ID the threatened native as Azolla caroliniana, a hybrid. [ • ] An unique Ecuadorian Azolla is the paternal ancestor of Azolla caroliniana. [Copyright &y& Elsevier]

The potential of an aquatic fern,Azolla filiculoides, in phytoremediation of a mono azo dye solution, C.I. Acid Blue 92 (AB92), was studied. The effects of operational parameters such as reaction time, initial dye concentration, fern fresh weight, pH, temperature and reusability of the fern on biodegradation efficiency were investigated. The intermediate compounds produced by biodegradation process were analyzed using GC–MS analysis. An artificial neural network (ANN) model was developed to predict the biodegradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R2= 0.961). The effects of AB92 solutions (10 and 20 mg L−1) on growth, chlorophylls and carotenoids content, activity of antioxidant enzymes such as superoxide dismutase, peroxidase and catalase and formation of malondialdehyde were analyzed. AB92 generally showed inhibitory effects on the growth. Moreover, photosynthetic pigments in the fronds significantly decreased in the treatments. An increase was detected for lipid peroxidation and antioxidant enzymes activity, suggesting that AB92 caused reactive oxygen species production in Azolla fronds, which were scavenged by induced activities of antioxidant enzymes. [ABSTRACT FROM PUBLISHER]