Water Fern Research Articles

Nanoporous activated carbons derived from water ferns as an adsorbent for removal of paraquat from contaminated water

Nanoporous activated carbons (NACs) were prepared from water ferns (Azollar Pinnata) via hydrothermal carbonization (HTC) followed by a chemical activation process using potassium hydroxide (KOH) at 700 °C. The ratio of hydrochar to KOH was varied at 1:1, 1:2, and 1:3. The morphology of the NACs exhibited a uniform sponge-like porous structure with enhanced specific surface area and porosity. With an increase in KOH content, the specific surface area increased from 26 to 2848 m2 g–1 while the pore volume increased from 0.037 to 1.552 cm3 g–1. The significant increase in the specific surface area and pore volume of NACs was attributed to the development of micro- and mesoporosity. Commercial paraquat (Gramoxone) at the concentration of 1.5–45 mg L–1 was used as the pollutant target to evaluate the adsorption ability of NACs. The removal efficiency of paraquat from water reached 100% up to a paraquat concentration of 7.5 mg L–1. Moreover, the paraquat adsorption of NACs could be explained with the Langmuir model. The maximum adsorption capacity of NACs ranged within 15–20 mg g–1, where their enhanced removal efficiency and maximum adsorption capacity for paraquat removal were attributable to the increase in surface area and development of micro- and mesoporosity. The results of this work indicated the practicality of water-fern-derived NACs as an alternative adsorbent for the removal of paraquat and other organic pollutants in water.

AN OVERVIEW OF AZOLLA IN RICE PRODUCTION: A REVIEW

Azolla is a free-floating water fern which in symbiotic association with cyanobacterium Anabaena azollaefixes the atmospheric nitrogen. Nitrogen fixing ability of cyanobacterialsymbiont varies between 30 and 60 kg N ha−1 which designates Azolla as an important biological nitrogen source for rice ecosystem. Inoculation of Azolla is an alternative and sustainable source of nitrogen to increase the rice productivity and it also can decrease the use of synthetic fertilizer. A number of past researches prove that Azolla has been used as apotential biofertilizer for rice production. Azolla is either incorporated in the soil before rice transplanting or grown as a dual crop along with rice. The objective of this paper is to provide a brief account of importance as well as developments in the utilization of Azolla-Anabaena system in agriculture, mainly rice production.

Optimization of the nutrient growing solution and inoculation rate for Azolla mexicana production and use as fertilizer

Azolla is a water fern that can be utilized and developed as a soil amendment or fertilizer. Azolla hosts Anabaena cyanobacteria in its vacuoles and benefits from atmospheric N fixation by the Anabaena. The purpose of this study was to enhance Azolla production in natural or artificial ponds for field application. We identified the optimum nutrient concentrations and inoculation rate to maximize growth of Azolla mexicana and measured the nutrient concentrations in A. mexicana for use as fertilizer. A. mexicana was cultivated in nutrient solutions in a greenhouse, and ten individual nutrients were examined at four different concentrations using a randomized complete block design with three replicates. In addition, studies on inoculation rate and combined nutrient solutions were conducted. Azolla growth parameters (biomass, relative growth rate (RGR), doubling time, and percent greenness) and nutrient concentrations were measured. There were no significant differences in Azolla growth parameters among nutrient concentrations with all other nutrients held constant, except for Zn which affected the percent greenness. Inoculation rates of 50 to 100 g m−2 were optimum for 14-day Azolla growing periods in the greenhouse. Azolla nutrient concentrations were influenced by nutrient concentrations in the media. A nutrient solution (Widiastuti2) was developed that resulted in excellent Azolla growth, while also being economical due to its lower nutrient concentrations. If, however, higher Azolla micronutrient concentrations are desired, Widiastuti3 or the original Watanabe solution may also be used.

Leaf dorsoventrality candidate gene CpARF4 has conserved expression pattern but divergent tasiR-ARF regulation in the water fern Ceratopteris pteridoides.

Leaves are traditionally classified into microphylls and megaphylls, and recently have been regarded as independently originating in lycophytes, ferns, and seed plants. The developmental genetics of leaf dorsoventrality, a synapomorphy in vascular plants, has been extensively studied in flowering plants. AUXIN RESPONSE FACTOR4 (ARF4) genes are key to leaf abaxial identity in flowering plants, but whether they exist in ferns is still an open question. ARF4 genes from Ceratopteris pteridoides, Cyrtomium guizhouense, and Parathelypteris nipponica were mined from transcriptomes and investigated in terms of evolutionary phylogeny and sequence motifs, with a focus on the tasiR-ARF binding site. In situ hybridization was used to localize expression of CpARF4 in Ceratopteris pteridoides. 5'RNA ligase-mediated-RACE was employed to verify whether CpARF4 transcripts were sliced by tasiR-ARF. ARF4 genes exist in ferns, and this lineage originates from a gene duplication in the common ancestor of ferns and seed plants. ARF4 genes are of a single copy in the ferns studied here, and they contain divergent and, at most, one tasiR-ARF binding site. CpARF4 is expressed in the abaxial but not the adaxial domain of leaf primordia at various developmental stages. Transcript slicing guided by tasiR-ARF is active in C. pteridoides, but CpARF4 probably has not been affected by it. Fern ARF4 genes differ in copy number and tasiR-ARF regulation relative to flowering plants, though they can be similarly expressed in the abaxial domain of leaves, revealing a key role for ARF4 genes in the evolution of leaf dorsoventrality of vascular plants.

Azolla filiculoides as a feedstock for biofuel production: cultivation condition optimization

Azolla, as a water fern, is among the fast-growing marine macrophytes in the world, which makes it a potentially important sequester of the greenhouse gas carbon dioxide. This study aimed to enhance the Azolla growth rate and enhance the lipid extraction for biodiesel production. The maximum growth rate is achieved at a temperature of 22 °C, a light intensity of 20 lx, a humidity of 75%, and a pH of 6.4 within 2.1 days considered as doubling time. In addition, by considering the effect of key variables, a model was proposed, which can predict the Azolla growth rate. Lipid content in Azolla is found to be 11.7%. Finally, this harmful weed with its fast growth rate can be the feedstock of biorefineries; besides, its elimination can help wetlands conservation.

Uptake of Trace Elements in the Water Fern Azolla filiculoides after Short-Term Application of Chestnut Wood Distillate (Pyroligneous Acid).

Treatments of crops with additives to increase their productivity may pose environmental risks and induce negative effects also on non-target organisms. In this study, we investigated the potential effect of chestnut wood distillate (pyroligneous acid) used in agriculture, on the accumulation of trace elements in aquatic plants. As a model species, the common water fern Azolla filiculoides Lam. was selected, being often used also in phytoremediation processes. The content of selected elements of toxicological concern (As, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Zn) was assessed in the fern after short-term treatments (1–3 days) over a range of wood distillate concentrations 1:300 (3.33 mL/L), 1:500 (2.00 mL/L), 1:700 (1.43 mL/L). A statistically significant accumulation of Cd, Cu, Mn, Pb, Zn (1:700) and Pb (1:300) was recorded after three days of incubation, despite the concentrations remained overall low. Using treatment vs. control ratios, a trend of increasing temporal uptake was detected for As, Ba, Fe, Mn, Pb (1:700); Mn, Pb (1:500), and only Pb at 1:300. The results suggested that, under the experimental conditions, element uptake is positively influenced by time and negatively by increasing concentrations of wood distillate, likely due to the acidification of the medium. On the whole, the element concentrations measured in A. filiculoides were low and did not pose any toxicological concern.

Feeding Preferences of Grass Carp (Ctenopharyngodon idella ) for Three Aquatic Plants

The present study was conducted to determine the feeding preferences of grass carp (Ctenopharyngodon idella) for three aquatic plants i.e. Water fern (Azolla filiculoides), duckweed (Lemna spp.) and water hyssop (Bacopa monnieri), in two different water temperature (22-24 and 27-29 oC ) for the period from 30 Oct.2019 to 12 Dec. 2019. Water hyssop were neglected from the second temperature experiment since no plant consumed in the first trail. The average fish weight in 22 -24 oC was 91.85±12.59 and in 27-29 oC was 89.19±16.18. Mean daily feeding rates (DFR) consumption of grass carp from water fern and duckweed were not significantly different (P>0.05), but both plants were eaten in significantly (P<0.05) greater quantities than water hyssop plant which was not eaten by grass carp. The consumed plants were 48.00 and 39.77% BW/day from water fern and duckweed in temperature 22-24 oC, while in 27-29 oC it was 47.19 and 41.83 %BW/day respectively. It was concluded from the present study that grass carp equally prefer water fern and duckweed but not water hyssop; this may be associated with the nature of taste and leave structure.

Reinterpretation of Paleoazolla: a heterosporous water fern from the Late Cretaceous of Patagonia, Argentina.

Undoubtedly, fossils are critical for understanding evolutionary transformations in deep time. Here, we reinvestigate the microspores and megaspores of Paleoazolla patagonica, a water fern found in Late Cretaceous sediments of the Chubut Province, Patagonia, Argentina, which provides novel evidence on the past history of the water fern clade. The study was based on recently collected specimens and additional observations of the original material. Most specimens analyzed herein were obtained from new palynological samples collected at the Cerro Bosta and Cañadón del Irupé localities, La Colonia Formation. Samples were mechanically disaggregated and treated with hydrofluoric and hydrochloric acid. Spores were studied using standard light microscopy and scanning electron microscopy. We also reexamined the original materials. The newly described characters of Paleoazolla include the presence of heterosporangiate sori composed of one ellipsoidal megasporangium surrounded by three to four oval microsporangia, megasporangium containing one hairy massula that encloses two trilete megaspores (rarely one or three), and microsporangia containing numerous microspore massulae with non-septate multibarbed glochidia and one trilete microspore per massula. The reinterpretation has revealed a novel set of characters for understanding the evolution of heterosporous water ferns. The presence of two megaspores in the megasporangium of Paleoazolla exposes serious gaps in the current knowledge on the evolution of monomegaspory in heterosporous water ferns, a fact that emphasizes the need of including fossils within phylogenies to elucidate patterns of character acquisition among water ferns.

Agents sans frontiers: cross-border aquatic weed biological control in the rivers of southern Mozambique

Biological control is an effective ways of controlling aquatic plants, especially in South Africa. Release of biological control agents has been limited to Mozambique, where water hyacinth (Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae)), water lettuce (Pistia stratiotes L. (Araceae)), red water ferns (Azolla spp. (Azollaceae)) and salvinia (Salvinia molesta DS Mitch. (Salviniaceae)) are significant weeds in the south of the country. In 2009, we assessed the status of these weeds in seven rivers across southern Mozambique and recorded whether any biocontrol agents were present. The weevils Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and N. bruchi Hustache (Coleoptera: Curculionidae) were on water hyacinth, along with the pathogen Acremonium zonatum (Sawada) W. Gams (Hypocreales) and the mite Orthogalumna terebrantis Wallwork (Acarina: Sarcoptiformes: Galumnidae). Pistia stratiotes supported small numbers of the weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae). The red water fern in the rivers was A. cristata Kaulfuss (Azollaceae) not the more widely recorded A. filiculoides Lam. (Azollaceae), and it supported small numbers of the weevil Stenopelmus rufinasus Gyllenhal (Coleoptera: Curculionidae). No agents were present on S. molesta. Most of these agents are likely to have dispersed from South Africa, and the rivers of southern Mozambique are likely to be benefitting from the transnational dispersal of these agents.

Contribution of Azolla filiculoides to hydrazine elimination from water

In this research we report the significant effect of the floating water fern Azolla filiculoides on the elimination of hydrazine (N2H4) from water, which is a remarkable role for an aquatic plant. Hydrazine is a highly toxic compound for human health and biodiversity with wide industrial applications. In search of a practical way for hydrazine removal from an industrial wastewater, we studied the possible ability of certain aquatic lower plants to consume hydrazine. In greenhouse experiments, algal samples including Cladophora glomerata, Cosmarium sp. and Chlorella sp. did not show a significant effect on the rate of hydrazine elimination from water. However, A. filiculoides showed considerable growth when using hydrazine as the sole source of nitrogen. It was able to tolerate up to 4 mg/l hydrazine in the nutrient solution. During more than one month at the scale of 1/1000, Azolla removed hydrazine from boiler blowdown in the real conditions of a combined-cycle power plant. To our knowledge, this is the first observation of hydrazine consumption by a eukaryotic structure. Although we have discussed some possibilities, the exact mechanism of the process remains to be uncovered. On the other hand, considering the well-known abilities for bioremediation of a large number of contaminants from water, Azolla would be able to work as part of a cost effective system for remediation of hydrazine along with many other pollutants from different kinds of contaminated water. However, using Azolla in a hydrazine remediation system needs detailed feasibility studies to take various considerations into account.

Growth and digestive enzyme activities of rohu labeo rohita fed diets containing macrophytes and almond oil-cake

The impact of plant-based diets on the digestive physiology of rohu Labeo rohita fingerlings (10.66 ± 0.53 g) was evaluated. A diet with all protein supplied by fishmeal was included as a control (F). Four test diets containing 300 g/kg protein were formulated using the following plant ingredients and fishmeal in a 1:1 blend: almond oil-cake Terminalia catappa (FTC), duckweed Lemna minor (FLM), water fern Salvania molesta (FSM) and combination of these three ingredients (FTCLMSM). The final body weight and specific growth rate were significantly higher in rohu fed diet FLM compared to the other treatments. Significantly lower feed conversion ratio in rohu fed diet FLM showed that diet was utilized efficiently in this feeding regime compared to the other diets. The composition of diets also influenced the digestive enzyme activities of the fish. Thus, amylase, trypsin and chymotrypsin activities were significantly higher in rohu fed diet FLM compared to the rohu fed the other diets. Protease activity was significantly higher in rohu fed diets FTC and F and lipase activity was significantly higher in rohu fed diet FTC compared to the rohu fed the other diets. The inclusion of raw duckweed in feed replaced 300 g/kg of dietary fishmeal without affecting growth.

Potential of water fern (Azolla pinnata R.Br.) in phytoremediation of integrated industrial effluent of SIIDCUL, Haridwar, India: removal of physicochemical and heavy metal pollutants

Integrated industrial effluent (IIE) released from SIIDCUL causes serious environmental problems in the vicinity of Haridwar, India. Therefore, this study investigated the potential of water fern (Azolla pinnata R.Br.) for phyto-treatment of IIE. Laboratory experiments with six IIE concentrations (0 as control with bore well water, 20, 40, 60, 80 and 100%) were performed for bio-removal of selected physicochemical, microbiological and heavy metal parameters of IIE in pot type experiments. The overall results described maximum removal of physico-chemical (pH, EC, TDS, BOD, COD, TKN, Ca, Mg, Na, K), microbiological (MPN and SPC) and heavy metals (Cd, Cu, Cr, Fe, Pb, Mn, and Zn) parameters in 60% concentration of IIE, respectively. The stimulus effect of IIE concentration on pollutant removal process was confirmed using Kruskal–Wallis post hoc test, one way ANOVA (p < 0.05), and linear regression (R2 < 0.85) tools. Besides this, A. pinnata relative plant growth rate was also maximum in 60% IIE treatment. This is the first report on phytoremediation of IIE while findings of this study showed that A. pinnata was useful for the eco-friendly treatment of SIIDCUL IIE and could minimize potential wastewater management issues.

D-Cysteine-Induced Rapid Root Abscission in the Water Fern Azolla Pinnata: Implications for the Linkage between d-Amino Acid and Reactive Sulfur Species (RSS) in Plant Environmental Responses.

Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) have been proposed as universal signaling molecules in plant stress responses. There are a growing number of studies suggesting that hydrogen sulfide (H2S) or Reactive Sulfur Species (RSS) are also involved in plant abiotic as well as biotic stress responses. However, it is still a matter of debate as to how plants utilize those RSS in their signaling cascades. Here, we demonstrate that d-cysteine is a novel candidate for bridging our gap in understanding. In the genus of the tiny water-floating fern Azolla, a rapid root abscission occurs in response to a wide variety of environmental stimuli as well as chemical inducers. We tested five H2S chemical donors, Na2S, GYY4137, 5a, 8l, and 8o, and found that 5a showed a significant abscission activity. Root abscission also occurred with the polysulfides Na2S2, Na2S3, and Na2S4. Rapid root abscission comparable to other known chemical inducers was observed in the presence of d-cysteine, whereas l-cysteine showed no effect. We suggest that d-cysteine is a physiologically relevant substrate to induce root abscission in the water fern Azolla.

Ferns with Benefits: Incorporating Ceratopteris into the Genomics Era

Ferns were the last major lineage of land plants without a reference genome. With the coming publication of the Ceratopteris genome assembly and recent publication of two water fern genomes, it is time to review the past and future applications of Ceratopteris and fern research. Here I delve into the utilization of a Ceratopteris genome assembly for studying the alternation of generations, reproductive biology, genome biology, and the C-Fern Curriculum.

Effects of shading, fertilization and snail grazing on the productivity of the water fern Azolla filiculoides for tropical freshwater aquaculture

Water ferns (Azolla spp.) are among the main important floating macrophytes used for feeding farmed animals such as fish, because they have high growth potential and high protein content. Nevertheless, their use as feed requires sustainable mass production, which can be difficult to maintain in field conditions. We performed a first experiment to assess the effects of shading and fertilization levels on the growth of Azolla filiculoides with complementary information regarding the morphology and the chemical composition of the plant cultivated under the different experimental conditions. Plants were cultivated in floating 50-L plastic drums at three fertilization levels (“no”, “low” and “high”) using an inorganic multi-nutrient fertilizer rich in P (NPK = 1:2:1) and maintained under full natural light or shaded by one of two different types of shading materials, transparent polyethylene sheet and 60% shade net, respectively. A second experiment was carried out to evaluate the effects of grazing by the invasive golden apple snail Pomacea canaliculata on A. filiculoides previously cultivated without addition of fertilizer (treatment “no”) or in high fertilizer concentrations (treatment “high”). Fertilization levels and shading materials significantly affected the growth of Azolla. The highest productivity was reached using the highest fertilization level under direct sunlight. Azolla produced in these culture conditions was preferentially grazed by snails compared to Azolla cultivated without added fertilizer. Based on these findings, we make recommendations regarding the best culture conditions for A. filiculoides in ponds for its use as sustainable fish feed.

Excellent adsorption of orange acid II on a water fern– derived micro- and mesoporous carbon

Abstract The present research has been focused on preparation, characterization and acid orange adsorption behavior of a porous activated carbon derived from water fern. Several basic and acidic activation including green approaches have been applied for the activation process. The prepared activated carbons were characterized using X-ray diffraction (XRD), differential thermal and thermal gravimetric analyses (DTA/TGA), Raman, Fourier transform infrared and X-ray photoelectron spectroscopy (FTIR), N2 sorption and high-resolution transmission electron microscopy (HR-TEM). XRD and Raman spectroscopy results confirmed the successful preparation of carbon with good crystallinity from all of the activation processes. These results confirmed that the prepared carbons from acidic approaches have better crystallinity. The obtained activated carbon with citric acid as a green activator can approximately be considered as microporous carbons with surface area and micropore volume of 617 m2 g−1 and 0.2 cm3 g−1, respectively. Maximum total pore volume and specific surface area of 0.74 cm3 g−1 and 1437.6 m2 g−1, was achieved for NaOH basic activation approach. The ability of the NaOH prepared activated carbons was investigated for removing acid orange II as an anionic adsorbate from aqueous solutions. Results showed that the adsorption follows the Langmuir theory and the adsorption capacity and energy were 666.6 mg g−1 and 14.9 kJ mol−1, respectively. A large amount of surface area and micro-porosities in the synthesized porous carbon, oxygen-containing functional groups and bridging effect of sulfur was explained as the reasons for this excellent adsorption behavior.

Uji Formulasi Pupuk Hayati Padat Berbasis Azolla Terhadap Populasi dan Fungsional Mikroba Tanah Menguntungkan

Inorganic fertilizer is a very important agricultural input to increase agricultural production. Uncalculated and continuous application of inorganic fertilizers will lead to the reduction of soil fertility and degradation of environmental quality. Therefore, a strategy is needed to support the environmental sustainability in agriculture. One of the efforts is through the production of biofertilizer and organic fertilizer from local resources. Organic fertilizer for rice plants can be made by utilizing the local water fern, Azolla pinnata. A. pinnata can be applied on rice fields as green manure by directly placing it into the soil or spread on the surface of rice fields. Organic fertilizer that made from Azolla will be more advantageous because it can be applied with biofertilizer. This study aimed to determine the formulation of Azolla based solid biofertilizer that can support the growth of functional microbial population based on the Agriculture Ministry (Permentan) standard number 70/2011. The design of the study method used was Completely Randomized Design with six replications. The treatments used were inoculant starter with 3% molasses, 3% molasses + 10% rice wash water, 3% molasses + 1% yeast extract, and 3% molasses + 10% rice wash water + 1% yeast extract. The results of this study showed that Azolla-based solids fertilizer with starter formula 3% inoculant molasses + 10% rice water + 1% yeast extract have the population of Azotobacter, Azospirillum, endophytic bacteria and phosphate solubilizing microbe were greater than 108 cfu/g dry weight. Functional microbial of solids fertilizers in all formulas used do not show the difference on inhabiting in the N-free media or Pikovskaya selective media. Keywords: Azolla pinnata, formulation, biofertilizer, organic fertilize

Effect of daily exposure to Pb-contaminated water on Salvinia biloba physiology and phytoremediation performance

Lead (Pb) removal from water column was evaluated in batch experiments using naturally occurring Salvinia biloba Raddi (S. biloba) specimens collected from Middle Paraná River and exposed every 24 h to a fresh discharge of water contaminated with 2.65 ± 0.07, 12.62 ± 0.02 or 30.57 ± 0.01 mg L−1 Pb, during 10 consecutive days. S. biloba demonstrated a great ability for metal concentration-dependent Pb removal under these stressful conditions. Additionally, Pb toxicity in plants was assessed by the quantification of physiological parameters in root-like modified fronds (named “roots”), and its aerial leaf-like fronds (named “leaves”) of submerged S. biloba. Photosynthetic (carotenoids, chlorophyll a, b, and total) and antioxidant pigments (anthocyanins and flavonoids), soluble carbohydrate content, and membrane stability index of both roots and leaves were affected as the metal concentration increased. In general, root deterioration was more pronounced than that in leaves, suggesting a greater implication of the former organs in Pb removal by S. biloba. All of these deleterious effects were well correlated with qualitative changes observed at plant phenotype during the assay. In conclusion, S. biloba may be considered as a water fern useful in phytoremediation strategies towards management of residual water bodies contaminated with Pb. In addition, these macrophytes could also be valuable for water biomonitoring contributing to improve risk assessments related to metal presence in wastewaters.

Biometric characteristics and surface microstructure of vegetative and reproductive organs of heterosporous water fern Salvinia natans

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.

Water fern induced mitogen-activated protein kinase signalling in Sesamum orientale L. var. thilarani involved in systemic resistance against Altertnaria leaf spot disease

Water fern induced mitogen-activated protein kinase signalling in Sesamum orientale L. var. thilarani involved in systemic resistance against Altertnaria leaf spot disease