Water Fern Research Articles

Phenolic and other constituents of fresh water fern Salvinia molesta

Two glycosides, 6′- O-(3,4-dihydroxy benzoyl)-β- d-glucopyranosyl ester ( 1), and 4- O-β- d-glucopyranoside-3-hydroxy methyl benzoate ( 2), along with five known compounds methyl benzoate ( 3), hypogallic acid ( 4), caffeic acid ( 5), paeoniflorin ( 6) and pikuroside ( 7) were isolated for the first time from a fresh water fern Salvinia molesta D.S. Mitch. These compounds showed a potent antioxidant radical scavenging activity in a non-physiological assay. Their structures were determined by NMR spectroscopic and CID mass spectrometry techniques.

P42. Lessons from water ferns: Involvement of reactive nitrogen species in root abscission response of plants

P42. Lessons from water ferns: Involvement of reactive nitrogen species in root abscission response of plants

Taxonomy and biostratigraphy of Cretaceous megaspores from Patagonia, Argentina

Megaspores from the Kachaike and Piedra Clavada formations of Albian and ?Cenomanian age in Santa Cruz Province, Argentina, are described and illustrated by scanning electron micrographs. These include six new species: Arcellites humilis, A. pentagonalis, A. sp. A, Erlansonisporites verrucatus, Minerisporites aequatus and Striatriletes areolatus. Striatriletes reticulatus (Zerndt) Sweet and Trileites cf. T. murrayi (Harris) Marcinkiewicz are recorded for the first time from Argentina. Another eight species that were previously recorded in Patagonia are also described based on specimens found in new localities. Comparison with similar megaspore taxa from other palaeofloristic regions suggests that the megaspores in these formations are of Albian age (perhaps extending into the Cenomanian), confirming previous data obtained from other studies of marine and terrestrial fossils from these formations. The botanical affinities of the megaspores with heterosporous lycopsids (Isoetaceae and Selaginellaceae) and water ferns (Marsileaceae and Salviniaceae) suggest that a warm, humid climate and abundant water bodies prevailed during the Albian in Patagonia. The stratigraphic distribution of all known Early Cretaceous Patagonian megaspores allows recognition of three separate assemblages, M1–M3, each characterized by several exclusive taxa. M1 spans the Berriasian–Barremian, M2 is Aptian, and M3 is Albian–?Cenomanian.

Histochemistry of simple hairs from the foliar cavities of Azolla filiculoides

The foliar cavities of the water fern Azolla filiculoides have as many as 20 – 25 simple hairs (SH) protruding from the epidermal cells that delimit the cavity. These SH have a transfer-like ultrastructure normally associated with secretion of metabolites. The aim of this study was the chemical characterization of the compounds that accumulated in the SH of the zones F1-12 (from 1st to 12th leaves) and F13 (from 13th until the end of the sporophyte) throughout the seasons during a 1-year study. The histochemical tests show that the vacuoles of simple hairs contain a mixture of lipids, unsaturated lipids, polysaccharides, polyphenols (o-dihydroxyphenols, phenols with free ‒OH groups and tannins) and alkaloids or alkaloid-like compounds. These substances do not show seasonal variation, having been present throughout the one-year study. The histochemical analysis demonstrated that the SH always have a variety of metabolites. The function within the Azolla-Anabaena symbiosis is not known.

The effect of nutrient addition on metal tolerance in Salvinia herzogii

Disappearance of floating macrophytes was observed in two successively constructed wetlands for the treatment of wastewater that contained Zn, Ni and Cr at a tool factory in Argentina. Experimental work was developed to test the hypothesis that nutrient enrichment enhances the metal tolerance of floating macrophytes. Relative growth rates, root biomass and chlorophyll concentration in Salvinia herzogii (water fern) were measured in greenhouse incubations exposed to different Zn, Ni and Cr concentrations, and compared with simultaneous treatments enriched with nitrogen and phosphorus. Relative growth rates were negatively correlated with metal exposures. Nutrient addition suppressed such effect. Root biomass was also negatively correlated with metal concentrations. Nutrient enrichment either attenuated (Cr and Zn) or suppressed (Ni) root biomass decrease in response to metal exposure. Chlorophyll concentration was negatively correlated with Ni exposures. Nutrient addition attenuated chlorophyll decrease in response to Ni exposure. Growth rate represented an early indicator of Cr and Zn toxicity, while growth rate and chlorophyll concentration represented suitable indicators of Ni toxicity. Metal concentration in leaves was correlated with metal exposure concentration. The effect of Zn exposure on Zn leaf concentration was attenuated by nutrient addition, apparently through P and Zn immobilization in the roots. Metal and nutrient concentration in water decreased throughout the experiments. Chromium removal from water was faster than that of Zn and Ni. Zinc and Ni were mainly sorbed by S. herzogii biomass, while Cr was also retained in the detrital fraction.

Occurrence of nutrients and plant hormones (cytokinins and IAA) in the water fern Salvinia molesta during growth and composting

The aquatic fern Salvinia molesta is classified as an invasive, noxious weed in southern Africa. It has rapid growth and forms a thick mat in slow moving water bodies. It is hypothesized that S. molesta is a suitable candidate to promote as an organic fertilizer. The aims of this study were to determine the mineral content as well as the cytokinin and auxin content in S. molesta. The release of these compounds into the culture medium and upon decomposition of the air-dried plant matter was also determined. Minerals detected in the fresh plant material were N > K > P > Ca > Mg > Fe > Na > Cu > Zn while Cd, Pb and Ni were below the level of detection. The mineral concentrations changed after 14 days decomposition with there being an increase in Ca, Mg and Fe and a decrease in K. Sixteen isoprenoid cytokinins were detected in the plant material (total concentration 81.62 pmol g −1 DW) while only four cytokinins occurred at a greatly reduced concentration in the culture medium (4.31 pmol 500 ml −1 medium). The material that had been composted for 14 days showed a 17% reduction in cytokinin concentration (67.96 pmol g −1 DW) compared to the plant material. Run-off, termed leachate, collected during the composting experiment also had high amounts of cytokinin-like activity measured using the soybean callus bioassay. This activity peaked on day 7 of the composting experiment, indicating a rapid release of cytokinin-like compounds. IAA occurred in much higher concentrations than the cytokinins in the plant material (393.6 pmol g −1 DW) while very little IAA was detected in the culture medium (30.8 pmol g −1 DW). IAA concentrations were much lower in the composted material (148.1 pmol g −1 DW) with a 62% loss being recorded compared to the plant material. No auxin-like activity was measured using the mungbean rooting bioassay in the leachate collected at the start of the composting experiment. However, the leachate collected on days 7 and 14 had biological activity indicating that auxin-like compounds were released from S. molesta upon decomposition.

Comparison of Aeration Status Measurements by Clark Sensor (DO) and ODR-Meter during Azolla caroliniana Willd. Growth in the Presence of Cd(II) and Hg(II)

The aim of this study was examination possibility of Azolla caroliniana Willd. to aerate its medium enriched with Cd(II) and Hg(II) and comparison of DO and ODR methods in measurement aeration status of solutions. Azolla system has been chosen to verify the validity of the measuring ODR method in water solution. Water aeration measurements, one of important environmental tests, are performed most often by measurement of dissolved oxygen with oxygen sensors. Other similar method called oxygen diffusion rate is generally used in different porous materials such as soil. Our first objective was to check if these both methods are comparable and may be use exchangeable in water solution. The both types of measurements were performed in medium saturated at different oxygen concentrations. The linear relationship and high correlation (R = 0.89) were found between values of ODR and DO. The object of the second part of our studies was A. caroliniana Willd. (Azollaceae), a floating water fern living in symbiosis with cyanobacterium Anabaena azollae Strasb. (Nostoceae) that fixes atmospheric nitrogen. Azolla plants are used for centuries as a nitrogen biofertilizer. The second aim of our work was to find out, if the fern reduces or increases oxygen concentration in water. The ODR method was used to determine the aeration status of the nutrient solution. During 12 days of the experiment at laboratory conditions, an active role of A. caroliniana in aeration of the nutrient solution containing Cd(II) and Hg(II) was stated.

Comparative Morphology of Reproductive Structures in Heterosporous Water Ferns and a Reevaluation of the Sporocarp

Heterosporous water ferns (Marsileaceae and Salviniaceae) are the only extant group of plants to have evolved heterospory since the Paleozoic. These ferns possess unusual reproductive structures traditionally termed “sporocarps.” Using an evolutionary framework, we critically examine the complex homology issues pertaining to these structures. Comparative morphological study reveals that all heterosporous ferns bear indusiate sori on a branched, nonlaminate structure that we refer to as the sorophore; this expanded definition highlights homology previously obscured by the use of different terms. By using a homology‐based concept, we aim to discontinue the use of historically and functionally based morphological terminology. We recognize the sorophore envelope as a structure that surrounds the sorophore and sori. The sorophore envelope is present in Marsileaceae as a sclerenchymatous sporocarp wall and in Azolla as a parenchymatous layer, but it is absent in Salvinia. Both homology assessments and phylogenetic character‐state reconstructions using the Cretaceous fossil Hydropteris are consistent with a single origin of the sorophore envelope in heterosporous ferns. Consequently, we restrict the term “sporocarp” to a sorophore envelope and all it contains. Traditional usage of “sporocarp” is misleading because it implies homology for nonhomologous structures, and structures historically called sporocarps in Salviniaceae are more appropriately referred to as sori.

Pre-treatment processes of Azolla filiculoides to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution in the batch and fixed-bed reactors

Intact and treated biomass can remove heavy metals from water and wastewater. This study examined the ability of the activated, semi-intact and inactivated Azolla filiculoides (a small water fern) to remove Pb 2+, Cd 2+, Ni 2+ and Zn 2+ from the aqueous solution. The maximum uptake capacities of these metal ions using the activated Azolla filiculoides by NaOH at pH 10.5 ± 0.2 and then CaCl 2/MgCl 2/NaCl with total concentration of 2 M (2:1:1 mole ratio) in the separate batch reactors were obtained about 271, 111, 71 and 60 mg/g (dry Azolla), respectively. The obtained capacities of maximum adsorption for these kinds of the pre-treated Azolla in the fixed-bed reactors ( N o) were also very close to the values obtained for the batch reactors ( Q max). On the other hand, it was shown that HCl, CH 3OH, C 2H 5OH, FeCl 2, SrCl 2, BaCl 2 and AlCl 3 in the pre-treatment processes decreased the ability of Azolla to remove the heavy metals in comparison to the semi-intact Azolla, considerably. The kinetic studies showed that the heavy metals uptake by the activated Azolla was done more rapid than those for the semi-intact Azolla.

Biological control of three floating water weeds,Eichhornia crassipes, Pistia stratiotes, and Salviniamolesta in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.

Indicators of phosphorus deficiency in Azolla pinnata (Salviniales, Pteridophyta)

Prolonged incubation of Azolla pinnata in phosphorus deficient medium resulted in the highest relative growth on 4th day but it ceased after 12th day. There was a decrease in heterocyst frequency of Anabaena azollae (endosymbiont) with prolonged incubation in such medium. The cyanobiont did not differentiate akinetes during the course of 16-days of incubation. Anthocyanin content and total proteins dropped in phosphorus starved Azolla plants. However, tissue phosphorus increased up to 8th day and decreased thereafter. Activity of acid and alkaline phosphatases elevated up to 12th day and declined afterward in phosphorus deprived Azolla. This investigation clearly reflected that Azolla pinnata sustained its growth and metabolic activities in -P conditions during early period of growth (up to 8th day) and further prolongation of phosphorus starvation resulted in appearance of phosphorus deficiency symptoms that can act as indicators of phosphorus deficiency in the water fern, Azolla pinnata.

Adsorptive uptake of arsenic (V) from water by aquatic fern Salvinia natans

The sorption potential of the As (V) ion from aqueous solution has been studied using the water fern Salvinia natans as a scavenging candidate for aquatic arsenic. Sodium arsenate was used to prepare the stock solution of As (V). The diluted stocks with nutrient as sample solutions with As-free pond water were kept in different Perspex cells of a multiple chamber and for each concentration a varying amount of dry mass of the plants were nourished under adequate lighting for supporting the growth of the plants. The samples were drawn from each chamber at 24 h intervals up to 5 days and for each sample the residual As (V) was estimated by the silver diethyl dithio carbonate (SDDC) method. Test results indicate that the plant could effectively uptake As (V) between 0.25 and 2 mg l−1 to the extent of 74.8 to 54%, respectively, after 120 h contact time for a plant mass of 20 g l−1 at neutral pH. The experimental data were fitted well to both Langmuir and Freundlich isotherms. The effect of pH and biomass quantities on sorption rate have been also investigated along with some metabolic parameters.

Evolution of DNA amounts across land plants (embryophyta).

DNA C-values in land plants (comprising bryophytes, lycophytes, monilophytes, gymnosperms and angiosperms) vary approximately 1000-fold from approx. 0.11 to 127.4 pg. To understand the evolutionary significance of this huge variation it is essential to evaluate the phylogenetic component. Recent increases in C-value data (e.g. Plant DNA C-values database; release 2.0, January 2003; http://www.rbgkew.org.uk/cval/homepage.html) together with improved consensus of relationships between and within land plant groups makes such an analysis timely. Insights into the distribution of C-values in each group of land plants were gained by superimposing available C-value data (4119 angiosperms, 181 gymnosperms, 63 monilophytes, 4 lycophytes and 171 bryophytes) onto phylogenetic trees. To enable ancestral C-values to be reconstructed for clades within land plants, character-state mapping with parsimony and MacClade was also applied. Different land plant groups are characterized by different C-value profiles, distribution of C-values and ancestral C-values. For example, the large ( approximately 1000-fold) range yet strongly skewed distribution of C-values in angiosperms contrasts with the very narrow 12-fold range in bryophytes. Further, character-state mapping showed that the ancestral genome sizes of both angiosperms and bryophytes were reconstructed as very small (i.e. < or =1.4 pg) whereas gymnosperms and most branches of monilophytes were reconstructed with intermediate C-values (i.e. >3.5, <14.0 pg). More in-depth analyses provided evidence for several independent increases and decreases in C-values; for example, decreases in Gnetaceae (Gymnosperms) and heterosperous water ferns (monilophytes); increases in Santalales and some monocots (both angiosperms), Pinaceae, Sciadopityaceae and Cephalotaxaceae (Gymnosperms) and possibly in the Psilotaceae + Ophioglossaceae clade (monilophytes). Thus, in agreement with several focused studies within angiosperm families and genera showing that C-values may both increase and decrease, it is apparent that this dynamic pattern of genome size evolution is repeated on a broad scale across land plants.

Bioremediation of Soils by Plant–Microbe Systems

Sustainable ecosystems can be designed to eliminate environmental toxins and reduce pathogen loads through the direct and indirect consequences of plant and microbial activities. We present an approach to the bioremediation of disturbed environments, focusing on petroleum hydrocarbon (PHC) contaminants. Treatment consists of incorporating a plant-based amendment to enhance ecosystem productivity and physiochemical degradation followed by the establishment of plants to serve as oxidizers and foundations for microbial communities. Promising amendments for widespread use are entire plants of the water fern Azolla and seed meal of Brassica napus (rapeseed). An inexpensive byproduct from the manufacture of biodiesel and lubricants, rapeseed meal is high in nitrogen (6% wt/wt), stimulates >100-fold increases in populations of resident Streptomyces species, and suppresses fungal infection of roots subsequently cultivated in the amended soil. Synergistic enzymatic and chemical activities of plant and microbial metabolism in root zones transform and degrade soil contaminants. Emphasis is given to mechanisms that enable PHC functionalization via reactive molecular species.

Removal of 60Co2+ and 137Cs+ ions from low radioactive solutions using Azolla caroliniana willd. water fern

AbstractThis study concerns the removal of the 137Cs+ and 60Co2+ β+γ-radioactive ions in Azolla caroliniana Willd. water fern. The living fern and two different types of biosorbent prepared from Azolla caroliniana were tested to remove the above-mentioned radioactive ions from dilute solutions, in the absence and in the presence of the ionic competition. Effective 137Cs+ and 60Co2+ ions removal from low radioactive wastewaters was demonstrated. The time dependent K d(t) values were calculated from the absorption data. These results indicate that removal process achieved equilibrium in about 120 min and that it involves two steps: rapid and slow absorption; the active process (metabolic bioaccumulation on the living fern) was responsible for above one half of the total removal process. A thin layer radiochromatography study leads to the conclusion that the biochemical components in which 137Cs+ and 60Co2+ place themselves are of a polysaccharide and lipoid fractions.

Taxonomical notes on the heterosporous water ferns

Taxonomical notes on the heterosporous water ferns

The ability of Azolla caroliniana to remove heavy metals (Hg(II), Cr(III), Cr(VI)) from municipal waste water

The aim of this paper was to investigate the capacity of a small water fern, Azolla caroliniana Willd. ( Azollaceae), to purify waters polluted by Hg and Cr. Many plants are capable of accumulating heavy metals (called hyperaccumulators) and one of them is the water fern A. caroliniana. During 12 days of the experiment the fern was grown on the nutrient solution containing Hg 2+, Cr 3+ and CrO 4 2− ions, each in a concentration 0.1, 0.5 and 1.0 mg dm −3. The presence of these ions caused a 20–31% inhibition of A. caroliniana growth, the highest in the presence of Hg(II) ions, in comparison to the control. After day 12 of the experiment, metal contents the solution decreased to 0–0.25 mg dm −3, and this decrease comprised between 74 (Cr 3+ 1.0 mg dm −3 treatment) and 100% (CrO 4 2− 0.1 mg dm −3 treatment). The fern took a lesser quantity of the metals from 0.1 mg dm −3 treatments compared to 0.5 and 1.0 mg dm −3 treatments. In the A. caroliniana tissues the concentration of heavy metals under investigation ranged from 71 to 964 mg kg −1 dm; the highest level being found for Cr(III) containing nutrient solution.

ISOLATION AND CHARACTERIZATION OF TRYPSIN INHIBITOR FROM THE WATER FERN, AZOLLA PINNATA R.Br.

Trypsin inhibitor from water fern (Azolla pinnata R. Br.) was isolated and characterized. Extraction of Azolla leaf meal in NaCI (0.15 M) rendered a higher recovery of trypsin inhibitor compared to other solvents tested (P < 0.05). The extraction time affected the inhibitor recovery significantly (P < 0.05). The extraction time of 3 h was optimum for the recovery of trypsin inhibitor. Based on inhibitor activity of a zone separated by electrophoresis, the molecular mass of the inhibitor from Azolla leaf was 21 kDa. The partially purified inhibitor was heat stable up to 10 min at 90C, at pH 7. 0. High activity was also retained over a wide pH range (4 - 8) at 37C.

Changes in the abundance and distribution of conserved centrosomal, cytoskeletal and ciliary proteins during spermiogenesis in Marsilea vestita.

Spermiogenesis in the male gametophytes of the water fern Marsilea vestita is a precise and rapid process resulting in the production of ciliated gametes. Development begins from a single cell within the microspore wall that undergoes nine rapid cell division cycles in distinct planes to produce 32 spermatids that are surrounded by 7 sterile cells. Thereafter, the de novo formation of basal bodies occurs in a discrete cytoplasmic particle known as a blepharoplast, with the subsequent formation of a complex ciliary apparatus in elongating spermatids. The rate and extent of development appear to be controlled at a post-transcriptional level, where the sudden translation of specific stored mRNAs (e.g., centrin) results in the formation of particular structures in the cells (e.g., blepharoplasts). We show here that additional centrosomal and cytoskeletal antigens known as SF assemblin, p95 kDa protein, delta tubulin, gamma tubulin, Xgrip109, Aik, CTR453, RanBPM, BX63, RSP6, and alpha tubulin each exhibit specific localization patterns both on immunoblots of gametophyte protein isolates and in fixed cells. BAp90, PP4, and RLC exhibit specific localization patterns in fixed cells. We show that the antigens exhibit complex patterns of abundance during spermiogenesis. In an attempt to identify regulatory agents involved in spermiogenesis, we employed a RNAi-based screen of 41 randomly selected gametophyte cDNAs on developing populations of synchronously growing gametophytes. The gametophytes treated with each of the RNAi probes exhibited arrest at a specific stage of development. A consequence of anomalous development was the block to assembly of the ciliary apparatus, an effect highlighted by altered staining with anti-centrin, anti-beta-tubulin, and anti-RSP6 antibodies. Our results show that complex, integrated processes of translation and protein partitioning apparently underlie the assembly of the ciliary apparatus during spermiogenesis in male gametophytes of M. vestita.

The impact and control of alien aquatic vegetation in South African aquatic ecosystems

Water hyacinth, water lettuce, salvinia, parrot's feather and red water fern are South American aquatic plant species that have become invasive in aquatic ecosystems in South Africa. The lack of indigenous natural enemies and the presence of nutrient rich waters have contributed to their invasiveness. The impacts of dense mats of these weeds include the reduction in quality and quantity of water for urban, agricultural and industrial uses, an increase in siltation of rivers, dams and wetlands, a reduction in water surface area for recreation, clogging of irrigation canals and pumps, drowning of livestock and severe deterioration of aquatic biodiversity. Biological control offers a sustainable management tool for all five species and significant success has been achieved in the control of these weeds. However, the long-term management of alien aquatic vegetation relies on the prevention of other species entering South Africa and, more importantly, the reduction of nutrients entering aquatic ecosystems.