Design of a sustainable development process between phytoremediation and production of bioethanol with Eichhornia crassipes.

Eichhornia crassipes is considered a problem in different aquatic ecosystems, due to its abundance it could become a solution to design and build economic and efficient treatment plants, and especially for the production of biofuels such as bioethanol. The objective of this research is to design and implement a process of sustainable development between phytoremediation and the production of bioethanol with E. crassipes, evaluating the incidence of chromium adhered to the biomass of this plant in the production of bioethanol. A system was installed to evaluate the phytoremediation with E. crassipes with water loaded with chromium, determining the effectiveness of this plant to eliminate this heavy metal even if it is alive in a body of water. After this process, we proceeded to take the biomass loaded with chromium to the bioreactors to evaluate the production of bioethanol, evaluating three types of biomass, one without chromium adhered and the other two with chromium adhered to the structure of its plant. There was a 25% decrease in the ethanol production of E. crassipes due to the presence of chromium. Concluding that the biomass of E. crassipes could be used totally for phytoremediation processes of waters contaminated with heavy metals and later use this biomass for the production of bioethanol, finding a sustainable system to be used on a larger scale.

The genetic architecture of tristyly and its breakdown to self-fertilization.

The floral polymorphism tristyly involves three style morphs with a reciprocal arrangement of stigma and anther heights governed by two diallelic loci (S and M). Tristyly functions to promote cross-pollination, but modifications to stamen position commonly cause transitions to selfing. Here, we integrate whole-genome sequencing and genetic mapping to investigate the genetic architecture of the M locus and the genetic basis of independent transitions to selfing in tristylous Eichhornia paniculata. We crossed independently derived semi-homostylous selfing variants of the long- and mid-styled morph fixed for alternate alleles at the M locus (ssmm and ssMM, respectively), and backcrossed the F1 to the parental ssmm genotype. We phenotyped and genotyped 462 backcross progeny using 1450 genotyping-by-sequencing (GBS) markers and performed composite interval mapping to identify quantitative trait loci (QTL) governing style-length and anther-height variation. A QTL associated with the primary style-morph differences (style length and anther height) mapped to linkage group 5 and spanned ~13-27.5 Mbp of assembled sequence. Bulk segregant analysis identified 334 genes containing SNPs potentially linked to the M locus. The stamen modifications characterizing each selfing variant were governed by loci on different linkage groups. Our results provide an important step towards identifying the M locus and demonstrate that transitions to selfing have originated by independent sets of mating-system modifier genes unlinked to the M locus, a pattern inconsistent with a recombinational origin of selfing variants at a putative supergene.

Advances in management and utilization of invasive water hyacinth (Eichhornia crassipes) in aquatic ecosystems - a review.

The objective of this review is to provide a concise summary of literature in the Chinese language since late 1970s and focuses on recent development in global scenarios. This work will replenish the FAO summary of water hyacinth utilization from 1917 to 1979 and review ecological and socioeconomic impacts of the water hyacinth from 1980 to 2010. This review also discusses the debate on whether the growth of the water hyacinth is a problem, a challenge or an opportunity. Literature suggested that integrated technologies and good management may be an effective solution and the perception of water hyacinth could change from that of a notorious aquatic weed to a valuable resource, including its utilization as a biological agent for the application in bioremediation for removing excess nutrients from eutrophic water bodies at low cost. Key aspects on system integration and innovation may focus on low-cost and efficient equipment and the creation of value-added goods from water hyacinth biomass. In the socioeconomic and ecological domain of global development, all the successful and sustainable management inputs for the water hyacinth must generate some sort of social and economic benefit simultaneously, as well as benefiting the ecosystem. Potential challenges exist in linkages between the management of water hyacinth on the large scale to the sustainable development of agriculture based on recycling nutrients, bio-energy production or silage and feed production. Further research and development may focus on more detailed biology of water hyacinth related with its utilization, cost-benefit analysis of middle to large-scale application of the technologies and innovation of the equipment used for harvesting and dehydrating the plant.

Salinity and pH effects on floating and emergent macrophytes in a constructed wetland.

Salvinia herzogii, Pistia stratiotes and Eichhornia crassipes (floating species) were the dominant macrophytes in a constructed wetland (CW) over the first years of operation. Later, the emergent Typha domingensis displaced the floating species, becoming dominant. The industrial effluent treated at this CW showed high pH and salinity. The aim of this work was to study the tolerance of floating species and T. domingensis exposed to different pH and salinity treatments. Treatments at pH 8, 9, 10 and 11 and salinities of 2,000; 3,000; 4,000; 6,000; and 8,000 mg L-1 were performed. Floating macrophytes were unable to tolerate the studied pH and salinity ranges, while T. domingensis tolerated higher pH and salinity values. Many industrial effluents commonly show high pH and salinity. T. domingensis demonstrated to be a suitable macrophyte to treat this type of effluents.

Recent mating-system evolution in Eichhornia is accompanied by cis-regulatory divergence.

The evolution of predominant self-fertilization from cross-fertilization in plants is accompanied by diverse changes to morphology, ecology and genetics, some of which likely result from regulatory changes in gene expression. We examined changes in gene expression during early stages in the transition to selfing in populations of animal-pollinated Eichhornia paniculata with contrasting mating patterns. We crossed plants from outcrossing and selfing populations and tested for the presence of allele-specific expression (ASE) in floral buds and leaf tissue of F1 offspring, indicative of cis-regulatory changes. We identified 1365 genes exhibiting ASE in floral buds and leaf tissue. These genes preferentially expressed alleles from outcrossing parents. Moreover, we found evidence that genes exhibiting ASE had a greater nonsynonymous diversity compared to synonymous diversity in the selfing parents. Our results suggest that the transition from outcrossing to high rates of self-fertilization may have the potential to shape the cis-regulatory genomic landscape of angiosperm species, but that the changes in ASE may be moderate, particularly during the early stages of this transition.

Clonal integration increases relative competitive ability in an invasive aquatic plant.

PREMISE OF THE STUDY: Physiological integration between connected ramets is well known to increase performance of clonal plant species. However, no direct evidence appears to exist that integration can increase the ability of clonal species to compete with other species within mixed communities. We tested this hypothesis using two floating, invasive, aquatic species in which fragmentation-and thus extent of integration-is likely to vary between habitats and times. METHODS: Individual ramets of Pistia stratiotes and Eichhornia crassipes were grown in monoculture or in mixture, and new stolons bearing new offspring were severed or left intact. After 6 wk, the numbers of offspring and second-generation (2°) offspring produced by each original ramet, or parent, were counted; and the final dry mass of each parent, its stolons, its offspring, and its 2° offspring were measured. KEY RESULTS: Fragmentation decreased the relative competitive ability of Pistia, but not that of Eichhornia. This was mainly because Pistia accumulated ∼30% less dry mass of offspring when fragmented and grown with Eichhornia than in other treatments. Offspring of Pistia were smaller than those of Eichhornia in all treatments. CONCLUSIONS: Our results show that clonal integration can increase competitive ability in some clonal species. In this case, integration appeared to enable the small offspring of Pistia to compete more effectively with the large offspring of Eichhornia. Lower rates of fragmentation may select for production of more numerous, smaller vegetative offspring in clonal species.

Postpollination discrimination between self and outcross pollen covaries with the mating system of a self-compatible flowering plant.

PREMISE OF THE STUDY: Variation in the mating system of hermaphroditic plant populations is determined by interactions between genetic and environmental factors operating via both pre- and postmating processes. Models predicting the maintenance of intermediate outcrossing rates in animal-pollinated plants often assume that the mating system is primarily controlled by floral morphology and pollinator availability, but rarely has the influence of postpollination processes on variation in outcrossing been examined. METHODS: We investigated the influence of stylar discrimination between illegitimate and legitimate pollen-tube growth and the pollen-load capacity of stigmas on mating-system variation in the annual, tristylous species Eichhornia paniculata using controlled crosses and genetic markers. This species exhibits an exceptionally broad range of outcrossing rates in natural populations. KEY RESULTS: There was significant variation among populations in the pollen-load capacity of stigmas and the ability of styles to discriminate between illegitimate vs. legitimate pollen. There was strong correspondence between stylar-discrimination ability and variation in outcrossing rate among populations and style morphs. The combination of stigmatic pollen-load capacity and stylar discrimination explained more than 80% of the variation in outcrossing rates among populations. CONCLUSIONS: The finding that stigmatic pollen-load capacity and stylar-discrimination ability contributed significantly to explaining the wide range of outcrossing rates in E. paniculata suggests that postpollination mechanisms play an important role in governing mating patterns in this species. The difference in levels of stylar discrimination between outcrossing and selfing populations may reflect a trade-off between selection for increased outcrossing and greater reproductive assurance.

Lead tolerance of water hyacinth (Eichhornia crassipes Mart. - Pontederiaceae) as defined by anatomical and physiological traits.

This study aimed at verifying the lead tolerance of water hyacinth and at looking at consequent anatomical and physiological modifications. Water hyacinth plants were grown on nutrient solutions with five different lead concentrations: 0.00, 0.50, 1.00, 2.00 and 4.00 mg L-1 by 20 days. Photosynthesis, transpiration, stomatal conductance and the Ci/Ca rate were measured at the end of 15 days of experiment. At the end of the experiment, the anatomical modifications in the roots and leaves, and the activity of antioxidant system enzymes, were evaluated. Photosynthetic and Ci/Ca rates were both increased under all lead treatments. Leaf anatomy did not exhibit any evidence of toxicity effects, but showed modifications of the stomata and in the thickness of the palisade and spongy parenchyma in the presence of lead. Likewise, root anatomy did not exhibit any toxicity effects, but the xylem and phloem exhibited favorable modifications as well as increased apoplastic barriers. All antioxidant system enzymes exhibited increased activity in the leaves, and some modifications in roots, in the presence of lead. It is likely, therefore, that water hyacinth tolerance to lead is related to anatomical and physiological modifications such as increased photosynthesis and enhanced anatomical capacity for CO2 assimilation and water conductance.

Invasive alien species water hyacinth Eichhornia crassipes as abode for macroinvertebrates in hypertrophic Ramsar Site, Lake Xochimilco, Mexico.

This paper presents information on the density, diversity and functional feeding groups of macroinvertebrate assemblages associated with water hyacinth in Antiguo Canal Cuemanco, part of Lake Xochimilco in Mexico City. Rare (low frequency and density) and dominant (high frequency and density) taxa prevailed in the assemblages, with the most predominant being Hyalella azteca, Chironomus plumosus and Ischnura denticollis. Nonmetric Multidimensional Scaling confirmed two climatic seasons: warm-rainy and cold-dry; the former with the highest diversity and density of taxa. Canonical Correspondence Analysis showed that conductivity, nitrates and turbidity explained the density variations of taxa. Antiguo Canal Cuemanco waters are spatially homogeneous with the characteristics of hypertrophic shallow lakes, inhabited by scrapers and gathering-collectors. The species found were tolerant to organic pollution.

Alien emergent aquatic plants develop better ciprofloxacin tolerance and metabolic capacity than one native submerged species.

Antibiotic pollution and biological invasion pose significant risks to freshwater biodiversity and ecosystem health. However, few studies have compared the ecological adaptability and ciprofloxacin (CIPR) degradation potential between alien and native macrophytes. We examined growth, physiological response, and CIPR accumulation, translocation and metabolic abilities of two alien plants (Eichhornia crassipes and Myriophyllum aquaticum) and one native submerged species (Vallisneria natans) exposed to CIPR at 0, 1 and 10 mg/L. We found that E. crassipes and M. aquaticum's growth were unaffected by CIPR while V. natans was significantly hindered under the 10 mg/L treatment. CIPR significantly decreased the maximal quantum yield of PSII, actual quantum yield of PSII and relative electron transfer rate in E. crassipes and V. natans but didn't impact these photosynthetic characteristics in M. aquaticum. All the plants can accumulate, translocate and metabolize CIPR. M. aquaticum and E. crassipes in the 10 mg/L treatment group showed greater CIPR accumulation potential than V. natans indicated by higher CIPR contents in their roots. The oxidative cleavage of the piperazine ring acts as a key pathway for these aquatic plants to metabolize CIPR and the metabolites mainly distributed in plant roots. M. aquaticum and E. crassipes showed a higher production of CIPR metabolites compared to V. natans, with M. aquaticum exhibiting the strongest CIPR metabolic ability, as indicated by the most extensive structural breakdown of CIPR and the largest number of potential metabolic pathways. Taken together, alien species outperformed the native species in ecological adaptability, CIPR accumulation and metabolic capacity. These findings may shed light on the successful invasion mechanisms of alien aquatic species under antibiotic pressure and highlight the potential ecological impacts of alien species, particularly M. aquaticum. Additionally, the interaction of antibiotic contamination and invasion might further challenge the native submerged macrophytes and pose greater risks to freshwater ecosystems.

Water hyacinth Eichhornia crassipes (Mart.) Solms-Laubach dynamics and succession in the Nyanza Gulf of Lake Victoria (east Africa): implications for water quality and biodiversity conservation.

This study, conducted in Nyanza Gulf of Lake Victoria, assessed ecological succession and dynamic status of water hyacinth. Results show that water hyacinth is the genesis of macrophyte succession. On establishment, water hyacinth mats are first invaded by native emergent macrophytes, Ipomoea aquatica Forsk., and Enydra fluctuans Lour., during early stages of succession. This is followed by hippo grass Vossia cuspidata (Roxb.) Griff. in mid- and late stages whose population peaks during climax stages of succession with concomitant decrease in water hyacinth biomass. Hippo grass depends on water hyacinth for buoyancy, anchorage, and nutrients. The study concludes that macrophyte succession alters aquatic biodiversity and that, since water hyacinth infestation and attendant succession are a symptom of broader watershed management and pollution problems, aquatic macrophyte control should include reduction of nutrient loads and implementing multifaceted approach that incorporates biological agents, mechanical/manual control with utilization of harvested weed for cottage industry by local communities.

De novo sequence assembly and characterization of the floral transcriptome in cross- and self-fertilizing plants.

BACKGROUND: The shift from cross-fertilization to predominant self-fertilization is among the most common evolutionary transitions in the reproductive biology of flowering plants. Increased inbreeding has important consequences for floral morphology, population genetic structure and genome evolution. The transition to selfing is usually characterized by a marked reduction in flower size and the loss of traits involved in pollinator attraction and the avoidance of self-fertilization. Here, we use short-read sequencing to assemble, de novo, the floral transcriptomes of three genotypes of Eichhornia paniculata, including an outcrosser and two genotypes from independently derived selfers, and a single genotype of the sister species E. paradoxa. By sequencing mRNA from tissues sampled at various stages of flower development, our goal was to sequence and assemble the floral transcriptome and identify differential patterns of gene expression. RESULTS: Our 24 Mbp assembly resulted in ~27,000 contigs that averaged ~900 bp in length. All four genotypes had highly correlated gene expression, but the three E. paniculata genotypes were more correlated with one another than each was to E. paradoxa. Our analysis identified 269 genes associated with floral development, 22 of which were differentially expressed in selfing lineages relative to the outcrosser. Many of the differentially expressed genes affect floral traits commonly altered in selfing plants and these represent a set of potential candidate genes for investigating the evolution of the selfing syndrome. CONCLUSIONS: Our study is among the first to demonstrate the use of Illumina short read sequencing for de novo transcriptome assembly in non-model species, and the first to implement this technology for comparing floral transcriptomes in outcrossing and selfing plants.

Taxonomic notes on Malaconothridae (Acari, Oribatida) associated with water hyacinth in Egypt.

Three Egyptian species of the oribatid mite family Malaconothridae, all found on roots of the floating aquatic plant Eichhornia crassipes in the River Nile, are analyzed. Trimalaconothrus crassipes Ramadan, Ismail Mustafa, 2017 is recombined to Tyrphonothrus crassipes (Ramadan, Ismail Mustafa, 2017) (comb. nov.). Malaconothrus ramadani Ramadan, Ismail Mustafa, 2018 and M. transversus Ramadan, Ismail Mustafa, 2018 are both considered to be tritonymphs of Ty. crassipes (=M. ramadani syn. nov.; =M. transversus syn. nov.).

Genetic uniformity characterizes the invasive spread of water hyacinth (Eichhornia crassipes), a clonal aquatic plant.

Aquatic plant invasions are often associated with long-distance dispersal of vegetative propagules and prolific clonal reproduction. These reproductive features combined with genetic bottlenecks have the potential to severely limit genetic diversity in invasive populations. To investigate this question we conducted a global scale population genetic survey using amplified fragment length polymorphism markers of the world's most successful aquatic plant invader -Eichhornia crassipes (water hyacinth). We sampled 1140 ramets from 54 populations from the native (South America) and introduced range (Asia, Africa, Europe, North America, Central America and the Caribbean). Although we detected 49 clones, introduced populations exhibited very low genetic diversity and little differentiation compared with those from the native range, and approximately 80% of introduced populations were composed of a single clone. A widespread clone ('W') detected in two Peruvian populations accounted for 70.9% of the individuals sampled and dominated in 74.5% of the introduced populations. However, samples from Bangladesh and Indonesia were composed of different genotypes, implicating multiple introductions to the introduced range. Nine of 47 introduced populations contained clonal diversity suggesting that sexual recruitment occurs in some invasive sites where environmental conditions favour seedling establishment. The global patterns of genetic diversity in E. crassipes likely result from severe genetic bottlenecks during colonization and prolific clonal propagation. The prevalence of the 'W' genotype throughout the invasive range may be explained by stochastic sampling, or possibly because of pre-adaptation of the 'W' genotype to tolerate low temperatures.

Socioeconomic effects of water hyacinth (Echhornia Crassipes) in Lake Tana, North Western Ethiopia.

Water hyacinth has been progressively advanced in Lake Tana since 2011 and covered vast areas of the lakeshore. The aim of this study was to assess how the lakeshore covered by the weed mats affected the socioeconomic of the local community. The study was based on a survey of 405 households, 8 group discussions and interviews of 15 key informants conducted from January to March 2018. The results revealed that crop production, livestock feed supply, water supply, fishing, the health of local people and livestock were impacted negatively by the infestation of water hyacinth. The range of socioeconomic problems caused by the weed generally implied the real impacts on the lives of local communities and national economic development. The efforts made to control water hyacinth has costed huge labor and financial resources. The results revealed that close to 800,000 human labor dedicated to manual removal of the weed from 2012 to 2018 and above one million USD spent for procurement of harvester machines and bioagent experiments. In spite of the devotion of huge labor and spending of a lot of money, the expansion of the weed has not controlled. Poor coordination of controlling efforts, dumping of harvested dense mats of the weed in the lakeshore, lack of genuine participation of the local people are principal factors for the failure of the controlling efforts A coordination of various stakeholders thus is needed to make eradicating methods more effective. Other alternative options should also be considered to control the weed expansion.

Large-Scale Green Liver System for Sustainable Purification of Aquacultural Wastewater: Construction and Case Study in a Semiarid Area of Brazil (Itacuruba, Pernambuco) Using the Naturally Occurring Cyanotoxin Microcystin as Efficiency Indicator.

The aquaculture industry in Brazil has grown immensely resulting in the production of inefficiently discarded wastewater, which causes adverse effects on the aquatic ecosystem. The efficient treatment of aquaculture wastewater is vital in reaching a sustainable and ecological way of fish farming. Bioremediation in the form of the Green Liver System employing macrophytes was considered as wastewater treatment for a tilapia farm, COOPVALE, in Itacuruba, Brazil, based on previously demonstrated success. A large-scale system was constructed, and the macrophytes Azolla caroliniana, Egeria densa, Myriophyllum aquaticum, and Eichhornia crassipes were selected for phytoremediation. As cyanobacterial blooms persisted in the eutrophic wastewater, two microcystin congeners (MC-LR and -RR) were used as indicator contaminants for system efficiency and monitored by liquid-chromatography-tandem-mass-spectrometry. Two trial studies were conducted to decide on the final macrophyte selection and layout of the Green Liver System. In the first trial, 58% MC-LR and 66% MC-RR were removed and up to 32% MC-LR and 100% MC-RR were removed in the second trial. Additional risks that were overcome included animals grazing on the macrophytes and tilapia were spilling over from the hatchery. The implementation of the Green Liver System significantly contributed to the bioremediation of contaminants from the fish farm.

Evolutionary pathways to self-fertilization in a tristylous plant species.

Evolutionary transitions from outcrossing to selfing occur commonly in heterostylous genera. The morphological polymorphisms that characterize heterostyly provide opportunities for different pathways for selfing to evolve. Here, we investigate the origins and pathways by which selfing has evolved in tristylous Eichhornia paniculata by providing new evidence based on morphology, DNA sequences and genetic analysis. The primary pathway from outcrossing to selfing involves the stochastic loss of the short-styled morph (S-morph) from trimorphic populations, followed by the spread of selfing variants of the mid-styled morph (M-morph). However, the discovery of selfing variants of the long-styled morph (L-morph) in Central America indicates a secondary pathway and distinct origin for selfing. Comparisons of multi-locus nucleotide sequences from 27 populations sampled from throughout the geographical range suggest multiple transitions to selfing. Genetic analysis of selfing variants of the L- and M-morphs demonstrates recessive control of the loss of herkogamy, although the number of factors appears to differ between the forms. Early stages in the establishment of selfing involve developmental instability in the formation of flowers capable of autonomous self-pollination. The relatively simple genetic control of herkogamy reduction and frequent colonizing episodes may often create demographic conditions favouring transitions to selfing in E. paniculata.

Modification of flower architecture during early stages in the evolution of self-fertilization.

BACKGROUND AND AIMS: The evolution of selfing from outcrossing is characterized by a series of morphological changes to flowers culminating in the selfing syndrome. However, which morphological traits initiate increased self-pollination and which are accumulated after self-fertilization establishes is poorly understood. Because the expression of floral traits may depend on the conditions experienced by an individual during flower development, investigation of changes in mating system should also account for environmental and developmental factors. Here, early stages in the evolution of self-pollination are investigated by comparing floral traits among Brazilian populations of Eichhornia paniculata (Pontederiaceae), an annual aquatic that displays variation in selfing rates associated with the breakdown of tristyly to semi-homostyly. METHODS: Thirty-one Brazilian populations under uniform glasshouse conditions were compared to investigate genetic and environmental influences on flower size and stigma-anther separation (herkogamy), two traits that commonly vary in association with transitions to selfing. Within-plant variation in herkogamy was also examined and plants grown under contrasting environmental conditions were compared to examine to what extent this trait exhibits phenotypic plasticity. KEY RESULTS: In E. paniculata a reduction in herkogamy is the principal modification initiating the evolution of selfing. Significantly, reduced herkogamy was restricted to the mid-styled morph and occurred independently of flower size. Significant genetic variation for herkogamy was detected among populations and families, including genotypes exhibiting developmental instability of stamen position with bimodal distributions of herkogamy values. Cloned genets exposed to contrasting growth conditions demonstrated environmental control of herkogamy and genotypic differences in plasticity of this trait. CONCLUSIONS: The ability to modify herkogamy independently of other floral traits, genetic variation in the environmental sensitivity of herkogamy, and the production of modified and unmodified flowers within some individuals, reveal the potential for dynamic control of the mating system in a species that commonly confronts heterogeneous aquatic environments.

Growth, accumulation and uptake of Eichhornia crassipes exposed to high cadmium concentrations.

A greenhouse experiment was performed to evaluate the growth, accumulation, and uptake rate of Eichhornia crassipes subject to high cadmium concentrations. Three doses of Cd were added to polluted river water (1, 5, and 10 mg Cd/L), and polluted water with basal Cd concentration (0.070 mg/L) was used as a control. The experiment lasted for 7 days. Signs of stress and toxicity were visible in all treatments from day 3 of the experiment. The growth of the water hyacinth was slightly stimulated in the presence of low Cd concentration (1 mg/L), but this could also be due to the chloride and other nutrients present in the polluted water. Cd was accumulated mainly in roots, showing a maximum concentration of 1742.1 mg Cd/kg dw (10 mg Cd/L). The translocation from roots to leaves was low, with a maximum accumulation of 147.4 mg Cd/kg dw (10 mg Cd/L). The uptake rate for roots reached a maximum of 248.7 mg Cd/kg·day while the uptake rate for leaves did not saturate in the range of the studied concentrations (max. 20.8 mg Cd/kg·day). The water hyacinth showed promising results for the application in the treatment of Cd-polluted waters given its ability to tolerate high Cd concentrations in the media (up to 10 mg Cd/L) and its capacity for uptake and accumulation.

Response of Eichhornia crassipes (Pontederiaceae) to water level fluctuations in two lakes with different connectivity in the Paraná River floodplain.

Floodplain lakes are especially dynamic due to the irregular flow regime of the Paraná River and its location along the geomorphologic gradient between the lakes and the river. The response of Eichhornia crassipes (Mart.) Solms (one of the most frequent aquatic plant) was studied in two floodplain lakes with different flooding regimes. Samples were taken between March 1997 and December 2001 on 13 different hydrologic conditions during prolonged hydrologic connection and prolonged hydrologic isolation. Leaf height, leaf density, biomass and nutrient content of the mature leaves of E. crassipes were measured and related to water level fluctuation and the hydrologic connectivity. The lake more connected with the main channel had a long lasting inundation phase. In this condition the surface area covered by water increased more than three times compared to prolonged hydrologic isolation condition. As river water entered the floodplain lakes, dissolved inorganic nitrogen increased to high values, especially NO3-, whereas the isolation condition was characterised by a decrease in NO3 concentrations to undetectable levels. Compared to plants growing in the more isolated lake, those growing in the more connected lake had a significantly lower leaf density, longer leaves, less root biomass and lower ratio between below-ground and above-ground biomasses. However, total and leaf biomasses were not significantly different between sites. In each lake, differences in leaf height, leaf biomass and root biomass between prolonged hydrologic connection and isolation, as well as the insignificant relationship between leaf size and leaf density, indicate that the morphological traits of E. crassipes respond to pluri-annual water level fluctuations. The highest nutrient concentration in mature leaves was registered at the end of the prolonged hydrologic connection in the more connected lake. During the prolonged isolation, leaves had more lignin and a higher L:N ratio than at high waters, at the same sites. The success of E. crassipes in occupying habitats subjected to wide and erratic fluctuations in water level, such as the Parana River floodplain, appears to be related to its ability to modify morphological traits according to water level.