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Concept: Eichhornia crassipes


Invasive aquatic plants from Lake Fúquene (Cundinamarca, Colombia), water hyacinth (Eichhornia crassipes C. Mart.) and Brazilian elodea (Egeria densa Planch.) have been removed mechanically from the lake and can be used for edible mushrooms production. The growth of the oyster mushroom (Pleurotus ostreatus) on these aquatic macrophytes was investigated in order to evaluate the possible use of fruiting bodies and spent biomass in food production for human and animal nutrition, respectively. Treatments included: water hyacinth, Brazilian elodea, sawdust, rice hulls and their combinations, inoculated with P. ostreatus at 3 %. Water hyacinth mixed with sawdust stimulated significantly fruiting bodies production (P = 3.3 × 10(-7)) with 71 % biological efficacy, followed by water hyacinth with rice husk (55 %) and elodea with rice husk (48 %), all of these have protein contents between 26 and 47 %. Loss of lignin (0.9-21.6 %), cellulose (3.7-58.3 %) and hemicellulose (1.9-53.8 %) and increment in vitro digestibility (16.7-139.3 %) and reducing sugars (73.4-838.4 %) were observed in most treatments. Treatments spent biomass presented Relative Forage Values (RFV) from 46.1 to 232.4 %. The results demonstrated the fungus degrading ability and its potential use in aquatic macrophytes conversion biomass into digestible ruminant feed as added value to the fruiting bodies production for human nutrition.

Concepts: Nutrition, Cellulose, Aquatic plants, Mushroom, Aquatic plant, Edible mushroom, Eichhornia crassipes, Water hyacinth


In the last decades, petroleum activities have increased in the Brazilian Amazon where there is oil exploration on the Urucu River, a tributary of the Amazon River, about 600 km from the city of Manaus. Particularly, transportation via the Amazon River to reach the oil refinery in Manaus may compromise the integrity of the large floodplains that flank hundreds of kilometers of this major river. In the Amazon floodplains, plant growth and nutrient cycling are related to the flood pulse. When oil spills occur, floating oil on the water surface is dispersed through wind and wave action in the littoral region, thus affecting the vegetation of terrestrial and aquatic environments. If pollutants enter the system, they are absorbed by plants and distributed in the food chain via plant consumption, mortality, and decomposition. The effect of oil on the growth and survival of vegetation in these environments is virtually unknown. The water hyacinth [Eichhornia crassipes (Mart.) Solms] has a pantropical distribution but is native to the Amazon, often growing in high-density populations in the floodplains where it plays an important role as shelter and food source for aquatic and terrestrial biota. The species is well known for its high capacity to absorb and tolerate high levels of heavy metal ions. To study the survival and response of water hyacinth under six different oil doses, ranging from 0 to 150 ml l(-1), and five exposure times (1, 5, 10, 15, and 20 days), young individuals distributed in a completely randomized design experiment composed of vessels with a single individual each were followed over a 50-day period (30-day acclimatization, 20 days under oil treatments). Growth parameters, biomass, visual changes in the plants, and pH were recorded at 1, 5, 10, 15, and 20 days. Increasing the time of oil exposure caused a decrease in biomass, ratio of live/dead biomass and length of leaves, and an increase in the number of dead leaves. Dose of oil and time of exposure are the most important factors controlling the effects of petroleum hydrocarbons on E. crassipes. Although the species is able to survive exposure to a moderate dose of oil, below 75 ml l(-1) for only 5 days, severe alterations in plant growth and high mortality were observed. Therefore, we conclude that Urucu oil heavily affects E. crassipes despite its known resistance to many pollutants.

Concepts: Water, Petroleum, River, Amazon River, Amazon Basin, Aquatic plant, Eichhornia crassipes, Water hyacinth


Cellulose decomposing microorganisms (CDMs) are important for efficient bioconversion of plant biomasses. To this end, we isolated seven fungal isolates (Aspergillus wentii, Fusarium solani, Mucor sp., Penicillum sp., Trichoderma harzaianum, Trichoderma sp.1 and Trichoderma sp.2) and three bacterial isolates (bacterial isolate I, II and III) from partially decomposed farm yard manure, rice straw and vermicompost, and evaluated them for decomposition of rice straw (Oryza sativa), Ipomoea camea and Eichhornia crassipes biomass. CDMs inoculation, in general, reduced the composting period by 14-28 days in rice straw, 14-34 days in Eichhornia and 10-28 days in Ipomoea biomass over control. Of the 10 CDMs tested, Mucor sp. was found to be the most effective as Mucor-inoculated biomass required minimum time, i.e. 84, 68 and 80 days respectively for composting of rice straw, Eichhornia and Ipomoea biomass as against 112, 102 and 108 days required under their respective control. CDMs inoculation also narrowed down the C:N ratio of the composts which ranged from 19.1-22.7, 12.9-14.7 and 10.5-13.1 in rice straw, Eichhornia and Ipomoea biomass respectively as against 24.1, 17.1 and 16.2 in the corresponding control treatments. Aspergillus wentii, Fusarium solani, Mucor sp., and Penicillum sp. were found most effective (statistically at par) in reducing C:N ratio and causing maximum loss of carbon and dry matter in composted materials. These benefits of CDMs inoculation were also accompanied by significant increase in NPK contents in the composted materials.

Concepts: Photosynthesis, Bacteria, Fungus, Compost, Chemical decomposition, Decomposition, Composting, Eichhornia crassipes


In this study, the interaction between temperature and light intensity was investigated in common water hyacinth (CWH) and purple root water hyacinth (PRWH). Effects of different temperatures (11/5, 18/11, 25/18, and 32/25 °C day/night) simultaneously applied at various light intensities (100, 300, and 600 μmol m(-2) s(-1)) to the plants were detected by measuring changes in the root lengths, protein content, sugar content, malondialdehyde (MDA) content, photosynthesis, and dissolved oxygen (DO). Temperature and light intensity significantly influence the growth of water hyacinths, and there was significant interaction among these environmental factors. The results suggest that several environmental factors act synergistically on the growth and physiology of water hyacinths. The higher new root length (NRL) in PRWH indicated that its root growth capacity is higher than in CWH. The soluble sugar content in leaves of CWH was higher than PRWH, indicating that relatively higher sugar content in CWH to low-temperature stress may support its tolerant nature. Lower temperature and light intensity can stimulate the accumulation of MDA content. The net photosynthetic rate (Pn) in leaves of CWH was higher than PRWH. In low temperature, increase light intensity can stimulate the Pn of PRWH and CWH. In CWH and PRWH, Pn showed a similar trend as noted for stomatal conductance (Cond) and transpiration rate (Tr). The capacity of PRWH in adding oxygen to the water column is better than those of CWH.

Concepts: Photosynthesis, Oxygen, Aquatic plant, Eichhornia crassipes, Water hyacinth, Pontederiaceae


The application potential of duckweed (Lemna japonica 0234) and water hyacinth (Eichhornia crassipes) were compared in two pilot-scale wastewater treatment systems for more than one year. The results indicated duckweed had the same total nitrogen (TN) recovery rate as water hyacinth (0.4g/m(2)/d) and a slightly lower total phosphorus (TP) recovery rate (approximately 0.1g/m(2)/d) even though its biomass production was half that of water hyacinth. The higher content of crude protein (33.34%), amino acids (25.80%), starch (40.19%), phosphorus (1.24%), flavonoids (2.91%) and lower fiber content provided duckweed with more advantages in resource utilization. Additionally, microbial community discovered by 454 pyrosequencing indicated that less nitrifying bacteria and more nitrogen-fixing bacteria in rhizosphere of duckweed provided it with higher nitrogen recovery efficiency (60%) than water hyacinth (47%). Under the presented condition, duckweed has more application advantages than water hyacinth because it more effectively converted the wastewater nutrients into valuable biomass.

Concepts: Bacteria, Ammonia, Metabolism, Microbiology, Nitrogen, Denitrification, Aquatic plant, Eichhornia crassipes


The liver fluke Fasciola gigantica is a trematode parasite of ruminants and humans that occurs naturally in Africa and Asia. Cases of human fascioliasis, attributable at least in part to F. gigantica, are significantly increasing in the last decades. The introduced snail species Galba truncatula was already identified to be an important intermediate host for this parasite and the efficient invader Pseudosuccinea columella is another suspect in this case. Therefore, we investigated snails collected in irrigation canals in Fayoum governorate in Egypt for prevalence of trematodes with focus on P. columella and its role for the transmission of F. gigantica. Species were identified morphologically and by partial sequencing of the cytochrome oxidase subunit I gene (COI). Among all 689 snails found at the 21 sampling sites, P. columella was the most abundant snail with 296 individuals (42.96%) and it was also the most dominant species at 10 sites. It was not found at 8 sites. Molecular detection by PCR and sequencing of the ITS1-5.8S-ITS2 region of the ribosomal DNA (rDNA) revealed infections with F. gigantica (3.38%), Echinostoma caproni (2.36%) and another echinostome (7.09%) that could not be identified further according to its sequence. No dependency of snail size and trematode infection was found. Both high abundance of P. columella in the Fayoum irrigation system and common infection with F. gigantica might be a case of parasite spill-back (increased prevalence in local final hosts due to highly susceptible introduced intermediate host species) from the introduced P. columella to the human population, explaining at least partly the observed increase of reported fascioliasis-cases in Egypt. Eichhornia crassipes, the invasive water hyacinth, which covers huge areas of the irrigation canals, offers safe refuges for the amphibious P. columella during molluscicide application. As a consequence, this snail dominates snail communities and efficiently transmits F. gigantica.

Concepts: Digenea, Irrigation, Canal, Snail, Invasive species, Fasciola hepatica, Eichhornia crassipes, Water hyacinth


We evaluated the response of the biomass of aquatic macrophytes under limnological changes after water level fluctuation (WLF) of two tropical reservoirs (R1 and R2), located in northeastern Brazil. Initially we tested the hypothesis that post-WLF limnological conditions and biomass of macrophytes increase or decrease, depending on the variable or species. We monitored a 4 × 50 m permanent plot, in four expeditions per period (pre- or post-WLF), assessing species biomass and 10 limnological variables. We utilized 0.25 × 0.25 m quadrats for biomass. Once the effect of WLF in limnological variables and species biomass was confirmed, we utilized Canonical Correspondence Analysis to understand the relationship between limnological variables and species biomass. The abundant and/or dominant species in pre-WLF of R1 ( Pistia stratiotes, Eichhornia crassipes and Salvinia auriculata) and R2 (Paspalidium geminatum and S. auriculata) reduced their biomass post-WLF and were correlated with temperature, total phosphorous and nitrate. The reduced biomass of P. stratiotes, E. crassipes and S. auriculata in post-WLF widened resource availability, allowing coexistence of species. Therefore, we suggest that the change of limnological conditions in post-WLF in artificial lakes acts only as a moderator factor of the interspecific interaction (especially coexistence), without direct relation between these conditions and species biomass.

Concepts: Biodiversity, Lake, Aquatic plants, Aquatic plant, Invasive plant species, Lakes, Eichhornia crassipes, Water hyacinth


The objective of this experiment was to determine effects of substituting concentrate mixture (CM) with water hyacinth (Eichhornia crassipes) leaves (WHL) at different inclusion levels of feed and nutrient intake, digestibility, and growth performance of Washera sheep. Twenty yearlings intact male sheep with initial body weight of 24.1 ± 1.68 kg (mean ± SD) were used in both 90 days of feeding and 7 days of digestibility trials. The experimental animals were arranged into four blocks of five animals based on their initial body weight. The dietary treatments used in the experiment were 100% concentrate mix (0WHL-T1), 50% WHL and 50% CM (50WHL-T2), 75% WHL and 25% concentrate mix (75WHL-T3), and 100% WHL (100WHL-T4). Rice straw was given ad libitum. The crude protein (CP) content of water hyacinth leaf is 14.4%. Dry matter digestibility was greater (p < 0.001) for 0WHL and 50WHL followed by 75WHL. The average daily weight gain was higher for 100% concentrate mix followed by 50 and 75% water hyacinth leave supplemented sheep. Therefore, wilted water hyacinth leave can safely substitute concentrate mix up to 75% and result in the optimum growth of Washera sheep from the feeding regime employed in this study.

Concepts: Nutrition, Aquatic plant, Eichhornia crassipes, Water hyacinth


This paper provides a circular win-win approach for recycling rhizofiltration biomass into multifunctional engineered biochar for various environmental applications (e.g. phosphate recovery) with a potential reuse of the exhausted biochar as an enriched soil amendment. Functionalized biochars were derived from the disposals of water hyacinth (Eichhornia crassipes) plants grown in synthetic contaminated water spiked with either Fe2+ (Fe-B), Mn2+ (Mn-B), Zn2+ (Zn-B) or Cu2+ (Cu-B) comparing with the original drainage water as a control treatment (O-B). The in-situ functionalization of biochar via the inherently heavy metal-rich feedstock produced homogenous organo-mineral complexes on biochar matrix without environmental hazards (e.g. volatilization or chemical sludge formation) associated with other post-synthetic functionalization methods. Physicochemical analyses (SEM-EDS, XRD, FTIR, BET and zeta potential (ζ)) confirmed the functionalization of Fe-B, Zn-B and Cu-B due to organo-mineral complexes formation, maximizing specific surface area, lowering the electronegativity, originating positively charged functional groups, and thus improving the anion exchange capacity (AEC) comparing with O-B. In contrary, physicochemical characteristics of Mn-B was in similarity with those of O-B. Phosphate recovery by the functionalized biochar was much greater than that of the unfunctionalized forms (O-B and Mn-B). Precipitation was the dominant chemisorption mechanisms for phosphate sorption onto biochar compared to other mechanisms (ion exchange, electrostatic attraction and complexation with active functional groups). The exhausted biochar showed an ameliorating effect on the low water and nutrient supply potentials of sandy soil, and thus improved fresh biomass yield and nutritional status of maize seedlings with some restrictions on its high micronutrient content.

Concepts: Electric charge, Nutrient, Ion, Heavy metal music, Ion exchange, Aquatic plant, Eichhornia crassipes, Water hyacinth


We evaluated the salinity reduction of the experimental saline solutions through ion uptake capacity of two plant species, purslane (Portulaca oleraceae) and water hyacinth (Eichhornia crassipes). These species were grown in experimental hydroponic units simulating a floating system. The hydroponic system contained treatments with three nutrient solutions identified as A1, A2, and A3 composed of fixed concentrations of macro and micronutrients to which three different concentrations of sodium chloride had been added. After the experimental period, physicochemical and volume changes in the saline nutrient solutions were evaluated. The relative growth rate results were similar for both plant species, but with lower consumption of hydroponic nutrient solutions by purslane. Despite higher solution volume loss, regardless of the nutrient solution applied, water hyacinth had greater weekly estimated potential of reduction of macronutrients (calcium and magnesium; > 50%); however, purslane showed the best weekly potential reduction of sodium (36%) with solution A2. Therefore, both plants present potential to be used for salinity reduction in the natural conditions.

Concepts: Plant, Chemistry, Nutrient, Soil, Sodium chloride, Sodium, Seawater, Eichhornia crassipes