Trends on adsorption of lead (Pb) using water hyacinth: Bibliometric evaluation of Scopus database.

Heavy metals (Cd, Ni, Zn, Cu, Cr, and Pb) are widely recognized as being hazardous to human health and environmentally deleterious. Therefore water hyacinth is used as a greener adsorption material. This study is a bibliometric analysis of research developments on the adsorption of lead (Pb) using water hyacinth (1995-2023). The data was retrieved from the Scopus database and analyzed using VOSviewer software to determine the relationship between keywords from each published document. The results of this research was divided into three parts: 1) publication output, 2) global research, and 3) keyword research. From the data obtained, it was found that there has been an increasing research trend of adsorption of lead using water hyacinth, although it is not significant and fluctuating. Overall, this study can be used by researchers to quantitatively assess trends and future directions of this research topic.

Alien species water hyacinth realizes waste into treasure: The preparation of biomass sorbent to determine benzoylurea insecticides in tea products.

A fast and effective analytical method with biomass solid-phase microextraction sorbent combined with a high-performance liquid chromatography-ultraviolet detector was proposed for the determination of benzoylurea (BU) insecticides in tea products. The novel sorbent was prepared by activating and then carbonizing water hyacinth with a fast growth rate and low application value as raw material and showed a high specific surface area and multiple interactions with analytes, such as electrostatic action, hydrogen bonding, and π-π conjugation. After optimizing the three most important extraction parameters (pH [X1], sample loading rate [X2], and solution volume [X3]) by Box-Behnken design, the as-established analytical method showed good extraction performance: excellent recovery (80.13%-106.66%) and wide linear range (1-400 µg/L) with a determination coefficient of 0.9992-0.9999, a low limit of detection of 0.02-0.1 µg/L and the satisfactory practical application results in tea products. All these indicate that the water hyacinth-derived material has the potential as a solid-phase extraction sorbent for the detection and removal of BU insecticides from tea products, and at the same time, it can also achieve the effect of rational use of biological resources, maintaining ecological balance, turning waste into treasure, and achieving industrial production.

Unveiling the Therapeutic Potentials of Water Hyacinth (Eichhornia crassipes (Mart.) Solms) Flower against Oxidative Stress, Inflammation and Depressive Disorders: GC-MS/MS, In Vitro, In Vivo and In Silico Approaches.

Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a highly invasive aquatic weed native to the Amazonia basin, known for its rapid propagation, adaptability and utilization in traditional medicine. The study aims to unveil the therapeutic potential of water hyacinth flowers methanolic extract (EC-CME) and its four kupchan fractions (EC-PESF, EC-DCMSF, EC-EASF, EC-ASF) through diversified chemical-pharmacological approaches. GC-MS/MS of EC-CME uncovered a rich tapestry of 72 phytochemical components. In vitro DPPH scavenging assay and total phenolic content determination assay deciphered promising antioxidant assays with remarkably low IC50 values of 0.353 and 0.485 µg/mL, respectively for EC-ESF and EC-ASF. Besides, different in vivo tests, including tail emersion, acetic acid-induced writhing, and thiopental-induced sleeping test of EC-CME, yielded a remarkable 8.61 ± 0.29 minutes of tail immersion time compared to the control's 2.05 ± 0.11 minutes at the highest dose (600 mg/kg). The best % inhibition of writhing was recorded as 47.96% accrued in 400 mg/kg dose, indicating robust pain-relieving properties. The onset and duration of sleep are significantly ameliorated for EC-CME, unveiling its antidepressant potential. Besides, molecular docking studies along with ADME/T analysis also validated the wet lab findings as well as their safety, efficacy and drug-likeliness profile.

Water Hyacinth Leaves Are an Efficient, Green, and Cost-Effective Biosorbent for the Removal of Metanil Yellow from Aqueous Solution: Kinetics, Isotherm, and Thermodynamic Studies.

Excessive water hyacinth growth in aquatic environments and metanil yellow (MY) dye in industrial wastewater pose severe environmental and public health challenges. Therefore, this study evaluated the effects of various process factors on batch MY biosorption onto water hyacinth leaves (LECs) and MY biosorption kinetics, equilibrium, and thermodynamics. The optimal pH for MY biosorption by LECs was 1.5-2.0. The initial MY concentration affected the equilibrium MY biosorption capacity but not the LEC particle size and solution temperature. However, the LEC particle size and solution temperature affected the MY biosorption rate; the biosorption rate was higher at a lower particle size (0.15-0.3 mm) and a higher temperature (62 °C) than at higher particle sizes and lower temperatures. The pseudo-second-order model adequately described the biosorption kinetics of MY by LECs at the different levels of the process factors, whereas the Sips and Redlich-Peterson models satisfactorily represented the biosorption isotherm of MY. The Sips model predicted a maximum MY biosorption capacity of 170.8 mg g-1. The biosorption of MY by LECs was endothermic and not spontaneous. These findings demonstrate that LECs exhibit great potential for bioremediating MY-contaminated wastewater, thereby providing valuable insights for effective water treatment and pollution control strategies.

Facile Green Gamma Irradiation of Water Hyacinth Derived-Fluorescent Carbon Dots Functionalized Thiol Moiety for Metal Ion Detection.

Fluorescent sensor-based carbon dots (CDs) have significantly developed for sensing metal ions because of their great physical and optical properties, including tunable fluorescence emission, high fluorescence quantum yield, high sensitivity, non-toxicity, and biocompatibility. In this research, a green synthetic approach via simple gamma irradiation for the carbon dot synthesis from water hyacinth was developed since water hyacinth has been classified as an invasive aquatic plant containing cellulose, hemicellulose, and lignin. The thiol moiety (SH) was further functionalized on the surface functional groups of CDs as the "turn-off" fluorescent sensor for metal ion detection. Fluorescence emission displayed a red shift from 451 to 548 nm when excited between 240 and 500 nm. The quantum yield of CDs-SH was elucidated to be 13%, with strong blue fluorescence emission under ultraviolet irridiation (365 nm), high photostability and no photobleaching. The limit of detection was determined at micromolar levels for Hg2+, Cu2+, and Fe3+. CDs-SH could be a real-time monitoring sensor for Hg2+ and Cu2+ as fluorescence quenching was observed within 2 min. Furthermore, paper test-strip based CDs-SH could be applied to detect these metal ions.

Microbial assemblages in water hyacinth silages with different initial moistures.

Making silage is a green process to use the fast-growing water hyacinth (Eichhornia crassipes) biomass. However, the high moisture (∼95%) of the water hyacinth is the biggest challenge to making silage while its effects on fermentation processes are less studied. In this study, water hyacinths silage with different initial moistures were conducted to investigate the fermentation microbial communities and their roles on the silage qualities. Results show that both silages with 70% (S70) and 90% (S90) of initial moistures achieved the target of silage fermentation, however, their microbial processes were significantly different. Their succession directions of microbial communities were different: Plant cells in S70 were destroyed by the air-dry treatment, thus there were more soluble carbohydrates, which helped the inoculated fermentative bacteria become dominant (Lactobacillus spp. > 69%) and produce abundant lactic acid; In contrast, stochastic succession became dominant over time in S90 (NST = 0.79), in which Lactobacillus spp. and Clostridium spp. produced butyric that also obviously decreased the pH and promoted the fermentation process. Different microbial succession led to different metabolic patterns: S70 had stronger starch and sucrose metabolisms while S90 had stronger amino acid and nitrogen metabolisms. Consequently, S70 had higher lactic acid, crude protein and lower ammonia nitrogen and S90 had higher in vitro digestibility of dry matter and higher relative feeding value. Moreover, the variance partitioning analysis indicated that moisture could only explain less information (5.9%) of the microbial assemblage than pH value (41.4%). Therefore, the colonization of acid-producing bacteria and establishment of acidic environment were suggested as the key on the silage fermentation no matter how much is the initial moisture. This work can provide a basis for the future preparation of high-moisture raw biomasses for silage.

The remediation of di-(2-ethylhexyl) phthalate-contaminated sediments by water hyacinth biochar activation of calcium peroxide and its effect on cytotoxicity.

The presence of di-(2-ethylhexyl) phthalate (DEHP) in the aquatic systems, specifically marine sediments has attracted considerable attention worldwide, as it enters the food chain and adversely affects the aquatic environment and subsequently human health. This study reports an efficient carbocatalytic activation of calcium peroxide (CP) using water hyacinth biochar (WHBC) toward the efficient remediation of DEHP-contaminated sediments and offer insights into biochar-mediated cellular cytotoxicity, using a combination of chemical and bioanalytical methods. The pyrolysis temperature (300-900 °C) for WHBC preparation significantly controlled catalytic capacity. Under the experimental conditions studied, the carbocatalyst exhibited 94% of DEHP removal. Singlet oxygen (1O2), the major active species in the WHBC/CP system and electron-rich carbonyl functional groups of carbocatalyst, played crucial roles in the non-radical activation of CP. Furthermore, cellular toxicity evaluation indicated lower cytotoxicity in hepatocarcinoma cells (HepG2) after exposure to WHBC (25-1000 µg mL-1) for 24 h and that WHBC induced cell cycle arrest at the G2/M phase. Findings clearly indicated the feasibility of the WHBC/CP process for the restoration of contaminated sediment and contributing to understanding the mechanisms of cytotoxic effects and apoptotic of carbocatalyst on HepG2.

Continuous successive cycles of biosorption and desorption of acid red 27 dye using water hyacinth leaves as an effective, economic, and ecofriendly biosorbent.

We investigated the capacity of water hyacinth leaves (LEC) to biosorb 75 mg/L acid red 27 (AR27) in a continuous system comprising 30 successive biosorption/desorption cycles in a packed-bed column at pH 2.0 and 56.5 L/m2·h volumetric flux. Using 0.025 M NaHCO3 eluent at 113 L/m2·h volumetric flux, all the dye was desorbed (100% desorption efficiency) from the loaded LEC biomass within 5-6 h. The same biosorbent was used for 147.5 consecutive days. The AR27 biosorption capacity, breakthrough time, and exhaustion time decreased from 69.4 to 34.5 mg/g, 74.81 to 14.1 h, and 101.1 to 34.1 h, respectively, and the critical bed height increased from 1.04 to 2.35 cm, as the number of biosorption/desorption cycles increased from 1 to 30. LEC life factor based on biosorption capacity predicted that the packed bed would be exhausted after 51.95 cycles. LEC is a promising biosorbent for bioremediation of AR27-laden wastewaters.

Exploring the potential of thermophilic anaerobic co-digestion between agro-industrial waste and water hyacinth: operational performance, kinetic study and degradation pathway.

Anaerobic co-digestion (co-AD) of agro-industrial waste, namely, palm oil mill effluent (POME) and sugarcane vinasse (Vn), with water hyacinth (WH) as co-substrate was carried out in two separate Anaerobic Suspended Growth Closed Bioreactors (ASGCBs) under thermophilic (55 °C) conditions. The highest chemical oxygen demand (COD) and soluble COD reduction in co-AD of POME-WH (78.61%, 78.86%) is slightly higher than co-AD of Vn-WH (75.75%, 78.24%). However, VFA reduction in co-AD of POME-WH (96.41%) is higher compared to co-AD of Vn-WH (85.94%). Subsequently, biogas production peaked at 13438 mL/day values and 16122 mL/day for co-AD of POME-WH and Vn-WH, respectively. However, the methane content was higher in the co-AD of POME-WH (72.04%) than in the co-AD of Vn-WH (69.86%). Growth yield (YG), maximum specific substrate utilization rate (rx,max) and maximum specific biomass growth rate (µmax) are higher in co-AD of POME-WH, as supported by the higher mixed liquor volatile suspended solids (MLVSS) and COD reduction efficiency compared to co-AD of Vn-WH. However, methane yield ([Formula: see text]) reported in the co-AD of POME-WH and Vn-WH are 0.2748 and 0.3112 L CH4/g CODreduction, respectively, which suggests that WH is a more suitable co-substrate for Vn compared to POME.

Remediation of potentially toxic elements -containing wastewaters using water hyacinth - a review.

For a long time, water hyacinth has been considered a very stubborn and troublesome weed. However, research has shown that it can be used to remove many pollutants from water. Among the different pollutants, potentially toxic elements (PTE) or their ions have been found to be very toxic for humans, animals, and plants. Among the many conventional methods for removing PTE from wastewaters, phytoremediation has several advantages. This method is highly eco-friendly, cost-effective, and can remove a wide range of metal pollutants and organic pollutants. Both, living and non-living water hyacinth plants, can be used for remediation - either entirely or their parts. Study on mechanisms and different factors involved in the process would help to effectively use water hyacinth for remediation. This review presents different studies conducted in the past thirty years for the removal of PTEs. Detailed analysis of the work done in this field showed that in spite of the main advantages provided by the plant, not much has been done to increase the efficiency of the remediation process and for reusing the water hyacinth biomass for other applications after desorption of the PTE. Hence, the section on scope for future work highlights these prospective ideas. Novelty statement: Water hyacinth, which is a very stubborn weed and has a negative impact on the environment, can be constructively used to remove potentially toxic elements (PTEs) along with other pollutants from wastewaters. Different parts of the water hyacinth plant like roots, leaves, and stems or the entire plant can be used. Further, either the live plant or its other forms, such as dried powder, biochar, or activated carbon can be used. This review focuses on different forms of water hyacinth plant used, the advantages and limitations associated with these methods and the scope for future work.

Performance and Mechanism of Functionalized Water Hyacinth Biochar for Adsorption and Removal of Benzotriazole and Lead in Water.

In this paper, water hyacinth is used to prepare biochar (WBC). A biochar-aluminum-zinc-layered double hydroxide composite functional material (WL) is synthesized via a simple co-precipitation method which is used to adsorb and remove benzotriazole (BTA) and lead (Pb2+) in an aqueous solution. In particular, this research paper uses various characterization methods to analyze WL and to explore the adsorption performance and adsorption mechanism of WL on BTA and Pb2+ in an aqueous solution through batch adsorption experiments combined with model fitting and spectroscopy techniques. The results indicate that the surface of WL contains a thick sheet-like structure with many wrinkles which would provide many adsorption sites for pollutants. At room temperature (25 °C), the maximum adsorption capacities of WL on BTA and Pb2+ are 248.44 mg·g-1 and 227.13 mg·g-1, respectively. In a binary system, during the process of using WL to adsorb BTA and Pb2+, compared with that in the absorption on Pb2+, WL shows a stronger affinity in the adsorption on BTA, and BTA would thus be preferred in the absorption process. The adsorption process of WL on BTA and Pb2+ is spontaneous and is endothermic monolayer chemisorption. In addition, the adsorption of WL on BTA and Pb2+ involves many mechanisms, but the main adsorption mechanisms are different. Among them, hydrogen bonding dominates the adsorption on BTA, while functional groups (C-O and C=O) complexation dominates the adsorption on Pb2+. When WL adsorbs BTA and Pb2+, the coexistence of cations (K+, Na+, and Ca2+) has a strong anti-interference ability, and WL can use a lower concentration of fulvic acid (FA) (<20 mg·L-1) to improve its adsorption performance. Last but not least, WL has a stable regenerative performance in a one-component system and a binary system, which indicates that WL has excellent potential for the remediation of BTA and Pb2+ in water.

Efficient Adsorption of Tebuconazole in Aqueous Solution by Calcium Modified Water Hyacinth-Based Biochar: Adsorption Kinetics, Mechanism, and Feasibility.

The application of fungicides (such as tebuconazole) can impose harmful impacts on the ecosystem and humans. In this study, a new calcium modified water hyacinth-based biochar (WHCBC) was prepared and its effectiveness for removing tebuconazole (TE) via adsorption from water was tested. The results showed that Ca was loaded chemically (CaC2O4) onto the surface of WHCBC. The adsorption capacity of the modified biochar increased by 2.5 times in comparison to that of the unmodified water hyacinth biochar. The enhanced adsorption was attributed to the improved chemical adsorption capacity of the biochar through calcium modification. The adsorption data were better fitted to the pseudo-second-order kinetics and the Langmuir isotherm model, indicating that the adsorption process was dominated by monolayer adsorption. It was found that liquid film diffusion was the main rate-limiting step in the adsorption process. The maximum adsorption capacity of WHCBC was 40.5 mg/g for TE. The results indicate that the absorption mechanisms involved surface complexation, hydrogen bonding, and π-π interactions. The inhibitory rate of Cu2+ and Ca2+ on the adsorption of TE by WHCBC were at 4.05-22.8%. In contrast, the presence of other coexisting cations (Cr6+, K+, Mg2+, Pb2+), as well as natural organic matter (humic acid), could promote the adsorption of TE by 4.45-20.9%. In addition, the regeneration rate of WHCBC was able to reach up to 83.3% after five regeneration cycles by desorption stirring with 0.2 mol/L HCl (t = 360 min). The results suggest that WHCBC has a potential in application for removing TE from water.

Bioaugmentation potential of inoculum derived from anaerobic digestion feedstock for enhanced methane production using water hyacinth.

The utilisation of water hyacinth for production of biogas is considered to be a solution to both its control and the global renewable energy challenge. In this instance, an investigation was conducted to evaluate the potential of water hyacinth inoculum to enhance methane production during anaerobic digestion (AD). Chopped whole water hyacinth (10% (w/v)) was digested to prepare an inoculum consisting mainly of water hyacinth indigenous microbes. The inoculum was incorporated in the AD of freshly chopped whole water hyacinth to set up different ratios of water hyacinth inoculum and water hyacinth mixture with appropriate controls. The results of batch tests with water hyacinth inoculum showed a maximal cumulative volume of 211.67 ml of methane after 29 days of AD as opposed to 88.6 ml of methane generated from the control treatment without inoculum. In addition to improving methane production, inclusion of water hyacinth inoculum reduced the electrical conductivity (EC) values of the resultant digestate, and, amplification of nifH and phoD genes in the digestate accentuates it as a potential soil ameliorant. This study provides an insight into the potential of water hyacinth inoculum to enhance methane production and contribute to the feasibility of the digestate as a soil fertility enhancer.

Endophytic microbiota of floating aquatic plants: recent developments and environmental prospects.

Plant-associated microorganisms play a critical role in plant survival and functional attributes. There are many studies on the taxonomical and functional aspects of microorganisms associated with terrestrial plants. However, the microbiome of aquatic plants is not much explored. This work details the studies on microbiomes and diversity in microbial communities inhabiting the three common free-floating aquatic plants of tropical regions viz. duckweed, water hyacinth and water lettuce, widely implicated for their bioremediation potential. Studies conducted till date reveal the prevalence and dominance of different Bacillus sp. Other genera, including Rhodanobacter, Pseudomonas, Rhizobium, Achromobacter, Serratia, Actinobacteria, Proteobacter, Klebsiella and Acidobacteria, have also been prominently reported. This lesser explored niche offers great bioprospecting opportunities to obtain taxonomically diverse and functionally distinct microorganisms. Bacterial endophytes from these aquatic plants have been primarily studied for their ability to produce indole acetic acid and degrade phenol. Limited studies reveal some fungal endophytes to have promising herbicidal effect. Not much is known on other functional attributes and hence microbial studies on these plants holds much promise for obtaining novel isolates or isolates with novel functions that would impact both aquatic and terrestrial ecosystems. This study proposes the need for exploring the role of endophytes as biocontrol agents and their potential to provide a pragmatic and robust solution to the aquatic weed menace in freshwater bodies. Bioprospecting of this lesser studied ecological niche hence is a promising field of research that has both environmental and economic potential.

Adsorption of hexavalent chromium using Water Hyacinth Leaf Protein Concentrate/Graphene Oxide hydrogel.

Water Hyacinth Leaf Protein Concentrate/Graphene Oxide (WHLPC/GO) hydrogel was synthesized for the removal of Cr(VI) from wastewater. About 90% of the prepared hydrogel constitutes WHLPC. The prepared material was characterized by FT-IR and XRD. The process variables such as pH, contact time, adsorbent dosage, initial Cr(VI) concentration, and temperature were optimized using a batch mode experiment. Kinetic studies were also conducted and it was observed that the chemosorptive pseudo-second-order best described the adsorption system with a correlation coefficient (R2) of 0.984. The highest adsorption capacity of 322.00 mg/g was achieved at pH 1.0, and equilibrium was achieved within 420 min. Various isotherm models were analyzed using non-linear fitting. It was found that the Sips model provides the best fit, indicating heterogeneous and uniform active site surface adsorption of Cr(VI) on the WHLPC/GO. The reuse efficiency of the synthesized material was also found to be greater than 84% for five consecutive cycles. Thermodynamic studies were conducted and results revealed that the adsorption was spontaneous and endothermic.

Implementation of water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in the re-treatment of conventionally treated pharmaceutical wastewater: a case study of Radiant Pharmaceuticals Limited, Dhaka, Bangladesh.

Since Bangladesh already has robust pharmaceutical industries, nearly all companies owned effluent treatment plant (ETP) facilities to improve the quality of wastewater. Water retreatment utilizing affordable, accessible, and environmentally sustainable techniques have not yet been thoroughly investigated. In this study, the potential of water hyacinth and water lettuce was investigated at three different concentrations: 50% of total volume coverages (1000 g macrophytes/2000 ml water), 75% of total volume coverages (1500 g macrophytes/2000 ml water), and 100% of total volume coverages (2000 g macrophytes/2000 ml water) on the post-treated ETP's wastewater for 3 weeks in a mesocosm environment. Heavy metals, such as chromium (Cr) and nickel (Ni) along with physicochemical parameters (pH, EC, TDS, DO, and BOD5) were measured after 7 days intervals. Results indicated that water hyacinth was considerably more efficient than water lettuce at removing many factors, including metals. Water hyacinth was able to remove 79.15% of nickel and 92.97% of chromium while also increasing DO and EC by 36.72% and 14.59%, respectively, at 100% of total volume coverages. On the other hand, 100% of the total volume coverage of water lettuce decreased the pH, TDS, and BOD5 readings by 6.70%, 31.62%, and 87.61%, respectively. With each treatment, the water quality significantly improved over the control. The findings suggest that the pharmaceutical industries may improve the quality of their treated wastewater even more by integrating phytoremediation technology with traditional ETP facilities.

Eichhornia crassipes Ameliorated Rheumatoid Arthritis by Modulating Inflammatory Cytokines and Metalloproteinase Enzymes in a Rat Model.

Background and Objectives: This study was planned to investigate the anti-arthritic property of flowers of E. crassipes in a Sprague-Dawley rat model by administering Freund's Complete Adjuvant (FCA). Materials and Methods: Arthritis was induced at day 0 in all rats except negative controls, while arthritic progress and paw edema were analyzed on specific days (8th, 13th, 18th, and 23rd) via the macroscopic arthritic scale and a digital Vernier caliper, respectively. Histopathological parameters were examined using a Hematoxylin and Eosin (H&E) staining method. Blood samples were withdrawn from rats to investigate the effects of the E. crassipes flower on the mRNA expression values of inflammatory markers, via a reverse transcription PCR technique. Serum samples were used to determine prostaglandin E2 (PGE2) levels using enzyme-linked immunosorbent assay (ELISA). Values of alanine transaminase (ALT), aspartate aminotransferase (AST), creatinine, and urea, besides hematological parameters, i.e., the hemoglobin (Hb) content and complete blood count (CBC), were investigated. Results: The data showed that E. crassipes inhibited the arthritic progress and ameliorated the paw edema. The amelioration of parameters assessed via the histopathological analysis of ankle joints, as well as via hematological analysis, confirmed the diminution of rheumatoid arthritis (RA) in the plant-treated groups. Treatment with E. crassipes inhibited the expression levels of tumor necrosis factor-α (TNF-α), interleukins (IL-1ß and IL-6), nuclear factor KappaB (NF-κB), matrix metalloproteinase (MMP-2 and MMP-3), and vascular endothelial growth factor (VEGF). Serum PGE2 levels were also found to be reduced in treatment groups. A biochemical investigation revealed the improvements in hepatic markers in plant-treated groups. The data indicated that the plant has no hepatotoxic or nephrotoxic effects at the studied dose. GC-MS (Gas Chromatography-Mass Spectrometry) analysis displayed the presence of phytochemicals having known anti-inflammatory and antioxidant properties. Conclusions: Therefore, it may be concluded that E. crassipes possesses anti-arthritic characteristics that could be attributed to the modulation of pro-inflammatory cytokines, MMPs, and PGE2 levels.

Genetic variation and clonal diversity in floating aquatic plants: Comparative genomic analysis of water hyacinth species in their native range.

Many eukaryotic organisms reproduce by sexual and asexual reproduction. Genetic diversity in populations can be strongly dependent on the relative importance of these two reproductive modes. Here, we compare the amounts and patterns of genetic diversity in related water hyacinths that differ in their propensity for clonal propagation - highly clonal Eichhornia crassipes and moderately clonal E. azurea (Pontederiaceae). Our comparisons involved genotype-by-sequencing (GBS) of 137 E. crassipes ramets from 60 locations (193,495 nucleotide sites) and 118 E. azurea ramets from 53 locations (198,343 nucleotide sites) among six hydrological basins in central South America, the native range of both species. We predicted that because of more prolific clonal propagation, E. crassipes would exhibit lower clonal diversity than E. azurea. This prediction was supported by all measures of clonal diversity that we examined. Eichhornia crassipes also had a larger excess of heterozygotes at variant sites, another signature of clonality. However, genome-wide heterozygosity was not significantly different between the species. Eichhornia crassipes had weaker spatial genetic structure and lower levels of differentiation among hydrological basins than E. azurea, probably because of higher clonality and more extensive dispersal of its free-floating life form. Our findings for E. crassipes contrast with earlier studies from the invasive range which have reported very low levels of clonal diversity and extensive geographic areas of genetic uniformity.

Biomass valorization of Eichhornia crassipes root using thermogravimetric analysis.

Present study focused on the thermo-chemical potential of waste biomass of Eichhornia crassipes or water hyacinth root (WHR). The pyrolysis-kinetic parameters are investigated using thermo-gravimetric analysis at the various heating rates (5, 10, 15, and 20 °C/min). Three model-free techniques, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starink, were used for the thermal kinetic analysis of biomass. The average activation energy for WHR biomass was determined using KAS, FWO, and Starink, with the values of 57.87, 64.69, and 58.27 kJ/mol, respectively. From the study it is observed that the roots of water hyacinth have rich in carbon, oxygen and hydrogen composition around 24%, 70% and 4% respectively. The higher heating value of water hyacinth root was observed around 15 MJ/kg.

First Report of Cercospora rodmanii Causing Leaf and Petiole Lesions on Water Hyacinth in China.

The rapid spread and colonization of water hyacinth (Eichhornia crassipes) leads to a series of serious environmental problems for water bodies, prompting microbiologists to develop effective mycoherbicides to alleviate the water hyacinth population (Julien et al. 2001). In September 2020, numerous leaftip diebacks and petiole rots of water hyacinth, with 40 to 50% incidence, were observed within an area of 2 ha (ca. 2 km) mat on Jinjiang River tributary, Fujian, China. Ten infected leaf samples were collected and symptomatic tissues were cut into small pieces, surface disinfected in 75% ethanol followed by 0.1% MgCl2 solution and placed on potato dextrose agar (PDA). Pure cultures (Isolates J1 and J5) were obtained and their colonies on PDA appeared as white villi with wrinkled surfaces and dense colorless mycelium on the upper surface, while they were dark olivaceous-gray at the bottom. Internal mycelium consisted of septate, branched, smooth hyphae. There lacked stromata. Conidiophores were solitary to 2 to 5 in loose fascicles, thick-walled, conically truncated, 40 to 80 × 5 to 8 µm. Conidiogenous cells integrated, terminal, 30 to 150 × 4 to 6 µm, slightly protuberant, apical and lateral. Conidia were solitary, hyaline, acicular to obclavate, slightly curved, acute at the apex, 50 to 80 ×3 to 6 µm, indistinctly 1 to 3 septate. Genomic DNA from the two isolates was extracted for PCR, and the internal transcribed spacers (ITS), calmodulin (CAL), translation elongation factor 1-alpha (TEF), actin (ACT), histone H3 (H3) and chitin synthase (CHS) were amplified and sequenced using the primer pairs ITS1/ITS4, CL1/CL2A, EF1Fd/EF1Rd, ACT1Fd/ACT1Rd, CYLH3F/CYLH3R and CHS-79F/CHS-345R (Weir et al. 2012; White et al. 1990), respectively. The ITS (MZ436974-MZ436975), CAL (MZ519385-MZ519386), TEF (OK340826-OK340827), ACT (OK340824-OK340825), H3 (OK340828-OK340829) and CHS (MZ519387-MZ519388) sequences were deposited in GenBank. A phylogenetic tree based on concatenated sequences of ITS-CAL-TEF-ACT-H3-CHS from the genus Cercospora was constructed using a maximum likelihood method, showing that the present isolates and Cercospora rodmanii formed a monophyletic group with 99% bootstrap support. Therefore, the fungus was identified as C. rodmanii (Groenewald et al. 2013; Nguanhom et al. 2015). To test Koch's postulates, petioles of a set of 20 water hyacinth seedlings of 30 to 40 days old were wounded using a sterile needle and then spray-inoculated with 20 µl of the spore suspension of each isolate at 106 CFU/ml. Another set of 20 seedlings inoculated with sterile distilled water served as the controls. Inoculated plants were kept in 50-liter plastic tanks and maintained in a greenhouse at room temperature 22 to 28°C with a relative humidity of 80 to 85%. After 7 to 20 days, lesions were observed on the inoculated leaves but not on the control leaves. The same fungus was reisolated and identified by microscopy and PCR-sequencing. The pathogenicity test was conducted twice. Cercospora rodmanii and C. piaropi have been reported on water hyacinth in America, Brazil, México, and Zambia (Charudattan et al. 1985; Montenegro-Calderón, 2011; Moran, 2015). To our knowledge, this is the first report of C. rodmanii causing leaf and petiole lesions on water hyacinth in China. This report will help identify indigenous plant pathogens in China and develop a novel bioherbicide strategy for control of water hyacinth.