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.

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.).

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.

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.

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.

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.

Effects on Eichhornia crassipes under Zn stress.

Eichhornia crassipes is a macrophyte widely used in phytoremediation, demonstrating a high ability to remove metals from water. The aim of this work was to evaluate its enzymatic detoxification strategies and metal accumulation when it is exposed to different Zn concentrations (0, 2, 4, 6, and 9 ppm) for periods of 24, 48, and 72 h. Zn concentration in roots was significantly higher than in aerial parts. Independently of the treatment, in the first 48 h, concentrations of photosynthetic pigments were not affected. However, a significant increase (between 19 and 34%) in Chl-b concentrations for all treatments was observed at 72 h. Carotenoid concentration was not affected during the first 48 h, while at 72 h, there was a significant increase regarding the control (between 11 and 24%) for all treatments. Malondialdehyde concentration in aerial parts and roots was not affected during the experiment. Nonetheless, a significant increase in the enzymatic activity of the antioxidant system was observed. Results suggest that Zn could have potential antioxidant properties, which may result in the activation of different antioxidant enzymes involved in the protection against metal stress.

Extending the geographic reach of the water hyacinth plant in removal of heavy metals from a temperate Northern Hemisphere river.

Water hyacinth (Eichhornia crassipes) has been used for environmentally sustainable phytoremediation of water, though its use has been geographically restricted. For the first time we extend its geographical reach by investigating its potential for clean-up of water from a highly polluted British river (Nant-Y-Fendrod, a tributary of the River Tawe). Investigations using the plant were conducted at three levels: a bench-scale study using polluted river water and synthetic solutions; an in-situ trial using water hyacinth within the Nant-Y-Fendrod; and a bankside trial to pump and treat river water. The removal of the largest number of heavy metals (21) from water in a single study using ICP-MS is reported, including Sb, for the first time. Results are promising, with bench-scale tests demonstrating up to 63% removal of Al, 62% Zn, 47% Cd, 22% Mn and 23% As, during just seven hours exposure to the plant. When extended to three weeks exposure, removal is evident in the order Al > Cd > Zn > Mn > Ni > As > V. Furthermore, in-situ mean removal of 6%, 11% and 15% of Mn, Zn and Cd respectively is demonstrated. As the world learns to adapt to climate change, studies of the type reported here are needed to exploit the remarkable phytoremediation potential of water hyacinth.

Dielectric spectroscopy study of water hyacinth collected from different media.

X-ray fluorescence (XRF) study has been shown that the water hyacinth plant is an effective tool for the removals of heavy metals (As, Ba, Cr, Cu, Ni, Pb, Rb, Sr, Zn and Zr) and metal oxides (SiO2, K2O, CaO, Al2O3, Fe2O3, MgO, Na2O, MnO, P2O5, SO3 and TiO2) from agriculture (media 1) and agriculture wastewaters drainage polluted with municipal wastewater (media 2). As a general description, the heavy metals and metal oxides were found at higher levels in the plant collected from media 1 than those in the plant collected from media 2. Similarly, these pollutants were found at higher levels in the plant roots than those in the plant shoots. The dielectric properties were investigated for the plant samples before (control) and after treating by microwave heating power. They were found at higher values in the control roots than those in the control shoots. Furthermore, the properties were found at relatively higher values in the control roots collected from media 1 (ε'=13 at 103Hz) than those in the control roots collected from media 2 (ε'=9 at 103Hz). The electrical conductivity of the microwave treated samples remarkably increased due to appearance of OH group through which the plant interacts with heavy metals. Accordingly, the pollutants removing ability could be enhanced upon treating the plant by microwave heating power. The plant-pollutant mixture behaves like highly conductive disordered polymers. The conductivity and dielectric properties of all plant samples are dominated by the media and concentration of pollutants.

Bioaccumulation of pharmaceutically active compounds and endocrine disrupting chemicals in aquatic macrophytes: Results of hydroponic experiments with Echinodorus horemanii and Eichhornia crassipes.

Information regarding the bioaccumulation behaviour of pharmaceutically active compounds (PhACs) and endocrine disrupting chemicals (EDCs) in aquatic plants is limited. The present study involved controlled hydroponic experiments to assess uptake and elimination rate constants (ku, ke), bioconcentration factors (BCFs) and translocation factors (TFs) of several PhACs and EDCs in two aquatic macrophyte species, including one submerged species (Echinodorus horemanii) and one free-floating species (Eichhornia crassipes). The results revealed that the studied compounds are readily taken up in these aquatic plants. While bioconcentration factors (BCFs) and translocation factors (TFs) of the test compounds varied substantially, no discernible relationship with physicochemical properties such as octanol-water distribution coefficient (Dow), membrane-water distribution coefficient (Dmw) and organic carbon-water partition coefficient (Koc). Diphenhydramine and triclosan exhibited the highest degree of uptake and bioaccumulation potential. For example, the whole-plant BCF of triclosan in E. horemanii was 4390L/kg, while the whole-plant BCF of diphenhydramine in E. crassipes was 6130L/kg. BCFs of 17ß-estradiol (E2), 17α-ethinylestradiol (EE2), estrone (E1) and bisphenol A (BPA) were relatively low (2-150L/kg). BCFs were generally higher in free-floating aquatic macrophyte species compared to the submerged species. For the free-floating species, E. crassipes, the majority of PhACs and EDCs were more allocated in roots compared to leaves, with TFs<1. However, some compounds such as caffeine, atrazine, diphenhydramine, E2 and carbamazepine were more allocated in leaf tissue (TFs>1). The study findings may be useful for design and implementation of phytoremediation systems, as well as aid future modeling and risk assessment initiatives for these emerging organic contaminants.

Water hyacinth a potential source for value addition: An overview.

Water hyacinth a fresh water aquatic plant is considered as a noxious weed in many parts of the world since it grows very fast and depletes nutrients and oxygen from water bodies adversely affecting the growth of both plants and animals. Hence conversion of this problematic weed to value added chemicals and fuels helps in the self-sustainability especially for developing countries. The present review discusses the various value added products and fuels which can be produced from water hyacinth, the recent research and developmental activities on the bioconversion of water hyacinth for the production of fuels and value added products as well as its possibilities and challenges in commercialization.

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.

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.

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.

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.

Assessing and Managing the Current and Future Pest Risk from Water Hyacinth, (Eichhornia crassipes), an Invasive Aquatic Plant Threatening the Environment and Water Security.

Understanding and managing the biological invasion threats posed by aquatic plants under current and future climates is a growing challenge for biosecurity and land management agencies worldwide. Eichhornia crassipes is one of the world's worst aquatic weeds. Presently, it threatens aquatic ecosystems, and hinders the management and delivery of freshwater services in both developed and developing parts of the world. A niche model was fitted using CLIMEX, to estimate the potential distribution of E. crassipes under historical and future climate scenarios. Under two future greenhouse gas emission scenarios for 2080 simulated with three Global Climate Models, the area with a favourable temperature regime appears set to shift polewards. The greatest potential for future range expansion lies in Europe. Elsewhere in the northern hemisphere temperature gradients are too steep for significant geographical range expansion under the climate scenarios explored here. In the Southern Hemisphere, the southern range boundary for E. crassipes is set to expand southwards in Argentina, Australia and New Zealand; under current climate conditions it is already able to invade the southern limits of Africa. The opportunity exists to prevent its spread into the islands of Tasmania in Australia and the South Island of New Zealand, both of which depend upon hydroelectric facilities that would be threatened by the presence of E. crassipes. In Europe, efforts to slow or stop the spread of E. crassipes will face the challenge of limited internal biosecurity capacity. The modelling technique demonstrated here is the first application of niche modelling for an aquatic weed under historical and projected future climates. It provides biosecurity agencies with a spatial tool to foresee and manage the emerging invasion threats in a manner that can be included in the international standard for pest risk assessments. It should also support more detailed local and regional management.

Potential pest transfer mediated by international ornamental plant trade.

In recent years, the keeping of ornamental freshwater animals and plants in garden ponds has been growing in popularity. Water hyacinth (Eichhornia crassipes) is one of the preferred macrophytes seasonally imported mainly from South-eastern Asia throughout the world. This constitutes a secondary introduction inasmuch as the species is native to South America. Although many assemblages of aquatic invertebrates have been described as associated with this plant in the wild, there has been no research focused on their potential introduction via the international plant trade. We examined 216 specimens of water hyacinths imported for ornamental purposes from Indonesia into the Czech Republic. Numerous meio- and macroinvertebrates belonging to at least 39 species were captured. On the total number of individuals, the highest prevalence was of Tubulinea and Rotifera. Most of these were still alive and vital, including a caterpillar of the Indo-Australian invasive moth Spodoptera litura. Water hyacinths are usually placed into outdoor ponds immediately after import, which facilitates the release of non-target alien species. The present paper aims to draw attention to "hitchhikers" associated with the ornamental trade.

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.

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.

[Ecological Effects of Algae Blooms Cluster: The Impact on Chlorophyll and Photosynthesis of the Water Hyacinth].

The response of chlorophyll and photosynthesis of water hyacinth leaves in different concentrations of clustered algae cells was studied in the simulation experiment, and the aim was to reveal the mechanism of the death of aquatic plants during algae blooms occurred through studying the physiological changes of the macrophytes, so as to play the full function of the ecological restoration of the plants. And results showed the dissolved oxygen quickly consumed in root zone of aquatic plants after algae blooms gathered and showed the lack of oxygen (DO < 0.2 g x L(-1)); and the ORP was lower than -100 mV after 1 d, and it declined to -200 mV at the end of the experiment. There were lots of nutrients releasing to the water after the algae cell died and concentration of DTN in treatment 1 and 2 were 44.49 mg x L(-1) and 111.32 mg x L(-1), and the content of DTP were 2.57 mg x L(-1) and 9.10 mg x L(-1), respectively. The NH4+ -N concentrations were as high as 32.99 mg x L(-1) and 51.22 mg x L(-1), and the root zone with the anoxia, strong reducing, higher nutrients environment had a serious stress effects to the aquatic plants. The macrophytes photosynthesis reduced quickly and the plant body damaged with the intimidation of higher NH4+ -N concentration (average content was 45.6 mg x L(-1)) and hypoxia after algae cell decomposed. The average net photosynthesis rate, leaf transpiration rate of the treatment 2 reduced to 3.95 micromol (M2 x S)(-1), 0.088 micromol x (m2 x s)(-1), and only were 0.18 times, 0.11 times of the control group, respectively, at the end of the experiment, the control group were 22 micromol x (m2 x s)(-1), 0.78 micromol x (M2 x s)(-1). Results indicated the algae bloom together had the irreversible damage to the aquatic plants. Also it was found large amounts of new roots and the old roots were dead in the treatment 1, but roots were all died in the treatment 2, and leaves were yellow and withered. Experiment results manifested that the serious environment caused by the algae blooms together was the main reason of the death of aquatic plants during the summer. So in the practice of ecological restoration, it should avoid the harm to the plant after the algae bloom cells gathered and decomposed, so as to play the purification function of the plant in the ecological rehabilitation project.