Phosphate-solubilizing bacteria improve the antioxidant enzyme activity of Potamogeton crispus L. and enhance the remediation effect on Cd-contaminated sediment.

Phosphorus-solubilizing bacteria (PSB) assisted phytoremediation of cadmium (Cd) pollution is an effective method, but the mechanism of PSB-enhanced in-situ remediation of Cd contaminated sediment by submerged plants is still rare. In this study, PSB (Leclercia adecarboxylata L1-5) was inoculated in the rhizosphere of Potamogeton crispus L. (P. crispus) to explore the effect of PSB on phytoremediation. The results showed that the inoculation of PSB effectively improved the Cd extraction by P. crispus under different Cd pollution and the Cd content in the aboveground and underground parts of P. crispus all increased. The µ-XRF images showed that most of the Cd was enriched in the roots of P. crispus. PSB especially showed positive effects on root development and chlorophyll synthesis. The root length of P. crispus increased by 51.7 %, 80.5 % and 74.2 % under different Cd pollution, and the Ca/Cb increased by 38.9 %, 15.2 % and 8.6 %, respectively. Furthermore, PSB enhanced the tolerance of P. crispus to Cd. The contents of soluble protein, MDA and H2O2 in 5 mg·kg-1 and 7 mg·kg-1 Cd content groups were decreased and the activities of antioxidant enzymes were increased after adding PSB. The results showed that the application of PSB was beneficial to the in-situ remediation of submerged plants.

Negative effects of a piscicide, rotenone, on the growth and metabolism of three submerged macophytes.

A piscicide, rotenone (RT), is frequently used for clear and management of aquatic systems such as fish pond, and even for illegal fishing throughout the world. The effects of RT on submerged macrophytes remain elusive although the effects of RT on many kinds of animals are well documented. We wanted to determine the effects of RT on the growth and metabolism of three submerged plants (Vallisneria natans, Myriophyllum spicatum, Potamogeton maackianus) and try to find the reasons of these effects. The results showed that the shoot height, shoot dry weight, root dry weight, root:shoot ratios, contents of soluble protein and soluble carbohydrate of the three tested submerged plants were significantly negatively affected by RT and the effects were different among the studied species. Furthermore, pH rised a little and light transmission was greatly reduced in the water with RT treatment. We think that the negative effects of RT on the growth and metabolism of submerged species is partially attributing to the lower light caused by RT application. Accordingly, we highlight that submerged species may be greatly suppressed by RT, and we should apply RT in water ecosystems with great caution.

Effects of warming, climate extremes and phosphorus enrichment on the growth, sexual reproduction and propagule carbon and nitrogen stoichiometry of Potamogeton crispus L.

Contemporary evidence suggests that submerged macrophytes are experiencing a global decline due to the multiple compounding anthropogenic stressors impacting shallow lake ecosystems. Eutrophication and climate change are two main widespread, often co-occurring stressors, yet evidence concerning their interactive effects on aquatic plants remains partial and fragmented. Predicting the response of submerged aquatic vegetation to the combined effects of nutrient pollution and compound climate warming (mean + variability) is therefore crucial for the conservation and management of these valuable and vulnerable ecosystems. Here, we present the results of an outdoor mesocosm experiment examining the combined effects of nutrient enrichment (phosphorus addition) and warming (a 4 °C increase in mean temperature above present ambient conditions applied as either a constant increase or a variable increase ranging between 0 and 8 °C to mimic the effect of extreme events but keeping an equivalent total amount of warming) on Potamogeton crispus L. Warming accelerated the growth and senescence of P. crispus suggesting a more important role in maintaining the clear water state in winter-early spring but concomitant to possible earlier turbid states in summer. Warming also consistently advanced the flowering phenology but had no significant effect on flowering duration. There were no significant differences in the life cycle between the two warming treatments, while phosphorus addition also had little effect. However, under phosphorus enrichment, P. crispus increased sexual reproduction investment producing higher seed setting rate per infructescence. In contrast, warming, especially variable warming, may decrease sexual reproduction investment by reducing the number of infructescences. Seed and turion stoichiometry were altered by the combination of warming and phosphorus addition, but the changes were complex and difficult to interpret.

Physiological differences between free-floating and periphytic filamentous algae, and specific submerged macrophytes induce proliferation of filamentous algae: A novel implication for lake restoration.

Restoration of submerged macrophytes is widely applied to counteract eutrophication in shallow lakes. However, proliferation and accumulation of filamentous algae (possessing free-floating and periphytic life forms) hamper growth of submerged macrophytes. Here, we explored factors triggering the excessive proliferation of filamentous algae during lake restoration using field investigations and laboratory experiments. Results showed that, compared with free-floating Oscillatoria sp. (FO), periphytic Oscillatoria sp. (PO) showed faster growth rate, greater photosynthetic capacities and higher phosphorus (P) affinity. Therefore, PO was physiologically competitively superior to FO under low P concentration and improved light conditions. And proliferation of filamentous algae was mainly manifested in periphytic life form. Besides, field results showed that density of filamentous algae in water column might be related to substrate types. Some macrophyte (Ceratophyllum oryzetorum and Potamogeton crispus) might provide proper substrates for proliferation of filamentous algae. Further physiological experiments found that Oscillatoria showed specific eco-physiological responses to different macrophyte species. Hydrilla verticillata and C. oryzetorum promoted growth and photosynthetic activity of Oscillatoria, while Potamogeton malaianus inhibited growth and P uptake of PO. Myriophyllum spicatum exhibited no impact on growth of Oscillatoria. Our results revealed the intrinsic (physiological differences between free-floating and periphytic life forms of filamentous algae) and extrinsic (different macrophytes) factors affect the proliferation of filamentous algae, which are important for guidance on planting of submerged macrophytes during lake restoration.

Effects of ammonium pulse on the growth of three submerged macrophytes.

Ammonium pulse attributed to runoff of urban surface and agriculture following heavy rain is common in inland aquatic systems and can cause profoundly effects on the growth of macrophytes, especially when combined with low light. In this study, three patterns of NH4-N pulse (differing in magnitude and frequency) were applied to examine their effects on the growth of three submersed macrophytes, namely, Myriophyllum spicatum, Potamogeton maackianus, and Vallisneria natans, in terms of biomass, height, branch/ramet number, root length, leaf number, and total branch length under high and low light. Results showed that NH4-N pulse caused negative effects on the biomass of the submerged macrphytes even on the 13th day after releasing NH4-N pulse. The negative effects on M. spicatum were significantly greater than that on V. natans and P. maackianus. The effects of NH4-N pulse on specific species depended on the ammonium loading patterns. The negative effects of NH4-N pulse on P. maackianus were the strongest at high loading with low frequency, and on V. natans at moderate loading with moderate frequency. For M. spicatum, no significant differences were found among the three NH4-N pulse patterns. Low light availability did not significantly aggregate the negative effects of NH4-N pulse on the growth of the submersed macrophytes. Our study contributes to revealing the roles of NH4-N pulse on the growth of aquatic plants and its species specific effects on the dynamics of submerged macrophytes in lakes.

Toxicity of linear alkylbenzene sulfonate to aquatic plant Potamogeton perfoliatus L.

Aquatic plants play an important role in maintaining the health of water environment in nature. Studies have shown that linear alkylbenzene sulfonate (LAS), a type of omnipresent pollutant, can cause toxic damage to aquatic plants. In the present research, we studied the physiological and growth response of submerged plant Potamogeton perfoliatus L. to different concentrations of LAS (0.1, 1.0, 10.0, 20.0, and 50.0 mg l-1). The results showed that LAS is toxic to P. perfoliatus, and the toxicity is dose-dependent. Only slightly reversible oxidative damages were observed in the physiological parameters of P. perfoliatus when P. perfoliatus was exposed to lower LAS doses (< 10 mg l-1): soluble sugar, soluble protein, H2O2, and malondialdehyde (MDA) content in P. perfoliatus increased significantly at 0.1 mg l-1 and then returned to normal levels at 1.0 mg l-1. Antioxidant enzymes were activated before the LAS concentration reached 10 mg l-1, and the activities of superoxide dismutase (SOD), catalase (CAT), and photosynthesis pigment content declined significantly when the concentration of LAS exceeded 10 mg l-1. In addition, at higher concentrations (20-50 mg l-1) of LAS, dry weight and fresh weight of P. perfoliatus showed significant declines. The results indicate that LAS above 10 mg l-1 can cause serious physiological and growth damage to P. perfoliatus.

Submerged freshwater plant communities do not show species complementarity effect in wetland mesocosms.

It is a generally accepted theory that ecological functions are enhanced with increased diversity in plant communities due to species complementarity effects. We tested this theory in a mesocosm study using freshwater submerged plant beds to determine if increasing species number caused overyielding and species complementarity. We applied a maximum of four species in the plant beds corresponding to the typical species number in natural freshwater plant beds. We found no clear effects of species number (1-4) on biomass production and thus no conclusive overyielding and complementarity effect. This may be explained by low species differentiation among the four species in plant traits relevant for resource acquisition in freshwater, or that other species interactions, e.g. allelopathy, were inhibiting overyielding. The existing knowledge on species complementarity in aquatic plant communities is sparse and inconclusive and calls for more research.

Environmental effects by introducing Potamogeton crispus to recover a eutrophic Lake.

Re-establishing submerged vegetation is considered an important tool to restore shallow eutrophic lakes. A whole year comparative field study was performed in a eutrophic lake and its connected pond with Potamogeton crispus in order to determine the effects of the growth and senescence of submerged macrophytes on structure of phytoplankton. P. crispus improved the water quality at the growing season in terms of improving transparency, decreasing total phosphorus, soluble reactive phosphorus (SRP) and chlorophyll a concentrations and slowering turnover rate of dissolved organic phosphorus (DOP). Meanwhile, dominant species shift from Chlorophyta to Diatom. Notably, senescence and decomposition of P. crispus in late spring resulted in an abrupt increase of DOP, providing a suitable growing environment for Euglena and dinoflagellates and a Peridiniopsis bloom occurred owing to their advantage in utilizing DOP. Peridiniopsis excreted phosphatase as evidence by simultaneously in situ enzyme labelled fluorescence (ELF) labelling and main alkaline phosphatase activity contributed by large particles, suggesting that the dominance of dinoflagellate with low SRP is enabled by its ability to efficiently hydrolyze DOP. Under the scenario of worldwide application of re-establishing submerged vegetation, our results provide the evidence of the negative environmental effects that occurred when transplanting P. crispus to recover a eutrophic lake.

Causes of large Potamogeton crispus L. population increase in Xuanwu Lake.

In July 2005, the first outbreak of cyanobacterial blooms, dominated by Microcystis, occurred in Xuanwu Lake, Nanjing, upon which clay flocculation was adopted to control algal blooms. The cyanobacterial blooms were restrained, after which Potamogeton crispus appeared in November 2005 and spread rapidly in the whole lake. Since then, large populations of P. crispus have occurred in Xuanwu Lake annually in winter for the last 10 years. To determine the reasons for the occurrence of P. crispus populations in Xuanwu Lake during 2005-2006, water quality indices were monitored regularly. The data collected included dissolved oxygen, transparency, pH, total nitrogen, and total phosphorus content. Data analysis indicated that the transparency was improved by 179.5 % after clay flocculation, dissolved oxygen content increased by 24.1 %; total nitrogen and total phosphorus content decreased by 54.1 and 74.5 %, respectively, and pH fell from 9.1 to 8.7, all of which can be attributed to the emergency control measures for the cyanobacterial bloom. Data analysis also indicated that the improved water transparency after clay flocculation was the key factor in turion sprouting and seedling propagation of P. crispus. The ameliorative light intensity and favorable nutrient level all promoted the growth of seedlings of P. crispus and later quick colonization. It is suggested that ecological restoration of macrophytic and algal lakes be conducted by some physical or chemical means to improve transparency, reduce nutrient concentration, and adjust water pH, with the purpose of improving water quality for germination and growth of aquatic plants.

Effect of Potamogeton crispus L. on bioavailability and biodegradation activity of pyrene in aged and unaged sediments.

In order to clarify the effect of Potamogeton crispus L. (P. crispus) on bioavailability and biodegradation activity of pyrene in aged and unaged sediments, model calculation based on experimental results was carried out. During a 36-day experiment, the dissipation ratio of pyrene was increased by planting but decreased by aging. P. crispus improved the dissipation more significantly in aged sediments (45.9%) than in unaged sediments (17.6%). Results derived from a two-compartment desorption model showed that the decrease of rapidly desorbing fraction of pyrene was in the order of aged sediments without plant (A)>unaged sediments without plant (U)>unaged sediments with plant (UP)>aged sediments with plant (AP). Moreover, the results of biodegradation kinetic model showed that the first-order biodegradation coefficient was in the order of AP>UP>U and A, which was consistent with that of sediment redox potential. These modeling results indicated that planting could enhance the bioavailability (73.9%) and biodegradation activity (277%) of pyrene more significantly in aged sediments as compared to unaged sediments (13.1% and 150%, respectively), which should be the key reasons leading to more significant dissipation increment of pyrene in aged sediments by P. crispus.

[Influence of Submerged Plants on Microbial Community Structure in Sediment of Hongze Lake].

Phospholipid fatty acids (PLFAs) method was applied to analyze the influence of submerged plants on sediment microbial community structure, in order to investigate the changes of sediment microbial community structure for different kinds of the submerged plants in different growth periods. Particularly, Potamogeton crispus L., Potamogeton pectinatus L and the mixed group were chosen as the typical submerged plants in Hongze Lake for investigation in this paper. The results indicated that the change of total PLFAs in different periods was significant, on the contrary, the PLFA change for different groups in the same period was insignificant. The values of G⁺ PLFA/G⁻ PLFA in the submerged plant group were also highly related to the different growth periods, which demonstrated that the root function of the submerged plant had a severe impact on the microbial community in sediment. Furthermore, some environmental factors, such as Temperature, pH, TOC and DO, were correlated to characteristic phospholipid of PLFAs in sediment, which means the environmental factors could also affect the microbial community structure.

Strong Genetic Differentiation of Submerged Plant Populations across Mountain Ranges: Evidence from Potamogeton pectinatus in Iran.

Biogeographic barriers for freshwater biota can be effective at various spatial scales. At the largest spatial scale, freshwater organisms can become genetically isolated by their high mountain ranges, vast deserts, and inability to cross oceans. Isolation by distance of aquatic plants is expected to be stronger across than alongside mountain ridges whereas the heterogeneity of habitats among populations and temporary droughts may influence connectivity and hamper dispersal. Suitable aquatic plant habitats became reduced, even for the widespread submerged Potamogeton pectinatus L. (also named Stuckenia pectinata) giving structure to various aquatic habitats. We compared the level of genetic diversity in a heterogeneous series of aquatic habitats across Iran and tested their differentiation over distances and across mountain ranges (Alborz and Zagros) and desert zones (Kavir), with values obtained from temperate region populations. The diversity of aquatic ecosystems across and along large geographic barriers provided a unique ecological situation within Iran. P. pectinatus were considered from thirty-six sites across Iran at direct flight distances ranging from 20 to 1,200 km. Nine microsatellite loci revealed a very high number of alleles over all sites. A PCoA, NJT clustering and STRUCTURE analysis revealed a separate grouping of individuals of southeastern Iranian sites and was confirmed by their different nuclear ITS and cpDNA haplotypes thereby indicating an evolutionary significant unit (ESU). At the level of populations, a positive correlation between allelic differentiation Dest with geographic distance was found. Individual-based STRUCTURE analysis over 36 sites showed 7 genetic clusters. FST and RST values for ten populations reached 0.343 and 0.521, respectively thereby indicating that allele length differences are more important and contain evolutionary information. Overall, higher levels of diversity and a stronger differentiation was revealed among Iranian P. pectinatus than previously observed for temperate European regions, due to regional differences across mountain ranges over long distances.

[Responses of Physiological Indices of Typical Submerged Macrophytes to Water Quality in Taihu Lake].

It was well known that physiological indices of submerged macrophytes could reflect change of water quality. The correlation between physiological indices of submerged macrophytes and change of water quality was studied under the cooperation of in-situ monitoring and lab analysis, combined with measuring Chlorophyll and free proline (PRO) contents as well as peroxidase (POD) activities in the leaves of Potamogeton wrightii Morong and Potamogeton crispus L. under different water quality and nutrition status. The results showed: ①there were significant spatial differences among water factors and the comprehensive eutrophication index (TLI) of distribution areas of Potamogeton wrightii Morong and Potamogeton crispus L. Mesotrophic water was more suitable for the growth of Potamogeton wrightii Morong, while Potamogeton crispus L. grew well in eutrophic water. ②there were significant spatial differences among physiological indices of Potamogeton wrightii Morong and Potamogeton crispus L. in Taihu Lake. Besides, there were significant relationships between Chlorophyll contents, POD activities of two species and TLI. ③water transparency as well as nitrogen and phosphorus nutrition were important factors leading to changes in Chlorophyll contents and POD activities of Potamogeton wrightii Morong and Potamogeton crispus L.. The findings from this study indicate that physiological properties of Potamogeton wrightii Morong and Potamogeton crispus L. have a very close correlation with nutrition status and physiochemical properties of water.

Studies on the treatment efficiency of sediment phosphorus with a combined technology of PCFM and submerged macrophytes.

The removal efficiency of sediment phosphorus (P) in all fractions with a combined technology of porous ceramic filter media (PCFM) and submerged macrophytes was studied in Donghu Lake, Wuhan, China. The adsorption kinetic models of the sediment P in all fractions on PCFM could be described well by a power function equations (Qt = k · t(a), 0 < a < 1). The P removal capacity of the combination of PCFM and Potamogeton crispus, a submerged macrophyte, was higher for all P forms than that of the combination of PCFM and another macrophyte, Vallisneria spiralis. This study suggested that the combination of PCFM and macrophytes could achieve a synergetic sediment P removal because the removal rates of the combinations were higher than the sum of that of PCFM and macrophytes used separately. The combined technology could be further applied to treat internal P loading in eutrophic waters.

Differences in the regeneration traits of Potamogeton crispus turions from macrophyte- and phytoplankton-dominated lakes.

Potamogeton crispus is widely used in submerged macrophyte restoration in China. Turions are an important means of reproduction in this species. To compare the regeneration abilities of P. crispus turions in macrophyte- and phytoplankton-dominated lakes, we collected P. crispus turions from a macrophyte-dominated lake (Liangzi Lake) and a phytoplankton-dominated lake (Taihu Lake). Both lakes are important lakes in the middle and lower reaches of the Yangtze River in China. Our field survey revealed that the turions from the phytoplankton-dominated lake had smaller sizes and higher concentrations of total nitrogen (TN) and total phosphorus (TP) than did those from the macrophyte-dominated lake. Rapid sprouting of the turions from the phytoplankton-dominated lake in 32 days was observed under experimental conditions, although the sprout sizes (heights and biomass) were smaller than those from the macrophyte-dominated lake. Compared with sprouted turions from macrophyte-dominated lake, the sprouted turions from the phytoplankton-dominated lake accumulated higher soluble sugar (SS) but lower starch and free amino acid (FAA) concentrations. A 12-day interval sprout removal treatment significantly stimulated the re-sprouting of turions from both lakes, but scale-leaf-removal treatments had no effect. This study provides evidence that the regeneration strategies of P. crispus turions differ in macrophyte- and phytoplankton-dominated lakes.

Remedial effects of Potamogeton crispus L. on PAH-contaminated sediments.

In this study, the remedial effects of submerged macrophyte Potamogeton crispus L. on polycyclic aromatic hydrocarbon (PAH)-contaminated sediments were investigated. After a 54-day experiment, the dissipation ratios of phenanthrene and pyrene were 84.8-88.3 and 72.4-78.5% in rhizosphere sediments, which were significantly higher than those in non-rhizosphere sediments (54.2-66.6 and 54.7-58.5%). The dissipation increment increased not only with increasing spiked concentration, but also over time, while plant uptake accounted for only a small portion (<6%) of the dissipation increment. Moreover, bioavailable fraction tests revealed that biodegradation was not controlled by the amount of bioavailable PAHs. For better understanding of the microbial mechanism involved, phospholipid fatty acid (PLFA) profiles were analyzed. Biomass of microorganisms indicated by the total PLFA content was higher in rhizosphere sediments than in non-rhizosphere sediments and was related well to the dissipation ratios of the two PAHs. Cluster analysis showed that community structure significantly changed in rhizosphere sediments. Moreover, the increments of PAH dissipation in rhizosphere sediments had a strong positive correlation with those of polyphenol oxidase activities in the same media. It can be concluded that the enhanced remediation of PAHs by P. crispus was mainly due to the increase of microbial biomass and activity as well as changes of microbial community structure in sediments as a result of plant growth stimulation.

Turion morphological responses to water nutrient concentrations and plant density in the submerged macrophyte Potamogeton crispus.

Asexual propagules are the dominant means of propagation in most submerged macrophytes. To improve the understanding of how water nutrient concentrations and population density influence the turion production of Potamogeton crispus L., the turions were planted in mesocosms with three water nutrient conditions (ambient lake water, high P and high N) and two plant density levels (4 and 15 turions m(-2)). After a 9-month experiment, the +P in the water column significantly increased the total turion number per plant under both of the plant density treatments. However, the +N in the water column did not affect the turion number per plant under low plant density. The +P in the water and high plant density significantly reduced the turion individual biomass. An examination of 3210 turion individuals from all treatments revealed that the increased water nutrient concentrations and plant density impacted the turion size by producing different stem diameters of individual turions. Most of the scale leaf morphological traits of the turions were significantly increased under higher water nutrients, but these traits were similar between the different plant density treatments. These results demonstrate that the water P concentration interacts with plant density, affecting both the production and traits of turions.

The response of epiphytic microbes to habitat and growth status of Potamogeton malaianus Miq. in Lake Taihu.

To investigate the effects of different habitats and plant growth status on abundance, biomass and community structure of epiphytic microbes, Potamogeton malaianus Miq. at two different habitats (Gonghu Bay and East Taihu) in Lake Taihu were collected in June, August and November (corresponding to the period of development of submerged macrophytes). The relative abundance of major epiphytic algae groups was determined with high performance liquid chromatography (HPLC), and the structures and dynamics of epiphytic bacteria were assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis. Results showed that the biomass of epiphytic microbes was not significant difference between the two sites, and the analysis of similarity found no significant intra-lake heterogeneity in community structure, but the temporal heterogeneity of epiphytic microbes was significant, which linked to the growth state of submerged macrophytes and water temperature. The difference in community structure between June and August was larger than that between August and November at each site, indicating that the growth status of submerged macrophytes has a greater impact on the community structure of epiphytic microbes than the seasonal variation of environmental conditions.

[Influence of two different species of aquatic plant communities on the concentration of various nitrogen forms in sediment of Lake Taihu].

To investigate the spatial distribution of nitrogen in the sediment from both internal and external sites of Potamogeton malaianus and Limnanthemun nymphoides communities, levels of various forms of nitrogen were quantified in sediment samples collected from Gonghu Bay, the southern region and the intermediate area between East and West mountains of Lake Taihu in June 2012. The results showed that: (1) Within the algae-type region in Gonghu Bay, the contents of organic (Org-N) and total nitrogen (TN) in the internal sediment (0-25 cm) from P. malaianus communities were higher than those of the external sediment, by 38.06% and 25.65%, respectively. (2) In the non-algal region, the contents of TN, Org-N, NH4(+)-N and NO3(-) -N in the internal sediments from P. malaianus communities were lower by 43.29%, 50.78%, 7.09% and 10.86% compared to those in the external sediments; for L. nymphoides communities, the contents of TN, Org-N, NH4(+) -N and NO3(-) -N in the external sediments were lower by 4.65%, 4.63%, 5.01% and 2.76% compared to the internal sediments. These values suggested that the promotion in reducing sedimentary nitrogen was more effective by the P. malaianus community than by the L. nymphoides community. (3) A significant positive correlation (P < 0.05, n = 24) was found between pH and TN within the external sediments and between pH and NO3(-) -N within the internal sediments (P < 0.05, n = 24), while a significant negative correlation (P < 0.05, n = 24) was found between pH and NH4(+)-N of both aquatic plant communities. The redox potential (Eh) was also found to be significantly positively correlated with TN in both the internal and external sediments of P. malaianus communities (GMN, P < 0.01, R = 0.922 8 * *; NMN, P < 0.01, R = 0.827 7 * *; GMW, P < 0.05, R = 0.748 9 *; NMW, P < 0.05, R = 0.663 7 *). It is therefore concluded that the presence of aquatic plant communities could impact the physical and chemical properties of the sediments.

[Influence of submerged macrophytes on phosphorus transference between sediment and overlying water in the growth period].

In order to study the process of phosphorus transfer between sediment and overlying water, Hydrilla verticillata and Vallisneria natans were cultured in spring, Potamogeton crispus was cultured in winter. Changes of environmental factors and phosphorus concentrations in water and sediment were investigated. The results indicated that: submerged macrophytes could reduce all phosphorus fractions in the overlying water. Phosphorus concentrations in overlying water maintained in a relative low level in the growth period of submerged macrophytes. The concentrations of total phosphorus (TP) in overlying water of H. verticillata, V. natans and P. crispus were 0.03-0.05, 0.04-0.12, 0.02-0.11 mg x L(-1), respectively. All phosphorus fractions in sediment were reduced. The maximum value between submerged macrophyte and control of H. verticillata, V. natans and P. crispus were 35.34, 60.67 and 25.92 mg x kg(-1), respectively. Dissolved oxygen (DO), redox potential (Eh) and pH in overlying water increased (DO 10.0-14.0 mg x L(-1), Eh 185-240 mV, pH 8.0-11.0) in the submerged macrophytes groups. Submerged macrophytes increased Eh( -140 - -23 mV) and maintained pH(7.2-8.0) in neutral range. The results indicated that submerged macrophytes affected phosphorus transferring between sediment and overlying water through increasing DO, Eh and pH in overlying water, and Eh in sediment.