Research Symposium-2013
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Item Antibacterial Efficacy of Mangrove Rhizophora mucronata Extracts on Aquatic Bacterial Pathogens(Uva Wellassa University of Sri Lanka, 2013) Bokalawella, S.H.K.; De Silva, D.P.N.; Jayamanne, S.C.; Gunasekara, A. J. M.; Piyadasa, H.T.N.I.Medicinal plants contain components of therapeutic value and are used as remedies for human/animal diseases. They are environmentally friendly due to less toxicity and have minimal health hazards (Opara and Wokocha, 2008). Mangrove plant extracts and its major chemical classes displayed various levels of antibacterial, antifungal, antifouling, antiviral and free radical scavenging effects due to their bioactive compounds (Bandaranayake, 2002). Bacterial infections cause severe economic losses to the aquaculture industry which increased the use of antimicrobial agents significantly as a treatment (Alderman and Michel, 1992). Improper usage and presence of drug residues lead to the development of resistant strains of pathogenic bacteria. Therefore, novel antibacterial compounds of natural products which degrade easily need to be synthesized to overcome above consequences. Aim of this study was to find out the antibacterial efficacy of Mangrove Rhizophora mucronata extracts on aquatic bacterial pathogens, to be used as a remedy to treat fish diseases. Methodology Fresh matured leaves of six mangrove plant species (Avicennia marina, Lumnitzera racemosa, Bruguiera sexangula, Acanthus ilicifolius, Excoecaria agallocha and Rhizophora mucronata) were collected from mangrove reserve at Kadolkele, Negombo and were brought to the laboratory for making extractions. Initially, preliminary trials were conducted for identification of most suitable species with antibacterial properties against four aquatic pathogens Listeria monocytogenes) in vitro by well diffusion method. Upon identification of Rhizophora mucronata having the highest inhibitory zone for tested bacteria, further analysis were performed using various parts such as roots, barks, flowers and fruits of R. mucronata. The solvent was extracted by mixing 8 g of each part of mangrove in powder form, with 125 ml of 95% methanol and evaporating methanol using rotary flash evaporator (model 519-00000-00- 3). Antibacterial efficacy was assessed against all four species of fish pathogens, using was used as the positive control against Rhizophora mucronata extractions of 350 mgml each. After 24 hour incubation at 25 o C, the diameters of the inhibitory zones were obtained and statistically analyzed by using One way-ANOVA incorporated in Minitab version 16. Results and Discussion All six mangrove species showed antibacterial activity against Listeria monocytogenes, Pseudomonas fluorescens, and Pseudomonas aeruginosa significantly (p<0.05) but insignificant for Shigella flexneri (p>0.05). Highest inhibition zones were observed in Rhizophora mucronata leaf extract against all bacteria examined for the study (Table 1). Rhizophora mucronata extracts (root, bark, fruit and flower) also exhibited positive inhibition zones for all the tested bacterial species cultured in vitro. Root and bark extracts possessed higher antibacterial potential when compared to the fruit and flower extracts. Rhizophora leaf extracts showed highest inhibition for Listeria monocytogenes and Pseudomonas fluorescens while root and bark extracts were effective against Shigella flexneri and Pseudomonas aeruginosa respectively (Figure 1). The overall mean comparative evaluation on antibacterial efficacy of Rhizophora mucronata extracts displayed the highest in leaves followed by the root, bark and fruit extracts. The minimum antibacterial activity was observed in the flower extracts.Item Antimicrobial Activity of Seagrss (Cymodocea serrulata) from South West Coast of Sri Lanka(Uva Wellassa University of Sri Lanka, 2013) Arulananthan, A.; De Silva, D. P. N.; Jayamanne, S. C.; Dalpatadu, S.L.; Senaratne, S. G.Sri Lanka has rich oceanic vegetation along its coastal water bodies. However, utilization of them is limited when compared to terrestrial plants which are used as natural alternatives especially in Ayurveda remedy. It is expected that marine vegetation also ensure the potential bioactivity. Marine plants derived natural products are known as secondary metabolites which are bioactive compounds responsible for antimicrobial activities. Documented results from most of the Atlantic, Pacific, and Indian Ocean resultant macro algae exhibits broad range of biological activities. Some of these are antibacterial, antifungal, antiviral etc. On the other hand, few literature are available on the therapeutic values of seagrasses in Sri Lanka. Therefore, the objective of this study was to test the antimicrobial activity of some selected seagrass species collected from the Beruwela beach rocky platforms and Hikkaduwa coast of Sri Lanka. Methodology Collection and preparation of samples - The fresh seagrass species (Cymodocea serrulata) was collected by hand picking during the low tidal conditions from the submerged rocky platforms of Barberrian reef and in Hikkaduwa coast. The collected vegetation was cleaned well with tap water and distilled water. Then the samples were drained and spread on the filter paper to remove excess water. Samples were chopped into nearly 1cm length pieces prior to grinding using liquid nitrogen. Solvent extraction - Coarsely powdered samples were subjected to solvent extraction by using chloroform, methanol and water solvents. The powdered form of samples and solvents were taken (1:10 w/v) and kept for 24 hours at room temperature (27 °C) in the orbital shaker at 150 rpm. Later, the extracts were filtered through a Buchner funnel with muslin cloth followed by Whatman number 1 filter paper. The resulting filtrates were concentrated by using rotary evaporator. Test microorganism - Human pathogenic Gram positive bacteria Staphylococcus aureus, Gram negative bacteria- Escherichia coli, and a fungal species Candida albicans were used to defeat the antimicrobial activity of C. serrulata. Antimicrobial susceptibility test - Antimicrobial activity of extracts was performed by using the disc diffusion method and agar well diffusion method. The stock solution was prepared with extract of 100 mg/ ml concentration of respective solvents. Sterile discs of 6 mm diameter were prepared in three different quantities (1 mg, 2 mg, and 5 mg). Each plate contained discs with three different quantities and negative control. Agar well diffusion method was carried with all extracts in same concentration as 100 mg/ ml in three different quantities (5 mg, 10 mg and 20 mg). In positive control Kanamycin 10 µl (3µg/ µl) was used for bacterial species and Flucanozole (1.25 µg/ µl) was used as antifungal agent. The plates were incubated overnight.Item Application of GIS to Identify Potential Areas for Aquaculture in Badulla District in Uva Province(Uva Wellassa University of Sri Lanka, 2013) Sandamali, M.A.N.; Rathnayake, R.M.C.W.M.; Liyanage, N.P.P.; Jayamanne, S.C.Aquaculture is farming aquatic organisms including fish, mollusks, crustaceans and aquatic plants (FAO, 1990). The main intent of the present study is to highlight the role Geographic Information System (GIS) in identifying potential areas for aquaculture in Badulla district. The study was carried out in Badulla district in Sri Lanka by the geographical coordinates of longitude 80 .45 to 81 .15. Latitude 6 .34 to 7 .18. Data have been collected from secondary sources and used to generate maps to identify fresh water bodies in Badulla district. Map of seasonal tanks, reservoirs and tanks, stream network and rivers of Badulla district were developed. Water availability (proximity to rivers), soil texture, soil pH, rainfall, temperature and topography (slope, elevation) and land use factors were considered to identify potential areas for aquaculture (pond culture). Protected areas are considered as constraints. Water availability, soil texture, soil pH, slope, elevation, rainfall, temperature, land use/ land cover thematic layers were created using ArcGIS 10.1 software. All these thematic layers have been assigned the weights according to their relative influence on pond construction using Analytic Hierarchy Process (AHP) and GIS approach. Finally, all thematic layers have been integrated in a ArcGIS 10.1 environment to generate an aquaculture potential map. Thus, four aquaculture potential areas have been Identified, viz. “Most suitable”, “Suitable”, “Fairly suitable”, “Unsuitable”. The north part of the Badulla district is identified as most suitable and the southern part of the Badulla district is identified fairly and unsuitable for aquaculture in Badulla district. Methodology Data collection: Secondary data were collected from secondary sources. GIS analysis: reservoirs and tanks, Rivers, Stream network of Badulla district were digitized using Arc View 3.1 software. GPS coordinates of seasonal tanks were stored & developed a map using ArcGIS 10.1 software to identify fresh water resources in Badulla district and all data were stored in ArcGIS 10.1 environment and factor thematic layers were generated to identify potential areas for aquaculture. Analytic Hierarchy Process (AHP) - AHP is a multi-objective, multi criteria decision making approach that employs a pair wise comparison procedure to arrive at a scale of preference among a set of alternatives (Dai et al., 2001). Thematic layers were evaluated using scores and each weighted according to their relative importance on the aquaculture using Analytic Hierarchy Process (AHP) and GIS approach. Map Generation -Each thematic layer was evaluated using the scores that were obtained according to the weighted linear combination in ArcGIS 10.1 environment. Vector format was converted to raster format. To reject the constraints the final result was multiplied by absolute constraints. The protected areas were allocated a zero score. Finally, the potential areas for aquaculture map was created and categorized into four levels: Most suitable, Suitable, Fairly suitable, Unsuitable based on the total scores obtained from the weighted linear combination.Item A Comparative Study on the Diversity of Seagrass Species in a Selected Area of Puttalam Lagoon(Uva Wellassa University of Sri Lanka, 2013) Ranahewa, T.H.; Jayamanne, S.C.; Gunasekara, A.J.M.Seagrasses are aquatic angiosperms which are widely spread in shallow marine environment (Kuo and Hartog, 2000). Providing habitat grounds for large numbers of fish and shellfish species, act as a largest carbon sink, support a large number of epiphytic organisms, bind the sediment together and stabilizing sea bottom (Johnson and Johnstone, 1995) are the importance of seagrasses. Puttalam lagoon which is located in Puttalam district of Northwestern Province of Sri Lanka that covers 32700 ha (Johnson and Johnstone, 1995). There are fifteen species of seagrasses have been recorded in Sri Lanka including two families, 12 genera (Amarasinghe and De Silva, 2007). Main objective of the research is to compare changes of seagrass distribution from 1991 to 2013 where as to evaluate relationship between distribution of seagrasses with the states of water quality of selected locations of Puttalam lagoon and to compare the distribution of seagrass species according to salinity levels of each location are specific objectives. Methodology The present study was carried out in selected areas of Puttalam lagoon during the period of May to September in 2013. Kalpitiya, Kuringipitiya, Palliwasalthurai, Kandakuda, Palavi and Puttalam were the selected sites for the data collection (Figure 1). Geographic Position System (GPS) data of the site were recorded and point transect method was used for the sampling. Three line transects of each location were used. Typically transects were perpendicular to the shore and parallel to each other. Cover of seagrasses within a quadrant with 0.5 m * 0.5 m was measured at every 3 m mark of the 30 m by walking and snorkeling until transect was completed. Transects were selected and procedure was carried out in such a way that as same as Jayasuriya, 1991 conducted. Water quality parameters including water temperature (°C), pH, salinity (ppt), conductivity (mS/cm) and dissolved oxygen (mg/L) were measured at the middle of transect two at 10 cm below to the sea surface using Multiparameter meter (Orion Water quality testing was repeated at the same time in the same place once a month and average values were calculated. Same procedure was repeated in other selected locations. Average abundance of seagrass distribution of three transects were calculated. Diversity of seagrass species of each sites were calculated using Shannon - Weiner diversity index. Comparision was conducted using analysis of variance (ANOVA). Percentage abundance of each species were calculated by dividing six sites into two regions as Northwestern and Southeastern according to Jayasuriya, 1991 and compared with the values recorded by Jayasuriya, 1991. Linear regression was conducted to find out relationship between seagrass distribution and water quality parameters.Item Distribution and Abundance of Seaweeds at Polhena Reef-Matara(Uva Wellassa University of Sri Lanka, 2013) Ediriweera, A.N.; Jayamanne, S.C.Polhena reef is among the most valuable marine ecosystems existing along the southern coastal belt of Sri Lanka. The reef is a fringing coral reef and is highly diverse both in flora and fauna. It is well known as an ecosystem that has significant ecological and economical value. Senaratne et al. (2013) has indicated that the reef is exposed to anthropogenic activities and is disturbed to some extent. Coral reef is covered with seaweeds that belong to categories of green, brown and red. Seaweeds also play a major role as live feed, breeding grounds and as habitats for marine fauna existing in coral reef. It is also economically important as human food, animal feed, pharmaceutical, fodder, stationary and cosmetic production. Growth, distribution and abundance of seaweeds vary spatially, seasonally and with other external factors of the environment. This study was focused on the identification of seaweed species, distribution and their abundance within a selected area of Polhena coral reef with an aim of finding their value as an ecological resource. Methodology The study was carried out during the period May, 2013 to July, 2013. An area with a length of 3 km parallel to the shore was selected for the study and five parallel transect lines (T1-T5) were laid across the coral reef perpendicular to shore up to the sea end of the reef using colour coded nylon ropes. An equal distance was maintained between every adjacent two transect lines by using a GPS (Garmin GPS 72). Each rope was marked at each 4 m. Triplicate samples of seaweeds were collected between each and every two marks using a 50 cm x50 cm quadrat and photographs were taken at each quadrat using an underwater camera (Panasonic-Lumix FT-20). Data on species composition and percent cover of the seaweeds that were collected from each quadrat. Species were identified at the laboratory using hand lenses and a binocular microscope (SN090933909 labomed binonular) (Coppejans et al., 2009). Species of seaweeds recorded in five transects during the study period was entered to a table created in Minitab-15 data sheet and Microsoft Excel data sheet. Statistical analysis was done using a Two-way ANOVA, One-way ANOVA and Turkey’s Test in Minitab 15 statistical software.Item Perfecting Explants Sterilization Procedure and Multiple Shoot Induction Medium for In-Vitro Propagation of Lagenandra Species(Uva Wellassa University of Sri Lanka, 2013) Premathilake, P.G.A.D.; Bambaranda, M.; Jayamanne, S.C.; Krishnarajah, S.A.Lagenandra species are important aquatic plants in the aquaculture industry of Sri Lanka (Yapabandara and Ranasinghe, 2006). In the absence of a regular supply due to lack of effective propagation methods, Lagenandra species are indiscriminately harvested from the wild to supply to the export market. In order to overcome the problem of species loss and inadequate supply to the local and foreign markets, an in vitro micro- propagation method was developed for Lagenandra lancifolia and Lagenandra ovata. The maintenance of aseptic or sterile conditions is essential for successful tissue culture procedures. Various sterilization agents are used for surface sterilization the tissues. These disinfectants are also toxic to the plant tissues, hence proper concentration of disinfectants, duration of exposing the explants to the various disinfectants, the sequences of using these disinfectants has to be standardized to minimize explants injury and achieve better survival (CPRI, 1992). Mercuric chloride and sodium hypochlorite were used for the present study to standardize the best sterilization protocol for in vitro culture of Lagenandra ovata and Lagenandra lancifolia. Culture initiation and multiplication, to a great extent, are dependent on the type and genotype of explants as well as the type of hormone and their concentration. Many commercial ornamental plants are being propagated by in-vitro culture on the culture medium containing auxins and cytokinins (Peril, 2003).BAP (6- Benzylaminopurine) and IAA (Indole acetic acid) hormone with different concentration were used in the present study to perfect the best combination of IAA and BAP in shoot multiplication procedure. Methodology The research was conducted at the tissue culture laboratory, Floriculture research and development unit, Royal botanic gardens, Peradeniya. The rhizomes (1 cm - 2 cm pieces) were used as explants. In the first experiment, explants were soaked in different concentrations of sodium hypochlorite (15%, 20%, and 25%) and mercuric chloride (0.1%, 0.2%, and 0.4%) to perfecting explants sterilization procedure. Each explant was soaked for twenty minutes in Sodium hypochlorite solution and two minutes in Mercuric chloride solutions. Number of contaminated cultures was observed after two weeks from explants establishment in hormone free Murashige and Skoog medium. In second experiment, effect of different hormone combinations (hormone free MS medium, , BAP 7 mgl +IAA 0.1 mgl ) in 0.5 MS semi solid medium, full MS semi solid medium and full MS liquid medium for shoot initiation and multiplication were evaluated. Number of shoot initiation, shoot length, number of shoots per culture and number of leaves per culture were recorded after six weeks from explants establishment in MS medium.All the data were analyzed using ANOVA in SAS and Minitab statistical package.Item A Preliminary Study on the Best pH Value of Water to Increase the Quality of Echinodorus Bleheri(Uva Wellassa University of Sri Lanka, 2013) Withanage, W.A.S.; Bambaranda, B.V.A.S.M.; Jayamanne, S.C.; Fernando, M.A.G.C.The Aquatic plant export industry of Sri Lanka has been developing rapidly. This industry requires a continuous supply of high quality plants. Echinodorus bleheri is one of the highest demanded aquatic plants in export market. Aquatic plants have adapted to life in water with a specific pH, Temperature, Electrical conductivity and may suffer from even a slight change. High quality plants can be supplied with in a short time period by finding the best pH value of water. In the world of plants each plant species is perfectly adapted to a certain pH range of the soil or water. Aquatic plant hobbyists are usually familiar with the different pH requirements of various plants and regulate the pH of water appropriately. Hydroponics is proved to have several advantages over soil gardening. The growth rate on a hydroponic plant is 30-50 percent faster than a soil plant. A nutrient solution for hydroponic systems is an aqueous solution containing mainly inorganic ions from soluble salts of essential elements for higher plants. Eventually, some organic compounds such as iron chelates may be present (Steiner, 1968). Changing the pH of a nutrient solution affects its composition, elemental speciation and bioavailability. An important feature of the nutrient solutions is that they must contain the ions in solution and in chemical forms that can be absorbed by plants, so in hydroponic systems the plant productivity is closely related with to nutrient uptake and the pH regulation (Marschner, 1995). Each nutrient shows differential responses to changes in pH of the nutrient solution. The proper pH values of nutrient solution for the development of crops, lies between 5.5 and 6.5. Plants need the right combination of nutrients to live, grow and reproduce. When plants suffer from malnutrition, they show symptoms of being unhealthy. Too little or too much of any one nutrient can cause problems. The main objective of the present study is to find out the best pH value of water to increase the quality of Echinodorus bleheri. Methodology This experiment was conducted under green house condition with 80% shade at Ruvini Aqua plants Lanka (pvt) Ltd, Koralawella, Moratuwa. Hundred and eighty Echinodorus bleheri plant pots(containing four plants in each pot) were used for the experiment. Experimental design was Complete Randomized Design. Fifteen Styrofoam boxes (46 cm×39.5 cm×19.5 cm) were used to plant them. HANNA (HI98107) portable digital pH meter was used to measure pH and HANNA portable digital EC meter (HI 98303) was used to measure Electrical Conductivity of water. Two months aged 180 Echinodorus bleheri plant pots were randomly selected and uprooted from culture tanks. Plant pots were washed thoroughly after removing sand and other objects. Randomly selected 12 plant pots were assigned in to a tank and measure the wet weight of 12 plant pots. Plant pots were planted in 15 Styrofoam boxes. Bottoms of the Styrofoam boxes were covered by black polythene sheets to prevent the algal growth. Placement of Styrofoam boxes were decided by lottery method. Five different pH solutions were used for the experiment as 6.0, 6.5, 7.0 (control), 7.5 and 8.0. Six grams of Albert solution was dissolved in 7 l of water and filtered the solution using a muslin cloth. pH of the solution was measured. NaOH or HCl was added drop wise until required pH value achieved and maintained the electrical conductivity 1000-1500 µs level. Prepared pH solutions were kept for 1 hour to see the fluctuations. pH solutions were poured in to tanks. After 2 days pH solutions of each tank were removed using manual squeeze water changer pump and filled the solutions again week, plant pots were uprooted from Styrofoam boxes and measured the wet weight of each replicate (12 plant pots). Total lengths of plants were measured using a tape weekly. Number of leaves was counted weekly. Wet weight of each replicate (12 plant pots) was measured before starting the experiment and at the end of the experiment. Data obtained from the experiment were analyzed by Microsoft Word. Treatment significances and significance among individual treatment levels were analyzed using one way analysis of variance (ANOVA).Item A Preliminary Study on the Influence of Herbal Extraction; Cardiospermum Halicacabum (Welpenela) on the Growth Performance of the Gold Fish (Carassius auratus)(Uva Wellassa University of Sri Lanka, 2013) Lakshman, L.H.D.H.K.; Jayamanne, S.C.; Mudalige, A.Carassius auratus (Gold fish) is an ornamental fish species which is an egg layer, commonly cultured in Sri Lanka. It’s annual production is 34,019 (NAQDA report 2011). Calico, Pearlscale, Ranchu, Red cap and Oranda are the common Gold fish varieties cultured in Sri Lanka. Producing gold fish for export market with optimum marketable size after grow-out period using low cost feed having appropriate nutritional properties is crucial. General proportions of various nutrients as proteins, carbohydrates, vitamins, minerals and some pigments are needed to be included in a standard fish diet (Metwally, 2009). Metwally (2009) has indicated that medicinal plants are regarded as potentially safe drugs and have been tested for biological, antimicrobial; antioxidant and hypoglycemic activities and their extracts can be potentially used for enhancing growth of fish by improving quality of their feed. In the present study, Cardiospermum halicacabum (Welpenela), a climber belongs to the family Sapindaceae which exhibit a wide range of biological and pharmacological properties was selected as the herb and its effect on the growth of gold fish was tested. Methodology The experiment was conducted at the Ornamental Fish Breeding and Training Center - Rambodagalla. Extractions of C. halicacabum was prepared by grinding the plant and three treatment feeds were prepared by replacing 20 g, 40 g and 60 g respectively from “0” Prima feed with 20 g, 40 g and 60 g of C. halicacabum extract. The feed used by the Rambodagalla Center was used as the control. Composition of the four types of feed is given in table 1. Prepared feed were stored in the refrigerator under 2 C. Proximate Analysis of all the feeds was carried out.Item A Preliminary Study on the Optimum Concentration of Copper Sulfate and Utilization of Valisneria Plant in Controlling Green Algal Growth Under Aquarium Condition(Uva Wellassa University of Sri Lanka, 2013) Priyadarshana, R.W.H.H.; Jayamanne, S.C.Ornamental fish industry plays a considerable role in the economy of Sri Lanka since the globalization ornamental fish industry (Wijesekara and Yakupitiyage, 2001) Maintenance of aquariums with ornamental fish has become a hobby of people and aquarium owners but the controlling excessive algal bloom has become a hindrance. Green algae are the most common form of algae in the home aquarium. Excessive algal growth is a nuisance for aquarists, due to decreasing dissolved oxygen level, absorbing the nutrients. It is also hazardous to fish and plants. Aquatic plants are known to control algae and Copper Sulfate is a chemical used in aquaculture ponds to control algae (Roy, 2009). Present study attempts to develop a method to control excessive green algal blooms in aquariums combining the effects of Copper Sulfate and aquatic plant Valisnaeria. Methodology Complete randomized design was used as an experimental design and it was carried out at the Uva Wellassa University Animal Science laboratory setting. Thirty six tanks of 12”x 6”x 6” size were used for experiment. Five treatments (concentrations) each for Copper Sulphate, Valisneria spiralis plants and controls for both treatments were used in triplicate. At the beginning, algal medium was created by fertilizing water in a stock tank (4’x 1 ½’x 1 ½’) and by keeping for one week. Ten ppm Copper Sulphate stock solution was prepared and Valisneria spiralis plants having more or less similar total biomass (1.43±0.14), shoot length (13.58±1.54) and root length (6.48±1.34) were selected for experiment. After one week, all tanks were filled using prepared algal water (approximately 230 l) and tanks were kept under black fabric net with 60 % of illumination. Two fighter fishes were stocked in each tank. Initial Chlorophyll content in all the tanks was measured using the spectrophotometer at 630 nm. Five tanks were treated with different concentrations of Copper Sulphate (T1=0.1 ppm, T2=0.2 ppm, T3=0.3 ppm, T4=0.4 ppm and T5=0.5 ppm), five tanks were treated by having different total biomass of Valisneria spiralis plants (T1=1.43 g, T2=3.15 g, T3=5.25 g, T4=7.12 g, T5=8.04 g). Control tanks were devoid of Copper sulphate as well as Valisneria spiralis plants. Light measurements were assured that all the tanks received similar light conditions. Results and Discussion Chlorophyll content at the initial stage was measured as 0.12 mg/l. Mean difference in Chlorophyll content was calculated by averaging the difference between initial and final Chlorophyll contents in each replicate. The values obtained for all treatments are shown in table 1. The Mean differences in Chlorophyll content in both treatments are also shown graphically in Figure 1. As depicted by the results there is a negligible difference in control tanks while treatments have shown differences according to the treatment type. It is evident that both the methods can be used successfully in controlling algae in aquariums effectively although the effect of Copper sulphate is better on algae control than that of using Valisneria spiralis.Item Uptake of Nitrate and Phosphate by Hydrilla verticillata and Vallisneria spiralis(Uva Wellassa University of Sri Lanka, 2013) Karunarathna, K.K.C.K.; Jayamanne, S.C.; Bambaranda, M.; Bandaranayake, R.The phosphate and nitrate are major inorganic components which are directly and indirectly accumulate in water bodies (Boundless, 1997). High concentrations of phosphates and nitrates present in the wastewater causes eutrophication that severely affects natural water bodies (Kenneth, 2006). To avoid accumulation of nitrate and phosphate in waterbodies, water purification systems should be established with P and N removal facilities. The cost of the advanced instruments that can purify water is not affordable by the developing countries such as Sri Lanka and water purification by aquatic plants is considered as a suitable method. The present study was carried out to evaluate the ability of two fresh water aquatic plants, Hydrilla verticillata and Vallisneria spiralis in removing nitrate and phosphate from the waste water. The main objective of the study was to identify the best plant which can absorb a large amount of nitrate and phosphate from the wastewater. Methodology The research was conducted in two stages to investigate the fluctuation of nitrate and phosphate in the wastewater with aquatic plants. The first experiment was conducted to investigate the changes of nitrate and phosphate by using Hydrilla verticillata and Vallisneria spiralis in equal biomass. The Hydrilla verticillata, Vallisneria spiralis, a combination of Hydrilla verticillata and Vallisneria spiralis and control treatment were used as different treatments and the same biomass was provided for each treatment units (16 g) except for the control. Then water samples were collected daily in the morning (8.00 a.m.) and used to estimate the nitrate and phosphate concentration. The experimental design was completely randomized design. The data was analyzed using one-way ANOVA and general liner model in Minitab 14. The second experiment was conducted to compare the ability of two aquatic plants Hydrilla verticillata and Vallisneria spiralis in removing nitrate and phosphate from wastewater and the appropriate density that can be used for controlling eutrophication. Different biomasses of 8 g, 16 g, 24 g and 32 g of Hydrilla verticillata and Vallisneria spiralis were used as treatments and the nitrate and phosphate concentration were measured daily following AOAC standard methods (1985). Two factor factorial design was employed as the experimental design and two- way ANOVA in Minitab 16 was used to analyze the data. Result and Discussion According to the Figure 1, T1 (Hydrilla) and T2 (Valisneria) could reduce phosphate concentration in the wastewater than T3 (combined plants) and T4 (Control). T1 and T2 had shown approximately same phosphate removal ability. Phosphate concentration in the water is significantly different between the treatments except T1 and T2 (p<0.05). Figure 2 shows that nitrate concentration of the T1 was lower than T2, T3, and T4. Nitrate concentration is significantly different between the treatments (p<0.05). The concentrations of the Nitrate and phosphate in the water has reduced in T1, T2 and T3. In T4, reduction of nitrate and phosphate in the water was lower than in treatment tanks with aquatic plants. According to Figure 3 the highest nitrate absorption was recorded in T1 with 8 g of biomass by absorbing 76 %. The nitrate absorption is significantly different between treatments and the level of biomass. The interaction among the plant type and biomass is also significantly affected on the nitrate absorption (p<0.05). Figure 4, shows the highest phosphate absorption in T1 with 32 g biomass and it absorbed only 40% in 5 days. Phosphate absorption is significantly different between treatment and the amount of biomass (p<0.05). The interaction among the plant species and biomass were also significantly affected on the phosphate absorption