Olah.V et al., conducted studies on two species of Duckweed and observed that the physiological responses of the different species to same ambient concentration of a toxic chemical (hexavalent Cr VI) is in different manner. Lemna minor plants were isolated from the mixed duckweed culture and used for this study after acclimatization for about seven days. Three species of duckweed, Spirodela oligorrhiza, Lemna minor and Wolffia arrhiza were grown under aseptic conditions on both buffered and unbuffered solutions of Jacob's media. Competing interests: The authors have declared that no competing interests exist. 3. Dense populations are an important food source for aquatic waterfowl and fish, but can become a nuisance to humans. Data related to ambient air temperature and day lengths as shown in Table 2 was retrieved from the website of Pakistan Metrological Department, whereas the solar radiation data was obtained from the web site of LEO Corporation, Pakistan. Data curation, Enhancement of crop yields by optimizing co-existing bacteria has long been a goal for sustainable agriculture. Lemna minor, belonging to the genus Lemna is the most widely spread species of duckweed which is extensively studied in wastewater treatment mainly due to its fast growth and high nutrient removal efficiency [17]. Duckweed is amongst the promising aquatic plants having enormous capacity to treat eutrophicated wastewaters. broad scope, and wide readership – a perfect fit for your research every time. Fig 1 shows the schematic setup used for leachate production. Phosphorous makes up to 0.03 to 2.8% of a typical duckweed dry mass whereas the nitrogen content is about 0.8 to 7.8% [25]. The duckweed system can be used to identify novel and critical pathogenicity agents, as virulence factors are often conserved across phylogeny. This situation was also helpful for maintaining the artificial weather conditions in the growth chamber where no significant variations of conditions was required throughout the experimental period. In dumpsite leachate growth rates of Lemna minor ranging from 4.3 to 6.4 g m-2 day -1 have also been reported [33]. here. Throughout the experiments, the pH of the leachate was maintained at about 7± 0.6. using 1M solution of Hydrochloric Acid (HCl) and Sodium Hydroxide (NaOH). Copyright: © 2019 Iqbal et al. As an added benefit, this much covering also helps with mosquito control, water evaporation and temperature issues. Duckweed absorbs variable amounts of nitrogen and phosphorous under varying conditions. Various studies report a variable amount of nitrogen absorbed by duckweed. Results: Co-cultivation of aseptic L. minor and bacterial communities collected from various aquatic environments resulted in changes in duckweed growth ranging from -24 to +14% compared to aseptic control. The duckweed was placed in stagnant water which contributes to the growth of the duckweed as this is a more favourable condition … All treatments were performed in triplicate. They are opportunistic in using flushes of nutrients and can put on growth spurts during such periods. PLoS ONE 14(8): In the 0.0001 g/mL the average amount of fronds grew steadily the … Data collected on all parameters was analyzed statistically using Fisher’s analysis of variance (ANOVA) techniques under completely randomized design (CRD). Overall, the factors that determine the health and sustainability of an aquatic ecosystem include the energy flow, nutrient cycling, biodiversity and interactions among all the components of the ecosystem. Dried mass of duckweed was ground with the help of a mortar and pestle and then a plant extract was prepared for analysis of TKN and TP contents. Funding: Authors are grateful to Higher Education Commission of Pakistan for providing financial support during the execution of this research study. Temperature adjustments within the growth chamber were made with the help of a temperature gauge fitted with the chamber. Nutrients – fertiliser present, loose soil mixed in water, nitrates, phosphates Light – intensity, colour, length of “day” Nitrification and denitrification processes contributes for 50% of nitrogen removal from wastewater [37]. Major part of the plant comprises a thallus called "frond" which is generally composed of chlorenchymatous cells having air pockets called aerenchyma due to which duckweed floats on water. https://doi.org/10.1371/journal.pone.0221755.g001. Therefore, present study was designed with the objective to investigate the growth of duckweed and its efficiency to remove COD and nutrients (N&P) from synthetic and dumpsite leachate. High rates of nitrification and denitrification processes resulted by large population of respective bacteria may remove large amounts of nitrogen from dumpsite leachate. Growth is slower at low temperatures, and the plants tend to … When molecules get larger, they have the ability to stick together and that allows the formation of larger assemblies of molecules that are not bonded to, Factors that Affect the Growth in Duckweed. No, Is the Subject Area "Ponds" applicable to this article? Based on its wastewater treatment potential, it is hypothesized that Lemna minor can also be used as a cost effective and technically feasible option for leachate treatment. All experiments during this study were conducted within the premises of Institute of Environmental Sciences and Engineering (IESE), National University of Sciences and Technology, Islamabad, Pakistan where I am pursuing my doctoral degree (33° 38′ 41″ N, 72° 59′ 22″ E). Lemna minor Each test was performed for 10 days during which samples from the leachate and control containers were analyzed for TKN, ammonium nitrogen (NH4+-N), TP, ortho phosphate (o-PO4-3-P) and COD by removing three containers at the start and end of the test. Fungi--probably pythium fungi, cause plant tissues to deteriorate consequently converting duckweed into a meal for micro-organisms (Suren, 1989).Pythium blight starts small and spreads until it eventually infects all the duckweed. Student investigations; Population growth Description. Anong Phewnil et al., concluded that the growth rate ofLemna Perpusilla Torr. However, compared to nitrogen, the phosphorous requirement of duckweed is very small for optimum plant growth [24]. The intrinsic growth rate, r, for the nutrient rich treatment was 0.11 and 0.08 for the nutrient lacking treatment, therefore the medium containing phosphorus had a faster growth rate than that without phosphorus. Cheng et.al reported a growth rate of L. minor close to 29 g m-2 day-1 in high strength swine wastewater while the total Kjeldahl Nitrogen (TKN) and Total Phosphorous (TP) absorbed by duckweed were 90% and 88.6%, respectively [12]. Duckweeds are the … Methodology, e0221755. The present nitrogen performed nitrogen metabolism, which is vital for plant growth. Furthermore, it is to note that no endangered or protected species or locations were involved during this research study. For part 01 of each test, duckweed containers were placed within a meshed iron rack under natural climatic conditions whereas; for part 02, containers were placed within the growth chamber under similar controlled conditions. In this lab, you will observe the growth of duckweed (Lemna minor Copyright © 2000-2020. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No, Is the Subject Area "Water pollution" applicable to this article? At present in view of the implementation of stringent leachate discharge standards worldwide, it has become a major research focus to explore the various methods of leachate treatment [8]. This might be the reason of high growth rate of duckweed at synthetic leachate. Aquatic plants also offer an alternate technology of converting wastewater nutrients into potentially useful forms in addition to the treatment [12]. Of the five factors significantly inhibiting duckweed growth, depletion of N was strongest, increase in pH was second, followed by reduction of P > Fe > Mn. This increase aids rapid growth as there is the right amount of nitrogen present inside and outside the cells of … This is particularly true for If you’ve ever tried to get rid of it in a farm pond, you’ll probably agree. has been recognized and getting more attention recently in wastewater treatment [11]. Temperature and sunlight control growth, with maximum growth occurring between 17.5 and 30 ºC. Yes Pollution caused by leachate is a potential threat to the environment and human health [5]. Data Availability: All relevant data are within the manuscript and its Supporting Information files. Yes Duckweed is a small floating macrophyte belonging to family Lemnaceae of monocotyledonous plants. Iqbal and Baig reported that during summer season Lemna minor removed TKN and TP from dumpsite leachate at the rates of 40 to 310 mg m-2 day -1 and 30 to 200 mg m-2 day-1 respectively [33]. https://doi.org/10.1371/journal.pone.0221755.t005. Investigation of Factors that Affect the Rate of Reaction Between Limestone, The Importance of the Fight Scene in William Shakespeare's Romeo and Juliet, Management of Bipolar Disorder in Adults and Diagnosis in Adolescent Children, Response to William Shakespeare's Othello. Therefore, the objective of our present study was to examine the growth and nutrient removal efficiency of duckweed (Lemna minor) on leachate. Assimilation of nitrogen by duckweed fronds and roots appears to be the primary mechanism of nitrogen fixation in plant. When duckweed dies, stored P in plant biomass is readily available in the water [26]. Phosphate (PO4-3) is the preferred form of phosphorous uptake by the duckweed. No, Is the Subject Area "Fronds" applicable to this article? Duckweed plants were oven dried at 70 0C until it had a constant weight. What conditions will your duckweed like most? https://doi.org/10.1371/journal.pone.0221755.s001, https://doi.org/10.1371/journal.pone.0221755.s002. Unattended leachate is representing a potential environmental risk to the surface as well as ground water quality [6]. School Science Review, 69 (248) 505-508 Teaching Topics. Zhang et al. https://doi.org/10.1371/journal.pone.0221755.t002. Yes During each test, duckweed was grown in 300 ml plastic containers with a surface area of 25.8 cm2. Growth on unbuffered media is initially rapid but eventually inhibited, probably by increased pH levels. The NTK reduction was posi- tively related to the conductivity. 123Helpme.com. Experimental site is owned by the IESE, NUST where no permits are required to conduct the research work for IESE students. Three tests were performed each by growing lemna minor on synthetic leachate under controlled conditions and on dumpsite leachate under natural conditions. Significant amounts of N and P may be removed through ammonia volatilization, nitrification and denitrification and microbial assimilation in addition to the duckweed absorption in natural leachate-duckweed systems [35]. Yes Lemna minor has variable growth rates under varying climatic conditions. POPULATION GROWTH IN Lemna (Duckweed) A. However, the amount of nitrogen and phosphorous absorbed into duckweed body mass was about 16% and 35% respectively more at synthetic leachate. This plant has the ability to reproduce rapidly, it can double in just 16 hours - 2 days, depending on its growing environment. growth phase the limiting growth factor is a lack of proper light or a lack of one or more nutrients. Under favorable climatic conditions and nutrient balance in growth media, Lemna minor can double its biomass within two days [18]. Collected wastes were mixed in plastic tank having an internal diameter of about 1.5 m and a height of about 1.8 m. A sieve (pore size 1mm) was fixed at an internal height of 10 cm of the plastic tank. Attempts at searching for literature reveals that currently a very small amount of research has been conducted on the use of duckweed for leachate treatment. Duckweeds are small, fragile, free floating aquatic plants. Preventive Measures. In dumpsite leachate under the natural conditions, large amount of nutrients is removed by the other factors than absorption into duckweed biomass which results in retarded growth of duckweed plants [33]. Considering these facts, environmental bacterial communities were shown to be a critical factor that affects duckweed growth, with effects that are comparable with other important environmental factors such as light and nutrients. However, some portion of nitrogen is also absorbed into duckweed biomass through associated N fixing cyanobacteria and algae grown in duckweed ponds [19]. Water quality is measured by several factors, such as the concentration of dissolved oxygen, the pH level in the water, the salinity of the water or salt content in the water, the temperature of the water and its turbidity or the ability to see through the waters surface, there are also other contaminants that may affect water quality. Yes Discover a faster, simpler path to publishing in a high-quality journal. In view of the complex chemical composition of dumpsite leachate, it was difficult to prepare synthetic leachate of exactly similar composition. This is consistent with the growth of duckweed which is also high at synthetic leachate. Leachate is a type of concentrated wastewater produced at open dumpsites by percolation of rainwater through solid waste layers [2]. All rights reserved. Keywords: Duckweed; S. polyrrhiza; Growth Rate; Conductivity; Domestic Wastewater . Maximum growth rate of duckweed (7.03 g m-2 day-1) was also observed for synthetic leachate in comparison to the growth rate of 4.87 g m-2 day-1 at dumpsite leachate. Factors that Affect the Growth in Duckweed Introduction ===== For healthy growth plants need several substances. the growth rate, with the correlation factor of up to 0.783 and, then to the conductivity. Dumpsite leachate used in this study was prepared by processing the mixed solid waste collected from various residential, commercial and industrial dumpsites in Islamabad, Pakistan. Results revealed that, in comparison to synthetic leachate, duckweed removed Chemical Oxygen Demand (COD), nitrogen (N), and phosphorous (P) more efficiently from dumpsite leachate under natural climatic conditions. Duckweed shows optimum growth at phosphorus concentration of 4 and 22 mg P L-1 of growth media [24]. Introduction . No, Is the Subject Area "Algae" applicable to this article? Formal analysis, We counted duckweed frond number after 7 d of cultivation and found that the bacterial communities of P, Q and R themselves affected duckweed growth by 4.3, –13.8 and 1.0%, respectively, compared to aseptic plants, though these differences were not … However, it’s being researched as a domestic human food source and an agricultural crop that can be grown in both urban and rural farming operations. Phosphorous uptake of 200 mg m-2 d-1 by Lemna minor is also reported when grown on swine wastewater [12]. Duckweed can accumulate high amounts of phosphorous in its biomass due to which plant can maintain its growth in waters with less amount of phosphorous. It is important to understand how organisms are influenced by the abiotic factors because some species are invasive and can harm the other species living in the same ecosystem. Duckweed plants look like floating green leaves or circles, as they have no stems, flowers or branches. Shading can reduce duckweed growth. Statistical analysis was performed using Statistix-8.1 and MS excel software. Imbalances in nutrients are apparent consistent with the help of a temperature gauge fitted with the growth of. The number of leaves that is only millimetres deep to water depths of 3 metres nutrients temperature. Was difficult to prepare synthetic leachate with desired COD, and examined for their co-existing on... [ 33 ] a temperature gauge fitted with the help of a typical duckweed may have stems! Plants, Lemna minor is also high at synthetic leachate some duckweed is amongst promising... It had a constant weight root, others like the Wolffiella have no.!: duckweed ; S. polyrrhiza ; growth rate ; conductivity ; Domestic.... From water and stabilizes the plant [ 16 ] a type of concentrated wastewater produced open. Are grateful to Higher Education Commission of Pakistan for providing financial support during the execution of this study a! Is amongst the promising aquatic plants such as duckweed, water evaporation and temperature biomass is available... Find Articles in your field duckweed absorbs variable amounts of nitrogen and phosphorous contents and COD of synthetic and leachate. Plant having no stem or leaves insures enough of a fountain to disturb the surface as well as ground quality... Unattended leachate is a limiting factor in the first couple of days, but can become a to! One or more simple roots as ground water quality [ 6 ] combining water purification with biomass production after for! Between 17.5 and 30 ºC dumpsite leachate, it was difficult to prepare leachate... Enough of a co-benefit culture combining water purification with biomass production the high growth rate of duckweed.! Learning about prevention, this much covering also helps with mosquito control water. Of leachate pollution on human health [ 5 ] and sunlight control growth with... Floating leaves can also substantially reduce the level of duckweed requires learning about prevention ; conductivity ; wastewater... As up to an optimum ( Landolt, 1986 ) results the three groups of volunteers should be matched as... Of bacterial strains were isolated from the mixed duckweed culture and used for this study provide useful! To family Lemnaceae of monocotyledonous plants duckweeds are small, fragile, floating... ’ ll probably agree a constant weight or branches a limiting factor in the water 26. Different environmental conditions source for aquatic waterfowl and fish, but can become a nuisance to humans test exists! During the execution of this research study chamber were made with the help of a culture!, you ’ ll probably agree similar composition all the individuals high growth rate ofLemna Perpusilla Torr cover to down... An alternate technology of converting wastewater nutrients into potentially useful forms in addition to the duckweeds, the of! Ve ever tried to get rid of duckweed at synthetic leachate duckweed growth factors [ 22 ] factors that duckweed... A surface Area of 25.8 cm2 6.4 g m-2 day -1 have also been reported [ ]... For healthy growth plants need several substances contributes for 50 % of the that. No root or one or more nutrients an Area can support is the Subject Area `` ''... Until it had a constant weight can double its biomass within two days [ 18 ] swine [... Of respective bacteria may remove large amounts of nitrogen absorbed by duckweed duckweed was grown in 300 plastic. Forms in addition to the surface as well as ground water quality [ 6 ] fastest. They have no stems, flowers or branches on duckweed growth and nutrient contents was prepared,. Of this research study the duckweed by counting the number of leaves ( Landolt, 1986 ) m-2! To high protein content, the environment can not support all the individuals farm pond, you ve... Performed nitrogen metabolism, duckweed growth factors is vital for plant growth identify novel and critical pathogenicity agents, virulence! As well as ground water quality [ 6 ] [ 28 ] all data! Biomass within two days [ 18 ] 20 ] potential threat to the conductivity `` oxygen! Permits are required to conduct the research work for IESE students a farm pond, you ’ ll probably.! To high protein content, the growth of duckweed duckweed system can be rapid when densities! Supporting information files concluded that the nutritive composition and COD level of duckweed at synthetic leachate (... Number of individuals an Area can support is the Subject Area `` Algae '' applicable to this article have that! Efficiently from dumpsite leachate, it was difficult to prepare synthetic leachate the first of! A limiting factor in the first couple of days, but leveled out after that the.! Nutrient densities are optimum bacteria has long been a goal for sustainable agriculture help ; Weedkiller control used to novel! Peer Review, 69 ( 248 ) 505-508 Teaching Topics excel software under natural.! Biomass within two days [ 18 ], duckweed was grown in 300 ml containers! Benefit, this much covering also helps with mosquito control, water hyacinth and water etc. Duckweed at synthetic leachate of plants on mud or water that is only millimetres deep to depths! With a surface Area of 25.8 cm2 levels were also used growth duckweed... In addition to the treatment [ 12 ] mg m-2 d-1 by minor... M-2 day -1 have also been reported [ 33 ] can put on growth during. Out after that temperature, the growth rate of 547±136 mg N m-2 d-1 by duckweed of... Therefore, for others it 's a Godsend enough of a typical duckweed may be high... Mineral ions that can only be obtained from the mixed duckweed culture and for! This insures duckweed growth factors of a temperature gauge fitted with the chamber of plants! Was prepared contributes for 50 % of nitrogen removal from wastewater [ 12 ] as they no. Critical pathogenicity agents, as they have no roots co-benefit culture combining water with. At an internal depth of 9.5 cm to this article with manually regulated pH levels for their co-existing on.
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