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Sample records for wolffia arrhiza lemnaceae

  1. The Flower Structure and Anther Dehiscence of Wolffia arrhiza (Lemnaceae

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    Chang-Sheng Kuoh

    2000-03-01

    Full Text Available Light and electron microscopic studies were undertaken on the flower structure and anther dehiscence of Wolffia arrhiza L. The anthesis is protogynous. The pistil and the stamen were located in dorsal flower cavity and the pistil protrude first. The inner structure of the pistil and the stamen described with special notes on the anther dehiscence line and the septal cells. The pistil is comprised of a concave stigma, a style and a unilocular ovary with one orthotropous ovule. The bitegumic ovule is covered with a secretary substance within the ovary. The stamen has a filament and bilobed monothecous anther. The tannin body in the stomial cells as well as stigma and style may act as a deterrent. Meanwhile, the uneven thickening of the septal walls and the massive central vacuole of the septal cells probably aid the dehiscence of the anther sac.

  2. Biochemical activity of auxins in dependence of their structures in Wolffia arrhiza (L. Wimm.

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    Romuald Czerpak

    2011-01-01

    Full Text Available Wolffia arrhiza (L. Wimm. (Lemnaceae as a mixotrophic plant reacts considerably weaker to used auxins with different chemical structures than typical photosynthetic vascular plants and algae especially from Chlorophyta. Among used auxin compounds, the highest stimulative activity on W. arrhiza growth and biochemical parameters which were analysed in biomass, can be attributed to phenylacetic acid (PAA, a somewhat smaller to indole-3-acetic acid (IAA and the smallest to 2-naphthaleneacetic acid (NAA used in optimal concentration of 10-6 M, in comparison with the control culture, devoid of exogenous auxins. The investigated auxins, especially PAA and IAA, were found to have the most powerful stimulative activity (prevailingly between the 10th and the 15th day of cultivation on the content of reducing sugars between 127 and 169%, chlorophyll a and b from 117 to 125%, total carotenoids from 115 to 132% and net photosynthetic rate from 127 to 144% in comparison with the control culture, which was treated as 100% for reference. However, the content of water-soluble proteins as well as nucleic acids (DNA and RNA in the biomass of W. arrhiza was less effectively stimulated, hardly from 110 to 116% when compared to the control culture (100%.

  3. Lemnaceae

    NARCIS (Netherlands)

    Plas, van der F.

    1972-01-01

    Monoecious, very rarely dioecious, small to minute aquatic annuals, floating at the surface of the water, or floating just below the surface whereby only a very small part of the frond is exposed to the air, or completely submerged and then rising to the surface in the flowering period. Fronds

  4. Comparative phytotoxicity of methylated and inorganic arsenic- and antimony species to Lemna minor, Wolffia arrhiza and Selenastrum capricornutum

    NARCIS (Netherlands)

    Duester, L.; van der Geest, H.G.; Moelleken, S.; Hirner, A.V.; Kueppers, K.

    2011-01-01

    The alkylation of metalloids through the transfer of methyl groups is an important factor in the biogeochemical cycling of elements like arsenic and antimony. In the environment, many different organic and inorganic forms of these elements can therefore be found in soils, sediments or organisms.

  5. Uptake and partitioning of zinc in Lemnaceae.

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    Lahive, Elma; O'Callaghan, Michael J A; Jansen, Marcel A K; O'Halloran, John

    2011-11-01

    Macrophytes provide food and shelter for aquatic invertebrates and fish, while also acting as reservoirs for nutrients and trace elements. Zinc accumulation has been reported for various Lemnaceae species. However, comparative accumulation across species and the link between zinc accumulation and toxicity are poorly understood. Morphological distribution and cellular storage, in either bound or soluble form, are important for zinc tolerance. This study shows differences in the uptake and accumulation of zinc by three duckweed species. Landoltia punctata and Lemna minor generally accumulated more zinc than Lemna gibba. L. minor, but not L. gibba or L. punctata, accumulated greater concentrations of zinc in roots compared to fronds when exposed to high levels of zinc. The proportion of zinc stored in the bound form relative to the soluble-form was higher in L. minor. L. punctata accumulated greater concentrations of zinc in fronds compared to roots and increased the proportion of zinc it stored in the soluble form, when exposed to high zinc levels. L. gibba is the only species that significantly accumulated zinc at low concentrations, and was zinc-sensitive. Overall, internal zinc concentrations showed no consistent correlation with toxic effect. We conclude that relationships between zinc toxicity and uptake and accumulation are species specific reflecting, among others, zinc distribution and storage. Differences in zinc distribution and storage are also likely to have implications for zinc bioavailability and trophic mobility.

  6. DNA barcoding of the Lemnaceae, a family of aquatic monocots

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    Wang Wenqin

    2010-09-01

    Full Text Available Abstract Background Members of the aquatic monocot family Lemnaceae (commonly called duckweeds represent the smallest and fastest growing flowering plants. Their highly reduced morphology and infrequent flowering result in a dearth of characters for distinguishing between the nearly 38 species that exhibit these tiny, closely-related and often morphologically similar features within the same family of plants. Results We developed a simple and rapid DNA-based molecular identification system for the Lemnaceae based on sequence polymorphisms. We compared the barcoding potential of the seven plastid-markers proposed by the CBOL (Consortium for the Barcode of Life plant-working group to discriminate species within the land plants in 97 accessions representing 31 species from the family of Lemnaceae. A Lemnaceae-specific set of PCR and sequencing primers were designed for four plastid coding genes (rpoB, rpoC1, rbcL and matK and three noncoding spacers (atpF-atpH, psbK-psbI and trnH-psbA based on the Lemna minor chloroplast genome sequence. We assessed the ease of amplification and sequencing for these markers, examined the extent of the barcoding gap between intra- and inter-specific variation by pairwise distances, evaluated successful identifications based on direct sequence comparison of the "best close match" and the construction of a phylogenetic tree. Conclusions Based on its reliable amplification, straightforward sequence alignment, and rates of DNA variation between species and within species, we propose that the atpF-atpH noncoding spacer could serve as a universal DNA barcoding marker for species-level identification of duckweeds.

  7. Elemental mapping of As and other elements in rootless duckweed Wolffia globosa

    International Nuclear Information System (INIS)

    Zhang Xin; Chen Baodong; Luo Lei; Huang Qing; Zhu Yongguan

    2010-01-01

    Distribution of arsenic and the relationship with other elements in aquatic macrophytes Wolffia globosa is helpful in understanding mechanisms of arsenic accumulation and detoxification, which will be important for arsenic phytofiltration in contaminated water by aquatic macrophytes. In this paper, we study the distribution features of As and seven more elements in rootless duckweed Wolffia globosa by means of μXRF. The results indicated that the distribution of As was similar to that of K, Mn and Zn while differs from that of Cu, Fe, Ni and Ca. (authors)

  8. Cadmium accumulation in the rootless macrophyte Wolffia globosa and its potential for phytoremediation.

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    Xie, Wan-Ying; Huang, Qing; Li, Gang; Rensing, Christopher; Zhu, Yong-Guan

    2013-01-01

    Cadmium (Cd) pollution around the world is a serious issue demanding acceptable solutions, one of which is phytoremediation that is both cost-effective and eco-friendly. Removal of Cd from contaminated water using plants with high growth rates and sufficient Cd accumulation abilities could be an appropriate choice. Here, we investigated a potential Cd accumulator, Wolffia, a rootless duckweed with high growth rate. Cd uptake, accumulation, tolerance, and phytofiltration ability by Wolffia globosa were examined. Furthermore, the effects of arsenic (As) on Cd uptake and phytofiltration by W. globosa were also studied. Cd uptake kinetics showed a linear pattern and a hyperbolic pattern without a plateau in lower (0-2 microM) and higher (0-200 microM) Cd concentration ranges, respectively, suggesting rapid Cd uptake by W. globosa Cd accumulation ability by W. globosa was higher at Cd concentrations 10 microM. All the five species of Wolffia exposed to I microM Cd for 5 days accumulated > 500 mg Cd kg(-1) DW. Ten gram fresh W. globosa could diminish almost all the Cd (2 microM) in a 200 mL solution. This enormous accumulation ability was mostly due to passive adsorption of Cd by the apoplast. Arsenic had no significant effect on Cd uptake and phytofiltration. The fresh fronds also showed a great As extracting ability. The results indicated that Wolffia is a strong Cd accumulator and has great Cd phytoremediation potential. Therefore, this plant can be used in fresh aquatic environments co-contaminated by low-levels of Cd and As.

  9. Phytochelatins play a key role in arsenic accumulation and tolerance in the aquatic macrophyte Wolffia globosa

    International Nuclear Information System (INIS)

    Zhang Xin; Uroic, M. Kalle; Xie Wanying; Zhu Yongguan; Chen Baodong; McGrath, Steve P.; Feldmann, Jörg; Zhao Fangjie

    2012-01-01

    The rootless duckweed Wolffia globosa can accumulate and tolerate relatively large amounts of arsenic (As); however, the underlying mechanisms were unknown. W. globosa was exposed to different concentrations of arsenate with or without L-buthionine sulphoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. Free thiol compounds and As(III)–thiol complexes were identified and quantified using HPLC – high resolution ICP-MS – accurate mass ESI-MS. Without BSO, 74% of the As accumulated in the duckweed was complexed with phytochelatins (PCs), with As(III)–PC 4 and As(III)–PC 3 being the main species. BSO was taken up by the duckweed and partly deaminated. The BSO treatment completely suppressed the synthesis of PCs and the formation of As(III)–PC complexes, and also inhibited the reduction of arsenate to arsenite. BSO markedly decreased both As accumulation and As tolerance in W. globosa. The results demonstrate an important role of PCs in detoxifying As and enabling As accumulation in W. globosa. - Highlights: ► W. globosa can accumulate and tolerate relatively large amounts of arsenic. ► Majority of the As accumulated in W. globosa was complexed with phytochelatins (PCs). ► As(III)–PC 4 and As(III)–PC 3 are the main complex species. ► Complexation of arsenite with phytochelatins plays a key role in As tolerance and accumulation. - Complexation of arsenite with phytochelatins plays a key role in both arsenic tolerance and accumulation in the aquatic macrophyte Wolffia globosa.

  10. Efecto del fotoperiodo en la remoción de plomo por Lemna gibba L. (Lemnaceae

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    Guadalupe Miranda

    2015-08-01

    Full Text Available El plomo llega a las aguas provenientes de las industrias de baterías, soldaduras, pinturas, etc. causando daños a los seres vivos, por lo que es necesario promover el desarrollo de tecnologías que ayuden a mejorar la calidad de los efluentes y que al mismo tiempo sean adecuadas al contexto socioeconómico del país. En este trabajo se plantea el uso de una angiosperma acuática, la especieLemna gibbade la familia Lemnaceae que tiene un crecimiento exponencial y su cultivo es fácil en laboratorio. Para absorber el plomo (PbNO32 se prepararon cinco concentraciones, a nivel de bioensayo en el laboratorio y bajo el efecto de dos diferentes condiciones de fotoperiodo (luz continua y 12 h luz/12 h oscuridad durante cuatro días, ya que a partir de este día libera el Pb al medio. Los resultados indican que en las dos concentraciones de Pb más bajas (30 y 50 mgl-1, el fotoperiodo 12/12 es más favorable para su absorción (9405 µgl-1más y 18,895 µgl-1 más respectivamente mientras que en las tres restantes (100, 200 y 300 mgl-1 lo fue la condición de luz continua. (6600 µgl-1, 1949 µgl-1, 5587 µgl-1 más respectivamente. Los conocimientos que se derivan de este estudio, permiten optimizar el uso deL. gibbaen el tratamiento terciario de aguas residuales.

  11. The different response mechanisms of Wolffia globosa: Light-induced silver nanoparticle toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Xiaoyan; Li, Penghui [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Huang, Qing [Key Laboratory of Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Zhang, Hongwu, E-mail: hwzhang@iue.ac.cn [Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen (China); Ningbo Research Center for Urban Environment, Chinese Academy of Sciences, Ningbo (China)

    2016-07-15

    Highlights: • The different physiological responses of AgNPs in Wolffia golbosa were studied. • Effects of AgNPs on W. golbosa relied on the illumination conditions. • Different phytotoxic mechanisms of AgNPs for different light schemes were proposed. - Abstract: Silver nanoparticles (AgNPs) have emerged as a promising bactericide. Plants are a major point of entry of contaminants into trophic chains. Here, the physiological responses of Wolffia globosa to AgNPs have been probed using different light schemes, and these data may reveal new insights into the toxic mechanism of AgNPs. W. globosa was grown in culture medium and treated with different concentrations of AgNPs for 24 h under pre- and post-illuminated conditions. However, fluorescence quenching, the accumulation of sugar and the reduction of Hill reaction activity were found in response to the AgNP-stresses. In the pre-illuminated condition, oxidative damage was obvious, as indicated by the higher malondialdehyde (MDA) content and an up-regulation of superoxide dismutase (SOD) activity. The maximum increases of MDA content and SOD activity were 1.14 and 2.52 times the respective controls when exposed to 10 mg/L AgNPs. In contrast, in the post-illuminated condition, the alterations in photosynthetic pigment and soluble proteins content were more significant than the alterations in oxidative stress. The contents of chlorophyll a, carotenoids and soluble protein decreased to 77.7%, 66.2% and 72.9% of the controls after treatment with the highest concentration of AgNPs (10 mg/L). Based on the different physiological responses, we speculated that in the pre-illuminated condition, oxidative stress was responsible for the decline in the oxygen evolution rate, while in the post-illuminated condition, the decrease in the Hill reaction activity could be attributed to the blocking of electron transfer and an insufficient proton supply. Our findings demonstrate that environmental factors regulate the

  12. The different response mechanisms of Wolffia globosa: Light-induced silver nanoparticle toxicity

    International Nuclear Information System (INIS)

    Zou, Xiaoyan; Li, Penghui; Huang, Qing; Zhang, Hongwu

    2016-01-01

    Highlights: • The different physiological responses of AgNPs in Wolffia golbosa were studied. • Effects of AgNPs on W. golbosa relied on the illumination conditions. • Different phytotoxic mechanisms of AgNPs for different light schemes were proposed. - Abstract: Silver nanoparticles (AgNPs) have emerged as a promising bactericide. Plants are a major point of entry of contaminants into trophic chains. Here, the physiological responses of Wolffia globosa to AgNPs have been probed using different light schemes, and these data may reveal new insights into the toxic mechanism of AgNPs. W. globosa was grown in culture medium and treated with different concentrations of AgNPs for 24 h under pre- and post-illuminated conditions. However, fluorescence quenching, the accumulation of sugar and the reduction of Hill reaction activity were found in response to the AgNP-stresses. In the pre-illuminated condition, oxidative damage was obvious, as indicated by the higher malondialdehyde (MDA) content and an up-regulation of superoxide dismutase (SOD) activity. The maximum increases of MDA content and SOD activity were 1.14 and 2.52 times the respective controls when exposed to 10 mg/L AgNPs. In contrast, in the post-illuminated condition, the alterations in photosynthetic pigment and soluble proteins content were more significant than the alterations in oxidative stress. The contents of chlorophyll a, carotenoids and soluble protein decreased to 77.7%, 66.2% and 72.9% of the controls after treatment with the highest concentration of AgNPs (10 mg/L). Based on the different physiological responses, we speculated that in the pre-illuminated condition, oxidative stress was responsible for the decline in the oxygen evolution rate, while in the post-illuminated condition, the decrease in the Hill reaction activity could be attributed to the blocking of electron transfer and an insufficient proton supply. Our findings demonstrate that environmental factors regulate the

  13. Caracterización molecular por patrones electroforéticos de isoenzimas esterasas en Lemna aequinoctialis y Lemna valdiviana (lemnaceae de Costa Rica (ING

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    Sharon Jiménez Delgado

    2016-03-01

    Full Text Available The Lemnaceae family lacks morphologic and anatomical characteristics with comparative aims and for that reason the molecular studies has been necessary a differentiation. In Costa Rica there are two species of Lemna: Lemna aequinoctialis and Lemna valdiviana. With the objective of a molecular characterization and differentiation of both species were extracted isoenzymes esterases. The study was carried out in the Molecular Genetics Laboratory of the School of Biological Sciences at Universidad Nacional, Heredia, Costa Rica. The technical electrophoresis in gel of polyacrylamida SDS-PAGE was used. It was difference in the pattern of isoenzymes between both species. According to previous molecular studies based on morphology and anatomy, flavonoides, isoenzymes, and DNA sequences of certain genes both species are very different; in addition they belong to different monophyletics groups. On the other hand, the importance of this molecular characterization is its possible use in water treatment, because the esterases have had important in the bioremediation. Also, species of the Lemnaceae family are used in the water treatment like bioremediation.

  14. A Comparison of growth on mercuric chloride for three Lemnaceae species reveals differences in growth dynamics that effect their suitability for use in either monitoring or remediating ecosystems contaminated with mercury.

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    Yang, Jingjing; Li, Gaojie; Bishopp, Anthony; Heenatigala, P. P. M.; Hu, Shiqi; Chen, Yan; Wu, Zhigang; Kumar, Sunjeet; Duan, Pengfei; Yao, Lunguang; Hou, Hongwei

    2018-04-01

    Mercury (Hg) is a toxic heavy metal that can alter the ecological balance when it contaminates aquatic ecosystems. Previously, researchers have used various Lemnaceae species either to monitor and/or remove heavy metals from freshwater systems. As Hg contamination is a pressing issue for aquatic systems worldwide, we assessed its impact on the growth of three commonly species of Lemnaceae - Lemna gibba 6745, Lemna minor 6580 and Spirodela polyrhiza 5543. We exposed plants to different concentrations of mercuric chloride (HgCl2) and monitored their growth, including relative growth rate, frond number, and fresh weight. These data were coupled with measurements of starch content, levels of photosynthetic pigment and the activities of antioxidant substances. The growth of all three lines showed significant negative correlations with Hg concentrations, and starch content, photosynthetic pigment, soluble protein and antioxidant enzymes levels were all clearly affected. Our results indicate that the L. gibba line used in this study was the most suitable of the three for biomonitoring of water contaminated with Hg. Accumulation of Hg was highest in the S. polyrhiza line with a bioconcentration factor over 1000, making this line the most suitable of the three tested for use in an Hg bioremediation system.

  15. A Comparison of Growth on Mercuric Chloride for Three Lemnaceae Species Reveals Differences in Growth Dynamics That Effect Their Suitability for Use in Either Monitoring or Remediating Ecosystems Contaminated With Mercury

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    Jingjing Yang

    2018-04-01

    Full Text Available Mercury (Hg is a toxic heavy metal that can alter the ecological balance when it contaminates aquatic ecosystems. Previously, researchers have used various Lemnaceae species either to monitor and/or remove heavy metals from freshwater systems. As Hg contamination is a pressing issue for aquatic systems worldwide, we assessed its impact on the growth of three commonly species of Lemnaceae- Lemna gibba 6745, Lemna minor 6580 and Spirodela polyrhiza 5543. We exposed plants to different concentrations of mercuric chloride (HgCl2 and monitored their growth, including relative growth rate, frond number (FN, and fresh weight (FW. These data were coupled with measurements of starch content, levels of photosynthetic pigment and the activities of antioxidant substances. The growth of all three lines showed significant negative correlations with Hg concentrations, and starch content, photosynthetic pigment, soluble protein and antioxidant enzymes levels were all clearly affected. Our results indicate that the L. gibba line used in this study was the most suitable of the three for biomonitoring of water contaminated with Hg. Accumulation of Hg was highest in the S. polyrhiza line with a bioconcentration factor over 1,000, making this line the most suitable of the three tested for use in an Hg bioremediation system.

  16. Diferenciación molecular de Lemna aequinoctialis y L. Valdiviana (lemnaceae por patrones proteicos

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    Mª del Milagro Montero Rojas

    2016-03-01

    Full Text Available El estudio se llevó a cabo en el Laboratorio de Genética Molecular de la Universidad Nacional, Heredia, Costa Rica. Se utilizaron plantas acuáticas macrófitas de Lemna valdiviana y L. aequinoctialis previamente identificadas. Estas especies habitan en aguas ricas en sales disueltas y aguas servidas. Recientemente se les consideró como un indicador de la contaminación ocasionada por pesticidas y herbicidas en el agua. La composición proteica llega a niveles entre 38 y 43% de materia seca, importante para diversos usos. La extracción de proteínas totales, por medio de electroforesis discontinua en gel de poliacrilamida, se realizó en condiciones reductoras con SDS (SDS-PAGE. Los geles separadores empleados fueron al 8 y 10%, gel espaciador al 4% y la tinción se efectuó con azul commassie. Los diversos patrones proteicos reflejaron diferencias genéticas entre ambas especies que se pueden deber a las diferencias de hábitat y de reproducción.

  17. 不同种类浮萍对磷的去除及其体内磷的累积变化研究%Study of Different Kinds of Duckweed in Different Low Concentration of Orthophosphate Culture Conditions on Phosphorus Removal and Float body Phosphorus Accumulation Change

    Institute of Scientific and Technical Information of China (English)

    叶平平; 金杰; 侍远

    2012-01-01

    Taking three common duckweed in the Chaohu Lake basin--Spirodela polyrrhiza, Lemna paucico- stata and wolffia arrhiza as the objects,this article studies the phosphorus removal function the three kinds of duckweed when the water is within the surface water concentration range (0.01 mgP/L,0. 05 mgP/L,0. 1 mgP/L,0.2 mgP/L,0.5 mgP/L),and also analyzes the accumulation change of phosphorus in three kinds of duckweed. Moreover, it discusses the treatment of phosphorus wastewater system on remove phosphorus way, and provides theoretical basis for duckweed in Chaohu Lake basin dephosphorization ecological restora- tion. The experimental results show that the plant body on phosphorus direct absorption is one of the main mechanisms for clean--up effect; three kinds of duckweed respectviely have high removal efficiency, and phosphorus removal rate is Spirodela polyrrhiza 〉 Lemna paucicostata 〉 wolffia arrhiza, and three float right utilization rate increase as the concentration reduce;the phosphorus removal rate of Spirodela polyrrhiza is 60% -48.9%,Lemna paucicostata is 90% - 47.2%,wolffia arrhiza is 90% - 34.2%. The phosphorus absorption of three duckweed basically account for more than 70% of the remove function. And there are differences among different varieties and different phosphorus concentration.%以巢湖流域常见的3种浮萍——紫背浮萍(以下称紫萍)、稀脉浮萍萍和芜萍为对象,研究了三种浮萍对地表水浓度范围内(0.01mgP/L,0.05mgP/L,0.1mgP/L,0.2mgP/L,0.5mgP/L)的磷的去除作用,以及磷在三种浮萍体内的积累变化和三种浮萍对磷的吸收作用占总去除作用。探讨了浮萍处理含磷污水系统的去除磷途径。实验表明:植物体对磷的直接吸收是其净化作用的主要机制之一。三种浮萍对磷都有较高的去除效率。并且磷去除率紫萍〉稀脉浮萍〉芜萍,并且随浓度的降低而增加。三种浮萍对磷的利用

  18. Aquatic food production modules in bioregenerative life support systems based on higher plants

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    Bluem, V.; Paris, F.

    Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity.

  19. Ensaios sobre a metodologia do estudo da influência de três herbicidas em Spirodela punctata (G.F.W. Meyer Thompson (Lemnaceae

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    Durvalina Maria Mathias dos Santos

    1988-01-01

    Full Text Available O presente trabalho visa conhecer a taxa de multiplicação e o índice de mortalidade de S. punctata a diversas concentrações do butaclora, propanila e glifosato bem como comparar dois métodos diferentes de investigações (ensaio 1 e 2. Os dados indicaram que no ensaio 1 as concentrações foram pouco tóxicas provocando baixos índices de mortalidade embora tenha ocorrido inibição do crescimento nas concentrações mais fortes. O ensaio 2 mostrou que a butaclora e a propanila são mais tóxicas que o glifosato, com valores de mortalidade de 100% em apenas 48 horas. A taxa de multiplicação, neste ensaio, somente foi determinada para o glifosato, pois os demais herbicidas foram altamente tóxicos para a espécie. Verificou-se, na comparação dos dois métodos diferentes, que os recipientes utilizados no ensaio 2 foram mais adequados ao cultivo da espécie e que os efeitos tóxicos devem ser observados em frondes consideradas individualmente e não em plantas inteiras.The present work looks for a knowledge of multiplícate rate and mortality index of. S. punctata to several concentrations of butachlor, propanil and gliphosate as well as to compare two different methods. On essay 1 the concentrations were a little toxic provoking low index of mortality in spite of it has occured inhibition of increasing on stronger concentrations. The essay 2 showed what, the butachlor and the propanil are more toxics than the gliphosate, with values of mortality of 100% in only 48 hours. The multiplícate rate, on this essay, was only determinated to the gliphosate, because the other herbicides were highly toxic to the species. It was checked on the comparation of the two different methods the posts used on essay 2 were more appropriate to the cultive specie and the toxic effects must be observated on considered individualy and not on whole plants.

  20. Investigations on photosynthetic pigments of Lemnaceae, pt. 14: The effect of UV-B radiation on deetiolating and autotrophically growing plants of Lemna gibba L

    International Nuclear Information System (INIS)

    Wejnar, R.; Döhler, D.

    1992-01-01

    In deetiolating plants of Lemma gibba L., the biosynthesis of photosynthetically active pigments (chlorophyll a and b, beta-carotene, lutein, violaxanthin and neoxanthin) was reduced by UV-B radiation (2,5 W cnt * m -2 ) in dependence on the exposure time (8-96-h). The biosynthesis of chlorophyll b was more inhibited than that of chlorophyll a, that of the chlorophylls more than that of the carotenoids and that of beta-carotene more than that of the xanthophylls notably lutein. In autotrophic plants. UV-B radiation (42, 72 and 120 h) causes a strong reduction of the pigment content. The alteration of the ratios between the pigments was the same as in deetiolating plants. In deetiolating as well as in autotropically cultivated plants of Lemma gibba, the termination of the UV-B radiation is followed by an approach to the original ratios

  1. Novel laboratory approaches to multi-purpose aquatic bioregenerative closed-loop food production systems

    Science.gov (United States)

    Blüm, V.; Andriske, M.; Kreuzberg, K.; Paassen, U.; Schreibman, M. P.; Voeste, D.

    Based on the construction principle of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) two novel combined animal-plant production systems were developed in laboratory scale the first of which is dedicated to mid-term operation in closed state up to two years. In principle both consist of the "classic" C.E.B.A.S. subcomponents: animal tank (Zoological Component), plant cultivators (Botanical Component), ammonia converting bacteria filter (Microbial Component) and data acquisition/control unit (Electronical Component). The innovative approach in the first system is the utilization of minimally three aquatic plant cultivators for different species. In this one the animal tank has a volume of about 160 liters and is constructed as an "endless-way system" surronding a central unit containing the heat exchanger and the bacteria filter with volumes of about 1.5 liters each. A suspension plant cultivator (1 liter) for the edible duckweed Wolffia arrhiza is externally connected. The second plant cultivator is a meandric microalgal bioreactor for filamentous green algae. The third plant growth facilitiy is a chamber with about 2.5 liters volume for cultivation of the "traditional" C.E.B.A.S. plant species, the rootless buoyant Ceratophyllum demersum. Both latter units are illuminated with 9 W fluorescent lamps. In the current experiment the animal tank contains the live-bearing teleost fish Xiphophorus helleri and the small pulmonate water snail Biomphalaria glabrata because their physiological adaptation to the closed system conditions is well known from many previous C.E.B.A.S. experiments. The water temperature is maintained at 25 °C and the oxygen level is regulated between 4 and 7 mg/1 by switching on and off the plant cultivator illuminations according to a suitable pattern thus utilizing solely the oxygen produced by photosynthesis. The animals and the micoorganisms of filter and bioflim provide the plants with a sufficient amount of carbon dioxide

  2. Reúso de água e polimento de efluentes de lagoas de estabilização por meio de cultivo consorciado de plantas da família Lemnaceae e tilápias

    OpenAIRE

    Tavares, Flávia de Almeida

    2008-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Ambiental. Recentemente, o interesse na utilização de lemnáceas no polimento de lagoas de estabilização é decorrente da alta remoção de nutrientes e algas que ocorre nesses sistemas, além da biomassa gerada ser rica em proteína. O presente estudo foi composto de três experimentos realizados na Estação de Tratamento de Esgotos da CASAN - Florianópolis. Os dois primeiros for...

  3. Aquatic modules for bioregenerative life support systems based on the C.E.B.A.S. biotechnology

    Science.gov (United States)

    Bluem, Volker; Paris, Frank

    2001-03-01

    working hypothesis was verified that aquatic organisms are nearly not affected at all by space conditions, i . e. that the plants exhibited biomass production rates identical to the ground controls and that as well the reproductive, and the immune system as the the embryonic and ontogenic development of the animals remained undisturbed. Currently the C.E.B.A.S. MINI MODLULE is prepared for a third spaceshuttle fligt (STS-107) in spring 2001. Based on the results of the space experiments a series of prototypes of aquatic food production modules for the implementation into BLSS were developed. This paper describes the scientific disposition of the STS-107 experiments and of open and closed aquaculture systems based on another aquatic plant species, the Lemnacean Wolffia arrhiza which is cultured as a vegetable in Southeastern Asia. This plant can be grown in suspension culture and several special bioreactors were developed for this purpose. W. arrhiza reproduces mainly vegetatively by buds but also sexually from time to time and is therefore especially suitable for genetic engineering, too. Therefore it was used, in addition, to optimize the C.E.B.A.S. MINI MODULE to allow experiments with a duration of 4 month in the International Space Station the basic principle of which will be explained. In the context of aquaculture systems for BLSS the continuous replacement of removed fish biomass is an essential demand. Although fish reproduction seems not to be affected in the short-term space experiments with the C.E.B.A.S. MIMI MODULE a functional and reliable hatchery for the production of siblings under reduced weightlessness is connected with some serious problems. Therefore an automated "reproduction module" for the herbivorous fish Tilapia rendalli was developed as a laboratory prototype. It is concluded that aquatic modules of different degrees of complexity can optimize the productivity of BLSS based on higher land plants and that they offer an unique opportunity for the

  4. 太湖地区高效除氮浮萍品种的筛选及其除氮机理的初步研究%Screening Duckweed(Lemnaceae)Species for Efficient Removal of Water-Body's Nitrogen in the Tai Lake Region and Preliminary Study on Nitrogen Removal Mechanism

    Institute of Scientific and Technical Information of China (English)

    周影茹; 袁晓燕; 王俊儒; 包涛芳; 施卫明

    2010-01-01

    农业面源污染是引起太湖水体富营养化的重要因素,而植物生态工程技术在面源污染的治理中起到了很大的作用.本文调查和收集了太湖地区13个稻田浮萍种质资源,研究了不同浮萍品种对低浓度稻田排水中氮(N)素的去除效果及其初步除N机理.结果表明,在实验营养条件下,4种浮萍品种中紫背浮萍(Spirodela polyrrhiza)具有最高的N去除效率,其次是少根紫萍(Spirodela oligorrhiza)或稀脉浮萍(Lemna perpusilla),而除N效果最低的品种是青萍(Lemna minor).供试材料对水体中总N的去除率范围为57.3%~85.2%,其中紫背浮萍HZ1具有最高的去除效果,15天后总N去除率可达到85%,青萍WX3去除效果最低,15天后去除率仅为57%.两个浮萍品种进行比较发现,HZ1生物量增长速度慢,鲜重和干重平均倍增时间分别为7.96天和7.82天,而WX3的鲜重和干重倍增时间分别为5.20天和4.73天.另一方面,HZ1和WX3的含N量分别为4.9%和5.7%.由此可以推知,紫背浮萍HZ1高效除N的主要机理不是通过生物体吸收,而更可能是微生物或化学作用共同引起.

  5. A simple method for analysing the effects of algae on the growth of Lemna and preventing algal growth in duckweed bioassays

    NARCIS (Netherlands)

    Szabo, S.; Roijackers, R.M.M.; Scheffer, M.

    2003-01-01

    A simple novel method for indoor culture experiments with small floating water plants, such as Lemnaceae, is described. Experiments demonstrate that the method allows for longer lasting culture experiments with Lemna, avoiding algal growth and self-shading of fronds by overcrowding. This is achieved

  6. Characterization of indole acetic acid endophyte producers in ...

    African Journals Online (AJOL)

    This work contributes to the knowledge of the phytobacteria diversity in aquatic plants, particularly in Lemnaceae species; here the majority of the isolates have been characterized as higher indole acetic acid producers, recommended as candidates for their use as biofertilizers. Key words: Plant growth-promoting bacteria, ...

  7. The maximization of the productivity of aquatic plants for use in controlled ecological life support systems (CELSS)

    Science.gov (United States)

    Thompson, B. G.

    Lemna minor (common duckweed) and a Wolffia sp. were grown in submerged growth systems. Submerged growth increased the productivity/unit volume (P/UV) of the organisms and may allow these plants to be used in a controlled ecological life support system (CELSS).

  8. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Midwest Region (Version 2.0)

    Science.gov (United States)

    2010-08-01

    bladderwort (Utricularia macrorhiza), white water crowfoot (Ranunculus longirostris), and duckweeds ( Lemna , Spirodela, and Wolffia). As mentioned...units. Map units usually contain more than one soil type or component. They often contain several minor components or inclusions of soils with...bladderworts (Utricularia spp.), and duckweeds ( Lemna spp.) (Figure 37). ERDC/EL TR-10-16 87 Figure 37. Dried remains of water-lilies in a

  9. Biofuel Production: Considerations for USACE Civil Works Business Lines

    Science.gov (United States)

    2014-12-01

    feedstock for biofuel production has led to research whereby several genera of duckweed ( Lemna , Landoltia, Spirodela, Wolffia, Wolfiella) have been...as well as the general public when rendering its final permit decisions. Regulatory responsibilities include evaluating minor activities such as...reservoirs scattered along minor river systems in other parts of the United States (Kasul et al. 1998) Through a series of legislative acts in the

  10. Study of Plant Species Composition of Grasslands in Mugla Village Region (Western Rhodopes, South Bulgaria

    Directory of Open Access Journals (Sweden)

    Plamen S. Stoyanov

    2016-06-01

    Full Text Available The study presents data on the diversity of grass species in the region of the village of Mugla (the Western Rhodopes. One hundred forty-one species of higher plants belonging to 40families were registered. (Apiaceae, Aspleniaceae, Asteraceae, Boraginaceae, Brassicaceae,Campanulaceae, Caryophyllaceae, Cistaceae, Cyperaceae, Dipsacaceae, Equisetaceae, Ericaceae,Euphorbiaceae, Fabaceae, Gentianaceae, Geraniaceae, Gesneriaceae, Hypericaceae, Juncaceae,Lamiaceae, Lemnaceae, Liliaceae, Linaceae, Menyanthaceae, Oleacea, Onagraceae, Orchidaceae,Parnassiaceae, Plantaginaceae, Plumbaginaceae, Poaceae, Polygalaceae, Primulaceae,Ranunculaceae, Rosaceae, Rubiaceae, Saxifragaceae, Scrophulariaceae, Valerianaceae andViolaceae. Their conservation status was presented, as well as medicinal plants.

  11. Inhibition of flowering in the long-day plant Lemna gibba G3 by Hutner's medium and its reversal by salicyclic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, O [Smithsonian Institution Radiation Biology Lab., Rockville, MD; Cleland, C F; Hillman, W S

    1979-01-01

    Flowering in the long-day plant Lemna gibba L., strain G3 is poor or absent in Hutner's medium even under continuous light, an effect generally ascribed to the ammonium content of the medium. However, flowering is also inhibited in ammonium-free modifications of Hutner's medium, particularly in the presence of sucrose, but is restored to high levels by the presence of 10 ..mu..M salicylic acid. These results link two of the least understood chemical effects in Lemnaceae flowering, and they provide a system in which large effects of salicylic acid can be readily obtained.

  12. Preliminary study of Lake Pontchartrain and vicinity using remotely sensed data from the ERTS-A satellite

    Science.gov (United States)

    Hidalgo, J. U. (Principal Investigator); Smalley, A. E.; Faller, K. H.; Irvin, M. B.

    1973-01-01

    The author has identified the following significant results. During the summer of 1972, huge mats of duckweeds (Lemnaceae) appeared on Lake Pontchartrain, a shallow estuary in southeastern Louisiana. In color infrared photography, duckweeds show a characteristic light lavender color, unlike algal mats or water hyacinth, as observed in low level aerial photography. Although at least five species are present in the area, most water coverage is by Lemna minor and Spirodela oligorrhiza. ERTS-1 imagery shows many areas of bayous, swamps, and marginal waters of Lake Pontchartrain covered with duckweeds. Subsequent passes show a seasonal decreases in duckweeds.

  13. Efficient transformation and artificial miRNA gene silencing in Lemna minor.

    Science.gov (United States)

    Cantó-Pastor, A; Mollá-Morales, A; Ernst, E; Dahl, W; Zhai, J; Yan, Y; Meyers, B C; Shanklin, J; Martienssen, R

    2015-01-01

    Despite rapid doubling time, simple architecture and ease of metabolic labelling, a lack of genetic tools in the Lemnaceae (duckweed) has impeded the full implementation of this organism as a model for biological research. Here, we present technologies to facilitate high-throughput genetic studies in duckweed. We developed a fast and efficient method for producing Lemna minor stable transgenic fronds via Agrobacterium-mediated transformation and regeneration from tissue culture. Additionally, we engineered an artificial microRNA (amiRNA) gene silencing system. We identified a Lemna gibba endogenous miR166 precursor and used it as a backbone to produce amiRNAs. As a proof of concept we induced the silencing of CH42, a magnesium chelatase subunit, using our amiRNA platform. Expression of CH42 in transgenic L. minor fronds was significantly reduced, which resulted in reduction of chlorophyll pigmentation. The techniques presented here will enable tackling future challenges in the biology and biotechnology of Lemnaceae. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. A marriage of convenience; a simple food chain comprised of Lemna minor (L.) and Gammarus pulex (L.) to study the dietary transfer of zinc.

    Science.gov (United States)

    Lahive, E; O'Halloran, J; Jansen, M A K

    2015-01-01

    Macrophytes contribute significantly to the cycling of metals in aquatic systems, through accumulation during growth and release during herbivory or decomposition. Accumulation of high levels of metals has been extensively documented in Lemnaceae (duckweeds). However, the degree of trophic transfer of metals from Lemnaceae to secondary consumers remains poorly understood. This study demonstrates that zinc accumulated in Lemna minor is bioavailable to the herbivore consumer Gammarus pulex. Overall, the higher the zinc content of L. minor, the more zinc accumulated in G. pulex. Accumulation in G. pulex was such that mortality occurred when they were fed high zinc-containing L. minor. Yet, the percentage of consumed zinc retained by G. pulex actually decreased with higher zinc concentrations in L. minor. We hypothesise that this decrease reflects internal zinc metabolism, including a shift from soluble to covalently bound zinc in high zinc-containing L. minor. Consistently, relatively more zinc is lost through depuration when G. pulex is fed L. minor with high zinc content. The developed Lemna-Gammarus system is simple, easily manipulated, and sensitive enough for changes in plant zinc metabolism to be reflected in metal accumulation by the herbivore, and therefore suitable to study ecologically relevant metal cycling in aquatic ecosystems. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  15. Water ferns Azolla spp. (Azollaceae as new host plants for the small China-mark moth, Cataclysta lemnata (Linnaeus, 1758 (Lepidoptera, Crambidae, Acentropinae

    Directory of Open Access Journals (Sweden)

    Atousa Farahpour-Haghani

    2017-01-01

    Full Text Available Water ferns (Azolla spp., Azollaceae are reported for the first time as host plants for the larvae of the small China-mark moth Cataclysta lemnata (Linnaeus (Lepidoptera: Crambidae: Acentropinae in rice fields and waterways of northern Iran. Cataclysta lemnata is a semi-aquatic species that has been recorded to feed on Lemnaceae and a few other aquatic plants. However, it has not been reported before on Azolla spp. Larvae use water fern as food source and shelter and, at high population density in the laboratory, they completely wiped water fern from the water surface. Feeding was confirmed after rearing more than eight continual generations of C. lemnata on water fern in the laboratory. Adults obtained this way are darker and have darker fuscous markings in both sexes compared with specimens previously reported and the pattern remains unchanged after several generations.

  16. Identification and characterization of glycosyltransferases involved in the synthesis of the side chains of the cell wall pectic polysaccharide rhamnogalacturonan II

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, Malcolm [Univ. of Georgia, Athens, GA (United States)

    2015-08-31

    Our goal was to gain insight into the genes and proteins involved in the biosynthesis of rhamnogalacturonan II (RG-II), a borate cross-linked and structurally conserved pectic polysaccharide present in the primary cell walls of all vascular plants. The research conducted during the funding period established that (i) Avascular plants have the ability to synthesize UDP-apiose but lack the glycosyltransferase machinery required to synthesize RG-II or other apiose-containing cell wall glycans. (ii) RG-II structure is highly conserved in the Lemnaceae (duckweeds and relatives). However, the structures of other wall pectins and hemicellulose have changed substantial during the diversification of the Lemnaceae. This supports the notion that a precise structure of RG-II must be maintained to allow borate cross-linking to occur in a controlled manner. (iii) Enzymes involved in the conversion of UDP-GlcA to UDP-Api, UDP-Xyl, and UDP-Ara may have an important role in controlling the composition of duckweed cell walls. (iv) RG-II exists as the borate ester cross-linked dimer in the cell walls of soybean root hairs and roots. Thus, RG-II is present in the walls of plants cells that grow by tip or by expansive growth. (v) A reduction in RG-II cross-linking in the maize tls1 mutant, which lacks a borate channel protein, suggests that the growth defects observed in the mutant are, at least in part, due to defects in the cell wall.

  17. Morphological, Molecular Identification and Their Genetic Diversity of Aquatic Plant Duckweeds in Fujian Province%福建水生植物浮萍的形态学和分子系统学鉴定及遗传多样性研究

    Institute of Scientific and Technical Information of China (English)

    叶松建; 韩冰莹; 张家明

    2017-01-01

    119 duckweed germplasms were collected in 53 cities or countries in Fujian Province.They were classified into four genera:Landoltia,Spirodela,Wolffia,and Lemna using morphological analysis based on leaf size,root and leaf number.The chloroplast atpF-atpH internal sequence and the rpS16 intron sequence were obtained by PCR amplification and sequencing.Phylogenetic analysis indicated that these germplams belong to four species:Landoltia punctata,Spirodela polyrhiza,Wolffia globosa,and Lemna aequinoctialis.Genetic diversity analysis using DnaSP 5.10.01 software showed that germplasms had rich diversity,and rpS16 presented more diversity than atpF-atpH.The nucleotide diversity of atpF-atpH and rpS16 was 0.031 53 and 0.051 23,respectively;the distinct nucleotide number per kb was 20.374 and 44.675,respectively;the population mutation rate was 0.03640 and 0.051 64,respectively,and the haplotype diversity was 0.577 and 0.617,respectively.The haplotype numbers of atpF-atpH and rpS16 were 4,2,and 2,respectively.The genetic diversity in South Fujian was higher than that in North Fujian,and the nucleotide diversity,different nucleotide number and the population mutation rate of atpF-atpH in South Fujian were twice as high as those in the North.%在福建53个市县(区)收集获得119份浮萍种质.通过叶片大小、根系和叶脉数等形态性状初步鉴定为4个属:少根紫萍属(Landohia)、多根紫萍属(Spirodela)、无根萍属(Wolffia)、浮萍属(Lemna).利用叶绿体atpF-atpH间隔序列和rpS16内含子序列进行系统发育分析.结果表明,119份浮萍种质分别属于4个种Landoltia punctata,Spirodela polyrhiza,Wolffia globosa,Lemna aequinoctialis.利用DnaSP 5.10.01软件分析结果显示,福建浮萍种质存在丰富的遗传多样性,且rpS16比atp F-atpH多样性大,两者的核苷酸多态性指数分别为0.051 23和0.031 53,每kb平均核苷酸差异数为44.675和20.374,群体突变率分别为0.051 64和0.036 40,单倍

  18. Differences in the availabilities of cesium-134,137 and ruthenium-106 from a Chernobyl-contaminated soil to a water plant, duckweed, and to the terrestrial plants, bean and lettuce

    International Nuclear Information System (INIS)

    Polar, E.; Bayuelgen, N.

    1991-01-01

    The aqueous solubilities of some radionuclides present in a Chernobyl-contaminated soil and their subsequent availabilities to an aquatic plant, duckweed (Lemnaceae), were compared to those obtained for bean (Phaseolus vulgaris) and lettuce (Lactuca sativa). During this investigation carried out in laboratory conditions, it was observed that, although around 0.06% of 134 Cs or 137 Cs present in the soil was detected in the aqueous phase, duckweed concentrated 1000-5500 times this amount, depending on plant species. By contrast, 106 Ru in the soil was leached more effectively into solution than was cesium but its accumulation into duckweed was less. The effects on the availabilities of ruthenium and cesium of depletion of soil organic matter and of amendment of the aqueous phase with nutrients were also investigated. The transfer factors of 134,137 Cs into bean and lettuce cultivated in the same soil were 0.02 and 0.06, respectively, while that for 106 Ru was around 0.2. The difference between aquatic and terrestrial plants in cycling radionuclides is briefly discussed. (author)

  19. Differences in the availabilities of cesium-134,137 and ruthenium-106 from a Chernobyl-contaminated soil to a water plant, duckweed, and to the terrestrial plants, bean and lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Polar, E.; Bayuelgen, N. (Cekmece Nuclear Research and Training Center, Istanbul (Turkey))

    1991-01-01

    The aqueous solubilities of some radionuclides present in a Chernobyl-contaminated soil and their subsequent availabilities to an aquatic plant, duckweed (Lemnaceae), were compared to levels found in bean (Phaseolus vulgaris) and lettuce (Lactuca sativa). During this investigation carried out in laboratory conditions, it was observed that, although around 0.06% of {sup 134}Cs or {sup 137}Cs present in the soil was detected in the aqueous phase, duckweed concentrated 1000-5500 times this amount, depending on plant species. By contrast, {sup 106}Ru in the soil was leached more effectively into solution than was cesium but its accumulation into duckweed was less. The effects on the availabilities of ruthenium and cesium of depletion of soil organic matter and of amendment of the aqueous phase with nutrients were also investigated. The transfer factors of {sup 134,137}Cs into bean and lettuce cultivated in the same soil were 0.02 and 0.06, respectively, while that for {sup 106}Ru was around 0.2. The difference between aquatic and terrestrial plants in cycling radionuclides is briefly discussed. (author).

  20. Development of a New Marker System for Identification of Spirodela polyrhiza and Landoltia punctata

    Directory of Open Access Journals (Sweden)

    Bo Feng

    2017-01-01

    Full Text Available Lemnaceae (commonly called duckweed is an aquatic plant ideal for quantitative analysis in plant sciences. Several species of this family represent the smallest and fastest growing flowering plants. Different ecotypes of the same species vary in their biochemical and physiological properties. Thus, selecting of desirable ecotypes of a species is very important. Here, we developed a simple and rapid molecular identification system for Spirodela polyrhiza and Landoltia punctata based on the sequence polymorphism. First, several pairs of primers were designed and three markers were selected as good for identification. After PCR amplification, DNA fragments (the combination of three PCR products in different duckweeds were detected using capillary electrophoresis. The high-resolution capillary electrophoresis displayed high identity to the sequencing results. The combination of the PCR products containing several DNA fragments highly improved the identification frequency. These results indicate that this method is not only good for interspecies identification but also ideal for intraspecies distinguishing. Meanwhile, 11 haplotypes were found in both the S. polyrhiza and L. punctata ecotypes. The results suggest that this marker system is useful for large-scale identification of duckweed and for the screening of desirable ecotypes to improve the diverse usage in duckweed utilization.

  1. Sequential ethanol fermentation and anaerobic digestion increases bioenergy yields from duckweed.

    Science.gov (United States)

    Calicioglu, O; Brennan, R A

    2018-06-01

    The potential for improving bioenergy yields from duckweed, a fast-growing, simple, floating aquatic plant, was evaluated by subjecting the dried biomass directly to anaerobic digestion, or sequentially to ethanol fermentation and then anaerobic digestion, after evaporating ethanol from the fermentation broth. Bioethanol yields of 0.41 ± 0.03 g/g and 0.50 ± 0.01 g/g (glucose) were achieved for duckweed harvested from the Penn State Living-Filter (Lemna obscura) and Eco-Machine™ (Lemna minor/japonica and Wolffia columbiana), respectively. The highest biomethane yield, 390 ± 0.1 ml CH 4 /g volatile solids added, was achieved in a reactor containing fermented duckweed from the Living-Filter at a substrate-to-inoculum (S/I) ratio (i.e., duckweed to microorganism ratio) of 1.0. This value was 51.2% higher than the biomethane yield of a replicate reactor with raw (non-fermented) duckweed. The combined bioethanol-biomethane process yielded 70.4% more bioenergy from duckweed, than if anaerobic digestion had been run alone. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Biting midges (Diptera: Ceratopogonidae from Martín García Island, Argentina

    Directory of Open Access Journals (Sweden)

    María M Ronderos

    2011-09-01

    Full Text Available Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. Rev. Biol. Trop. 59 (3: 1183-1194. Epub 2011 September 01.

  3. Potential of some aquatic plants for removal of arsenic from wastewater by green technology

    Directory of Open Access Journals (Sweden)

    Mohammed Barznji Dana A.

    2015-03-01

    Full Text Available Phytoremediation or green technology is counted among the successful and effective biological contaminated water treatment techniques. Basically, the concept of this green, cost-effective, simple, environmentally nondisruptive method consists in using plants and microbiological processes to reduce contaminants in the ecosystem. Different species from aquatic plants (emerged, free-floating, and submerged have been studied to mitigate toxic contaminants such as arsenic, cadmium, chromium, copper, lead, mercury, zinc, etc. Arsenic is one of the most severe toxic elements; it is widely distributed in the environment, usually found in combination with chloride, oxygen, sulphur and metal ions as a result of mineral dissolution from sedimentary or volcanic rocks and the dilution of geothermal water. The effluents from both industrial and agricultural sectors are also regarded as sources to contaminate water. From the accumulation point of view, several aquatic plants have been mentioned as good arsenic accumulators and their performance is evaluated using the green technology method. These include Spirodela polyrhiza, Wolffia globosa, Lemna gibba, L. minor, Eichhornia crassipes, Azolla caroliniana, Azolla filiculoides, Azolla pinnata, Ceratophyllum demersum and Pistia stratiotes. The up-to-date information illustrated in this review paper generates knowledge about the ability of some common aquatic plants around the globe to remediate arsenic from contaminated water.

  4. SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: I. NUTRİENTLER

    Directory of Open Access Journals (Sweden)

    Murat Topal

    2012-08-01

    Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde nutrientlerin değişimleri araştırılmıştır. Çalışmada, NH4+-N, NO2--N, NO3—N ve O-PO43- konsantrasyonları tespit edilmiştir. Deneysel çalışmalar 2 farklı derinlikte (5 ve 10 cm ve farklı hidrolik bekletme sürelerinde gerçekleştirilmiştir. En yüksek NH4+-N giderim verimi (%75,3, 5 cm derinlikteki reaktörde 9. günde tespit edilmiştir. NO2- -N ve NO3- -N konsantrasyonlarında herhangi bir giderim olmadığı gözlenmiştir. En yüksek O-PO43- giderim verimi 5 cm derinlikteki reaktörde %44,6 olarak tespit edilmiştir.

  5. SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: II. DİĞER PARAMETRELER

    Directory of Open Access Journals (Sweden)

    Murat Topal

    2012-08-01

    Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde KOİ, pH ve elektriksel iletkenlik değişimleri araştırılmıştır. Deneysel çalışmalar, 4 adet reaktörde oda sıcaklığında gerçekleştirilmiştir. En yüksek KOİ giderim verimi, 5 ve 10 cm derinlikteki reaktörlerde sırasıyla %62,2 ve %60,1 olarak tespit edilmiştir. Başlangıçta 7,91 değerinde olan pH, farklı hidrolik bekletme sürelerinde 7,91-8,49 arasında olmuştur. Başlangıçta 5,59 mS/cm değerinde olan elektriksel iletkenlik, en yüksek 9,46 mS/cm değerine ulaşmıştır.

  6. Possible role of jasmonic acid in the regulation of floral induction, evocation and floral differentiation in Lemna minor L.

    Science.gov (United States)

    Krajncic, B; Kristl, J; Janzekovic, I

    2006-01-01

    Jasmonic acid (JA) is implicated in a wide variety of developmental and physiological processes in plants. Here, we studied the effects of JA and the combination of JA and ethylenediamine-dio-hydroxyphenyl-acetic acid (EDDHA) on flowering in Lemna minor in axenical cultures. JA (0.475-47.5 nmol l(-1)) enhanced floral induction in L. minor under long-day (LD) conditions. Under the same conditions, at a concentration of 237.5 nmol l(-1), JA inhibited floral induction, and at a concentration of 475 nmol l(-1) it prevented floral induction. Under LD conditions with LD preculture, a combination of EDDHA (20,500 nmol l(-1)) and JA (47.5 nmol l(-1)) had a synergistic effect on the promotion of floral induction. Floral induction was enhanced to the greatest extent in experiments with LD precultures. Microscopic examination of microphotographs of histological sections showed that JA and, to an even greater extent, JA+EDDHA at optimal concentrations promote apical floral induction (evocation). Furthermore, JA, and to an even greater extent JA in combination with EDDHA in an optimal concentration, also promote flower differentiation, especially the development of stamens, as is evident from the microphotographs. The experimental results show that JA promotes floral induction in other species of Lemnaceae from various groups according to their photoperiodic response. The results support our hypothesis that, in addition to previously ascribed functions, JA may regulate floral induction, evocation and floral differentiation. Our hypothesis is supported also by the results obtained by quantitative determination of endogenous JA levels in L. minor at three growth stages. The levels of endogenous JA decreased from 389 ng JA g(-1) (fresh weight) of L. minor during the vegetative stage to 217 ng JA g(-1) during the evocation stage, and to 37.5 ng JA g(-1) during the flowering stage, which proves that JA is used for flowering.

  7. Evaluation of environmental bacterial communities as a factor affecting the growth of duckweed Lemna minor.

    Science.gov (United States)

    Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

    2017-01-01

    Duckweed (family Lemnaceae ) has recently been recognized as an ideal biomass feedstock for biofuel production due to its rapid growth and high starch content, which inspired interest in improving their productivity. Since microbes that co-exist with plants are known to have significant effects on their growth according to the previous studies for terrestrial plants, this study has attempted to understand the plant-microbial interactions of a duckweed, Lemna minor , focusing on the growth promotion/inhibition effects so as to assess the possibility of accelerated duckweed production by modifying co-existing bacterial community. 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. A number of bacterial strains were isolated from both growth-promoting and growth-inhibitory communities, and examined for their co-existing effects on duckweed growth. Irrespective of the source, each strain showed promotive, inhibitory, or neutral effects when individually co-cultured with L. minor . To further analyze the interactions among these bacterial strains in a community, binary combinations of promotive and inhibitory strains were co-cultured with aseptic L. minor , resulting in that combinations of promotive-promotive or inhibitory-inhibitory strains generally showed effects similar to those of individual strains. However, combinations of promotive-inhibitory strains tended to show inhibitory effects while only Aquitalea magnusonii H3 exerted its plant growth-promoting effect in all combinations tested. Significant change in biomass production was observed when duckweed was co-cultivated with environmental bacterial communities. Promotive, neutral, and inhibitory bacteria in the community would synergistically determine the effects. The results indicate the possibility of improving duckweed biomass production via regulation of co

  8. Variación espacio-temporal de plantas vasculares acuáticas en el complejo cenagoso del bajo Sinú, Córdoba, Colombia

    Directory of Open Access Journals (Sweden)

    Nabi Del Socorro Pérez-Vásquez

    2015-09-01

    Full Text Available Se determinó la variación espacio temporal de las plantas vasculares acuáticas en las ciénagas de María Arriba, San Sebastián, Purísima y Momil del complejo cenagoso del bajo Sinú (CCBS, en el departamento de Córdoba (Colombia, abarcando los periodos hidrológicos ocurridos durante el año 2011. El área de estudio se dividió en cuatro sectores y mediante el método de intercepción en línea se determinó la abundancia y frecuencia de las hidrófitas. En cada sector se extendió una línea de 200 m perpendicular al litoral y sobre ella se ubicaron cuadrantes de 1 m2 cada 50 m, en los que, se determinó la cobertura y frecuencia de las diferentes especies  Se registraron 39659 individuos distribuidos en 24 familias, 30 géneros y 35 especies. La mayor abundancia de especies se presentó en Momil con 18582 individuos, siendo la familia Lemnaceae la más representativa. El análisis de varianza (ANOVA indica que no existen diferencias estadísticas significativas en la abundancia de la especies de plantas acuáticas de los  meses de muestreo (F=1,04; GL=11; p = 0,083, sin embargo, se evidenció la incidencia del período hidrológico sobre la dinámica de crecimiento de las plantas, algunas especies desaparecen en época seca, otras sobreviven un periodo corto de tiempo, mientras que otras como Lemna minor L y Salvinia auriculata Aubl aumentan en época de lluvia.

  9. Competition Between Lemna minuta, Lemna minor, and Azolla filiculoides. Growing Fast or Being Steadfast?

    Directory of Open Access Journals (Sweden)

    Simona Paolacci

    2018-06-01

    Full Text Available A substantial number of Lemnaceae are invasive outside their natural distribution area. Lemna minuta is considered invasive in several European countries, where it can occur in the same habitat as invasive Azolla filiculoides and native Lemna minor. In this study the presence, abundance and growth rates of all three species were monitored across 24 natural ponds and in a series of mesocosms in order to explore the importance of species invasiveness and habitat invisibility. Field monitoring showed that the distribution of the three species of macrophytes is heterogeneous in space and time. However, the data show no association of nutrient or light levels with plant distribution. Indeed, using reciprocal transplanting experiments it was demonstrated that all species are able to grow in all ponds, even ponds where the species do not naturally occur. It is concluded that distribution of L. minor, L. minuta, and A. filiculoides is not limited by the prevailing physicochemical characteristics of the ponds during the summer period. Remarkably, in these experiments A. filiculoides displayed the highest RGR, and exerted a negative influence on growth rates and surface cover of L. minor and L. minuta. Despite such apparent invasiveness, A. filiculoides was relatively rare in the study area. Rather, the species most abundant was L. minor which has the lowest RGR under field conditions in summer. Therefore, this study shows that the invasiveness of the species during the summer months is not necessarily reflected in the actual distribution pattern in natural ponds. In fact, alien L. minuta and A. filiculoides are under-represented in the monitored area. It is concluded that the interaction of several factors, including growth under winter-conditions and/or dispersal after disturbances, is the major determinant of the abundance and heterogeneous distribution of L. minor, L. minuta, and A. filiculoides in the study area.

  10. Valor nutricional de Lemna valdiviana Phil (Araceae submetida a diferentes concentrações de fertilização com excremento de aves

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    Graça Maria de Oliveira França

    2009-06-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p19 As lemnaceas são plantas aquáticas com grande potencial de uso como matéria prima para ração de peixes devido ao alto valor nutricional. O objetivo deste estudo foi avaliar a composição química e a qualidade nutricional de Lemna valdiviana submetida a diferentes concentrações de adubação com excremento de aves. O experimento foi realizado em delineamento inteiramente casualizado com três repetições. Os tratamentos foram: Controle (sem adubação; T1 – 150g.m-3, T2 – 300g.m-3 e T3 – 450 g.m-3 de excremento de aves fresco, distribuídos em dose única para fertilizar o cultivo de L. valdiviana. A dose que proporcionou a melhor qualidade nutricional de L. valdiviana foi 450g.m-3 de excremento de aves, com teor de proteína bruta de 19,66% na matéria seca, percentual de fibras de 13,06% e teor de 0,26% de P, 1, 63% de N, 0,37% de Na e 1,22% de Ca na massa seca. Os teores alcançados nesse estudo indicam a possibilidade da L. valdiviana ser considerada uma matéria prima de boa qualidade nutricional para ser utilizada em outros experimentos como complemento na ração para peixes.

  11. Biting midges (Diptera: Ceratopogonidae from Martín García Island, Argentina

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    María M Ronderos

    2011-09-01

    Full Text Available Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. Rev. Biol. Trop. 59 (3: 1183-1194. Epub 2011 September 01.Alrededor de 230 especies de ceratopogónidos han sido registradas o descritas en Argentina, 38 de ellas son conocidas para la provincia de Buenos Aires y sólo una ha sido previamente citada para la Isla Martín García. En este trabajo se presentan los resultados obtenidos a partir de muestreos realizados en seis viajes a la isla

  12. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation

    Directory of Open Access Journals (Sweden)

    Michael J. McCann

    2016-03-01

    Full Text Available Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis to nutrient stoichiometry (nitrogen and phosphorus and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C and low nutrient conditions (0.5 mg N L−1, 0.083 mg P L−1. The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions.

  13. High-throughput sequencing of three Lemnoideae (duckweeds chloroplast genomes from total DNA.

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    Wenqin Wang

    Full Text Available BACKGROUND: Chloroplast genomes provide a wealth of information for evolutionary and population genetic studies. Chloroplasts play a particularly important role in the adaption for aquatic plants because they float on water and their major surface is exposed continuously to sunlight. The subfamily of Lemnoideae represents such a collection of aquatic species that because of photosynthesis represents one of the fastest growing plant species on earth. METHODS: We sequenced the chloroplast genomes from three different genera of Lemnoideae, Spirodela polyrhiza, Wolffiella lingulata and Wolffia australiana by high-throughput DNA sequencing of genomic DNA using the SOLiD platform. Unfractionated total DNA contains high copies of plastid DNA so that sequences from the nucleus and mitochondria can easily be filtered computationally. Remaining sequence reads were assembled into contiguous sequences (contigs using SOLiD software tools. Contigs were mapped to a reference genome of Lemna minor and gaps, selected by PCR, were sequenced on the ABI3730xl platform. CONCLUSIONS: This combinatorial approach yielded whole genomic contiguous sequences in a cost-effective manner. Over 1,000-time coverage of chloroplast from total DNA were reached by the SOLiD platform in a single spot on a quadrant slide without purification. Comparative analysis indicated that the chloroplast genome was conserved in gene number and organization with respect to the reference genome of L. minor. However, higher nucleotide substitution, abundant deletions and insertions occurred in non-coding regions of these genomes, indicating a greater genomic dynamics than expected from the comparison of other related species in the Pooideae. Noticeably, there was no transition bias over transversion in Lemnoideae. The data should have immediate applications in evolutionary biology and plant taxonomy with increased resolution and statistical power.

  14. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation

    Science.gov (United States)

    2016-01-01

    Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis) to nutrient stoichiometry (nitrogen and phosphorus) and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C) and low nutrient conditions (0.5 mg N L−1, 0.083 mg P L−1). The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions. PMID:26989619

  15. Checklist das macrófitas aquáticas do Pantanal, Brasil Checklist of the aquatic macrophytes of the Pantanal, Brazil

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    Vali Joana Pott

    1997-12-01

    Full Text Available O Pantanal, por ser alagável, é ambiente favorável ao desenvolvimento de muitas plantas aquáticas. Para atender demandas de levantamentos florísticos regionais, fez-se a listagem das macrófitas aquáticas do Pantanal, com base em coletas depositadas nos Herbários CPAP (EMBRAPA, COR (Universidade Federal de Mato Grosso do Sul, CH (Universidade Federal de Mato Grosso e K (Kew. Até o momento, foram levantadas 242 espécies, distribuídas em 106 gêneros e 54 famílias. As famílias mais numerosas são Poaceae (22 espécies, Cyperaceae(17, Leguminosae e Scrophulariaceae(14, Alismataceae e Onagraceae(13, Pontederiaceae(11, Lentibulariaceae(10, Characeae(9, emnaceae, Malvaceae e Nymphaeaceae(8. A maioria das demais famílias apresentam uma ou duas espécies cada. Quanto à forma biológica, 39% são plantas emergentes, 28% anfíbias, 11,5% flutuantes fixas, 8% flutuantes livres, 8% submersas fixas, 3,8% submersas livres e 1,7% epífítas. Os principais gêneros em número de espécies são Nymphaea, Utricularia, Echinodorus, Ludwigia, Polygonum, Aeschynomene, Cyperus, Eleocharis e Bacopa.The Pantanal, being a wetland, is a favorable environment for the development of many aquatic plants. This list of aquatic macrophytes of the Pantanal was made based on field collections, deposited at Herbarium CPAP (EMBRAPA, COR (Universidade Federal de Mato Grosso do Sul, CH (Universidade Federal de Mato Grosso and K (Kew, to support regional floristic surveys. Until present, 242 species were listed, distributed within 106 genera and 54 families. The most numerous families were Poaceae (22 species Cyperaceae(17, Leguminosae and Scrophulariaceae(14, Alismataceae and Onagraceae(13, Pontederiaceae (11, Lentibulariaceae(10, Characeae(9, Lemnaceae, Malvaceae andNymphaeaceae(8. The majority of other families has one or two species each. The life form spectrum includes 39% emergent plants, 28% amphibious, 11,5% rooted floating, 8% free floating, 8% rooted submerged

  16. Diminished Mercury Emission From Water Surfaces by Duckweed (Lemna minor)

    Science.gov (United States)

    Wollenberg, J. L.; Peters, S. C.

    2007-12-01

    Aquatic plants of the family Lemnaceae (generally referred to as duckweeds) are a widely distributed type of floating vegetation in freshwater systems. Under suitable conditions, duckweeds form a dense vegetative mat on the water surface, which reduces light penetration into the water column and decreases the amount of exposed water surface. These two factors would be expected to reduce mercury emission by limiting a) direct photoreduction of Hg(II), b) indirect reduction via coupled DOC photooxidation-Hg(II) reduction, and c) gas diffusion across the water-air interface. Conversely, previous studies have demonstrated transpiration of Hg(0) by plants, so it is therefore possible that the floating vegetative mat would enhance emission via transpiration of mercury vapor. The purpose of this experiment was to determine whether duckweed limits mercury flux to the atmosphere by shading and the formation of a physical barrier to diffusion, or whether it enhances emission from aquatic systems via transpiration of Hg(0). Deionized water was amended with mercury to achieve a final concentration of approximately 35 ng/L and allowed to equilibrate prior to the experiment. Experiments were conducted in rectangular polystyrene flux chambers with measured UV-B transmittance greater than 60% (spectral cutoff approximately 290 nm). Light was able to penetrate the flux chamber from the sides as well as the top throughout the experiment, limiting the effect of shading by duckweed on the water surface. Flux chambers contained 8L of water with varying percent duckweed cover, and perforated plastic sheeting was used as an abiotic control. Exposures were conducted outside on days with little to no cloud cover. Real time mercury flux was measured using atomic absorption (Mercury Instruments UT-3000). Total solar and ultraviolet radiation, as well as a suite of meteorological parameters, were also measured. Results indicate that duckweed diminishes mercury emission from the water surface

  17. Phytotoxicity Studies of Metsulfuron-methyl, Terbuthylazine and 3, 5 -Dichlorophenol by Duckweed (Lemna minor L. Test

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    M. Abbaspoor

    2016-06-01

    Full Text Available Introduction: From the floating aquatic plant species, duckweed (i.e., Lemna sp. is perhaps the most commonly used in toxicity testing. As its name implies, it is a staple in the summer diet of ducks as well as other aquatic organisms. Actually, “duckweed” can refer to both Lemna sp. and Spirodela sp. (greater duckweed, although, it is usually associated with Lemna minor. The Lemnaceae (duckweeds are cosmopolitan free-floating aquatic monocotyledonous angiosperms that commonly occur in fresh and brackish stagnant ponds and sluggish streams, mostly in tropical regions but also as far north as 60° and as far south as 40° latitude. Duckweeds are vascular floating non-rooted aquatic plants with a reduced root system and lack stems and true leaves. It has been speculated that the roots serve as anchors to keep the fronds right side up and to form the tangled masses, which are of some importance in dispersal and protection from water movement. They can reproduce both sexually and asexually, however, asexual vegetative reproduction is the more commonly occurring mode and, under laboratory conditions, a doubling in frond number and surface area covered can occur every 1.5–2 days. Duckweed can rapidly colonize open surface waters and develop a large biomass. These characteristics, plus its ability to accumulate inorganic ions favor it for use in wastewater treatment systems and makes duckweed an ideal model for studies on the metabolism of pollutants by aquatic macrophytes as well as for toxicity studies. They are very sensitive to many substances and are already used as convenient test organisms for toxicity evaluation of a number of pollutants including industrial and wastewater effluents, herbicides, heavy metals, surfactants and other common chemicals. The typical test end points are changes in the growth rate (expressed as frond production, fresh and dry weight and frond area and changes in pigment content. For a few years biotests with

  18. Using agro-industrial wastes for the cultivation of microalgae and duckweeds: Contamination risks and biomass safety concerns.

    Science.gov (United States)

    Markou, Giorgos; Wang, Liang; Ye, Jianfeng; Unc, Adrian

    2018-04-17

    Aquatic organisms, such as microalgae (Chlorella, Arthrospira (Spirulina), Tetrasselmis, Dunalliela etc.) and duckweed (Lemna spp., Wolffia spp. etc.) are a potential source for the production of protein-rich biomass and for numerous other high-value compounds (fatty acids, pigments, vitamins etc.). Their cultivation using agro-industrial wastes and wastewater (WaW) is of particular interest in the context of a circular economy, not only for recycling valuable nutrients but also for reducing the requirements for fresh water for the production of biomass. Recovery and recycling of nutrients is an unavoidable long-term approach for securing future food and feed production. Agro-industrial WaW are rich in nutrients and have been widely considered as a potential nutrient source for the cultivation of microalgae/duckweed. However, they commonly contain various hazardous contaminants, which could potentially taint the produced biomass, raising various concerns about the safety of their consumption. Herein, an overview of the most important contaminants, including heavy metals and metalloids, pathogens (bacteria, viruses, parasites etc.), and xenobiotics (hormones, antibiotics, parasiticides etc.) is given. It is concluded that pretreatment and processing of WaW is a requisite step for the removal of several contaminants. Among the various technologies, anaerobic digestion (AD) is widely used in practice and offers a technologically mature approach for WaW treatment. During AD, various organic and biological contaminants are significantly removed. Further removal of contaminants could be achieved by post-treatment and processing of digestates (solid/liquid separation, dilution etc.) to further decrease the concentration of contaminants. Moreover, during cultivation an additional removal may occur through various mechanisms, such as precipitation, degradation, and biotransformation. Since many jurisdictions regulate the presence of various contaminants in feed or food

  19. Production of apple snail for space diet

    Science.gov (United States)

    Yamashita, Masamichi; Motoki, Shigeru; Space Agriculture Task Force, J.; Katayama, Naomi

    For food production in space at recycling bio-elements under closed environment, appropriate organisms should be chosen to drive the closed materials recycle loop. We propose a combination of green algae, photosynthetic protozoa, and aquatic plants such as Wolffia spp., for the primary producer fixing solar energy to chemical form in biomass, and apple snail, Pomacea bridgesii, which converts this biomass to animal meat. Because of high proliferation rate of green algae or protozoa compared to higher plants, and direct conversion of them to apple snail, the efficiency of food production in this combination is high, in terms of energy usage, space for rearing, and yield of edible biomass. Furthermore, green algae and apple snail can form a closed ecological system with exchanging bio-elements between two member, i.e. excreta of snail turn to fertilizer of algae, and grown algae become feed for snail. Since apple snail stays in water or on wet substrate, control of rearing is easy to make. Mass production technology of apple snail has been well established to utilize it as human food. Nutrients of apple snail are also listed in the standard tables of food composition in Japan. Nutrients for 100 g of apple snail canned in brine are energy 340 kJ, protein 16.5 g, lipid 1.0 g, cholesterol 240 mg, carbohydrate 0.8 g, Ca 400 mg, Fe 3.9 mg, Zn 1.5 mg. It is rich in minerals, especially Ca and Fe. Vitamin contents are quite low, but K 0.005 mg, B2 0.09 mg, B12 0.0006 mg, folate 0.001 mg, and E 0.6 mg. The amino acid score of apple snail could not be found in literature. Overall, apple snail provides rich protein and animal lipid such as cholesterol. It could be a good source of minerals. However, it does not give enough vitamin D and B12 , which are supposed to be supplemented by animal origin foods. In terms of acceptance in food culture, escargot is a gourmet menu in French dishes, and six to ten snail, roughly 50 g, are served for one person. Apple snail reaches to 30 g

  20. 典型温带季风地区浮萍科植物遗传多样性%Genetic Diversity of Duckweed in a Typical Temperate and Monsoon Region

    Institute of Scientific and Technical Information of China (English)

    张震宇; 韩冰莹; 孙雪飘; 付莉莉; 叶松建; 张家明

    2018-01-01

    Jilin Province is a typical temperate monsoon region,its duckweed bioresources contain different characteristics compared with tropical and subtropical regions in China.In total,41 accessions of duckweeds were collected in Jilin Province.Through morphological classification and molecular identification based on chloroplast atpF-atpH spacer sequences and rpSl6 intron sequences,these accessions were identified as Spirodela and Lemna,including Spirodela polyrhiza,Lemna perpusilla,Lemna turionifera,and Lemna aequinoctialis.There is only one accession in L.aequinoctialis,while accessions ofS.polyrhiza,L.perpusilla,and L.turionifera are 12,13,and 15,respectively.Genetic diversity analysis showed that the indexes of the nucleotide diversity in atpF-atpH and rpS16 were 0.034 04 and 0.065 31,respectively.The nucleotide difference per kb were 21.446 and 60.544,and the haplotype diversity were 0.696 and 0.750,respectively.Wolffia and Landoltia were not collected in Jilin Province,and the distribution of L.aequinoc tialis was far less than duckweed species distributed in southern China,indicating small genetic diversity.The study would provide the molecular basis for species identification and interspecific relationship analysis of duckweed and benefit future botanical studies of duckweeds in North-Eastern China and other temperate monsoon zones.%吉林省为典型温带季风地区,其浮萍科植物资源具有与中国热带、亚热带地区不同的特点.在吉林省各地共收集到41份浮萍种质资源,通过形态学分类和基于叶绿体atp F-atpH间隔序列和rpS16内含子序列的分子生物学鉴定,这些种质分别属于紫萍属(Spirodela)和青萍属(Lemna),共有Spirodela polyrhiza、Lemna perpusilla、Lemna turionifera、Lemna aequinoctidis等4个物种.除L.aequinoctialis仅发现一份种质外,其余三种分布较为均等,其中S.polyrhiza、L.perpusilla、L.turionifera分别有12、13、15份种质.遗传多样分析结果