Wyniki wyszukiwania

1

Contribution on the Lemnaceae of Ecuador

100%

Landolt E.

Fragmenta Floristica et Geobotanica

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2000

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tom 45

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nr 1-2

2

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

The new kenophyte in Poland - Lemna minuta Humb., Bonpl. and Kunth

86%

Banaszek A., Musial K.

Acta Societatis Botanicorum Poloniae

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2009

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tom 78

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nr 1

69-72

For the first time in Poland two habitats of Lemna minuta were found in 2007. Both of them are located in the warmest south-western region of the country. L. minuta is a North-American kenophyte which has come to Poland probably from Germany. This species grows no bigger than 1-3 mm, which makes it the smallest representative of genus Lemna. The most characteristic features of L. minuta are the lack of purple pigmentation and the presence of only one hardly visible vein in the frond.

3

Size of duckweed Lemna minor: an energy optimization model

72%

Uchmanski J., Czapczak A., Hawro V.

Acta Scientiarum Polonorum. Biologia

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2009

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tom 09

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nr 1-4

4

Growth rate of duckweeds (Lemnaceae) in relation to the internal and ambient nutrient concentrations - testing the Droop and Monod models

72%

Kufel L., Strzalek M., Wysokinska U., Biardzka E., Okninska S., Rys K.

Polish Journal of Ecology

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2012

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tom 60

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nr 2

The Monod model describes the relationship between growth rate and ambient nutrient concentration, the Droop model focuses on internal nutrient resources as the driving factor. Both were applied mainly to explain phytoplankton dynamics in lakes or in experimental cultures. Our test plants were two species of duckweeds – Lemna minor L. and Spirodela polyrhiza (L.) Schleiden sampled from 18 natural stands situated in 6 different water bodies. Plants were grown outdoor in original lake water or in mineral media of varying N and P concentrations (0–21 mg N-NO3 L-1 and 0–1853 μg P-PO4 L-1 for L.minor and 0–4.2 mg N-NO3 L-1 and 0–371 μg P-PO4 L-1 for S. polyrhiza). Moreover, we analysed concentrations of mineral forms of N and P in lake water and tissue nutrient concentrations in plants. Tissue N of both plants was significantly correlated with ambient inorganic nitrogen sources, no such relationship was observed for tissue P. The growth rate of both plants measured under experimental outdoor conditions was better explained by tissue N and P variability (the Droop model) than by the external nutrient availability (the Monod model). The latter also failed to fit the growth rate of both plants in artificial mineral media with a decreasing gradient of N and P concentrations. The plants grew at the expense of internal N and P resources which remarkably declined during 9-day long experiments. Calculated minimum tissue contents (11.19 ± 1.11 mg N g-1 and 0.97 ± 0.07 mg P g-1 in L. minor and 6.10 ± 1.85 mg N and 1.25 ± 0.37 mg P g-1 in S. polyrhiza) show that the latter species would be a superior competitor under N limiting conditions and the former – under P limitation. We confront obtained results with literature data on N uptake kinetics and postulate that the luxury consumption of nutrients and plant growth dependent mainly on internal N and P resources might be an adaptation of duckweeds to varying habitat conditions typical of astatic water bodies.

5

Starch grain surface and starch degradation in turions of the duckweed Spirodela polyrhiza [Lemnaceae]

72%

Appenroth K. J., Reimann R., Krok F., Szymonska J.

Żywność Nauka Technologia Jakość. Suplement

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2002

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tom 09

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nr 4

Turions are survival organs of aquatic plants such as the great duckweed {Spirodela polyrhiza). They consist of approximately 50% storage starch (per dry weight) used to support the growth of newly formed sprouts following germination. They could be employed as a good model system for investigations of the storage starch degradation in plants. To induce starch degradation in the plant cells turions must be irradiated for a few days with continuous light absorbed by the plant photoreceptor phytochrome. During such treatment changes in the profile of proteins associated with the starch grain surface have been observed. It was shown by in vitro binding studies that several proteins (α-amylase, starch dikinase R1, ß- amylase) are desorbed from the surface or lose the ability to bind to it. This effect was especially obvious when starch grains from turions irradiated for 4 days (irradiated samples) were compared to those from turions kept in darkness (dark control). A hypothesis was presented that unknown changes in the surface properties of starch grains might be very important in the mechanism of starch degradation, by altering the binding of proteins. The aim of the study was to investigate these properties immediately before and after the start of the starch degradation. Precise structural analysis of the starch grain surface was performed using a non- contact atomic force microscopy (nc-AFM). The grain surface revealed increasing roughness and a reduced density of the structural elements in the samples after irradiation. Two different kinds of randomly organized surface elements were detected by nc-AFM: the one type of a globular structure and the other one more oblong. They could be considered as the carbohydrate lamellas situated in the different way at the starch granule surface. Both were observed to become larger after irradiation. This might be a result of binding of water molecules to the carbohydrate lamellas or bending the surface carbohydrate helices into superhelices by new inter-carbohydrate hydrogen bonds. Such a modification of the starch granule surface could be a consequence of events started by the photoreceptor phytochrome involving starch phosphorylation / dephosphorylation, perhaps mediated by the newly discovered starch dikinase.

6

Metabolic responses of Lemna minor to lead ions. I. Growth, chlorophyll level and activity of fermentative enzymes

72%

Garnczarska M., Ratajczak L.

Acta Physiologiae Plantarum

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2000

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tom 22

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nr 4

7

Metabolic responses of Lemna minor to lead ions. II. Induction of antioxidant enzymes in roots

72%

Garnczarska M., Ratajczak L.

Acta Physiologiae Plantarum

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2000

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tom 22

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nr 4

8

Hydraulic characteristics of a wastewater treatment pond evaluated throuhg tracer test and multi-flow mathematical approach

72%

Maloszewski P., Wachniew P., Czuprynski P.

Polish Journal of Environmental Studies

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2006

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tom 15

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nr 1

Use of tracers and mathematical modelling to evaluate of hydraulic characteristics of constructed wetlands is presented for a duckweed pond in Mniów, Poland. Instantaneously injected bromide was used to obtain residence time distribution (RTD) of wastewater in that wetland. Flow components were identified and their hydraulic characteristics were derived from tracer concentration curve measured in the outflow by partial fitting of the analytical solution of one-dimensional advection-dispersion equation to the experimental data. The modelling has shown that the wastewater flows along three different flow-paths to the exit. The mean weighted transit time obtained from modelling of tracer data combined with measured mean flow rate of waste water yields the volume of wastewater in the pond.

9

Vermicomposting of duckweed [Lemna minor L.] biomass by Eisenia fetida [Sav.] earthworm

58%

Kostecka J., Kaniuczak J.

Journal of Elementology

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2008

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tom 13

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nr 4

571-579

This work presents the dynamics of E. fetida (Sav.) earthworm populations during vermicomposting of duckweed (Lemna minor L.) biomass in small containers, and provides properties of the vermicomposts produced. An experiment was conducted under laboratory conditions (in darkness, at an average temperature 25±5oC, with substrate moisture 70-75%). Test pots (3 replications for each duckweed treatment) were filled with one litre of garden soil, into which 100 individuals of E.fetida, of known biomass, were introduced per pot. Duckweed was fed to earthworms regularly, in two treatments: (1) duckweed + + cattle manure (1:1), and (2) duckweed only. Earthworm number and biomass of tested populations were determined after 4 months of vermicomposting, and it was found that an average number of E.fetida in containers with duckweed and manure was 121±5 ind./container with a total biomass of 25.8±1.1 g. Populations in pure duckweed were significantly smaller (p<0.05), with 57±6 ind./container and a total biomass of 9.8±1 g. Cocoon production was also different across treatments. Populations in duckweed alone produced 55±13 cocoons /per container, significantly less (p<0.05) than the 231±37 cocoones when manure was added. Duckweed vermicomposts were odourless and had good granular structure. Chemical characteristics of both vermicompost types (with or without a manure supplement) were desirable. Content of macroelements in duckweed vermicomposts was high, whereas microelements, cadmium and lead were within the permitted levels, making these vermicomposts extremely useful in environmental reclamation, including agriculture. The manure addition was important for characteristics and chemical content of duckweed vermicomposts. The vermicomposts produced from duckweed and manure contained more ash, N, P, K, Mg, Zn, Cu, Ni, Cr, Cd and Pb.

Ograniczanie wyników

Contribution on the Lemnaceae of Ecuador

The new kenophyte in Poland - Lemna minuta Humb., Bonpl. and Kunth

Size of duckweed Lemna minor: an energy optimization model

Growth rate of duckweeds (Lemnaceae) in relation to the internal and ambient nutrient concentrations - testing the Droop and Monod models

Starch grain surface and starch degradation in turions of the duckweed Spirodela polyrhiza [Lemnaceae]

Metabolic responses of Lemna minor to lead ions. I. Growth, chlorophyll level and activity of fermentative enzymes

Metabolic responses of Lemna minor to lead ions. II. Induction of antioxidant enzymes in roots

Hydraulic characteristics of a wastewater treatment pond evaluated throuhg tracer test and multi-flow mathematical approach

Vermicomposting of duckweed [Lemna minor L.] biomass by Eisenia fetida [Sav.] earthworm