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Wyświetlanie 1-6 z 6
Tytuł:
Changes in the aquatic moss Sphagnum denticulatum Brid. population abundance in a softwater lake over a period of three years
Autorzy:
Szmeja, J
Powiązania:
https://bibliotekanauki.pl/articles/57078.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
aquatic moss
population dynamics
Sphagnum denticulatum
population abundance
soft water lake
lake
phenology
Opis:
Changes in population abundance of submerged Sphagnum denticulatum Brid. were studied in an acidic and oligotrophic lake in NW Poland over three years. Individuals were counted in a moss carpet at a depth of 2.5 m on 4 experimental plots, 1 × 1 m each, every 30 days for 36 months using the SCUBA method. PAR intensity was seasonally variable (in winter higher than in summer). Changes in water pH, conductivity, HCO3- concentration, hydration and sediment pH were statistically insignificant (p > 0.05). In the summer of the second study year the moss carpet disappeared almost completely due to a massive bloom of filamentous green algae. Periods of growth, regression and regeneration were observed in the population. The stabilisation of population size took 24 months and followed the pattern: slight fluctuations, then rapid growth and repetition of slight fluctuations. The first stage lasted nine, the second four and the third nine months. These stages took place irrespective of seasons, temperature or PAR intensity. Each rapid increase in abundance lasted about 30 days, at PAR intensity >20% and water temperature ranging from 11 to 16oC (in winter, spring or autumn). The regression stage brought about by the algal bloom started in the second year (in summer) and lasted six months (until the end of January in the third year). The population regeneration began in winter (in February, water temperature 3.0oC, PAR about 20%, ice cover 0.15 m) and finished with the end of spring. The population of S. denticulatum shows a repetitive pattern of abundance variations, which is seriously disturbed in summer, especially after a warm spring, by a massive bloom of filamentous green algae.
Źródło:
Acta Societatis Botanicorum Poloniae; 2010, 79, 2; 167-173
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phenotypic responses to water flow and wave exposure in aquatic plants
Autorzy:
Szmeja, J
Galka, A.
Powiązania:
https://bibliotekanauki.pl/articles/57001.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
water flow
aquatic plant
Polska
river
clonal growth
wave exposure
allocation
botany
current velocity
phenotypic variation
lake
Opis:
Plastic responses of 10 aquatic plant species from 5 rivers and 5 lakes in NW Poland were examined. Chara fragilis, C. delicatula, Potamogeton pectinatus, P. perfoliatus, P. natans, Spirodela polyrhiza, Hydrocharis morsus-ranae, Salvinia natans, Nymphoides peltata and Juncus bulbosus were the subject of research. In the running water of rivers, rhizophytes were generally bigger and they allocated from 0.6% to 58.6% more biomass for anchoring in the substrate than in stagnant water (ox bow lakes). In both flow variants rhizophytes allocated a similar biomass fraction for generative reproduction. On the other hand, under the influence of water flow pleustophytes reduced the mass of an individual (Spirodela by 25%, Hydrocharis 67%, Salvinia 77%) and emergent structures (p<0.001), and the number of sporangia (p<0.001). In both flow variants the input of biomass to generative reproduction was the same (Salvinia), or it was greater in running water (Hydrocharis; an increase from 4.9±1.3% to 15.1±3.6%). Under the conditions of strong wave action, in comparison with the lack of this environmental factor, Chara delicatula was several times shorter (p<0.001). However, it was also stouter, and as a result it had similar mass. In the areas of wave action the plant allocated 88.8% of its mass for anchoring in the substrate, whereas when there were no waves, only 22.7%.
Źródło:
Acta Societatis Botanicorum Poloniae; 2008, 77, 1
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of water conditions on the phenology and age structure of Luronium natans [L.] Raf. populations
Autorzy:
Szmeja, J
Bazydlo, E.
Powiązania:
https://bibliotekanauki.pl/articles/56879.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
development stage
water condition
Luronium natans
age structure
European endemic plant
aquatic plant
phenology
population
Opis:
The study presents the results of the analysis of development stages of Luronium natans (L.) Raf. depending on water conditions (pH, light, total nitrogen, total phosphorus, organic carbon) in 21 populations in north-western Poland. The fractions of seedlings, juvenile, mature and generative stems, as well as the course of phenological phenomena were determined. Seedlings are sparse and can be found from May to July. Most of them occur in waters ranging from slightly acid to neutral (pH 6.0-7.0) with TP concentrations of 10-20 µg dm-3, TN concentrations < 1.0 mg dm-3 and DOC concentrations of 3.5-5.0 mg dm-3, on a mineral (5-10% OC) and fairly well lit (31-40% PAR) substrate. The generative phase lasts from May to October. The flowering period is between August and mid-September. Only 35.2±9.4% of flowering stems produce fruits. The plant flowers abundantly in waters with total nitrogen concentrations > 1.2 mg dm-3, that is above the level of TN concentrations most favourable to seedlings and both juvenile and mature individuals. TP and DOC concentrations, and light intensity (PAR) do not influence the size of the generative stems fraction in populations. However, sediment structure is of importance in this respect: about 62.9% of stems flower and fruit on a mineral substrate (< 1% OC), whereas only 17.4% do so on an organic one. The results of this study may be useful in the conservation of this endangered European endemic species.
Źródło:
Acta Societatis Botanicorum Poloniae; 2005, 74, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The disintegration of populations of underwater plants in soft water lakes enriched with acidic organic matter
Autorzy:
Szmeja, J
Bociag, K.
Powiązania:
https://bibliotekanauki.pl/articles/57349.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
soft water lake
disturbance
acidic organic matter
Isoetes lacustris
population structure
Sphagnum denticulatum
underwater plant
Lobelia dortmanna
Fontinalis antipyretica
Opis:
The characteristics of habitats, individuals and populations of four submerged macrophytes, Lobelia dortmanna L., Isoetes lacustris L., Sphagnum denticulatum Brid. and Fontinalis antipyretica Hedw., were studied in 12 soft water oligohumic lakes which had no inflow of allochtonic DOM and the DOC concentration in the water was <4.0 mg C dm-3 and 13 humic lakes enriched with allochthonous dissolved organic matter (DOM) from drained peat bogs and ranging in DOC water concentration from 4.1 to 44.0 mg C dm-3. The analyses of population disintegration were conducted basing on characteristics of individuals (size, habitat, fertility) and populations (aggregation density index, settlement index of the population area). The settlement index of the population area for Lobelia, Fontinalis, Isoetes, Sphagnum decreased from 8.4 to 6.2 g d.w. m-2, 4.6 to 0.01 g d.w. m-2, 85.4 to <0.001 g d.w. m-2 and 39.3 to 7.2 g d.w. m-2, respectively. Similar trends were observed in aggregation density. The general pattern of the disintegration of populations of these species was always similar. It was independent of the source macrophytes drew resources from or their susceptibility to environmental changes. Individuals began to be eliminated from the deep and central parts of the population area. The remainder of the populations, which persist in the shallowest, best-illuminated part of the area, are themselves endangered by disturbances caused by wavy motion. The only populations of submerged macrophytes which can survive in polyhumic lakes under such conditions are those which are resistant to disturbances common in the shallow littoral (Lobelia dortmanna, Fontinalis antipyretica).
Źródło:
Acta Societatis Botanicorum Poloniae; 2004, 73, 2
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical strength of stems in aquatic macrophytes
Autorzy:
Bociag, K
Galka, A.
Lazarewicz, T.
Szmeja, J.
Powiązania:
https://bibliotekanauki.pl/articles/57817.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
aquatic macrophyte
water flow
macrophyte
stretching
stem anatomy
stem resistance
mechanical property
submerged macrophyte
Opis:
In populations of submerged macrophytes, individuals are selected in terms of resistance to the effect of hydrodynamic forces. The aim of this study was to check whether individuals growing in river water are more tensile and bending resistant than plants occurring in places not exposed to flow stress. We determined the ultimate tensile strength of stems in four macrophyte species, Potamogeton natans, P. pectinatus, Batrachium fluitans and Chara fragilis, which occur in two environmental variants: in running (current velocity of 0.1-0.6 m/s-1) and stagnant water. In addition, flexure of P. natans stems from both environmental variants was examined. What is more, the type and arrangement of strengthening structures in stems of the plants under study were determined. Potamogeton natans stems are the most resistant to stretching (15.6±4.7 N), while stems of P. pectinatus (3.3±1.0 N) and Batrachium fluitans (2.6±0.8 N) are less resistant. Chara fragilis (0.6±0.3 N) has the least resistant stems. Batrachium, Chara and P. pectinatus are more resistant to stretching if they occur in a river current, whereas P. natans, in stagnant lake water. Ultimate bending moment of P. natans stems from lakes is also much greater than of stems from a river (9.75•10-3 – 4.25•10-3 Nm as compared to 2.12•10-3 – 1.00•10-3 Nm). The resistance of stems to breaking is directly proportional to the stem and thallus cross sectional areas. On the one hand, in all the studied Cormophyta species, the more resistant stems (in P. natans from stagnant water, in the others from running water) are thicker and characterised by a higher contribution of air spaces in the overall stem cross-section. On the other hand, the stems retain their species specific structure and have a similar proportion of strengthening elements.
Źródło:
Acta Societatis Botanicorum Poloniae; 2009, 78, 3; 181-187
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biomass allocation to anchoring structures in the aquatic macrophytes from the subcontinental and Atlantic climates in Europe
Autorzy:
Szmeja, J
Clement, B.
Bociag, K.
Galka, A.
Skurzynski, P.
Powiązania:
https://bibliotekanauki.pl/articles/56563.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
aquatic macrophyte
aquatic plant
plant ecology
biomass
climate
anchoring structure
inland macrophyte
Atlantic climate
macrophyte
botany
allocation
Europe
subcontinental climate
Opis:
Biomass allocation to anchoring structures in 10 species of aquatic macrophytes in two types of the cool and humid temperate climate in Europe, subcontionental (NW Poland) and Atlantic (W France), was examined. The study focused on the weight of anchoring organs in Chara delicatula Ag., Ch. fragilis Desv., Juncus bulbosus L., Littorella uniflora (L.) Asch., Luronium natans (L.) Raf., Potamogeton pectinatus L., P. perfoliatus L., P. natans L. and Ranunculus fluitans (Lam.) Wimm., as well as submerged structures in Hydrocharis morsus-ranae L. The plants were collected from 10 geographically distant lakes and 2 rivers with a current velocity of 0.3-0.5 m s-1. It was assumed that biomass allocation to anchoring structures in rooting macrophytes depends on the time that mechanical forces, which can remove the plants from the occupied area, exert their effect. It was found that, in the Atlantic and subcontinental climates, the ratio between the biomass of underground (or submerged) and above-ground structures (U/A index), calculated for the ramets of Chara fragilis, Hydrocharis morsus-ranae and Ranunculus fluitans, has similar values (p>0.05). Nevertheless, among seven species of Cormophyta, which were anchored in the lake or pond littoral, six (Juncus bulbosus, Littorella uniflora, Luronium natans, Potamogeton pectinatus, P. perfoliatus and P. natans) had higher values of the U/A index in the Atlantic climate than in the subcontinental type (p < 0.05). This can be explained by the lack of ice cover and, consequently, a longer time of wave action than in the subcontinental climate.
Źródło:
Acta Societatis Botanicorum Poloniae; 2008, 77, 2
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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