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Growth and reproduction of Potamogeton alpinus Balbis growing in disturbed habitats
Abstract
Growth and reproduction of Potamogeton alpinus in North German water bodies are described. General schema of the life cycle of Potamogeton alpinus was constructed. The development of the maximum standing crop for three years period is presented; both continuous (light, temperature etc.) and discontinuous (drought, spate, cutting etc.) ecological factors have been considered. Seasonal development of an individual is described, its productivity calculated and morphometrical data are involved. Six reproductive possibilities of Potamogeton alpinus are listed and the evolutionary consequences of life cycle (sexual and asexual reproduction) are shown.
... Areas located in temperate climates are characterized by seasonal phenomena in plant populations, which very often makes them the object of phenological studies. An example of such research might be the course of periodic events in the development of P. alpinus, as described by Brux et al. (1987Brux et al. ( , 1989 and Germ et al. (2002). Nevertheless, to the best of our knowledge, the complete phenological spectrum of this species in undisturbed conditions has never been determined. ...
... In N Poland, the species flowers and fruits, but probably does not reproduce sexually, because seedlings have never been found (personal observation). Similar observations of the reaction of this plant were recorded in other localities on the Central European Plain and Western Europe (Wiegleb & Todeskino 1985;Brux et al. 1987). There is nothing unusual in this reaction, because some species of remnant populations in the periphery of their geographic range, such as Decodon verticillatus, lose their capacity for sexual reproduction, and permanent inability of a population to reproduce sexually is defined as sexual extinction (Eckert et al. 1999;Eckert 2002;Honnay & Bossuyt 2005;Eckert et al. 2008). ...
We have determined the timing of periodic events, such as leaf formation, flowering, fruiting and wintering of the aquatic plant Potamogeton alpinus. This study was performed in 15 watercourses situated in NW Poland in 2014-2015. Characteristics of the age stages were determined on the basis of 728 modules and phenological data were collected from permanent plots. In the study area, the plant appeared in week 12 of the calendar year, when water temperature in the streams was 5.4 ± 0.16°C. At that time, the first leafy juvenile shoots developed from winter buds. In week 22 (water temperature 13.9 ± 0.85°C), juvenile shoots became mature, whereas the first flowers were formed in week 24 (15.6 ± 1.04°C). The generative phase lasted twelve weeks with water temperature from 15.6 ± 1.04°C to 18.9 ± 3.23°C. Between weeks 37 and 44 (water temperature from 13.7 ± 0.77°C to 6.3 ± 1.05°C), senile shoots dominated in the population. From week 45 until week 11 of the next year (water temperature < 5.4 ± 0.16°C), the plants were in the winter resting stage. In our view, climate warming might disturb the phenology of P. alpinus, decreasing the probability of sexual reproduction of the species and the phenological distance between the Central European Plain and the Scandinavian populations. © 2018 Faculty of Oceanography and Geography, University of Gdańsk, Poland 2018.
... Using seeds for propagating the macrophytes may be a better option for some submerged macrophytes, such as Vallisneria spiralls and Hydrilla verticillata, known to produce seeds in large numbers (Barrat-Segretain, 1996). However, these seeds are usually very small and light, easily dispersed by wind, and most often fail to germinate (Brux et al., 1987). Among the various propagules produced by submerged plants, turions of Potamogeton crispus L. are large and store enough nutrients to support the plants to grow tall enough (Boedeltje et al., 2003). ...
... In the subtemperate climate in the early summer, rhizomes grow leafy stems with roots, which in full summer develop flowers and fruits. In the autumn, aboveground stems decline, and the plant overwinters as rhizomes or turions (Brux et al. 1987;Germ et al. 2002). In north-western and central Europe, P. alpinus occurs locally (Baattrup-Pedersen et al. 2008) and in some countries is a vulnerable or endangered element of flora of lowland streams due to eutrophication and/or intoxication (Sand-Jensen et al. 2000;Sand-Jensen 2001, 2002). ...
Aquatic plants anchored in streams are under pressure from various constraints linked to the water flow and display strategies to prevent their damage or destruction. We assume that the responses of aquatic plants to fast-water flow are a manifestation of a trade-off consisting in either maximizing the resistance to damage (tolerance strategy) in minimizing the hydrodynamic forces (avoidance strategy), or both. Our main hypothesis was that Potamogeton alpinus demonstrate the avoidance strategy. We analyzed architecture traits of the modules of this clonal plant from slow- and fast-flowing streams. In fast-flowing waters, the avoidance strategy of P. alpinus is reflected by the following: (1) the presence of floating leaves that stabilize the vertical position of the stem and protect the inflorescence against immersion; (2) elongation of submerged leaves (weakens the pressure of water); and (3) shoot diameter reduction and increase in shoot density (weakens the pressure of water, increases shoot elasticity), and by contrast in slow-water flow include the following: (4) the absence of floating leaves in high intensity of light (avoiding unnecessary outlays on a redundant organ); (5) the presence of floating leaves in low intensity of light (avoidance of stress caused by an insufficient assimilation area of submerged leaves).
... noLJKaMH (Brux eta!. , 1987(Brux eta!. , , 1988(Brux eta!. , , 1989. (Wiegleb, Todeskino, 1983;Brux et al. , 1987;op11r. ) x. T. c. ...
Potamogeton × vepsicus A. A. Bobrov et Chemeris (Potamogetonaceae Dumort.), a new hybrid pondweed from the Upper Volga Region, originated from the result of crossing P. alpinus Balb. and P. natans L., is described. It was found in the Nozhema River near Pyazhelka village (Vologda Region, Babaevo Distr.). It was recorded so far only in the Eastern Europe (Estonia: the Konuvere River, vicinity of Rapla town (?); Russia: the Nozhema River, Vepsovskaya Hills, Vologda Region). It differs from the parental species by intermediate morphological and anatomical characters. It occurs in flowing parts of small soft water rivers, that is not very typical for the both parental species: P. alpinus and P. natans avoid fast current, though able to grow in soft, subacidic waters. The bottom in the place of P. × vepsicus occurrence is strongly cluttered up with sunken logs. The biology of P. × vepsicus is closer to that of P. natans, that gives the hybrid certain advantages in the flowing river conditions (high vegetative mass, good attachment to the bottom and resistance to the current). The hybrid genome provides ecological and biological success of P. × vepsicus that leads to its high productivity and the leading part in creation of primary organic matter in the occupied section of the river. The composition of P. × vepsicus communities is closer to that of the river coenoses of P. alpinus, that is probably due to similarity of hydrochemical, trophic and temperature regimes in ecotopes of these phytocoenoses. P. × vepsicus, like other pondweed hybrids in watercourses of the Upper Volga Region, in better adapted to river conditions than parental species, and together with many among the first ones it inhabits new free econiches formed under human impact.
Note. Parentage of P. × vepsicus was corrected to P. natans L. × P. praelongus Wulf. based on molecular methods by Kaplan Z., Fehrer J. Erroneous identities of Potamogeton hybrids corrected by molecular analysis of plants from type clones. Taxon. 2011. 60(3): 758—766.
... Stands decline in autumn and only turions remain as hibernating organs. New stands usually arise from turions and not from seeds (Brux, Todeskino & Wiegleb, 1987). ...
1. High water column NO 3 ⁻ concentrations, low light availability and anoxic, muddy sediments are hypothesised to be key factors hampering growth of rooted submerged plants in shallow, eutrophic fresh water systems. In this study, the relative roles and interacting effects of these potential stressors on survival, growth, allocation of biomass and foliar nutrient concentrations of Potamogeton alpinus were determined in a mesocosm experiment using contrasting values of each factor (500 versus 0 μ mol L ⁻¹ NO 3 ⁻ ; low irradiance, corresponding to the eutrophic environment, versus ambient irradiance; and muddy versus sandy sediment).
2. Low irradiance, high NO 3 ⁻ and sandy sediment led to reduced growth. In a muddy sediment, plants had lower root : shoot ratios than in a sandy sediment.
3. Growth at high NO 3 ⁻ and on the sandy sediment resulted in lower foliar N and C concentrations than in the contrasting treatments. The C : N ratio was higher at high NO 3 ⁻ and on the sandy sediment. Foliar P was higher on the muddy than on the sandy sediment but was not affected by irradiance or NO 3 ⁻ . The N : P ratio was lowest at high NO 3 ⁻ on the sandy sediment.
4. Total foliar free amino acid concentration was lowest on sand, low irradiance and high NO 3 ⁻ . Total free amino acid concentration and growth were not correlated.
5. Turbidity and ortho‐PO 4 ³⁻ concentration of the water layer were lower at high water column NO 3 ⁻ indicating that the growth reduction was not associated with increased algal growth but that physiological mechanisms were involved.
6. We conclude that high water column NO 3 ⁻ concentrations can significantly reduce the growth of ammonium preferring rooted submerged species such as P. alpinus , particularly on sediments with a relatively low nutrient availability. Further experiments are needed to assess potential negative effects on other species and to further elucidate the underlying physiological mechanisms.
Under current EU regulation, the potential risks to aquatic organisms must be assessed for uses of plant protection products (PPPs) that may result in exposure to the environment. For herbicidal PPPs, aquatic macrophytes are often the most sensitive taxa. For some herbicidal modes of action, macrophytes may only be affected while they are actively growing. For the risk assessment, it is therefore useful to know whether application timings would result in surface water exposure during periods when aquatic macrophytes are actively growing (therefore potentially resulting in effects). Toxicity endpoints, which are based on studies with active growth, may be over‐conservative for cases where exposure of PPPs will not co‐occur with active macrophyte growth. A comprehensive literature search was performed, using systematic and manual approaches, with the aim of identifying the main active growth period for macrophytes in natural freshwater bodies in climates relevant to Central and Northern Zones of the EU. The results of the searches were initially screened to identify all potentially relevant references, for which a full evaluation was then performed. Reliability was assessed using the principles of the Klimisch scoring system. As part of the full evaluation, growth periods were identified for each macrophyte species studied. Finally, the extracted growth periods were considered together to determine an overall active growth period for aquatic macrophytes representative of Central and Northern EU zones. Based on this literature review, the active growth period identified for the majority of aquatic macrophyte species representative of Central and Northern EU Zones is April to September. Relating to the regulatory implication of these results, it may be possible to conclude a low risk for aquatic macrophytes if the predicted surface water exposure period for certain PPPs is demonstrated to be outside of the periods of active growth.
Der vorliegende Beitrag beschreibt auf der Grundlage eigener Untersuchungen sowie Literaturauswertungen, auf welche Weise naturschutzorientierte Unterhaltungsmaßnahmen an Gräben der Kulturlandschaft durchgeführt werden können. Trotz des durch Meliorationsmaßnahmen verursachten Verlustes feuchter und nasser Lebensräume können die zunächst als Landschaftseingriff zu bewertenden Entwässerungsgräben die Funktion von Refugialstandorten für einige Arten dieser Standorte übernehmen. Dies wird anhand von Beispielen erläutert. Abgeleitet aus den Auswirkungen verschiedener Unterhaltungsmaßnahmen wie Böschungsmahd, Entkrautung oder Sohlenräumung auf Flora und Fauna werden allgemeine wie artspezifisch ausgerichtete Vorschläge für eine naturgemäßere Ausgestaltung dieser Maßnahmen entwickelt.
This chapter summarises current knowledge about the macrophyte vegetation of Central Europe’s freshwater habitats including lakes, ponds, streams and rivers. Based on a characterization of physical and chemical conditions, the vegetation of still water bodies and streams and rivers is presented in detail, followed by sections on plant adaptations to the environment, population biology and community ecology in freshwater habitats, productivity and water and nutrient cycling, vegetation dynamics, and an assessment of past and recent human influence and conservation issues.
Method for monitoring aquatic macrophytes according to European Water Framework Directive in marsh water bodies
The following plant groups are generally considered as macrophytes: macrophytic green, red and brown algae, stone worts, mosses and liverworts, and hydrophytic vascular plants (with the main growth forms of the submerged, floating leaved and free-floating plants) and helophytic vascular plants (incl. creeping and high-growing graminoids as well as dicotyledons). The sections of rivers where physical and chemical conditions allow the growth of macrophytes are called the “macrophyte region” (Roll 1938). They can also be considered as “macrophyte-dominated ecosystems” in the sense of den Hartog (1979). Macrophytes are connected to other compartments of the ecosystem in several ways (see Dahl & Wiegleb 1984):
Besides phytoplankton and “Aufwuchs” algae, macrophytes are very important primary producers connecting the inorganic environment to the biotic community. The organic substances produced are mainly not used by herbivores but are transferred into the detritus food chain.
Macrophytes are food and habitat for the macrofauna that shows many functional relations to the plants. Furthermore relations to epiphytic bacteria and algae as well as to the phytoplankton are evident.
Macrophytes have a strong chemical effect on the water. Nutrient elimination from the water as well as nutrient pumping from the sediment into the water have been discussed. Furthermore, oxygen production and elimination of toxic substances and microbes are important.
Macrophytes also have physical effects on the environment. Especially sediment stabilization, differentiation of the current velocity and the influence on the microclimate and on quantity and quality of the light consumption shall be mentioned.
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