Ontogenesis of the genets and ramets of some European species of the genus Sparganium subgenus Xanthosparganium

E. A. Belyakov; A. G. Lapirov

doi:10.15421/021921

Ontogenesis of the genets and ramets of some European species of the genus Sparganium subgenus Xanthosparganium

Regulatory Mechanisms in Biosystems ◽

10.15421/021921 ◽

2019 ◽

Vol 10 (1) ◽

pp. 136-146

Author(s):

E. A. Belyakov ◽

A. G. Lapirov

Keyword(s):

Natural Selection ◽

Ecological Group ◽

Model Species ◽

Natural Conditions ◽

European Species ◽

Level Regime ◽

Bud Initiation ◽

Vegetative Origin ◽

Ecological Forms ◽

Vegetative Season

Representatives of the Sparganium L. genus belong to an ecological group of short grass helophytes which live in the shoreline area of different water bodies. Despite the fact that most representatives of the genus exhibit notable polymorphism (depending on the level regime of a water body, they can form various ecological forms), characteristic of all of them is presence of only one living form – vegetative mobile clear polycentric long-rhizomatous pseudoannual polycarpic plant with racemose root system. The objective of the article was to study the ontogenesis of genets and ramets on the example of representatives of the Xanthosparganium subgenus (S. emersum Rehm., S. glomeratum (Laest. ex Beurl.) Neum., S. gramineum Georgi and S. natans L.). The research was conducted using the ontogenetic approach. In the study, we analyzed ontogenesis of genet (from generative diaspore) and ontogenesis of ramets (from vegetative diaspores – tuber-like structures and axillary buds of vegetative-generative monocarpic and vegetative rosette shoots). We demonstrated that ontogenesis of genets and ramets (on the basis of tuber-like structures) in laboratory conditions is abrupt. It was found that the model species of Sparganium are characteristic in combining of incomplete and special ontogenesis, which is related to the omission of phases of the post-generative period. Such peculiarity is conditioned by increase in tempi of ontogenetic development. On the basis of specific ontogenesis, a variant of shortened ontogenesis is possible, during which the virginile ontogenetic condition is omitted. This feature could be characterized as dynamic polyvariance of ontogenesis, whereas bud initiation and development of shoots throughout the vegetative season, characterized as heterochrony, has been formed over the process of natural selection. Heterochrony (on the basis of iterative branching without periods of rest) includes a property of formation of vegetative-generative shoots which develop on the basis of sylleptic shoots of subsequent orders of branching. The main course of ontogenesis in natural conditions corresponds to D-type which occurs in order of generations of individuals of vegetative origin.

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Why many Batesian mimics are inaccurate: evidence from hoverfly colour patterns

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.1585 ◽

2016 ◽

Vol 283 (1842) ◽

pp. 20161585 ◽

Cited By ~ 6

Author(s):

Christopher H. Taylor ◽

Tom Reader ◽

Francis Gilbert

Keyword(s):

Natural Selection ◽

Multiple Model ◽

Wild Populations ◽

Model Species ◽

Trade Off ◽

Binary Images ◽

Classic Problem ◽

Pattern Similarity ◽

Colour Patterns ◽

Shed Light

Mimicry is considered a classic example of the elaborate adaptations that natural selection can produce, yet often similarity between Batesian (harmless) mimics and their unpalatable models is far from perfect. Variation in mimetic accuracy is a puzzle, as natural selection should favour mimics that are hardest to distinguish from their models. Numerous hypotheses exist to explain the persistence of inaccurate mimics, but most have rarely or never been tested against empirical observations from wild populations. One reason for this is the difficulty in measuring pattern similarity, a key aspect of mimicry. Here, we use a recently developed method, based on the distance transform of binary images, to quantify pattern similarity both within and among species for a group of hoverflies and their hymenopteran models. This allowed us to test three key hypotheses regarding inaccurate mimicry. Firstly, we tested the prediction that selection should be more relaxed in less accurate mimics, but found that levels of phenotypic variation are similar across most hoverfly species. Secondly, we found no evidence that mimics have to compromise between accuracy to multiple model species. However, we did find that darker-coloured hoverflies are less accurate mimics, which could lead to a trade-off between mimicry and thermoregulation in temperate regions. Our results shed light on a classic problem concerning the limitations of natural selection.

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Aerosol measurement methods to quantify spore emissions from fungi and cryptogamic covers in the Amazon

Atmospheric Measurement Techniques ◽

10.5194/amt-13-153-2020 ◽

2020 ◽

Vol 13 (1) ◽

pp. 153-164 ◽

Cited By ~ 1

Author(s):

Nina Löbs ◽

Cybelli G. G. Barbosa ◽

Sebastian Brill ◽

David Walter ◽

Florian Ditas ◽

...

Keyword(s):

Relative Humidity ◽

Amazon Basin ◽

Large Fraction ◽

Fungal Spores ◽

Measurement Data ◽

Minor Role ◽

Model Species ◽

Natural Conditions ◽

Experimental Conditions ◽

Spore Release

Abstract. Bioaerosols are considered to play a relevant role in atmospheric processes, but their sources, properties, and spatiotemporal distribution in the atmosphere are not yet well characterized. In the Amazon Basin, primary biological aerosol particles (PBAPs) account for a large fraction of coarse particulate matter, and fungal spores are among the most abundant PBAPs in this area as well as in other vegetated continental regions. Furthermore, PBAPs could also be important ice nuclei in Amazonia. Measurement data on the release of fungal spores under natural conditions, however, are sparse. Here we present an experimental approach to analyze and quantify the spore release from fungi and other spore-producing organisms under natural and laboratory conditions. For measurements under natural conditions, the samples were kept in their natural environment and a setup was developed to estimate the spore release numbers and sizes as well as the microclimatic factors temperature and air humidity in parallel to the mesoclimatic parameters net radiation, rain, and fog occurrence. For experiments in the laboratory, we developed a cuvette to assess the particle size and number of newly released fungal spores under controlled conditions, simultaneously measuring temperature and relative humidity inside the cuvette. Both approaches were combined with bioaerosol sampling techniques to characterize the released particles using microscopic methods. For fruiting bodies of the basidiomycetous species, Rigidoporus microporus, the model species for which these techniques were tested, the highest frequency of spore release occurred in the range from 62 % to 96 % relative humidity. The results obtained for this model species reveal characteristic spore release patterns linked to environmental or experimental conditions, indicating that the moisture status of the sample may be a regulating factor, whereas temperature and light seem to play a minor role for this species. The presented approach enables systematic studies aimed at the quantification and validation of spore emission rates and inventories, which can be applied to a regional mapping of cryptogamic organisms under given environmental conditions.

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A Method for the Direct Study of Natural Selection

Journal of Experimental Biology ◽

10.1242/jeb.16.3.278 ◽

1939 ◽

Vol 16 (3) ◽

pp. 278-285

Author(s):

CECIL GORDON

Keyword(s):

Drosophila Melanogaster ◽

Natural Selection ◽

Wild Type ◽

Natural Conditions ◽

Direct Study ◽

Recessive Type ◽

Selection Of

1. Decisive experiments on selection of mutants of Drosophila melanogaster can be carried out under natural conditions in Britain where this species is not indigenous. 2. This communication records an experiment in which a balanced population containing 25% ebony mutants was released in South Devon. 3. The frequency of the genotype among the descendants was estimated after a period equivalent to six discrete generations, by testing trapped flies, most of which were wild type in appearance, for heterozygosis. 4. The frequency estimated was very close to what would be deduced on the assumption that elimination of the recessive type before maturity was complete.

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Induction of the prophenoloxidase-activating system of Simulium (Diptera: Simuliidae) following Onchocerca (Nematoda: Filarioidea) infection

Parasitology ◽

10.1017/s0031182000076538 ◽

1994 ◽

Vol 109 (5) ◽

pp. 649-655 ◽

Cited By ~ 17

Author(s):

H.-E. Hagen ◽

J. Grunewald ◽

P. J. Ham

Keyword(s):

Recognition System ◽

Injection Technique ◽

Filarial Infection ◽

Natural Conditions ◽

European Species ◽

Humoral Immune ◽

Feeding Experiments ◽

Self Recognition ◽

Sterile Medium ◽

Prophenoloxidase System

Trials were carried out to study the humoral immune response of blackflies to filariae following infection using the intrathoracic injection technique. An induced 66 kDa protein was abundant in the haemolymph of the European species Simulium ornatum following infection with bovine Onchocerca lienalis. This protein was apparently at higher concentrations in the haemolymph of sham-inoculated flies, i.e. flies that received sterile medium without the parasites. A molecule of the same size was also observed in the haemolymph of infected S. damnosum s.l. following infection with human O. volvulus or bovine O. ochengi. However, the level of this protein was lower in blackflies injected with microfilariae of bovine O. dukei. Unlike O. volvulus and O. ochengi this species is not transmitted by S. damnosum s.l. under natural conditions. No such reaction was observed if the African blackflies had received a sham inoculation. Feeding experiments with wild-caught nulliparous S. damnosum sl. on Onchocerca-infected cattle supported the results of the injection trials. The 66 kDa protein could only be found in the haemolymph of specimens infected via a blood meal. This 66 kDa molecule was identified as phenoloxidase. It appeared in the haemolymph due to the activation of the prophenoloxidase system following the filarial infection and we hypothesize that it may be sequestered by the parasites, as part of a non-self recognition system.

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Natural selection drives leaf divergence in experimental populations of Senecio lautus under natural conditions

Ecology and Evolution ◽

10.1002/ece3.5263 ◽

2019 ◽

Vol 9 (12) ◽

pp. 6959-6967 ◽

Cited By ~ 3

Author(s):

Thomas J. Richards ◽

Daniel Ortiz‐Barrientos ◽

Katrina McGuigan

Keyword(s):

Natural Selection ◽

Natural Conditions ◽

Experimental Populations

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Black cattle in the cool pastoral highlands of Kenya

The Journal of Agricultural Science ◽

10.1017/s0021859600037114 ◽

1981 ◽

Vol 97 (3) ◽

pp. 739-742 ◽

Cited By ~ 1

Author(s):

Virginia A. Finch

Keyword(s):

Natural Selection ◽

Thermal Effects ◽

Laboratory Experiments ◽

Bos Indicus ◽

Coat Colour ◽

Natural Conditions ◽

White Cattle ◽

Metabolic Significance ◽

Semi Arid ◽

Cool Climate

On the cool semi-arid highlands of Kenya (1400–2500m) Boran cattle (Bos indicus) with dark coats predominate over white ones in pastoralist herds. Natural selection appears to favour dark-coated Boran cattle in these areas because significantly fewer black than white cattle die during drought and black cattle recover weight faster in wet seasons (Finch & Western, 1977). To investigate why cattle with dark coats are favoured, an experiment was designed to test whether the thermal effects of black coats in a cool climate interacted advantageously with the animal's metabolic economy. To date, interest in the metabolic significance of colour in cool climates has been confined largely to laboratory experiments (De Jong, 1976; Hamilton & Heppner, 1967; 0ritsland, 1971). The present experiment was different in that the thermal effect of coat colour on metabolic rate of cattle was investigated in the natural conditions in which they live.

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The Dominance of Chitosan Hydrochloride over Modern Natural Agents or Basic Substances in Efficacy against Phytophthora infestans, and Its Safety for the Non-Target Model Species Eisenia fetida

Horticulturae ◽

10.3390/horticulturae7100366 ◽

2021 ◽

Vol 7 (10) ◽

pp. 366

Author(s):

Martin Žabka ◽

Roman Pavela

Keyword(s):

Phytophthora Infestans ◽

Plant Protection ◽

Crop Protection ◽

Model Species ◽

Natural Conditions ◽

Natural Agents ◽

Modern Natural ◽

Chitosan Hydrochloride

Growing pressure to reduce the environmental pesticide burden has the greatest impact on agriculture and crop protection. There is an enormous increase in the demand for research on new, effective, naturally based agents that do not pose an environmental risk. Phytophthora infestans is one of the most destructive phytopathogens, especially in cases where synthetic fungicides are not allowed. This paper describes the high efficacy and safety of the natural polymer chitosan under in vitro and in vivo conditions and its dominance over other natural agents or products. Chitosan demonstrated the highest efficacy against P. infestans. A concentration of 0.2–0.4% was highly effective. The protective effect of chitosan was 99.3% in natural conditions. Direct activity, equivalent to synthetic fungicides (MIC50 0.293 mg/mL), was confirmed. Chitosan was rated non-toxic to useful non-target species. We promote further chitosan expansion within legislation and implementation of chitosan as a safe substance that could reduce the pesticide burden, particularly in eco-friendly plant protection and production of non-harmful foods.

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Aerosol measurement methods to quantify spore emissions from fungi and cryptogamic covers in the Amazon

10.5194/amt-2019-238 ◽

2019 ◽

Author(s):

Nina Löbs ◽

Cybelli G. G. Barbosa ◽

Sebastian Brill ◽

David Walter ◽

Florian Ditas ◽

...

Keyword(s):

Relative Humidity ◽

Amazon Basin ◽

Large Fraction ◽

Fungal Spores ◽

Measurement Data ◽

Minor Role ◽

Model Species ◽

Natural Conditions ◽

Experimental Conditions ◽

Spore Release

Abstract. Bioaerosols are considered to play a relevant role in atmospheric processes, but their sources, properties and spatio-temporal distribution in the atmosphere are not yet well characterized. In the Amazon Basin, primary biological aerosol particles (PBAP) account for a large fraction of coarse particulate matter, and fungal spores are among the most abundant PBAP there as well as in other vegetated continental regions. Furthermore, PBAP could also be important ice nuclei in Amazonia. Measurement data on the release of fungal spores under natural conditions are, however, sparse. Here we present an experimental approach to analyze and quantify the spore release from fungi and other spore producing organisms under natural and laboratory conditions. For measurements under natural conditions, the samples were kept in their natural environment and a setup was developed to estimate the spore release numbers and sizes together with the microclimatic factors temperature and air humidity, as well as the mesoclimatic parameters, net radiation, rain, and fog occurrence. For experiments in the laboratory, we developed a cuvette to assess the particle size and number of newly released fungal spores under controlled conditions, simultaneously measuring temperature and relative humidity inside the cuvette. Both approaches were combined with bioaerosol sampling techniques to characterize the released particles by microscopic methods. For fruiting bodies of the basidiomycetous species, Rigidoporus microporus, the model species for which these techniques were tested, the highest frequency of spore release occurred in the range of 62 and 96 % relative humidity. The results obtained for this model species reveal characteristic spore release patterns linked to environmental or experimental conditions, indicating that the moisture status of the sample may be a regulating factor, while temperature and light seem to play a minor role, at least for this species. The presented approach enables systematic studies aimed at the quantification and validation of spore emission rates and inventories, which can be applied to a regional mapping of cryptogamic organisms under given environmental conditions.

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