Phenotypic plasticity in leaves of four species of arctic Festuca (Poaceae)

1995 ◽  
Vol 73 (11) ◽  
pp. 1810-1823 ◽  
Author(s):  
Nicole S. Ramesar-Fortner ◽  
Nancy G. Dengler ◽  
Susan G. Aiken
Keyword(s):  
Phenotypic Plasticity ◽  
Cross Sections ◽  
Leaf Blade ◽  
Growth Traits ◽  
Continuous Light ◽  
Taxonomic Status ◽  
Trichome Density ◽  
Experimental Conditions ◽  
University Of Toronto ◽  
Species Specific

Leaf phenotypic plasticity of 12 morphological, anatomical, and growth traits was investigated using four species of arctic Festuca (F. baffinensis, F. brachyphylla, F. edlundiae, and F. hyperborea). Plants collected around 78°N in the Canadian Arctic Archipelago were grown for 10 weeks at the University of Toronto in growth chambers in continuous light, under four regimes of temperature and moisture. Significant differences were found between leaves at the time of field collection and leaves of the same plant at the end of the experiment in (i) leaf blade length, (ii) surface vestiture, both in trichome density and angle of the trichomes to the blade surface, and (iii) characters seen in leaf cross sections: blade width, rib thickness, and inter-rib thickness. The four species responded similarly to the experimental conditions, indicating that most of these changes represent part of the developmentally inevitable component of plasticity rather than species-specific adaptations. Trichome density was the only characteristic for which species showed different patterns of response, with a unique pattern of response in F. edlundiae. This and certain growth traits support the taxonomic status of this newly recognized species. The significant effects of temperature and to a lesser degree, water treatments on these leaf anatomical traits indicate that they should be used with caution for the purposes of taxonomy and identification. Key words: Festuca, leaf blade anatomy, phenotypic plasticity.

scholarly journals Geographical Variation in Phenotypic Plasticity of Intertidal Sister Limpet’s Species Under Ocean Acidification Scenarios

2021 ◽  
Vol 8 ◽  
Author(s):  
Marco Antonio Lardies ◽  
Paz Caballero ◽  
Cristián Duarte ◽  
María Josefina Poupin
Keyword(s):  
Growth Rate ◽  
Phenotypic Plasticity ◽  
Ocean Acidification ◽  
Carbonate Content ◽  
Experimental Conditions ◽  
Variable Environment ◽  
Chilean Coast ◽  
Stable Environment ◽  
Evolutionary Level ◽  
Species Specific

Ocean Acidification (OA) can have pervasive effects in calcifying marine organisms, and a better understanding of how different populations respond at the physiological and evolutionary level could help to model the impacts of global change in marine ecosystems. Due to its natural geography and oceanographic processes, the Chilean coast provides a natural laboratory where benthic organisms are frequently exposed to diverse projected OA scenarios. The goal of this study was to assess whether a population of mollusks thriving in a more variable environment (Talcaruca) would present higher phenotypic plasticity in physiological and morphological traits in response to different pCO2 when compared to a population of the same species from a more stable environment (Los Molles). To achieve this, two benthic limpets (Scurria zebrina and Scurria viridula) inhabiting these two contrasting localities were exposed to ocean acidification experimental conditions representing the current pCO2 in the Chilean coast (500 μatm) and the levels predicted for the year 2100 in upwelling zones (1500 (μatm). Our results show that the responses to OA are species-specific, even in this related species. Interestingly, S. viridula showed better performance under OA than S. zebrina (i.e., similar sizes and carbonate content in individuals from both populations; lower effects of acidification on the growth rate combined with a reduction of metabolism at higher pCO2). Remarkably, these characteristics could explain this species’ success in overstepping the biogeographical break in the area of Talcaruca, which S. zebrina cannot achieve. Besides, the results show that the habitat factor has a strong influence on some traits. For instance, individuals from Talcaruca presented a higher growth rate plasticity index and lower shell dissolution rates in acidified conditions than those from Los Molles. These results show that limpets from the variable environment tend to display higher plasticity, buffering the physiological effects of OA compared with limpets from the more stable environment. Taken together, these findings highlight the key role of geographic variation in phenotypic plasticity to determine the vulnerability of calcifying organisms to future scenarios of OA.

Leaf anatomy of the South African Danthonieae (Poaceae). II. Merxmuellera disticha

Bothalia ◽  
1980 ◽  
Vol 13 (1/2) ◽  
pp. 185-189 ◽  
Author(s):  
R. P. Ellis
Keyword(s):  
South African ◽  
Leaf Anatomy ◽  
Leaf Blade ◽  
Transverse Section ◽  
Taxonomic Status ◽  
Anatomical Structure ◽  
The South ◽  
Abaxial Epidermis ◽  
Environmental Requirements

The anatomical structure, of the leaf blade as seen in transverse section, and of the abaxial epidermis, of Merxmuellera disticha (Nees) Conert is described and illustrated. Three distinct anatomical “forms” are recognized viz. typical M. disticha, the Drakensberg form and the alpine bog form. These three anatomical groups also appear to have differing environmental requirements and probably warrant taxonomic status.

scholarly journals Sex aggregation and species segregation cues in swarming mosquitoes: role of ground visual markers

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Serge B. Poda ◽  
Charles Nignan ◽  
Olivier Gnankiné ◽  
Roch K. Dabiré ◽  
Abdoulaye Diabaté ◽  
...  
Keyword(s):  
Experimental Conditions ◽  
Closely Related Species ◽  
Laboratory Setup ◽  
Visual Markers ◽  
Constant Distance ◽  
Species Specific ◽  
Marker Size ◽  
Swarm Size ◽  
Species Segregation

Abstract Background Mating swarm segregation in closely related insect species may contribute to reproductive isolation. Visual markers are used for swarm formation; however, it is unknown whether they play a key role in swarm location, species segregation and sex aggregation. Methods Using two sympatric closely related species of the Anopheles gambiae complex, An. coluzzii and An. gambiae (s.s.), we investigated in both laboratory and semi-field conditions (i) whether males of the two species use visual markers (black cloths) to locate their swarm; and (ii) whether the presence/absence and size of the marker may differentially affect swarm characteristics. We also investigated whether conspecific virgin females use these markers to join male swarm sites. Results We showed that males of the two species used visual markers but in different ways: An. coluzzii swarm right above the marker whereas An. gambiae (s.s.) locate their swarm at a constant distance of 76.4 ± 0.6 cm from a 20 × 20 cm marker in the laboratory setup and at 206 ± 6 cm from a 60 × 60 cm marker in the semi-field setup. Although increased marker size recruited more mosquitoes and consequently increased the swarm size in the two species, An. coluzzii swarms flew higher and were stretched both vertically and horizontally, while An. gambiae (s.s.) swarms were only stretched horizontally. Virgin females displayed a swarm-like behavior with similar characteristics to their conspecific males. Conclusions Our results provided experimental evidence that both An. coluzzii and An. gambiae (s.s.) males use ground visual markers to form and locate their swarm at species-specific locations. Moreover, the marker size differentially affected swarm characteristics in the two species. Our results also showed that virgin females displayed a swarm-like behavior. However, these “swarms” could be due to the absence of males in our experimental conditions. Nevertheless, the fact that females displayed these “swarms” with the same characteristics as their respective males provided evidence that visual markers are used by the two sexes to join mating spots. Altogether, this suggests that visual markers and the way species and sexes use them could be key cues in species segregation, swarm location and recognition.

scholarly journals The Role of Plasticity and Adaptation in the Incipient Speciation of a Fire Salamander Population

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 875
Author(s):  
Joana Sabino-Pinto ◽  
Daniel J. Goedbloed ◽  
Eugenia Sanchez ◽  
Till Czypionka ◽  
Arne W. Nolte ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phenotypic Plasticity ◽  
Local Adaptation ◽  
Habitat Preferences ◽  
Genetic Change ◽  
Incipient Speciation ◽  
Expression Of Genes ◽  
Species Specific ◽  
Reciprocal Transfer ◽  
High Degree

Phenotypic plasticity and local adaptation via genetic change are two major mechanisms of response to dynamic environmental conditions. These mechanisms are not mutually exclusive, since genetic change can establish similar phenotypes to plasticity. This connection between both mechanisms raises the question of how much of the variation observed between species or populations is plastic and how much of it is genetic. In this study, we used a structured population of fire salamanders (Salamandra salamandra), in which two subpopulations differ in terms of physiology, genetics, mate-, and habitat preferences. Our goal was to identify candidate genes for differential habitat adaptation in this system, and to explore the degree of plasticity compared to local adaptation. We therefore performed a reciprocal transfer experiment of stream- and pond-originated salamander larvae and analyzed changes in morphology and transcriptomic profile (using species-specific microarrays). We observed that stream- and pond-originated individuals diverge in morphology and gene expression. For instance, pond-originated larvae have larger gills, likely to cope with oxygen-poor ponds. When transferred to streams, pond-originated larvae showed a high degree of plasticity, resembling the morphology and gene expression of stream-originated larvae (reversion); however the same was not found for stream-originated larvae when transferred to ponds, where the expression of genes related to reduction-oxidation processes was increased, possibly to cope with environmental stress. The lack of symmetrical responses between transplanted animals highlights the fact that the adaptations are not fully plastic and that some level of local adaptation has already occurred in this population. This study illuminates the process by which phenotypic plasticity allows local adaptation to new environments and its potential role in the pathway of incipient speciation.

scholarly journals Cytogenetics of two Farlowella species (Loricariidae: Loricariinae): implications on the taxonomic status of the species

2018 ◽  
Vol 16 (4) ◽  
Author(s):  
Leandro Marajó ◽  
Patrik F. Viana ◽  
Milena Ferreira ◽  
Lúcia H. Rapp Py-Daniel ◽  
Eliana Feldberg
Keyword(s):  
Chromosome Number ◽  
Species Complex ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Taxonomic Status ◽  
Specific Marker ◽  
Genetic Studies ◽  
Molecular Cytogenetic ◽  
Metacentric Pair ◽  
Species Specific

ABSTRACT Farlowella is one of the most diverse genera of the Loricariinae, restricted to South America rivers. The taxonomic and phylogenetic relationships among its species are contentious and, while genetic studies would contribute to the understanding of their relationships, the only available datum refer to the karyotype description of only one species. In the present study two Amazonian species, Farlowella cf. amazonum and F. schreitmuelleri, were analyzed using conventional and molecular cytogenetic procedures. Both species had diploid chromosome number 58, but different fundamental numbers (NF) 116 and 112, respectively, indicative of chromosomal rearrangements. C-banding is almost poor, especially in F. cf. amazonum, and occurs predominantly in the centromeric and in some telomeric regions, although genome of F. schreitmuelleri possessed a much larger heterochromatin amount then those of F. cf. amazonum. The chromosomes bearing the NOR sites were likely the same for both species, corresponding to the 1st metacentric pair in F. cf. amazonum and to the 28th acrocentric in F. schreitmuelleri. The location of the 5S rDNA was species-specific marker. This study expanded the available cytogenetic data for Farlowella species and pointed the remarkable karyotype diversity among species/populations, indicating a possible species complex within genus.

Intraluminal three-dimensional optical coherence tomography – a tool for imaging of the Eustachian tube?

2019 ◽  
Vol 133 (2) ◽  
pp. 87-94 ◽  
Author(s):  
R Schuon ◽  
B Mrevlje ◽  
B Vollmar ◽  
T Lenarz ◽  
G Paasche
Keyword(s):  
Optical Coherence Tomography ◽  
Eustachian Tube ◽  
Cross Sections ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Diagnostic Value ◽  
Optical Coherence ◽  
Experimental Conditions ◽  
Non Invasive ◽  
Tube Dysfunction

AbstractObjectivesThe cause of Eustachian tube dysfunction often remains unclear. Therefore, this study aimed to examine the feasibility and possible diagnostic use of optical coherence tomography in the Eustachian tube ex vivo.MethodsTwo female blackface sheep cadaver heads were examined bilaterally. Three conditions of the Eustachian tube were investigated: closed (resting position), actively opened and stented. The findings were compared (and correlated) with segmented histological cross-sections.ResultsIntraluminal placement of the Eustachian tube with the optical coherence tomography catheter was performed without difficulty. Regarding the limited infiltration depth of optical coherence tomography, tissues can be differentiated. The localisation of the stent was accurate as was the lumen.ConclusionThe application of optical coherence tomography in the Eustachian tube under these experimental conditions is considered to be a feasible, rapid and non-invasive diagnostic method, with possible diagnostic value for determining the luminal shape and superficial lining tissue of the Eustachian tube.

Variability of leaf blade anatomical traits in the Sesleria juncifolia complex (Poaceae) on the Balkan Peninsula

Phytotaxa ◽  
2020 ◽  
Vol 442 (3) ◽  
pp. 138-152
Author(s):  
TIJANA ĐENADER ◽  
DMITAR LAKUŠIĆ ◽  
NEVENA KUZMANOVIĆ
Keyword(s):  
Cross Sections ◽  
Leaf Blade ◽  
Function Analysis ◽  
A Priori ◽  
Principal Component ◽  
Balkan Peninsula ◽  
Character State ◽  
Adaxial Side ◽  
Qualitative Characters ◽  
Different Populations

This paper presents the results of a detailed study of leaf blade anatomical traits of populations of the Sesleria juncifolia complex from the Balkan Peninsula. The measurements were performed on cross sections of 302 tiller leaf blades from 24 populations. We calculated basic descriptive statistics for each character state. Principal component and canonical discriminant analyses were used to identify the structure of variability and the characters that majorly contributed to the differentiation of the defined groups. Cluster analysis was done to estimate the distances among the studied populations. We provide a detailed description of the leaf blade anatomy of the different populations of S. juncifolia complex investigated within Croatia, Bosnia and Herzegovina, Montenegro, Serbia and North Macedonia. The results show that most of the characters exhibit moderate degrees of variation. The principal component analysis shows slight separation of populations from northwestern Croatia. Canonical discriminant analysis shows that the three a priori defined groups—three species, S. interrupta, S. juncifolia and S. ujhelyii, can be distinguished based on leaf blade anatomical characters. In addition to the characters that were singled out as statistically most significant for differentiation of the three species in discriminant function analysis, the most useful characters for their delimitation are the length of the trichomes on the adaxial side of the leaf, as well as qualitative characters such as the sclerenchyma on the abaxial side of the leaf (continuous or interrupted) and the type of indumentum of the adaxial side of the leaf (very hairy, hairs long vs. very weakly hairy, hairs short). The northwestern populations of S. juncifolia mostly have glabrous leaves or single hairs on the adaxial side of the leaf, while in S. interrupta and S. ujhelyii populations, individuals always have hairy leaves. The presence of continuous subepidermal sclerenchyma has proven to be a good differential character for separating S. ujhelyii from the S. juncifolia and S. interrupta.

scholarly journals Polyploidy as a chromosomal component of stochastic noise: variable scalar multiples of the diploid chromosome complement in the invertebrate species Girardia schubarti from Brazil

2017 ◽  
Vol 77 (4) ◽  
pp. 745-751 ◽  
Author(s):  
E. G. F. Benya ◽  
A. M. Leal-Zanchet ◽  
J. Hauser
Keyword(s):  
Phenotypic Plasticity ◽  
Chromosome Complement ◽  
Dorsal Surface ◽  
Phenotypic Variance ◽  
Stochastic Noise ◽  
Body Width ◽  
Invertebrate Species ◽  
Geometric Progressions ◽  
Species Specific ◽  
Kinetics Of

Abstract Chromosome stoichiometry, a form of genetic plasticity, specifically refers to variation in the standard diploid genomic composition of an individual or species. In the present work, freshwater planarians (Girardia schubarti) were analyzed to recognize variations in chromosomal stoichiometry especially of complete ploidal change between specimens, within specimens and between cells within specimens and any relations they might have with selected components of phenotypic plasticity. Homoploid polyploids for the group reached rational scalar multiples (e.g. tetraploids) or irrational scalar multiples (e.g. triploids). Karyotypic mosaics emerged where individual cells presented polyploid multiples in arithmetic and geometric progressions. Ploidal multiplicity, a chromosomal component of stochastic noise, had positive phenotypic effects (increased dimensions) on morphologic criteria of body length, body width and dorsal surface reflecting a significant genotypic plasticity (GP) and robust phenotypic plasticity (PP). Variable but significant association of genotypic plasticity with robust phenotypic variance suggests kinetics of phenotypic homeostasis that is species-specific permitting phenotypic adaptability to environmental variables by means of GP. That association is diminished, deactivated or lost in more advanced and more complex organisms.

scholarly journals The MGED Ontology: A Framework for Describing Functional Genomics Experiments

2003 ◽  
Vol 4 (1) ◽  
pp. 127-132 ◽  
Author(s):  
Christian J. Stoeckert ◽  
Helen Parkinson
Keyword(s):  
Functional Genomics ◽  
Microarray Gene Expression Data ◽  
Experimental Information ◽  
Experimental Sample ◽  
Experimental Conditions ◽  
Microarray Gene Expression ◽  
Microarray Experiments ◽  
Different Types ◽  
Species Specific ◽  
Initial Focus

The Microarray Gene Expression Data (MGED) society was formed with an initial focus on experiments involving microarray technology. Despite the diversity of applications, there are common concepts used and a common need to capture experimental information in a standardized manner. In building the MGED ontology, it was recognized that it would be impractical to cover all the different types of experiments on all the different types of organisms by listing and defining all the types of organisms and their properties. Our solution was to create a framework for describing microarray experiments with an initial focus on the biological sample and its manipulation. For concepts that are common for many species, we could provide a manageable listing of controlled terms. For concepts that are species-specific or whose values cannot be readily listed, we created an ‘OntologyEntry’ concept that referenced an external resource. The MGED ontology is a work in progress that needs additional instances and particularly needs constraints to be added. The ontology currently covers the experimental sample and design, and we have begun capturing aspects of the microarrays themselves as well. The primary application of the ontology will be to develop forms for entering information into databases, and consequently allowing queries, taking advantage of the structure provided by the ontology. The application of an ontology of experimental conditions extends beyond microarray experiments and, as the scope of MGED includes other aspects of functional genomics, so too will the MGED ontology.

scholarly journals Modeling radiative proton-capture reactions in mid-heavy nuclei

2019 ◽  
Vol 23 ◽  
pp. 146
Author(s):  
E. Batziou ◽  
V. Koutsilianou ◽  
L. Stavropoulos ◽  
A. Psaltis ◽  
T. J. Mertzimekis
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Systematic Study ◽  
Low Energy ◽  
Heavy Nuclei ◽  
Proton Capture ◽  
Experimental Conditions ◽  
Energy Regime ◽  
Theoretical Predictions ◽  
Near Future

A systematic study of (p,γ) reactions was carried out using the reaction codes EMPIRΕ, TALYS and NON-SMOKER (web). The calculated (p,γ) cross sections of seed nuclei 89Y, 107,109Ag, 106,108,110Pd, 112Cd, 121,123Sb, 127I, and 133Cs can be used in a three-fold way: (a) perform an intercomparison of the models in a low-energy regime (b) compare existing experimental data to the theoretical predictions and (c) predict cross sections of reactions planned to be studied experimentally in the near future by our group. The results of the study are presented in a concise way focusing on the experimental conditions.

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