Phenotypic plasticity and contrasting habitat colonization in Festuca pallescens

1993 ◽  
Vol 71 (7) ◽  
pp. 970-977 ◽  
Author(s):  
Gabriel Oliva ◽  
Arturo Martínez ◽  
Marta Collantes ◽  
Jorge Dubcovsky
Keyword(s):  
Phenotypic Plasticity ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Widespread Species ◽  
Southern Patagonia ◽  
Spikelets Per Panicle ◽  
Habitat Colonization ◽  
Components Analysis ◽  
Festuca Pallescens ◽  
Plastic Components

Eight populations of Festuca pallescens (Poaceae) from southern Patagonia (Argentina) were chosen to test whether their morphology and anatomy were associated with climatic and edaphic characteristics of their habitats and to discriminate genetic and plastic components of the variation. Fourteen environmental variables were measured to characterize eight localities. Cluster analysis classified them into four habitats. Principal components analysis based on 22 morphological and anatomical characters of five individuals from each population was performed. This ordination grouped them by habitat. Small plants with a low number of spikelets were found in the xeric habitat, whereas plants of the saline habitat showed a significantly higher number of spikelets. Large plants were characteristic of the humid habitats, but at higher elevations of foothill humid valleys the plants produced few spikelets per panicle with larger lemmas and heavier propagules than those in the coastal humid plains. A larger sample of 10 populations drawn from across the distribution of F. pallescens showed that seed collected at high altitudes were significantly heavier then those collected near sea level. The same characters were measured again 1 year after transplanting to uniform conditions. Significant differences between habitats disappeared. These data showed that phenotypic plasticity allows for diverse habitat colonization of this widespread species. Key words: Gramineae, phenotypical plasticity, seed weight, principal components analysis, ecotypes.

Genetic and environmental contributions to multivariate morphological pattern in Puccinellia (Poaceae)

1988 ◽  
Vol 66 (12) ◽  
pp. 2436-2444 ◽  
Author(s):  
Jerrold I. Davis
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Morphological Characters ◽  
Morphological Pattern ◽  
The North ◽  
Two Samples ◽  
Environmental Component ◽  
Components Analysis ◽  
Complex Variation ◽  
Plastic Components

The contributions of genetic and environmental variation to multivariate patterns in morphology were investigated in a comparative analysis of two samples of plants representing the Puccinellia nuttalliana complex (Poaceae). The first sample is a series of individuals (genotypes) collected live, vegetatively divided, and grown under controlled environmental conditions. Phenotypic variation in this sample, in individual characters and in multivariate factors, can be apportioned between genetic (among genotype) and environmental (among treatment) causes. The second sample consists of field-collected individuals from throughout the North American range of the complex. Variation in this sample, as in most field-collected samples, cannot be assigned directly to its underlying causes. Multivariate patterns in the two samples were analyzed by identical principal-components analyses of 48 morphological characters. The strongest factor identified by the greenhouse principal-components analysis correlates with the strongest of the field principal-components analysis; they are similar in character makeup, both reflecting spikelet size and plant scabrousness. These factors have a genetic component and no environmental component and appear to differentiate Puccinellia distans from the rest of the complex. The second strongest factor of the greenhouse principal-components analysis correlates with the second of the field principal-components analysis. These axes reflect general vegetative stature; they have genetic and plastic components. The overall analysis indicates that multivariate patterns in phenotype can reflect both genetic and environmental effects, in varying proportions; patterns of genetic affinity therefore may be difficult to dissociate from those reflecting plasticity.

Zooplancton limnétique de 46 lacs et 17 rivières du territoire de la baie de James

1979 ◽  
Vol 57 (8) ◽  
pp. 1693-1709 ◽  
Author(s):  
Bernadette Pinel-Alloul ◽  
Pierre Legendre ◽  
Etienne Magnin
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Statistical Analyses ◽  
Environmental Data ◽  
James Bay ◽  
Single Linkage ◽  
Widespread Species ◽  
Bay Area ◽  
Components Analysis ◽  
Western Portion

From June through October 1973, 335 samples of limnetic plankton were collected from 46 lakes and 17 rivers of the James Bay area. Sixty zooplanktonic species were identified (20 Copepoda, 27 Cladocera, and 13 Rotifera). The most common and widespread species are cold stenotherms (Leptodiaptomus minutus, Diacyclops bicuspidatus thomasi, Epischura lacustris, Holopedium gibberum, Bosmina longirostris, Daphnia longiremis, and Kellicottia longispina). In order to study the typology of the lake samples, the data were subjected to three types of statistical analyses: principal components analysis, single linkage, and complete linkage clustering. Five groups of lakes emerged from these analyses: types IV and V are located in the northeastern portion of the studied area, whereas types I and II were identified in the western portion, corresponding with the area occupied by the Tyrrell glacial sea. Type III fills an intermediate position. Types II, III, and V are smalt lakes. The characteristic zooplanktonic communities of each group are described, whereas the principal components and the components of the diversity are correlated with the environmental data.

Diagnoses Generated by Numerical Taxonomic Methods Applied to Standard Blood Variables

1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton
Keyword(s):  
Liver Cirrhosis ◽  
Renal Disease ◽  
Principal Components Analysis ◽  
Discriminant Function ◽  
Principal Components ◽  
Discriminant Function Analysis ◽  
Chronic Renal Disease ◽  
Function Analysis ◽  
Infectious Hepatitis ◽  
Components Analysis

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.

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