Relationships of mycorrhizal symbiosis, rooting strategy, and phenology among tallgrass prairie forbs

1992 ◽  
Vol 70 (8) ◽  
pp. 1521-1528 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
T. C. Todd
Keyword(s):  
Regression Analysis ◽  
Discriminant Analysis ◽  
Tallgrass Prairie ◽  
Arbuscular Mycorrhizae ◽  
Dry Weight ◽  
Mycorrhizal Symbiosis ◽  
Stepwise Discriminant Analysis ◽  
Life Strategy ◽  
Mycorrhizal Dependency ◽  
Group 2

The response of 23 tallgrass prairie forbs to mycorrhizal symbiosis and P fertilization was assessed in steamed and non-sterile prairie soil. For each plant species, root diameters, root fibrousness, root to shoot ratio, plant dry weight, mycorrhizal root colonization, mycorrhizal dependence, P dependence, and phenology were measured. Using these data, cluster analysis, stepwise discriminant analysis, and canonical discriminant analysis of the data revealed that the forbs could be divided into three distinct groups based on mycorrhizal dependence, root morphology, and phenology in descending order of importance. Cluster groups 1 and 2 contained obligately and facultatively mycotrophic forbs, respectively, while the third group did not benefit from the symbiosis. Models for prediction of mycorrhizal dependence, constructed using stepwise regression analysis, were based largely on root fibrousness. A regression analysis comparing mycorrhizal dependence and root fibrousness was conducted, and group means and 95% confidence ellipses were examined for each group. These revealed that the mycorrhizal dependence and root fibrousness of groups 1 and 3 are relatively constant regardless of P level, while the response of forbs of group 2 is more plastic, i.e., mycorrhizal dependence decreases and root fibrousness increases as P level increases. The relationship between plant response to mycorrhizal symbiosis and life strategy or growth pattern is discussed. Key words: mycorrhizal dependency, vesicular–arbuscular mycorrhizae, root systems.

Parental representation in twins discordant for schizophrenia

1993 ◽  
Vol 23 (2) ◽  
pp. 335-340 ◽  
Author(s):  
Sidsel Onstad ◽  
Ingunn Skre ◽  
Svenn Torgersen ◽  
Einar Kringlen
Keyword(s):  
Regression Analysis ◽  
Discriminant Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Parental Bonding ◽  
Important Variable ◽  
Stepwise Discriminant Analysis ◽  
Parental Bonding Instrument ◽  
Parental Representation

SynopsisParental representation was assessed with the Parental Bonding Instrument (PBI) in 12 monozygotic (MZ) and 19 dizygotic (DZ) same-sexed twin pairs discordant for DSM-III-R schizophrenia. The schizophrenic twins reported less care and more overprotection from both parents than the non-schizophrenic co-twins. Multiple regression analysis disclosed that the results were independent of sex and age. Furthermore, the analysis demonstrated that whether the twins were monozygotic or dizygotic had no impact on the results. A stepwise discriminant analysis showed that difference in perceived paternal protection was the most important variable distinguishing between schizophrenic probands and their non-schizophrenic co-twins.

scholarly journals Die voorspelling van kredietrisiko met behulp van biografiese veranderlikes: Is dit die antwoord?

1983 ◽  
Vol 14 (4) ◽  
pp. 166-171
Author(s):  
P. L.S. Ackermann ◽  
W. P. Jansen van Rensburg
Keyword(s):  
Regression Analysis ◽  
Discriminant Analysis ◽  
Credit Risk ◽  
Representative Sample ◽  
Stepwise Regression ◽  
Stepwise Regression Analysis ◽  
Stepwise Discriminant Analysis ◽  
Relative Importance ◽  
Multiple Stepwise Regression Analysis

The prediction of credit risk by means of biographic variables: Is this the answer? The objective of this study is to identify specific biographical variables, to quantity them and to investigate their relative importance in the prediction of credit risk. A representative sample of 250 bad credit risk clients and 250 good credit risk clients is used in the study. A multiple stepwise regression analysis and multiple stepwise discriminant analysis were carried out. Nine biographical variables were identified which explain approximately 16% of the variance of credit risk.

Mycorrhizal dependence and growth habit of warm-season and cool-season tallgrass prairie plants

1988 ◽  
Vol 66 (7) ◽  
pp. 1376-1380 ◽  
Author(s):  
B. A. Daniels Hetrick ◽  
D. Gerschefske Kitt ◽  
G. Thompson Wilson
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungi ◽  
Warm Season ◽  
Dry Weight ◽  
Root Systems ◽  
Mycorrhizal Symbiosis ◽  
Photosynthetic Pathway ◽  
Fibrous Root ◽  
Cool Season ◽  
Warm Season Grasses

Warm-season (C4) and cool-season (C3) mycorrhizal grasses were 63–215 and 0.12–4.1 times larger in dry weight than non-inoculated controls, respectively. Nonmycorrhizal warm-season plants did not grow and frequently died, while cool-season plants grew moderately well in the absence of mycorrhizal symbiosis. Like warm-season grasses, tallgrass prairie forbs were highly dependent on mycorrhizal symbiosis, even though they are not known to employ the C4 photosynthetic pathway. Thus, phenology may be more critical than photosynthetic pathway in determining mycorrhizal dependence. Warm-season grasses and forbs had coarser, less frequently branched root systems than cool-season grasses, supporting the hypothesis that mycorrhizal dependence is related to root morphology. Cool-season grasses may have developed more fibrous root systems because mycorrhizal nutrient uptake was not effective in the colder temperate environment in which they evolved. In contrast, warm-season plants and dependence on mycorrhizal fungi may have coevolved, because both symbionts are of tropical origin.

Relationship between mycorrhizal dependence and competitive ability of two tallgrass prairie grasses

1989 ◽  
Vol 67 (9) ◽  
pp. 2608-2615 ◽  
Author(s):  
B. A. D. Hetrick ◽  
G. W. T. Wilson ◽  
D. C. Hartnett
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungus ◽  
Warm Season ◽  
Dry Weight ◽  
Andropogon Gerardii ◽  
Mycorrhizal Symbiosis ◽  
P Fertilization ◽  
Growing Seasons ◽  
Prairie Grasses ◽  
The Impact

The impact of mycorrhizal symbiosis on growth of Andropogon gerardii (big bluestem) and Koeleria pyranidata (junegrass) was compared. Andropogon gerardii was 98% dependent on the symbiosis, whereas K. pyranidata displayed less than 0.02% dependence. Mycorrhizal fungus inoculation resulted in 50 times larger A. gerardii plants but did not alter growth of K. pyranidata. When competing in pairs, A. gerardii dominated when the mycorrhizal symbiosis was present and K. pyranidata dominated when it was not present. Dry weight of mycorrhizal A. gerardii was altered, whether grown alone or with K. pyranidata, but mycorrhizal K. pyranidata grew well only in the absence of competition and failed to grow appreciably if A. gerardii was present. Without mycorrhizal fungus inoculation, A. gerardii did not grow and had no deleterious effects on K. pyranidata. When P fertilization was substituted for mycorrhizal fungus inoculation, A. gerardii grew better alone than in competition with K. pyranidata at low P levels but was not affected by competition at high P levels. Koeleria pyranidata was not affected by competition at low P levels, but high P fertilization resulted in reduced dry weight of K. pyranidata plants when in competition with A. gerardii. Phenologic separation of growing seasons avoids interspecific competition between these two grasses and may be one mechanism contributing toward their coexistence. Since low temperatures limit mycorrhizal nutrient uptake, phenologic separation of growing seasons could also avoid the competitive advantage of warm-season grasses conferred by their mycorrhizal dependence.

Use of Continuous Blood Volume Monitoring to Detect Inadequately High Dry Weight

1996 ◽  
Vol 19 (7) ◽  
pp. 411-414 ◽  
Author(s):  
F. Lopot ◽  
P. Kotyk ◽  
J. Bláha ◽  
J. Forejt
Keyword(s):  
Blood Volume ◽  
Vena Cava ◽  
Extracellular Fluid ◽  
Dry Weight ◽  
Whole Body ◽  
The Status ◽  
Varying Length ◽  
Group 3 ◽  
Group 2 ◽  
Total Body

A continuous blood volume monitoring (CBVM) device (Inline Diagnostics, Riverdale, USA) was used to study response to prescribed ultrafiltration during haemodialysis (HD) in 66 stabilised HD patients. Fifty percent of patients showed the expected linear decrease in BV right from the beginning of HD (group 1), 32% exhibited no decrease at all (group 2), while eighteen percent formed the transient group 3 which showed a plateau of varying length after which a decrease occurred. The correct setting of dry weight was verified through evaluation of the ratio of extracellular fluid volume to total body water (VEC/TBW) in 26 patients by means of whole body multifrequency impedometry MFI (Xitron Tech., San Diego, USA) and through measurement of the Vena Cava Inferior diameter (VCID) pre and post HD (in 6 and 5 patients from groups 1 and 3 and from group 2, respectively). The mean VEC/TBW in groups 1 and 3 was 0.56 pre and 0.51 post HD as compared to 0.583 and 0.551 in group 2. VCID decreased on average by 14.1% in groups 1 and 3 but remained stable in group 2. Both findings thus confirmed inadequately high estimation of dry weight. Since CBVM is extremely easy to perform it can be used as a method of choice in detecting inadequately high prescribed dry weight. The status of the cardiovascular system must always be considered before final judgement is made.

Epicuticular waxes of the genus Hordeum: a survey of their chemical composition and ultrastructure

1989 ◽  
Vol 67 (11) ◽  
pp. 3219-3226 ◽  
Author(s):  
Bernard R. Baum ◽  
A. Pat Tulloch ◽  
L. Grant Bailey
Keyword(s):  
Chemical Composition ◽  
Discriminant Analysis ◽  
Alcohol Content ◽  
Total Absence ◽  
Average Alcohol ◽  
The Common ◽  
Group 2 ◽  
Whole Plants ◽  
Almost All ◽  
Group 1

This study was based on 148 accessions representing 39 species of Hordeum. SEM ultrastructural morphology of waxes was based on individual spikelets, whereas waxes' chemical composition was assessed from whole plants. When all the data, in the form of individual accessions, were subjected to various cluster analyses methods, no groupings were revealed. But when the data were first summarized by species and then subjected to clustering, two polythetic groups of species were detected. Group 1 is characterized by species with 40–60% average alcohol content and by the common presence of diketones, whereas group 2 is characterized by species with 61 – 80% average alcohol content, by the total absence of hydroxy-β-diketone, and almost all species without β-diketone. The chemical data were then subjected to classificatory discriminant analysis to assess if a single previously unclassified accession could be identified into one of the two groupings. The nature of the differences between the two groupings was described by means of a canonical discriminant analysis. Mostly only plates and filaments were detected, and in many accessions the filaments were widened, appeared platelike, and were characteristic for one group. Presence of β-diketone varied within species. Hordeum violaceum was found to be unique in chemical composition.

scholarly journals BETTER ALTERNATIVES FOR STEPWISE DISCRIMINANT ANALYSIS

2015 ◽  
Vol 1 (311) ◽  
Author(s):  
Katarzyna Stąpor
Keyword(s):  
Feature Selection ◽  
Discriminant Analysis ◽  
Tabu Search ◽  
Stepwise Discriminant Analysis ◽  
Selection Methods ◽  
Discrimination Power ◽  
Statistical Software ◽  
Software Packages ◽  
Benchmark Datasets

Discriminant Analysis can best be defined as a technique which allows the classification of an individual into several dictinctive populations on the basis of a set of measurements. Stepwise discriminant analysis (SDA) is concerned with selecting the most important variables whilst retaining the highest discrimination power possible. The process of selecting a smaller number of variables is often necessary for a variety number of reasons. In the existing statistical software packages SDA is based on the classic feature selection methods. Many problems with such stepwise procedures have been identified. In this work the new method based on the metaheuristic strategy tabu search will be presented together with the experimental results conducted on the selected benchmark datasets. The results are promising.

Relationship of Specific and Nonspecific Variables to Successful Basketball Performance among High School Players

1987 ◽  
Vol 64 (3) ◽  
pp. 823-827 ◽  
Author(s):  
Mark A. Brooks ◽  
Larry W. Boleach ◽  
J. L. Mayhew
Keyword(s):  
High School ◽  
Regression Analysis ◽  
Reaction Time ◽  
Discriminant Analysis ◽  
Multiple Regression Analysis ◽  
Canonical Correlation ◽  
Vertical Jump ◽  
The Third ◽  
Male High School ◽  
Relationship Of

To determine the predictive potential of selected cognitive and psychomotor variables to estimate basketball performance, 50 male high school players from 3 schools in the same conference were evaluated. One team won the Iowa state championship; the second team had a 12 and 10 record while the third team had a 4 and 16 record. The 3 coaches rated each player's ability from 1 to 10. Multiple regression analysis to predict coaches' rating of ability from vertical jump, hand reaction time, weight, and playing experience gave an R of .76. However, discriminant analysis to classify players on the 3 teams indicated as important knowledge about basketball, dribbling, shooting accuracy, and height. The canonical correlation for the 4 variables and team membership was .64. Using the 4 variables, 60% of the players could be correctly classified to their teams.

Dual mycorrhizal symbiosis: an asset for eucalypts out of Australia?

2017 ◽  
Vol 47 (4) ◽  
pp. 500-505 ◽  
Author(s):  
Djamila Adjoud-Sadadou ◽  
Rosa Halli-Hargas
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Dry Season ◽  
Mycorrhizal Symbiosis ◽  
Limiting Factor ◽  
Wet Season ◽  
Opposite Pattern ◽  
Symbiotic Associations ◽  
Mycorrhizal Status ◽  
Old Trees

The dual symbiotic habit of the genus Eucalyptus is well documented: while arbuscular mycorrhizae are always dominant in seedlings and young trees, they are replaced by ectomycorrhizae in older trees. Here, the mycorrhizal status of eucalypts of different ages was assessed over the year in three plantations in the humid Mediterranean climate zone of Algeria (using morphological, anatomical, and histological criteria) and quantified in the dry and wet seasons over three years (using the grid-line intersect method of Giovannetti and Mosse (1980, New Phytol. 84: 489–500, doi: 10.1111/j.1469-8137.1980.tb04556.x ) on randomized fine root segments). Unexpectedly, the results revealed the persistence of arbuscular mycorrhizae in old trees and their dominance over ectomycorrhizae during the dry season, while the opposite pattern was observed in the wet season. Composite mycorrhizae displaying intimately mixed arbuscular mycorrhizae and ectomycorrhizae anatomical structures also occurred and were more frequent during the dry season. Eucalypts were clearly able to form a wide diversity of symbiotic associations with arbuscular mycorrhizal and ectomycorrhizal fungi locally associated with native trees, shrubs, and herbaceous plants. Therefore, the mycorrhizal status should not be a limiting factor to the silviculture of eucalypts in this area of Algeria because the dual symbiotic habit provides complementary benefits in a poor soil and in an alien environment.

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