Inheritance and linkage relationships of allozymes of eastern white cedar (Thuja occidentalis) in northwestern Ontario

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 245-250 ◽  
Author(s):  
D. J. Perry ◽  
P. Knowles
Keyword(s):  
Recombination Frequency ◽  
Segregation Ratio ◽  
Starch Gel Electrophoresis ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Locus Pair ◽  
Northwestern Ontario ◽  
Northern White Cedar ◽  
Starch Gel ◽  
Eastern White Cedar

Allozyme variants of 12 enzyme systems were examined in seed tissues of eastern white cedar (Thuja occidentalis L.), using starch gel electrophoresis. Nine loci were polymorphic and deviation from a 1:1 segregation ratio was observed between two of three alleles at one locus (Mdh-1). Of the possible 36 locus-pair combinations, 23 could be tested for linkage. Significant linkage was detected for three pairs of loci (Aat-1/Mdh-1, Aat-1/Pgm, and Idh-2/Me). Trees jointly segregating for Aat-1 and Pgm fell into two classes, one with a low recombination frequency (9.1%) and the other with a higher recombination frequency (26.6%). An inversion polymorphism is a possible cause of this linkage heterogeneity observed among trees.Key words: allozymes, isozymes, inheritance, linkage, eastern white cedar, northern white cedar, Thuja occidentalis L., Cupressaceae.

Evidence of high self-fertilization in natural populations of eastern white cedar (Thuja occidentalis)

1990 ◽  
Vol 68 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Daniel J. Perry ◽  
Peggy Knowles
Keyword(s):  
Natural Populations ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
Embryo Survival ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Northwestern Ontario ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Eastern White Cedar

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at four loci (Mdh-1, Me, 6Pg-2, and Pgm) to obtain estimates of outcrossing rates for three eastern white cedar populations in northwestern Ontario, Canada. Multilocus population outcrossing rate estimates were low, ranging from 0.507 to 0.745, with significant heterogeneity among populations. Low stand densities and relatively high selfed embryo survival may have contributed to the low effective outcrossing rates observed. Single-tree multilocus outcrossing rate estimates were obtained for nine trees from one population. When estimated jointly with outcross pollen pool allele frequencies, these outcrossing rate estimates ranged from 0.253 to 1.023 with significant heterogeneity among trees. Key words: mating system, outcrossing rate, Thuja occidentalis L.

Patterns of Architectural Variation in Thuja occidentalis L. (Eastern White Cedar) from Upland and Lowland Sites

1991 ◽  
Vol 152 (4) ◽  
pp. 494-499 ◽  
Author(s):  
Christopher H. Briand ◽  
Usher Posluszny ◽  
Douglas W. Larson ◽  
Uta Matthes-Sears
Keyword(s):  
Thuja Occidentalis ◽  
White Cedar ◽  
Eastern White Cedar

Concentration of highway deicing agents along roadsides near London

1978 ◽  
Vol 56 (8) ◽  
pp. 1081-1085 ◽  
Author(s):  
A. C. Foster ◽  
M. A. Maun
Keyword(s):  
Filter Paper ◽  
Strong Correlation ◽  
Soil Samples ◽  
Freezing Rain ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
The Road ◽  
Eastern White Cedar ◽  
Snow Storms ◽  
Deicing Agents

Analysis of snow and soil samples showed that the concentrations of Na and Cl were higher near the road and decreased with increasing distance from the pavement. The level of calcium in soil did not change with distance. The concentration of calcium in the foliage of eastern white cedar trees (Thuja occidentalis L.) facing the highway was not significantly different from the concentration in the foliage on the opposite side. The filter paper discs attached to the foliage accumulated significantly high amounts of salts on days with freezing rain or snow storms. A strong correlation was found between element levels in the foliage and the levels found in filter paper discs.

Comparative seed morphology of Thuja occidentalis (eastern white cedar) from upland and lowland sites

1992 ◽  
Vol 70 (2) ◽  
pp. 434-438 ◽  
Author(s):  
Christopher H. Briand ◽  
Usher Posluszny ◽  
Douglas W. Larson
Keyword(s):  
Significant Variation ◽  
Morphological Characters ◽  
Seed Morphology ◽  
Right Wing ◽  
Habitat Types ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Character Variation ◽  
Eastern White Cedar ◽  
Individual Trees

As part of an investigation of the extent of habitat-specific variation in Thuja occidentalis L., cones were collected from cliff (dry upland) and swamp (wet lowland) sites in southern Ontario. The number of seeds per cone, number of fully developed seeds per cone, seed fresh weight, length, and width, length and width of embryo area, and length and width of right wing were determined. Seed yield on a per cone basis did not vary between habitat types or among sites within habitats. There was, however, significant variation among trees within sites. Individual seed characters did not vary between habitat types, but significant variation existed among sites within habitats, among trees within sites, and among cones within trees. Only the width of right wing failed to show cone to cone variation within individual trees. The majority of explainable variance for all characters could be apportioned to trees within sites. This and a relatively low degree of cone to cone variation suggest that the seed morphological characters were under strong maternal control. Differences among sites are thought to be the result of local environmental variation rather than genetic differences. The lack of habitat-specific seed character variation indicates that contrasting moisture regimes have little effect on quantitative seed morphology. No evidence exists for ecotypic variation with respect to seed morphology. Key words: Thuja occidentalis, eastern white cedar, seed morphology, ecotypes, cliff, swamp.

Decreased fire frequency and increased water levels affect riparian forest dynamics in southwestern boreal Quebec, Canada

2008 ◽  
Vol 38 (5) ◽  
pp. 1083-1094 ◽  
Author(s):  
Bernhard Denneler ◽  
Hugo Asselin ◽  
Yves Bergeron ◽  
Yves Bégin
Keyword(s):  
Riparian Forest ◽  
Fire Frequency ◽  
Water Levels ◽  
Ice Age ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Fraxinus Nigra ◽  
Eastern White Cedar ◽  
Black Ash ◽  
Forest Fringe

The relative importance of fire and flooding on the population dynamics of eastern white-cedar ( Thuja occidentalis L.) and black ash ( Fraxinus nigra Marsh.) was evaluated in eight old-growth riparian stands of southwestern boreal Quebec, Canada. Rising water levels and decreasing fire frequency since the end of the Little Ice Age (ca. 1850) were expected to have favoured an inland migration of the riparian forest fringe, with the flood-tolerant black ash colonizing the lower parts of the shore terraces and eastern white-cedar the upper parts. Black ash was found to be restricted to the riparian zone (<200 cm elevation), whereas eastern white-cedar trees did not occur below 100 cm above lake level. Gaps of postfire eastern white-cedar recruitment were noted in stands exposed to riparian disturbances, whereas relatively continuous recruitment occurred at protected sites. Black ash, more tolerant to flooding and ice push, invaded the shore terrace sites left vacant by eastern white-cedar. The riparian forest fringe surrounding Lake Duparquet is currently migrating upland and this trend is expected to continue as water levels continue to increase and fire frequency continues to decrease during the 21st century.

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