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Jane has the kind of selflessness that everyone looks for in a friend. Lately the perennial bridesmaid has begun to feel as if something is missing in her life. Kevin is a local newspaper reporter who spots Jane racing between two receptions - one in Manhattan and the other in Brooklyn. He quickly surmises that her quirky tale may be just the story to get him into the big leagues. Jane butts heads with Kevin just as her younger sister, Tess, shows up in town. Now, Jane is prompted to reevaluate her priorities when her boss - with whom she is secretly in love - falls for her younger sister. As the bride-to-be makes plans to marry, she mistakenly assumes Jane will be happy to take part in the wedding. Jane finally comes to terms with her true feelings and her life begins to change in ways she never expected.
DVD
AILANTHUS ALTISSIMA STIMULATES LEGUME NODULATION IN TRIFOLIUM PRATENSE VIA ROOT EXUDATES
Ailanthus altissima, an invasive Asiatic tree, is notable for its rapid growth rate (particularly in nutrient-poor soils), root-based cloning, and allelopathy. We investigated whether root exudates from A. altissima stimulate nodulation of red clover, Trifolium pratense, as a mechanism by which the former species may increase nitrogen availability and facilitate its own rapid growth and reproduction. To test this possibility and account for the effects of nutrient availability, we conducted a greenhouse experiment that included a full factorial design with 30 T. pratense in each of the following treatments: (1) presence versus absence of A. altissima in leachate source pots, (2) fertilization versus nonfertilization of leachate source pots, and (3) fertilization versus nonfertilization of pots containing T. pratense. Soil leachates acquired from source pots (half of which contained 8-wk-old A. altissima) were applied to pots containing 1-wk-old T. pratense for 7 wk and harvested 1 wk thereafter. (1) Total biomass and shoot:root ratio of T. pratense were unaffected by the presence of A. altissima in leachate source pots. (2) Presence of A. altissima resulted in a 2.57-fold increase in the proportion of T. pratense possessing nodules, an effect that was greatest when the leachate source pots were also fertilized. (3) Presence of A. altissima was associated with a 261% increase in the number of nodules per unit total (Trifolium) biomass and a 171% increase in nodule biomass per unit total biomass; these traits were otherwise unaffected. Root exudates from A. altissima stimulate nodulation by T. pratense, regardless of the nutrient status (fertilization) experienced by either species. The nodule-stimulating mechanism reported here may be responsible -- at least in part -- for previous reports of increased soil nitrogen levels associated with invasion by A. altissima, a nutrient increase that likely facilitates its growth, allelopathy, and reproduction.
Journal Article
Pheromonal Interactions among Gametophytes of Osmundastrum cinnamomeum and the Origins of Antheridiogen Systems in Leptosporangiate Ferns
Antheridiogen systems, whereby notch-bearing, archegoniate gametophytes induce maleness in ameristic neighbors, have been detected in many core leptosporangiate ferns. Previous studies have failed to detect an antheridiogen system in Osmundales, which is sister to all other extant leptosporangiates; hence, antheridiogen systems are thought to have evolved after their divergence. Detailed studies of morphological development and patterns of gender expression in Osmundales and other basal leptosporangiate clades are needed to clarify how antheridiogen systems evolved. Here, we tracked the development and gender expression of gametophytes of Osmundastrum cinnamomeum grown in isolation and multispore populations exposed to basal media (control), gibberellic acid (GA3), and an older generation of gametophytes. A notch-producing apical meristem invariably preceded antheridia and archegonia production in O. cinnamomeum. Exposure to either GA3 or an older generation of gametophytes delayed growth rates and prolonged asexual and male status, whereas the multispore control possessed significantly greater proportions of females relative to isolates. Our observations confirm the existence of a putative antheridiogen system in Osmundales and a mechanism by which male-first expression is bypassed by a subset of the population. The evolution of fully developed antheridiogen systems in core leptosporangiate families may have involved the decoupling of the formation of a notch meristem from the production of antheridia in an ancestor with an Osmundales-type pattern of gender expression.
Journal Article
Tree Architecture as a Determinant of and Respondent to Forest Stand Structure
Trees are under strong selection to optimize water transport and self-support, particularly in crowded settings. However, tradeoffs exist between optimizing water transport or self-support, because one tissue (xylem) is responsible for both functions. Trees, therefore, need to optimize these functions while maintaining safety margins. One facet of this optimization is the architecture characteristic of each tree species that results from rates of taper and branching, and mass-dependent angle(s) of branching. These traits are plastic to varying degrees among species and hence responsive to environmental circumstance (e.g., crowding, wind, drought). All published research regarding tree architecture has involved destruction of trees or their limbs, a cumbersome if accurate approach that eliminates longitudinal study of a tree or forest stand. We studied tree architecture in a quarter-hectare plot in the GVSU Ravines in which 178 trees were mapped and photographed. Correlation and principle components analyses were used to investigate: (1) Does species dominance in the plot correspond to tree architecture or to a combination of architectural and anatomical traits? (2) Does architecture for the most common species in the plot differ in a consistent manner in response to crowding and architecture of neighbors?
Journal Article
Genetic Structure of the Invasive Tree Ailanthus altissima in Eastern United States Cities
Ailanthus altissima is an invasive tree from Asia. It now occurs in most US states, and although primarily an urban weed, it has become a problem in forested areas especially in the eastern states. Little is known about its genetic structure. We explore its naturalized gene pool from 28 populations, mostly of the eastern US where infestations are especially severe. Five microsatellite markers were used to examine presumed neutral genetic variation. Results show a gene pool that is moderately diverse and sexually active and has significant but small genetic differences among populations and little correspondence between geographic and genetic distance. These findings are consistent with a model of multiple introductions followed by high rates of gene exchange between cities and regions. We propose movement along road and railway systems as the chief mode of range expansion.
Journal Article
Gametophytic Plasticity among Four Species of Ferns with Contrasting Ecological Distributions
The goals of this study were to test the hypothesis that plasticity
of life history traits is greater among species with broad ecological
distributions than among species with narrow ecological distributions and
to determine whether homosporous filicalean fern gametophytes exhibit
adaptively meaningful responses to soil substrates. Sporophyte populations
of Asplenium platyneuron and Polystichum
acrostichoides have broader ecological distributions and were
therefore expected to exhibit a greater amount of gametophytic plasticity
than either Asplenium rhizophyllum or
Diplazium pycnocarpon. Changes in reproductive effort (i.e.,
gametangia mm−2) were investigated across the four
following soil treatments, which represent major edaphic environments on
which sporophyte populations of these species occur: stream bank,
Pinus strobus canopy, oak forest ridge top, and soil from a
lime-bearing rock outcrop. Our results failed to support the
\"ecological breadth\" hypothesis. Three of the four
species-A. rhizophyllum, D. pycnocarpon,
and P. acrostichoides-exhibited similar amounts and
directions of plasticity, with reproductive effort greatest in
treatments that were unfavorable to growth; A. platyneuron
exhibited the least amount of plasticity. Nevertheless,
species-specific patterns in gametophytic size and reproductive
effort reflected the distributions of their sporophytic counterparts.
Plasticity of size-related reproductive effort may be common among
homosporous filicalean fern gametophytes because of their short life spans
and limited capacity for vegetative competition.
Journal Article
Pheromonal Interactions among Gametophytes ofOsmundastrum cinnamomeumand the Origins of Antheridiogen Systems in Leptosporangiate Ferns
Antheridiogen systems, whereby notch-bearing, archegoniate gametophytes induce maleness in ameristic neighbors, have been detected in many core leptosporangiate ferns. Previous studies have failed to detect an antheridiogen system in Osmundales, which is sister to all other extant leptosporangiates; hence, antheridiogen systems are thought to have evolved after their divergence. Detailed studies of morphological development and patterns of gender expression in Osmundales and other basal leptosporangiate clades are needed to clarify how antheridiogen systems evolved. Here, we tracked the development and gender expression of gametophytes ofOsmundastrum cinnamomeumgrown in isolation and multispore populations exposed to basal media (control), gibberellic acid (GA3), and an older generation of gametophytes. A notch-producing apical meristem invariably preceded antheridia and archegonia production inO. cinnamomeum. Exposure to either GA3or an older generation of gametophytes delayed growth rates and prolonged asexual and male status, whereas the multispore control possessed significantly greater proportions of females relative to isolates. Our observations confirm the existence of a putative antheridiogen system in Osmundales and a mechanism by which male-first expression is bypassed by a subset of the population. The evolution of fully developed antheridiogen systems in core leptosporangiate families may have involved the decoupling of the formation of a notch meristem from the production of antheridia in an ancestor with an Osmundales-type pattern of gender expression.
Journal Article