Modeling temporal dynamics of genetic diversity in stage-structured plant populations with reference to demographic genetic structure.

Predicting temporal dynamics of genetic diversity is important for assessing long-term population persistence. In stage-structured populations, especially in perennial plant species, genetic diversity is often compared among life history stages, such as seedlings, juveniles, and flowerings, using neutral genetic markers. The comparison among stages is sometimes referred to as demographic genetic structure, which has been regarded as a proxy of potential genetic changes because individuals in mature stages will die and be replaced by those in more immature stages over the course of time.

Temporal skewness of pollination success in the spring ephemeral Trillium camschatcense.

Phenological overlap with pollinators is crucial for reproductive success in insect-pollinated plants. In this study, we examined whether pollinator visitation successfully occurred during an entire flowering season in two populations of the insect-pollinated spring ephemeral Trillium camschatcense in the Tokachi region of Hokkaido, northern Japan. We bagged flowers and excluded pollinator visitation during either the first or the last half of the entire flowering season to compare pollination success between the two periods.

Seasonal variation of responses to herbivory and volatile communication in sagebrush (Artemisia tridentata) (Asteraceae).

Plants can respond to insect herbivory in various ways to avoid reductions in fitness. However, the effect of herbivory on plant performance can vary depending on the seasonal timing of herbivory. We investigated the effects of the seasonal timing of herbivory on the performance of sagebrush (Artemisia tridentata).

Demographic response of plant populations to habitat fragmentation and temporal environmental variability.

Many plant species currently exist in fragmented populations of different sizes, while they also experience unpredictable climatic fluctuation over time. However, we still understand little about how plant demography responds to such spatial and temporal environmental variability. We studied population dynamics of an understory perennial herb Trillium camschatcense in the Tokachi plain of Hokkaido, Japan, where a significant effect of forest fragmentation on seedling recruitment was previously reported.

The evolution of self-compatible and self-incompatible populations in a hermaphroditic perennial, Trillium camschatcense (Melanthiaceae).

The evolution of selfing from outcrossing ancestors is known to have occurred repeatedly in angiosperms. Theoretical studies have argued that the transition from outcrossing to selfing is accomplished more easily than the reverse case, and phylogenetic analyses involving self-compatible (SC) and self-incompatible (SI) species has basically supported this assumption. The evolutionary direction of self-compatibility and self-incompatibility was examined in Trillium camschatcense, which contains geographically widespread SC populations, and restricted SI populations.

Dynamics of distribution and performance of ramets constructing genets: a demographic-genetic study in a clonal plant, Convallaria keiskei.

Background And Aims: In clonal plants producing vegetative offspring, performance at the genet level as well as at the ramet level should be investigated in order to understand the entire picture of the population dynamics and the life history characteristics. In this study, demography, including reproduction and survival, the growth patterns and the spatial distributions of ramets within genets of the clonal herb Convallaria keiskei were explored.

Methods: Vegetative growth, flowering and survival of shoots whose genets were identified using microsatellite markers were monitored in four study plots for 3 years (2003-2005).

Adaptive significance of self-fertilization in a hermaphroditic perennial, Trillium camschatcense (Melanthiaceae).

The evolution of self-fertilization from primarily outcrossing ancestors is one of the most common evolutionary transitions in plants; however, the ecological mechanisms that maintain self-fertilization have remained controversial. Theoretical studies suggest that selfing is advantageous over outcrossing in terms of genetic transmission and assurance of seed production under pollen-limited circumstances. Trillium camschatcense is a herbaceous perennial distributed in Hokkaido and northern Honshu, Japan.

Reproductive demography of ramets and genets in a rhizomatous clonal plant Convallaria keiskei.

Clonal growth occurring below the ground makes it difficult to identify individuals and demonstrate the demographic features of a focal plant species. In this study, genotypically identified ramets of a rhizomatous clonal herb, Convallaria keiskei Miq., were monitored for their growth, survival, and reproduction from 2003 to 2006.

Fine-scale spatial genetic structure within continuous and fragmented populations of Trillium camschatcense.

Spatial genetic structure (SGS) within populations was analyzed for the ling-lived understory perennial herb Trillium camschatcense using allozyme loci. We used Sp statistics to compare SGS between 2 life-history stages, juveniles (J) and reproductives (R), as well as between 2 populations, continuous and fragmented, with different habitat conditions. In the continuous population, significant SGS was detected in both stages but the extent was greatly reduced with the progress of the stage (J, Sp = 0.

Genetic structure in aquatic bladderworts: clonal propagation and hybrid perpetuation.

Background And Aims: The free-floating aquatic bladderwort Utricularia australis f. australis is a sterile F(1) hybrid of U. australis f.

Predominance of clonal reproduction, but recombinant origins of new genotypes in the free-floating aquatic bladderwort Utricularia australis f. tenuicaulis (Lentibulariaceae).

Aquatic plants are a biological group sharing several adaptations to aquatic conditions. The most striking evolutionary convergence in this group is the extensive reliance on clonal reproduction, which largely determines the patterns and process of evolution in aquatic plants. Utricularia australis f.

Genetic diversity and multilocus genetic structure in the relictual endemic herb Japonolirion osense (Petrosaviaceae).

Plant clonality may greatly reduce effective population size and influence management strategies of rare and endangered species. We examined genetic diversity and the extent of clonality in four populations of the monotypic herbaceous perennial Japonolirion osense, which is one of the most rare flowering plants in Japan. Allozyme analysis revealed moderate levels of genetic variation, and the proportion of polymorphic loci (P=66.

Effects of ants, ground beetles and the seed-fall patterns on myrmecochory of Erythronium japonicum Decne. (Liliaceae).

Erythronium japonicum (Liliaceae) inhabits deciduous mesic forests of Hokkaido, northern Japan. Myrmecochory of this species was investigated, especially the dispersal frequency, the effect of seed predators and the seed fall pattern. In the quadrat census using marked seeds of E.