Effects of the soil microbiome on the demography of two annual prairie plants.

Both mutualistic and pathogenic soil microbes are known to play important roles in shaping the fitness of plants, likely affecting plants at different life cycle stages.In order to investigate the differential effects of native soil mutualists and pathogens on plant fitness, we compared survival and reproduction of two annual tallgrass prairie plant species ( and ) in a field study using 3 soil inocula treatments containing different compositions of microbes. The soil inocula types included fresh native whole soil taken from a remnant prairie containing both native mutualists and pathogens, soil enhanced with arbuscular mycorrhizal (AM) fungi derived from remnant prairies, and uninoculated controls.

Effects of removing woody cover on long-term population dynamics of a rare annual plant (): A study comparing remnant prairie and oldfield habitats.

Worldwide, grasslands are becoming shrublands/forests. In North America, eastern red cedar () often colonizes prairies. Habitat management can focus on woody removal, but we often lack long-term data on whether removal leads to population recovery of herbaceous plants without seeding.

Drivers of vegetative dormancy across herbaceous perennial plant species.

Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times.

Assessing the Influence of Temporal Autocorrelations on the Population Dynamics of a Disturbance Specialist Plant Population in a Random Environment.

Biological populations are strongly influenced by random variations in their environment, which are often autocorrelated in time. For disturbance specialist plant populations, the frequency and intensity of environmental stochasticity (via disturbances) can drive the qualitative nature of their population dynamics. In this article, we extended our earlier model to explore the effect of temporally autocorrelated disturbances on population persistence.

Crop-associated virus reduces the rooting depth of non-crop perennial native grass more than non-crop-associated virus with known viral suppressor of RNA silencing (VSR).

As agricultural acreage expanded and came to dominate landscapes across the world, viruses gained opportunities to move between crop and wild native plants. In the Midwestern USA, virus exchange currently occurs between widespread annual Poaceae crops and remnant native perennial prairie grasses now under consideration as bioenergy feedstocks. In this region, the common aphid species Rhopalosiphum padi L.

Reliable Method for Assessing Seed Germination, Dormancy, and Mortality under Field Conditions.

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester fabric and glue can be folded and glued to construct a strip of compartments that house seeds and identifying information, while allowing contact with soil leachate, water, microorganisms, and ambient temperature. Strips may be constructed with a wide range of compartment numbers and sizes and allow the researcher to house a variety of genotypes within a single species, different species, or seeds that have experienced different treatments.

Effects of crop viruses on wild plants.

Global land conversion and intensification of agriculture mean that remnant native plant populations are increasingly exposed to crop viruses. What are the consequences for wild plants? In natural unmanaged systems, the key consideration is how crop virus infection influences plant fitness. Field studies of virus effects on wild plant fitness are scant.

Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression.

Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds.

Seed fates in crop-wild hybrid sunflower: crop allele and maternal effects.

Domestication has resulted in selection upon seed traits found in wild populations, yet crop-wild hybrids retain some aspects of both parental phenotypes. Seed fates of germination, dormancy, and mortality can influence the success of crop allele introgression in crop-wild hybrid zones, especially if crop alleles or crop-imparted seed coverings result in out-of-season germination. We performed a seed burial experiment using crop, wild, and diverse hybrid sunflower (Helianthus annuus) cross types to test how a cross type's maternal parent and nuclear genetic composition might affect its fate under field conditions.

Fitness of crop-wild hybrid sunflower under competitive conditions: implications for crop-to-wild introgression.

Understanding the likelihood and extent of introgression of novel alleles in hybrid zones requires comparison of lifetime fitness of parents and hybrid progeny. However, fitness differences among cross types can vary depending on biotic conditions, thereby influencing introgression patterns. Based on past work, we predicted that increased competition would enhance introgression between cultivated and wild sunflower (Helianthus annuus) by reducing fitness advantages of wild plants.

Roles of maternal effects and nuclear genetic composition change across the life cycle of crop-wild hybrids.

• Premise of the study: The fitness of an offspring may depend on its nuclear genetic composition (via both parental genotypes) as well as on genetic maternal effects (via only the maternal parent). Understanding the relative importance of these two genetic factors is particularly important for research on crop-wild hybridization, since traits with important genetic maternal effects (e.g.

Detection and plant monitoring programs: lessons from an intensive survey of Asclepias meadii with five observers.

Monitoring programs, where numbers of individuals are followed through time, are central to conservation. Although incomplete detection is expected with wildlife surveys, this topic is rarely considered with plants. However, if plants are missed in surveys, raw count data can lead to biased estimates of population abundance and vital rates.

Selection on seedling emergence timing and size in an annual plant, Helianthus annuus (common sunflower, Asteraceae).

Premise: Variation in seedling emergence timing is considered adaptive over the long term in wild populations, but early emergence can result in a fitness advantage. To explore the adaptive significance of seedling emergence timing, it should be studied under realistic conditions and in the context of other traits that influence fitness.

Methods: In a common garden, we monitored maternal families from seed to flowering (including over winter) with intra- and interspecific competition.

TIR-NBS-LRR genes are rare in monocots: evidence from diverse monocot orders.

Background: Plant resistance (R) gene products recognize pathogen effector molecules. Many R genes code for proteins containing nucleotide binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. NBS-LRR proteins can be divided into two groups, TIR-NBS-LRR and non-TIR-NBS-LRR, based on the structure of the N-terminal domain.

Population ecology of wild sunflowers: effects of seed density and post-dispersal vertebrate seed predators.

Assessing the effects of seed density on the population dynamics of wild plant species with crop relatives will be vital in determining the potential effects of introducing traits into wild populations as a result of crop-to-wild gene flow. We examined experimental sunflower (Helianthus annuus) patches in eastern Kansas to determine the effects of seed density and predation on seedling recruitment and seed production in the next generation. High seed density treatment plots had significantly more seedlings and adult plants than did low seed density treatment plots.

Increased pre-dispersal seed predation in sunflower crop-wild hybrids.

The fitness of crop-wild hybrids can influence gene flow between crop and wild populations. Seed predation levels in crop-wild hybrid plants can be an important factor in determining plant fitness, especially in large-seeded crops such as sunflower. To determine patterns of pre-dispersal seed predation, seeds were collected from wild sunflowers (Helianthus annuus L.

Ecological genetic interactions between a clonal host plant (Spartina pectinata) and associated rust fungi Puccinia seymouriana and Puccinia sparganioides.

The spatial scale of genetic diversity among patches of a host plant could affect the likelihood of pathogen adaptation to the host. If host patches are genetically distinct, pathogen adaptation to local host genotypes may occur. To study this issue, we focused on the ecological and genetic interactions between two rust fungi, Puccinia seymouriana and P.

Plant population heterogeneity and pathogen and herbivore levels: a field experiment.

The identity of neighbouring plants in a population is thought to affect the disease levels of an individual plant: disease levels are expected to be higher for susceptible plants surrounded by other susceptible plants as compared to susceptible plants that have resistant plants as neighbours. To explore this idea, plants in a natural population of the annual sunflower, Helianthus annuus, were scored in 1988 for levels of the rust pathogen Puccinia helianthi. Progeny of plants with high rust levels (families predicted to be susceptible to the disease) were grown in 1989 in a series of field plots at either high frequency (all plants in a plot of one family) or in low frequency (a plot with plants of many families).

Anther-smut infection of Silene alba caused by Ustilago violacea: factors determining fungal reproduction.

The anther-smut fungus Ustilago violacea sporulates in flowers of the dioecious host plant Silene alba. Growth chamber comparisons of healthy and diseased plants, with the genetic background of host and pathogen controlled, revealed that fungal infection increases the number of flowers produced per plant and decreases the size of individual flowers. There were few consistent effects of plant genotype or fungal isolate on diseased flower traits, but differences between the plant sexes were apparent.

AN EXPERIMENTAL FIELD STUDY OF ANTHER-SMUT DISEASE OF SILENE ALBA CAUSED BY USTILAGO VIOLACEA: GENOTYPIC VARIATION AND DISEASE INCIDENCE.

Twenty cloned genotypes of Silene alba differed greatly (0-100%) in the percentage of flowering plants that became diseased by the anther-smut fungus Ustilago violacea following natural spore dispersal in a two-year field experiment. Male genotypes with the highest percentage of disease had high rates of flower production; this trait may increase the probability of spore deposition on flowers, a common site of infection. Because of this relationship, male genotypes with the highest percentage of disease also produced the most healthy flowers in the two-year period.

Intraspecific variation in the response to CO enrichment in seeds and seedlings of Plantago lanceolata L.

Four genotypes of P. lanceolata were grown to maturity at combinations of two levels of atmospheric CO concentrations and two temperature conditions. Seed weight was determined, and seed germination and seedling growth were measured for the progeny of each genotype under the same environmental conditions.

Relationship of phenotypic and genetic variation in Plantago lanceolata to disease caused by Fusarium moniliforme var. subglutinans.

Naturally established individuals of Plantago lanceolata with the inflorescence disease caused by Fusarium moniliforme var. subglutinans had more inflorescences and were more likely to be male-sterile than healthy plants. Half-sib families planted in the field varied in the percentage of diseased plants, the number of inflorescences per plant, the incidence of male-sterility, and the pattern of inflorescence phenology.