Effects of Parentage and Size of the Pollen Load on Progeny Performance in Campanula americana

Richardson, Thomas E.; Stephenson, Andrew G.

doi:10.2307/2410027

Cited by 42 publications

(44 citation statements)

References 37 publications

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“…Similar patterns of maternal effect have been observed in Campanula americana, in which seed size is only correlated with early seedling performance, while maternal effects extend to final height, total seed mass, and mean seed mass per fruit (Richardson and Stephenson, 1992). Similar results were obtained in the field cross when analyses were conducted after regression against seed mass; maternal effects remained for number of stems, leaf and leaflet characters, and for size at 2 and 4 mo.…”

Section: Discussionsupporting

confidence: 74%

Genetic and maternal effects on offspring fitness inLupinus texensis(Fabaceae)

Helenurm

Schaal

1996

American J of Botany

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Two experiments were designed to examine jointly the roles of maternal effect, genetic load, and other genetic variability at nuclear loci in determining offspring fitness in Lupinus texensis, an outbreeding annual herb. A diallel crossing design was used to generate seeds in the greenhouse. This design directly compares maternal and paternal contribution to offspring survival, growth, and flowering, and also assesses the role of genetic load because selfs are included in the crossing design. A nested crossing design was used to generate seeds at a field site. This design addresses the contribution of parental plants to their offspring under natural conditions. Maternal effects occur throughout the life cycle, but dominate the early growth of offspring in L. texensis. Inbreeding depression also occurs throughout the life cycle, but primarily affects size and survival of offspring. Overall inbreeding depression is substantial (δ = 0.66), exceeding the twofold threshold required for maintenance of an outcrossing mating system. However, lineages vary in the stages at which inbreeding depression occurs. Moreover, extreme heterogeneity was observed among lineages, with inbreeding depression ranging from negligible (δ = 0.02) to complete (δ = 1.00). This heterogeneity could allow the invasion and maintenance of selfing genotypes in natural populations of L. texensis.

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Section: Discussionsupporting

confidence: 74%

Genetic and maternal effects on offspring fitness inLupinus texensis(Fabaceae)

Helenurm

Schaal

1996

American J of Botany

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“…In natural systems, fitness may increase with the number of pollen grains received by a plant's stigmas either because seed set can be pollen limited (Bierzychudek 1981), or because increased stigmatic pollen density facilitates pollen germination (Niesenbaum 1999), or because intense pollen competition improves progeny vigor (Richardson and Stephenson 1992). First, can differentials in pollen deposition translate into fitness differentials?…”

Section: Discussionmentioning

confidence: 99%

Manipulation of Female Architecture in Flowers Reveals a Narrow Optimum for Pollen Deposition

Cresswell

2000

Ecology

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The invariability of animal-pollinated flowers relative to vegetative organs, such as leaves, suggests that these flowers may have been finely tuned for an optimum pollination performance. The evolutionary mechanism that could optimize and conserve a species' flower architecture is stabilizing selection, which occurs when intermediate phenotypes attain the highest fitness. Evidence for the operation of such a mechanism is rare in this context, however. Here, I report an experiment that used oil-seed rape (Brassica napus cv. Westar) as the basis of a model system in which the spatial disposition of flowers' sexual organs was manipulated in order to characterize the relationship between form and function. Specifically, individual flowers were manipulated by replacing a section of the style with a length of fine wire in order to produce flowers with pistils of various lengths. The pollination performance of these virgin, model flowers was then assessed by measuring the amount of pollen removed and deposited during a single bumblebee visit. There was no evidence that pollen removal was affected by pistil length. Variation in pistil length, however, was associated with a pronounced optimum in pollen deposition, which was attained by only a narrow range of pistil variants of intermediate length. These results suggest that stabilizing selection may maintain the architectural invariability of animalpollinated flowers.

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“…Campanula americana is self-compatible, protandrous, and insect pollinated; therefore seeds from a single plant are likely a mix of full and half-sibs (Richardson andStephenson 1992, Johnson et al 1995). I will refer to a group of siblings as a ''family.''…”

Section: Methodsmentioning

confidence: 99%

Parental Environmental Effects on Life History in the Herbaceous Plant Campanula americana

Galloway¹

2001

Ecology

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Although environmental parental effects, especially maternal effects, are well known in plants we have almost no information about their expression in nature. This study explores the influence of maternal and paternal light and nutrient environments on germination characters under natural conditions in the herbaceous plant Campanula americana. Families were grown in a greenhouse under three levels of light or three levels of nutrients, and crosses were conducted within each environmental gradient to produce seeds with all combinations of maternal and paternal environments. Seeds produced under the controlled environments were planted into the home site of the population and another local site, and germination was monitored over the fall and spring germinating seasons. The paternal light environment influenced percentage germination, demonstrating that the offspring phenotype may depend on the environment a set of pollen donors is grown in. The effect of maternal nutrient level on percentage germination depended on the offspring environment. Percentage germination in response to maternal nutrient and paternal light environments varied among families, suggesting that these parental environmental effects are genetically variable. Both maternal light and nutrient environments influenced season of germination. Germination season determines life history in C. americana: fall-germinating individuals are annuals while spring-germinating seeds are biennials. Maternal plants grown under low and high light and low nutrient conditions produced more biennial offspring while the remaining maternal environments had an equal frequency of annual and biennial offspring. In C. americana maternal environments influence life history and therefore fitness through their effects on season of germination.

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Effects of Parentage and Size of the Pollen Load on Progeny Performance in Campanula americana

Cited by 42 publications

References 37 publications

Genetic and maternal effects on offspring fitness inLupinus texensis(Fabaceae)

Genetic and maternal effects on offspring fitness inLupinus texensis(Fabaceae)

Manipulation of Female Architecture in Flowers Reveals a Narrow Optimum for Pollen Deposition

Parental Environmental Effects on Life History in the Herbaceous Plant Campanula americana

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