Some Genetic Consequences of Being a Plant

Levin, Donald A.

doi:10.1007/978-1-4612-6330-2_11

Cited by 49 publications

(24 citation statements)

References 100 publications

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“…T o a considerable degree, this classification follows earlier accounts of adaptive variation, particularly those of Schmalhausen (1949), Bradshaw (1965Bradshaw ( , 1974, Levins (1968) and Maynard Smith (1979). The classes are based on the frequency distributions of phenotypes among both single structures and individual plants, and they also take into account whether the variation is elicited by internal, environmental or genetical factors.…”

Section: Classes Of Variation Strategiesmentioning

confidence: 86%

Variation strategies of plants in heterogeneous environments

Lloyd

1984

Biological Journal of the Linnean Society

201

138

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T h e dependence of individual development upon certain environmental factors is a truism. However what matters in this interaction betwecn organisms and environments is that the morphological reaction is typical of the organism under given conditions. I. I. Schmalhausen, 1949. Plant structures exhibit five principal classes of variation in heterogeneous environments, namely uniformity, continuous lability, genetic specialization (polymorphism), environmentally-or statuscued alternatives (conditional choices) and multiple strategies-the simultaneous operation by one plant of distinct types of structures that perform the same function. Multiple strategies are a diverse but neglected class that includes simultaneous cosexuality (hermaphroditism and other monomorphic sex conditions), facultative cleistogamy, heteromorphic diaspores, and reproduction by both seeds and ramets. An analysis of seven functions in the angiosperm flora of New Zealand shows that uniform and labile strategies considered jointly are most common, and multiple strategies are more common than either polymorphisms or conditional choices. Phenotypic models of the natural selection of structural variation are presented. They predict the general conditions under which multiple, conditional and uniform strategies are selected when the environment is spatially heterogeneous for either parents or their offspring. The models can explain many features of variation strategies, including why multiple strategies are a plant speciality, why conditional strategies such as sex choosing are rare and random choices are even more rare (unknown?), and why some self-fertilizing plants have distinct cleistogamous flowers. The models also suggest further avenues of research.

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Section: Classes Of Variation Strategiesmentioning

confidence: 86%

Variation strategies of plants in heterogeneous environments

Lloyd

1984

Biological Journal of the Linnean Society

201

138

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“…Inequality seems to be more relevant to ecological and evolutionary questions than is skewness. For example, Levin (1978) and Begon (1984) discuss the fact that size hierarchies and resultant fecundity variation will tend to reduce the effective population size (since many individuals may be too small to reproduce) and therefore should be expected to reduce genetic variation within the population. There will also be differences in size among those which are large enough to reproduce.…”

Section: Analysis and Interpretation Of Size Variabilitymentioning

confidence: 98%

Size Variability and Competition in Plant Monocultures

Weiner¹,

Thomas²

1986

Oikos

663

483

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“…Moreover, while the evolution of unilateral S-allele related incompatibility (Abdalla and Hermsen 1972) and incongruity (Hogenboom 1975(Hogenboom , 1984 has been addressed, little attempt has been made to integrate this unilateral phenomenon with the Wallace Effect. Nevertheless, it is easy to envisage situations where disparities in population size (King 1985) or shape (Levin 1978b), flowering time or intensity could result in asymmetrical production of maladapted F1 hybrids and thus asymmetrical selection for reproductive isolation. For example, the actual levels of FI hybridisation may not only be greater in small populations (Levin 1978a), but the effect would be distributed through a greater proportion of the population compared with larger populations.…”

Section: Evolution Of Unilateral Cross-incompatibilitymentioning

confidence: 99%

Unilateral Cross-Incompatibility in Eucalyptus: the Case of Hybridisation Between E. globulus and E. nitens

Gore¹,

Potts²,

Volker³

et al. 1990

Aust. J. Bot.

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The growth of E. globulus and E. nitens pollen tubes in styles of E. globulus was examined in order to elucidate the site of the unilateral barrier to hybridisation. Pollen tubes of E. nitens failed to grow the full length of the larger E. globulus style. E. globulus pollen tubes grew an average of 1.4 mm per day for the first 4 days, compared with 0.8 mm per day for pollen tubes of E. nitens. From days 4 to 14, the growth of E. nitens pollen tubes slowed to an average of 0.2 mm per day and virtually no growth occurred after day 14. In contrast, E. globulus pollen tubes grew through the style and into the ovary between days 5 and 14. By day 28, at about the time of style abscission, E. nitens tubes had grown only 6 mm, well short of the full length of the E. globulus style (9-10 mm). A similar difference in growth was obtained in vitro where E. nitens pollen tubes were significantly shorter than those of E. globulus. A comparison also including E. ovata, E. urnigera and E. gunnii indicated a significant correlation between style length and in vitro pollen tube length. It is argued that the unilateral cross-incompatibility between E. globulus and E. nitens is due to a structural barrier arising from an inherent limit to pollen tube growth which is associated with pistil size.

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Some Genetic Consequences of Being a Plant

Cited by 49 publications

References 100 publications

Variation strategies of plants in heterogeneous environments

Variation strategies of plants in heterogeneous environments

Size Variability and Competition in Plant Monocultures

Unilateral Cross-Incompatibility in Eucalyptus: the Case of Hybridisation Between E. globulus and E. nitens

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