Reproductive Systems and Chromosome Races of Oxalis Pes-Caprae L. and Their Bearing on the Genesis of a Noxious Weed

Ornduff, Robert

doi:10.2307/2399264

Cited by 37 publications

(60 citation statements)

References 5 publications

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“…A classic example is Oxalis pes-caprae (Oxalidaceae), a tristylous clonal geophyte that multiplies from bulbils and is native to South Africa, where populations are almost exclusively diploid or tetraploid. In contrast, invasive populations in Australia, California, Chile, and the Mediterranean are largely composed of a sterile, short-styled pentaploid (5x) cytotype, which remarkably is known only from a few localities in the native range near Cape Town (63,64). The renowned botanist Herbert G. Baker used the sterile 5x form of O. pes-caprae to illustrate his concept of the "general-purpose genotype" involving a "jack-of-all-trades-masterof-none" strategy based on high phenotypic plasticity (65).…”

Section: Sexual Dysfunction Somatic Mutations and Sterility In Clonmentioning

confidence: 99%

“…Moreover, surveys in the Iberian Peninsula have recently discovered the occurrence of sexual tetraploids (4x) of all three style morphs (67). These discoveries raise the possibility that they may have originated by residual sexuality in the 5x cytotype (63) and could explain how genetic diversity may have arisen in supposedly asexual populations. Plants with odd ploidy levels often produce viable gametes, and, indeed, some viable seed has been produced from intramorph crosses of the 5x cytotype of O. pes-caprae (68) although it is unclear whether these seeds enable sexual recruitment in populations.…”

Section: Sexual Dysfunction Somatic Mutations and Sterility In Clonmentioning

confidence: 99%

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Influences of clonality on plant sexual reproduction

Barrett

2015

Proc. Natl. Acad. Sci. U.S.A.

217

195

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Flowering plants possess an unrivaled diversity of mechanisms for achieving sexual and asexual reproduction, often simultaneously. The commonest type of asexual reproduction is clonal growth (vegetative propagation) in which parental genotypes (genets) produce vegetative modules (ramets) that are capable of independent growth, reproduction, and often dispersal. Clonal growth leads to an expansion in the size of genets and increased fitness because large floral displays increase fertility and opportunities for outcrossing. Moreover, the clonal dispersal of vegetative propagules can assist "mate finding," particularly in aquatic plants. However, there are ecological circumstances in which functional antagonism between sexual and asexual reproductive modes can negatively affect the fitness of clonal plants. Populations of heterostylous and dioecious species have a small number of mating groups (two or three), which should occur at equal frequency in equilibrium populations. Extensive clonal growth and vegetative dispersal can disrupt the functioning of these sexual polymorphisms, resulting in biased morph ratios and populations with a single mating group, with consequences for fertility and mating. In populations in which clonal propagation predominates, mutations reducing fertility may lead to sexual dysfunction and even the loss of sex. Recent evidence suggests that somatic mutations can play a significant role in influencing fitness in clonal plants and may also help explain the occurrence of genetic diversity in sterile clonal populations. Highly polymorphic genetic markers offer outstanding opportunities for gaining novel insights into functional interactions between sexual and clonal reproduction in flowering plants.clonal growth | dioecy | geitonogamy | heterostyly | somatic mutations

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Section: Sexual Dysfunction Somatic Mutations and Sterility In Clonmentioning

confidence: 99%

Section: Sexual Dysfunction Somatic Mutations and Sterility In Clonmentioning

confidence: 99%

Influences of clonality on plant sexual reproduction

Barrett

2015

Proc. Natl. Acad. Sci. U.S.A.

217

195

View full text Add to dashboard Cite

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“…This species arrived in the central Mediterranean Basin at the end of the eighteenth century (Rappa, 1911), and its rapid and vigorous vegetative reproduction and dispersal resulted in a high rate of colonization success. In the native region both wild populations and weedy races are found (Ornduff, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…1A -C) and a self-and morph-incompatibility reproductive system (Ornduff, 1987). In heterostylic species this usually implies that legitimate pollinations are only possible between opposite sex organs at the same height level (Lewis and Jones, 1992;Lloyd and Webb, 1992a).…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, in its native habitat, individuals of O. pes-caprae present different ploidy levels, with floral morphs being diploids (2n ¼ 2x ¼ 14), tetraploids (2n ¼ 4x ¼ 28) or pentaploids (2n ¼ 5x ¼ 35), with the latter individuals reproducing mainly asexually by bulbils (Ornduff, 1987). In most of the areas invaded, only the pentaploid SS morphotype has been reported (Baker, 1965).…”

Section: Introductionmentioning

confidence: 99%

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Distribution of Flower Morphs, Ploidy Level and Sexual Reproduction of the Invasive Weed Oxalis pes-caprae in the Western Area of the Mediterranean Region

et al. 2007

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Aims Oxalis pes-caprae is a widespread invasive weed in regions with a Mediterranean climate. In its native habitat (southern Africa) this species has been reported as heterostylous with trimorphic flowers and a self-and morph-incompatible reproductive system. In most of the areas invaded, only a pentaploid short-styled morphotype that reproduces mainly asexually by bulbils is reported, but this has only been confirmed empirically. This study aims to analyse the floral morph proportions in a wide distribution area, test the sexual female success, and explain the causes of low sexual reproduction of this species in the western area of the Mediterranean Basin. † Methods Fifty-five populations of O. pes-caprae were sampled in the Iberian Peninsula and Morocco to evaluate the floral morph ratio and individual fruit set. In plants from a dimorphic population, hand-pollination experiments were performed to evaluate the effect of the pollen source on pollen tube growth through the style. The ploidy level and genome size of individuals of each floral morph were analysed using flow cytometry. † Key Results From the populations studied 89 . 1 % were monomorphic, with most of them containing the shortstyled (SS) floral morph, and 10 . 9 % were dimorphic containing long-styled (LS) and SS morphs. In some of these, isoplethy was verified but no fruit production was observed in any population. A sterile form was also recorded in several populations. Hand-pollination experiments revealed that pollen grains germinated over recipient stigmas. In intermorph crossings, pollen tubes were able to develop and fruit initiation was observed in some cases, while in intramorph pollinations, pollen tube development was sporadic and no fruit initiation was observed. All individuals within each floral form presented the same DNA ploidy level: SS plants were pentaploid and LS and the sterile form were tetraploid. † Conclusions The low or null sexual reproduction success of this species in the area of invasion studied seems related with the high frequency of monomorphic populations, the unequal proportion of floral morphs in dimorphic populations and the presence of different ploidy levels between SS and LS morphs. The discovery of the occurrence of an LS floral morph and a sterile form, whose invading capacity in these areas is as yet unknown, will be valuable information for management programmes.

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