Adaptive variation in physiological traits underpinning stem elongation responses among nodally-rooting stoloniferous herbs

Thomas, R. G.; Hay, M. J. M.

doi:10.1007/s10682-007-9200-x

Cited by 19 publications

(11 citation statements)

References 21 publications

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“…In terms of pollen dispersal, many clonal plants do indeed appear to have highly restricted pollen dispersal distances regardless of whether pollen dispersal occurs via wind pollination [e.g., Typha latifolia (40)] or insect pollination [e.g., Glechoma hederacea (41)]. For these plants, which can generally be characterized as having guerrilla growth forms (42)(43)(44), strong outward growth via the production of rhizomes should usually be associated with extensive intermingling of genets, enhancing the dispersal of pollen to other genets. In general therefore, we predict that, among closely related plants, pollen dispersal distances should be inversely related to the capacity for the outward spread of genets and the spatial intermingling of clones.…”

Section: Discussionmentioning

confidence: 99%

Consequences of clonality for sexual fitness: Clonal expansion enhances fitness under spatially restricted dispersal

Drunen

Kleunen

Dorken

2015

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

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Clonality is a pervasive feature of sessile organisms, but this form of asexual reproduction is thought to interfere with sexual fitness via the movement of gametes among the modules that comprise the clone. This within-clone movement of gametes is expected to reduce sexual fitness via mate limitation of male reproductive success and, in some cases, via the production of highly inbred (i.e., self-fertilized) offspring. However, clonality also results in the spatial expansion of the genetic individual (i.e., genet), and this should decrease distances gametes and sexually produced offspring must travel to avoid competing with other gametes and offspring from the same clone. The extent to which any negative effects of clonality on mating success might be offset by the positive effects of spatial expansion is poorly understood. Here, we develop spatially explicit models in which fitness was determined by the success of genets through their male and female sex functions. Our results indicate that clonality serves to increase sexual fitness when it is associated with the outward expansion of the genet. Our models further reveal that the main fitness benefit of clonal expansion might occur through the dispersal of offspring over a wider area compared with nonclonal phenotypes. We conclude that, instead of interfering with sexual reproduction, clonal expansion should often serve to enhance sexual fitness.asexual reproduction | geitonogamy | genet | modularity | ramet M odular growth, clonality, and hermaphroditism are widespread features of sessile organisms. Sessile organisms might benefit from modularity and the spatial expansion of the individual via enhanced resource capture, and thereby improved growth and survival (1-3). However, growth and survival are only two of the key components of an organism's life history, and the third, reproduction, is the one that is most intimately linked to fitness. Indeed, during reproduction, the growth of a modular hermaphrodite might interfere with its success as a parent. In particular, it has been argued that the production of numerous partially or fully autonomous clonal modules (i.e., ramets) should interfere with mating success because there is a nonzero chance that sperm (or pollen) will encounter the receptive tissues associated with the female function of the same genetic individual (i.e., the genet). All else being equal, the larger the clone, the greater the chance that this kind of mating interference should occur (4, 5). The negative effects of such intraclonal mating is expected to occur through reductions in the number of offspring sired on other genets (i.e., outcross siring success, corresponding with the fitness of individuals via their male function) and, in self-compatible organisms, through inbreeding depression (i.e., a reduction in offspring fitness, with negative effects on the fitness of individuals through their female function; e.g., ref. 5). However, these forms of mating interference are simply by-products of attaining a larger size and are not exclusiv...

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Section: Discussionmentioning

confidence: 99%

Consequences of clonality for sexual fitness: Clonal expansion enhances fitness under spatially restricted dispersal

Drunen

Kleunen

Dorken

2015

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

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“…Although the spatial heterogeneity of the environment and its effect on morphological plasticity has often been studied experimentally in clonal research (e.g., Hutchings and Wijesinghe 2008;Janeček et al 2008;Thomas and Hay 2008;Johansen 2009;Zhang and He 2009), only rarely (Alpert 1996;Magyar et al 2007;Roiloa et al 2007) have either physiological adjustment affecting resource uptake rates or the temporal aspects of achieving or losing this specialization been considered. On the other hand, temporal aspects of local specialization have been studied intensively in non-clonal plants in the framework of investigating transgenerational plasticity (see below).…”

Section: Introductionmentioning

confidence: 99%

Transgenerational plasticity in clonal plants

Latzel

Klimešová

2010

Evol Ecol

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Transgenerational plasticity has recently been recognized as a mechanism allowing phenotypic adjustments to local conditions to be passed onto sexually produced offspring. Although thus far it has been studied mainly in non-clonal plants, the present paper proposes that transgenerational plasticity is also applicable to asexually generated progeny, and that it can have multiple consequences for clonal plants. Indeed, in clonal plants, local phenotypic adjustment transferred to the next generation-whether produced sexually or asexually-can provide a mechanism that assists the population better exploit spatial heterogeneity. Moreover, this concept provides a framework allowing investigation of how long environmental heterogeneity will affect growth of asexually as well as sexually generated progeny.

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“…Trifolium repens L. (white clover, family Fabaceae) is a dicotyledonous species that we have used previously as our 'model species'. It can be considered a type intermediate between the extremes of 'phalanx' and 'guerrilla' (Thomas and Hay 2008a).…”

Section: Study Speciesmentioning

confidence: 99%

“…This is consistent with these roots all exporting a branching stimulus (RS) that activates axillary buds for outgrowth. The level of bud activation is then dependent on degree of exposure to the RS signal, the intensity of which decreases upon enlargement of the plant (Thomas and Hay 2007, 2008a, b, 2009). Thus the three species differ only in the degree to which they respond to the presence or absence of nodal roots.…”

Section: Common Responses To Nodal Rootsmentioning

confidence: 99%

“…In contrast, 'guerrilla' types are characterised by the development of long explorative stems that arise because their stems have a low frequency of branching and long internodes and confer on them a wandering habit (Harper 1981). As Trifolium repens sits in the middle of the 'phalanx-guerrilla' continuum (Thomas and Hay 2008a) it acts as a good exemplar for the group. To gain a better understanding of the significance of nodal roots across the full spectrum of the group, however, we selected two further species from the extremes of the 'phalanx-guerrilla' continuum that were readily available to us-namely the strongly branched monocotyledonous Tradescantia fluminensis (an extreme 'phalanx' type) and the weakly branched dicotyledonous Calystegia silvatica (an extreme 'guerrilla' type)-to compare with our exemplar, T. repens.…”

Section: Introductionmentioning

confidence: 99%

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The role of nodal roots in prostrate clonal herbs: ‘phalanx’ versus ‘guerrilla’

Thomas

Hay

2010

Evol Ecol

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The influence of nodal rooting on branching was studied in three evolutionarily and morphologically diverse species of prostrate clonal herbs: Tradescantia fluminensis (a monocotyledonous extreme 'phalanx' species), Calystegia silvatica (a dicotyledonous extreme 'guerrilla' species) and Trifolium repens (a dicotyledonous intermediate species). In all three, branch development from axillary buds is regulated by a positive signal produced by roots together with inhibitory influences from both pre-existing branches and shoot apical buds (apical dominance). Responses to nodal roots are cumulative and increased root activity leads to more vigorous bud outgrowth. In the absence of nodal roots, a single basal root system is unable to maintain continued extension growth of the shoot. We suggest that as individual nodal roots and stem internodes are both short-lived in these nodally-rooting clonal species, the plants' investment in them is minimal. Thus, in contrast to perennial species lacking nodal roots, individual root systems in prostrate clonal herbs are small and stems have little secondary thickening and development of long-distance transport tissues. Hence the decline in extension growth of the shoot in the absence of nodal roots could be linked to the weak development of long-distance transport tissues in their relatively thin horizontal stems and to resource sharing between primary stems and lateral branches (as suggested by the greater retardation of primary stem growth in the more profusely branched 'phalanx' species (Trifolium and Tradescantia) than in the weakly branched 'guerrilla' species, Calystegia). These findings are consistent with the view that the long-term persistence of genotypes of nodally-rooting prostrate species is dependent upon them encountering the moist conditions required to facilitate the continual development of new young nodal root systems.

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Adaptive variation in physiological traits underpinning stem elongation responses among nodally-rooting stoloniferous herbs

Cited by 19 publications

References 21 publications

Consequences of clonality for sexual fitness: Clonal expansion enhances fitness under spatially restricted dispersal

Consequences of clonality for sexual fitness: Clonal expansion enhances fitness under spatially restricted dispersal

Transgenerational plasticity in clonal plants

The role of nodal roots in prostrate clonal herbs: ‘phalanx’ versus ‘guerrilla’

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