THE EFFECT OF A FOREIGN POLLEN ON OVULE DEVELOPMENT IN <i>DIERVILLA LONICERA</i> (CAPRIFOLIACEAE)

Thomson, James D.; Andrews, Brenda; Plowright, R. C.

doi:10.1111/j.1469-8137.1982.tb03286.x

Cited by 137 publications

(101 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, Sukhada and Jayachandra (1980) found that pollen germination and pollen tube growth of conspecific pollen on eight test species was inhibited to varying degrees by the application of pollen from the tropical weed Parthenium hysterophorus (Asteraceae), with germination in one of those, Crotalaria pellida (Leguminosae), being completely suppressed. A similar allelopathic effect of foreign pollen was suggested in the study of Thomson et al (1981) where the addition of Hieracium floribundum (Asteraceae) pollen significantly reduced embryo development in DiervilIa lonicera (Caprifoliaceae), while Randall and Hilu (1990) showed that reduction in fruit set in Impatiens capensis (Balsaminaceae) pollinated with mixtures of conspecific pollen and pollen from the related I. pallida was due to clogging of the stigma and style with foreign pollen tubes which interfered with the conspecific ~ fertilisation process. It was very unusual to observe germination of foreign pollen on orchid stigmas and therefore interspecific pollen tube competition is unlikely to be an explanation of fertilisation failure.…”

Section: Effects Of Heterospecific-pollen Deposition On Reproductive mentioning

confidence: 78%

The presence of heterospecific pollen on stigmas of nectariferous and nectarless orchids and its consequences for their reproductive success

Neiland

Wilcock

1999

Protoplasma

View full text Add to dashboard Cite

Summary. The widespread occurrence of nonorchid, heterospecific pollen grains on the stigmatic surfaces of a range of nectariferous and nectarless European orchids (Dactylorhiza, Orchis, Goodyera, and Gymnadenia species) is reported for the first time, and the impact of heterospecific pollination on orchid reproductive success is experimentally investigated. There are three main components of stigmatic contamination by heterospecific pollen: the frequency of contamination, the diversity of foreign species present on the stigma, and the amount of pollen deposited. Six out of seven of the species examined have greater than 85% of stigmas contaminated with wind and insect-dispersed pollen. From one to nine insect-dispersed foreign pollen species are present per stigma, including pollen of members of the families Apiaceae, Asteraceae, Caryohpyllaceae, Ericaceae, and Primulaceae. Average loads per stigma vary from 13 to 176 grains, with individual stigma loads ranging from one to 909.Whether or not the orchid provides nectar has a major impact on these three components. Nectarless orchids have the greatest frequencies of contamination, diversity of species, and average load per stigma. Insect-dispersed pollen is deposited both by pollinators and visitors but, in spite of low levels of pollination, nectarless orchids still exhibit higher frequencies of heterospecific pollen contamination. The effect of the presence of heterospecific pollen on the reproductive success of orchids is tested in this study for the first time. Average-to-high, naturally occurring loads of heterospecific pollen derived from a mixture of Armeria maritima, Caltha palustris, Cochlearia officinalis, Cytisus scoparius, and Primula vulgaris and consisting of 50-250 grains per load are placed onto stigmas of Dactylorhiza purpurella which are subsequently self-pollinated with half of a pollinium. All pollinations produce capsules indicating that heterospecific pollen does not affect fruit set. Although experimental and control fruits are similar in size, they differ in total seed weight and composition. Total seed weight is reduced and the proportion of seeds with normal embryos decreased while the proportion of unfertilised ovules increased following pollination with heterospecific pollen, indicating a detrimental effect on fertilisation. Lower reproductive success caused by fertilisation failure is likely to be most severe in nectarless species because of their generally higher levels of contaminated stigmas. As nectarless orchids are * Correspondence and reprints: Department of Plant and Soil Science, Cruickshank Building, University of Aberdeen, St. Machar Drive, Aberdeen AB24 3UU, Scotland, U.K. known to have lower fruit set compared with nectariferous ones, this finding suggests that the reproductive success of nectarless orchids may be even lower than previously realised.

show abstract

Section: Effects Of Heterospecific-pollen Deposition On Reproductive mentioning

confidence: 78%

The presence of heterospecific pollen on stigmas of nectariferous and nectarless orchids and its consequences for their reproductive success

Neiland

Wilcock

1999

Protoplasma

View full text Add to dashboard Cite

show abstract

“…It is unlikely that the reduction is due to pollen allelopathy given that previous studies of allelopathy show a considerable reduction in seed set with only a small number of allelopathic pollen grains present. For example, Thomson et al (1981) found almost complete reproductive failure in ovule development with additions of 50% allelopathic pollen. Murphy and Aarssen (1995d) found a 70% reduction in seed set when pollen extract from only five pollen grains from Phleum pratense was applied to stigmas of Agropyron repens.…”

Section: Foreign Pollenmentioning

confidence: 98%

“…Such interspecific pollen transfer (IPT; Waser 1983, also Rathcke 1983) has been recognized as an important mechanism through which plants can compete for pollination services (Waser 1983;Rathcke 1983), in part because it can impair seed set even in the absence of pollinator limitation (Waser 1983;Randall and Hilu 1990;Petanidou et al 1995;Bergman 1996). IPT can reduce seed production in several ways, including pollen allelopathy (Char 1977;Sukhada and Jayachandra 1980;Thomson et al 1981;Murphy and Aarssen 1995a, b, c, d), stigma clogging (Shore and Barrett 1984;Galen and Gregory 1989;Proctor et al 1996), stigma closing (Waser and Fugate 1986), stylar clogging (Palmer et al 1989;Scribailo and Barrett 1994), and stylar inhibition (Williams et al 1982;Cruzan 1990Cruzan , 1993. Even when IPT does not reduce seed set (Schemske 1981;Shore and Barrett 1984;Kohn and Waser 1985;Kwak and Jennersten 1986;Galen and Gregory 1989;McGuire and Armbruster 1991), it may reduce male fitness (Waser 1978;Campbell and Motten 1985;Feinsinger et al 1986;Jennersten and Kwak 1991; McGuire and Armbruster 1991) through pollen loss.…”

Section: Introductionmentioning

confidence: 95%

Competition for pollination: effects of pollen of an invasive plant on seed set of a native congener

2001

View full text Add to dashboard Cite

Competition for pollination can be an important factor in plant reproduction, but little attention has been given to the effect of the growing number of invasive plant species on pollination of native species. As a first step in understanding this threat, we used hand pollination to investigate the effects of pollen from an invasive species (Lythrum salicaria) on seed set in a sympatric and co-flowering native congener (L. alatum). Dispersal of fluorescent dyes in the field confirms that pollinators (bumble bees and honey bees) transfer pollen between species. To determine the potential effect of such interspecific pollen transfer on seed set of the native, we pollinated 773 flowers on 20 plants with one of three treatments: legitimate conspecific pollen, a mixture of conspecific and foreign pollen, and foreign pollen. The mixed-pollen treatment resulted in 28.8% lower seed set relative to conspecific pollination. Foreign crosses resulted in extremely low seed set. Observations of pollen germination indicate that events at the stigmatic surface contribute to the reduction in seed set for mixed pollination. Our results indicate that the impacts of invasive species may extend beyond vegetative competition to include competition for pollination.

show abstract

“…A link may also exist between the number of heterospecific grains received by the plants we examined and floral fecundity or plant fitness (Waser 1978b, Thomson et al 1981, Rathcke 1983. Numbers ofheterospecific grains varied widely within and among the four species.…”

Section: Ls Variation Among Pollen Loads Significant To the Plants Inmentioning

confidence: 99%

Floral Neighborhood and Pollination Success in Four Hummingbird‐Pollinated Cloud Forest Plant Species

Feinsinger¹,

Murray²,

Kinsman³

et al. 1986

Ecology

137

129

View full text Add to dashboard Cite

Abstract. In a cloud forest at Monteverde, Costa Rica, we examined pollen loads received by self-compatible flowers of two pairs of plant species pollinated by hummingbirds: Hansteinia blepharorachis and Razisea spicata (Acanthaceae), and Besleria triflora and Drymonia rubra (Gesneriaceae). Each pair consisted of one species (Hansteinia or Besleria) pollinated by short-billed hummingbirds and a related species (Razisea or Drymonia) pollinated by long-billed hummingbirds. At three different times per species, separated by 1-3 mo, we examined flowers on 28-40 focal plants from a wide variety of floral neighborhoods, ranging from plants isolated from conspecifics, either by distance or by other flowering species pollinated by the same hummingbirds, to plants surrounded by conspecifics.Because short-billed hummingbirds often restrict foraging to areas ofhigh flower density, and because short-tubed flowers adapted for hummingbirds often have similar pollen placement, we predicted that short-tubed flowers isolated from conspecifics would receive fewer conspecific grains and more heterospecific grains than short-tubed flowers surrounded by conspecifics. Because long-billed hummingbirds often forage over large areas and because long-tubed flowers adapted for hummingbirds tend to diverge in pollen placement, we predicted that pollination of long-tubed flowers would be relatively unaffected by floral neighborhood.Effects on pollen loads of floral neighborhood (nearness to or isolation from other flowers) followed few patterns consistent with our prediction or with conventional theory. (1) There were no consistent effects of floral neighborhoods on numbers of heterospecific grains deposited on stigmas; in all four species, regardless of corolla length, effects of particular neighborhood variables (as determined with stepwise multiple regression) were as likely to run exactly counter to conventional models as to corroborate models. (2) In none of the 12 sampling runs did increases in absolute densities of neighboring heterospecific flowers adversely affect pollination. (3) However, in two runs, loads of conspecific grains increased with increases in the absolute density of neighboring conspeci:fic flowers, and/or (in three runs) with increases in their relative density (proportion of conspecifics among neighboring flowers). These runs all involved short-flowered species rather than long-flowered species, tending to confirm our initial prediction, but half the sampling runs, even of short-flowered species, failed to show any density-dependent effects from neighboring flowers pollinated by the same hummingbirds.Flowers frequently received fewer conspeci:fic grains than they had ovules to be fertilized. Therefore, the potential existed for floral neighborhoods to affect seed set and fitness of plants. Nevertheless, even though neotropical hummingbird-pollinated flowers have been cited as examples of species whose flowering peaks are displaced through competition for pollination, competitive effects from neighboring heterospeci...

show abstract

THE EFFECT OF A FOREIGN POLLEN ON OVULE DEVELOPMENT IN DIERVILLA LONICERA (CAPRIFOLIACEAE)

Cited by 137 publications

References 20 publications

The presence of heterospecific pollen on stigmas of nectariferous and nectarless orchids and its consequences for their reproductive success

The presence of heterospecific pollen on stigmas of nectariferous and nectarless orchids and its consequences for their reproductive success

Competition for pollination: effects of pollen of an invasive plant on seed set of a native congener

Floral Neighborhood and Pollination Success in Four Hummingbird‐Pollinated Cloud Forest Plant Species

Contact Info

Product

Resources

About