Replacement of Cakile edentula by C. maritima in the Strand Habitat of California

1993 ◽  
Vol 130 (2) ◽  
pp. 209 ◽  
Author(s):  
Robert S. Boyd ◽  
Michael G. Barbour
Keyword(s):  
1994 ◽  
Vol 72 (3) ◽  
pp. 402-406 ◽  
Author(s):  
Jianhua Zhang

Cakile edentula produces dimorphic seeds from the upper and lower fruit segments. The upper seeds are well adapted to long-distance dispersal and have greater mean seed mass and surface area than those from the lower seeds. Great mean mass of the upper seeds is probably adaptive because it ensured early independent growth of seedlings and thus enhanced their chances of surviving environmental stresses. Large seed reserves also resulted in high chlorophyll content of the cotyledons. Large seed surface area resulted in large cotyledon area and cotyledon area to biomass ratio of the subsequent seedlings, but the adaptive advantage is not clear. Since increased seed surface area necessitates great protective tissues (fruit coat) that may improve the buoyant ability of seeds, large seed surface area of the upper seeds may be a result of selection for dispersal. Key words: seed mass, seed dimorphism, establishment, sand dune, selection, Cakile edentula.


1981 ◽  
Vol 59 (12) ◽  
pp. 2595-2602 ◽  
Author(s):  
Anita M. Payne ◽  
M. A. Maun

Cakile edentula (Bigel) Hook var. lacustris occurs abundantly along sandy beaches of Lakes Huron, Erie and Ontario. Until now the species had not been reported to occur along Georgian Bay but we located one population at Deanlea Beach. The deciduous upper fruit segments disperse long distances by water waves and currents and short distances by rolling caused by strong winds. The lower fruit segments usually remain attached to the parents which may be uprooted by high waves and then transported as tumble weeds to new locations. The floatation experiment showed that the agitation of jars containing the fruits improved their floating ability. Agitated upper fruit segments showed a significantly lower sinking index than agitated lower fruit segments and upper and lower fruit segments in the still treatment. The overwintering of fruits improved their floating ability.


2018 ◽  
Vol 42 (1) ◽  
Author(s):  
Tae-Bok Ryu ◽  
Dong-Hui Choi ◽  
Deokki Kim ◽  
Jung-Hyo Lee ◽  
Do-Hun Lee ◽  
...  

2019 ◽  
Vol 125 (4) ◽  
pp. 639-650 ◽  
Author(s):  
Chengjun Li ◽  
Mohsen B Mesgaran ◽  
Peter K Ades ◽  
Roger D Cousens

Abstract Background and Aims Hybridization is commonly assumed to aid invasions through adaptive introgression. In contrast, a recent theoretical model predicted that there can be non-adaptive demographic advantages from hybridization and that the population consequences will depend on the breeding systems of the species and the extent to which subsequent generations are able to interbreed and reproduce. We examined cross-fertilization success and inheritance of breeding systems of two species in order to better assess the plausibility of the theoretical predictions. Methods Reciprocal artificial crosses were made to produce F1, F2 and backcrosses between Cakile maritima (self-incompatible, SI) and Cakile edentula (self-compatible, SC) (Brassicaceae). Flowers were emasculated prior to anther dehiscence and pollen was introduced from donor plants to the recipient’s stigma. Breeding system, pollen viability, pollen germination, pollen tube growth and reproductive output were then determined. The results were used to replace the assumptions made in the original population model and new simulations were made. Key Results The success rate with the SI species as the pollen recipient was lower than when it was the pollen donor, in quantitative agreement with the ‘SI × SC rule’ of unilateral incompatibility. Similar outcomes were found in subsequent generations where fertile hybrids were produced but lower success rates were observed in crosses of SI pollen donors with SC pollen recipients. Much lower proportions of SC hybrids were produced than expected from a single Mendelian allele. When incorporated into a population model, these results predicted an even faster rate of replacement of the SC species by the SI species than previously reported. Conclusions Our study of these two species provides even clearer support for the feasibility of the non-adaptive hybridization hypothesis, whereby the colonization of an SI species can be assisted by transient hybridization with a congener. It also provides novel insight into reproductive biology beyond the F1 generation.


2011 ◽  
Vol 4 (2) ◽  
pp. 260-263 ◽  
Author(s):  
Roger D. Cousens ◽  
Jane M. Cousens

AbstractOn the west coast of North America and in Australia, there have been parallel cases of sequential invasion and replacement of the shoreline plant American sea-rocket by European sea-rocket. A similar pattern has also occurred in New Zealand. For 30 to 40 yr, from its first recording in 1921, American sea-rocket spread throughout the eastern coastlines of the North and South Islands of New Zealand. European sea-rocket has so far been collected only on the North Island. From its first collection in 1937, European sea-rocket spread to the northern extremity of the island by 1973, and by 2010, it had reached the southernmost limit. In the region where both species have occurred in the past, American sea-rocket is now rarely found. This appears to be another example of congeneric species displacement.


1992 ◽  
Vol 70 (12) ◽  
pp. 2467-2475 ◽  
Author(s):  
Kevin E. Gedge ◽  
M. A. Maun

Cakile edentula var. lucustris (sea rocket) and Corispermum hyssopifolium (bugseed) are two annual flowering plants that grow on the sandy shores of the Great Lakes. This habitat is extremely unpredictable and plants are subject to grazing by a number of insect herbivores as well as browsing by white-tailed deer. The objectives of these studies were to estimate the extent of herbivore damage under natural conditions, to determine the most vulnerable stage of damage, and to examine the compensatory ability of each species to tolerate herbivory. Greenhouse experiments showed that both species were able to compensate for low to moderate levels of artificial defoliation. However, high levels near the time of anthesis reduced the growth and reproductive output of both species. Similar experiments in the field revealed that although the critical time of damage was still the same, the plants were less able to tolerate herbivory. Cakile edentula plants exposed to natural herbivory in an unsprayed cabbage field were quickly attacked by large numbers of specialist insect herbivores and completely defoliated in 11 days. The fact that such damage does not occur in its natural habitat suggests that Cakile edentula escapes heavy damage because insects are unable to locate these populations along the shoreline. Key words: white-tailed deer, defoliation intensity, defoliation stage, compensatory response, indeterminate growth.


2016 ◽  
Vol 113 (36) ◽  
pp. 10210-10214 ◽  
Author(s):  
Mohsen B. Mesgaran ◽  
Mark A. Lewis ◽  
Peter K. Ades ◽  
Kathleen Donohue ◽  
Sara Ohadi ◽  
...  

The founding population in most new species introductions, or at the leading edge of an ongoing invasion, is likely to be small. Severe Allee effects—reductions in individual fitness at low population density—may then result in a failure of the species to colonize, even if the habitat could support a much larger population. Using a simulation model for plant populations that incorporates demography, mating systems, quantitative genetics, and pollinators, we show that Allee effects can potentially be overcome by transient hybridization with a resident species or an earlier colonizer. This mechanism does not require the invocation of adaptive changes usually attributed to invasions following hybridization. We verify our result in a case study of sequential invasions by two plant species where the outcrosser Cakile maritima has replaced an earlier, inbreeding, colonizer Cakile edentula (Brassicaceae). Observed historical rates of replacement are consistent with model predictions from hybrid-alleviated Allee effects in outcrossers, although other causes cannot be ruled out.


1993 ◽  
Vol 71 (9) ◽  
pp. 1231-1235 ◽  
Author(s):  
Jianhua Zhang

Previous studies showed that the two seed morphs produced from the upper and lower fruit segments of Cakile edentula differed significantly in their germinability and carry-over effects on the growth of the subsequent plants. By partitioning variables into seed-morph and seed-mass components, this study suggests that both seed germination and the growth of the subsequent plants depend on seed mass rather than seed morph. Plants from large seeds generally had greater leaf area, shoot to root ratio, biomass, and smaller leaf area ratio than those from small seeds. Within the same seed-mass class, plants from the lower fruit segment showed greater shoot to root ratio only at the end of the experiment. Since specific leaf area, leaf area ratio, and shoot to root ratio depended significantly on plant dry mass, the effect of seed mass on these variables may be actually achieved indirectly through the influence on plant size. Key words: seed dimorphism, seed mass, maternal effect, germination, growth, Cakile edentula.


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