scholarly journals Selfing rates vary with floral display, pollinator visitation and plant density in natural populations of Mimulus ringens

Author(s):  
Dorothy A. Christopher ◽  
Jeffrey D. Karron ◽  
Wendy R. Semski ◽  
Patrick A. Smallwood ◽  
Dorset W. Trapnell ◽  
...  
2004 ◽  
Vol 18 (1) ◽  
pp. 116-124 ◽  
Author(s):  
R. J. Mitchell ◽  
J. D. Karron ◽  
K. G. Holmquist ◽  
J. M. Bell

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenliu Zhang ◽  
Jiangyun Gao

Abstract Background Most orchid species have been shown to be severely pollination limited, and the factors affecting reproductive success have been widely studied. However, the factors determining the reproductive success vary from species to species. Habenaria species typically produce nectar but exhibit variable fruit set and reproductive success among species. Here, we investigated the influence of the flowering plant density, inflorescence size, breeding system, and pollinator behaviour on the reproductive success of two rewarding Habenaria species. Results Our observations indicated that Habenaria limprichtii and H. petelotii co-occur in roadside verge habitats and present overlapping flowering periods. Both species were pollination limited, although H. limprichtii produced more fruits than H. petelotii under natural conditions during the 3-year investigation. H. petelotii individuals formed distinct patches along roadsides, while nearly all H. limprichtii individuals clustered together. The bigger floral display and higher nectar sugar concentration in H. limprichtii resulted in increased attraction and visits from pollinators. Three species of effective moths pollinated for H. limprichtii, while Thinopteryx delectans (Geometridae) was the exclusive pollinator of H. petelotii. The percentage of viable seeds was significantly lower for hand geitonogamy than for hand cross-pollination in both species. However, H. limprichtii may often be geitonogamously pollinated based on the behaviours of the pollinators and viable embryo assessment. Conclusions In anthropogenic interference habitats, the behaviours and abundance of pollinators influence the fruit set of the two studied species. The different pollinator assemblages in H. limprichtii can alleviate pollinator specificity and ensure reproductive success, whereas the more viable embryos of natural fruit seeds in H. petelotii suggested reducing geitonogamy by pollinators in the field. Our results indicate that a quantity-quality trade-off must occur between species with different breeding strategies so that they can fully exploit the existing given resources.


Genetics ◽  
1995 ◽  
Vol 139 (1) ◽  
pp. 397-406 ◽  
Author(s):  
R G Shaw ◽  
G A Platenkamp ◽  
F H Shaw ◽  
R H Podolsky

Abstract Recent investigations of evolution in heterogeneous environments have begun to accommodate genetic and environmental complexity typical of natural populations. Theoretical studies demonstrate that evolution of polygenic characters depends heavily on the genetic interdependence of the expression of traits in the different environments in which selection occurs, but information concerning this issue is scarce. We conducted a field experiment to assess the genetic variability of the annual plant Nemophila menziesii in five biotic regimes differing in plant density and composition. Significant, though modest, additive genetic variance in plant size was expressed in particular treatments. Evidence of additive genetic tradeoffs between interspecific and intraspecific competitive performance was found, but this result was not consistent throughout the experiment. Two aspects of experimental design may tend to obscure genetically based tradeoffs across environments in many previously published experiments: (1) inability to isolate additive genetic from other sources of variation and (2) use of novel (e.g., laboratory) environments.


2015 ◽  
Vol 39 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Edyta Jermakowicz ◽  
Beata Ostrowiecka ◽  
Izabela Tałałaj ◽  
Artur Pliszko ◽  
Agata Kostro-Ambroziak

Abstract In the presented study, male and female reproductive success was analyzed in relation to the population size, floral display and pollinators’ availability in natural and anthropogenic populations of the orchid Malaxis monophyllos (L.) Sw. Our results indicated significant differences between all investigated populations in parameters of floral display, including heights and number of flowers per inflorescence, as well the number of flowering individuals and their spatial structure. Additionally, populations differed both in male (pollinia removal) and female (fruit set) reproductive success, but only the fruit set clearly differentiated anthropogenic and natural populations. Despite the average flower number per plant being significantly higher in two of the anthropogenic populations, it was not related to the fruits set, which was significantly lower there. Moreover, our preliminary study concerning the potential pollinators of M. monophyllos showed a higher contribution of flies in natural habitats than in anthropogenic ones. Thus, we can suspect that the main factors influencing the level of female reproductive success in M. monophyllos populations are abundance of effective pollinators, as well as flower visitors, which may have resulted in a different level of pollen discounting in populations. Therefore, further studies concerning breeding system and pollination as important forces that shape demographic processes in M. monophyllos populations are necessary. Our results also indicate that suitable conservation methods in M. monophyllos should always include the preservation of potential pollinators, especially in these new, secondary habitats.


1981 ◽  
Vol 29 (5) ◽  
pp. 579 ◽  
Author(s):  
D Monk ◽  
JS Pate ◽  
WA Loneragan

Growth, reproduction and longevity of the fire weed Acacia pulchella var. glaberrima were examined in natural populations of known age in coastal sands in and around Perth, W.A. Dense populations (10000 plantsiha) were established after a summer burn; plant density was 30% of its initial value at 4 years. less than 8% at 13 years. Plants accumulated dry matter, nitrogen and phosphorus throughout a 13-year growth period. Seed production commenced at 2 years, reached a maximum (12000 seeds per plant per year) at 3 or 4 years declining to 2000 seedsiplant in the 13th year. Only a small fraction of the shed seed accumulated in soil under the stands. Changes in total plant N, nodule weightlplant, and C2H2 reduction capacity of detached nodules were followed in populations in their first, second and fourth growing seasons. A new set of nodules formed with the autumn rains, peak nodule mass and C2H2 reduction activity were recorded in July-October, and virtually no nodules survived the summer into a second growing season. A glasshouse study of N accumulation and C2H2 reduction by nodules in minus N sand culture gave acalibration value of 2.26 mol C2H2 : mol N2 fixed. Applying this value to data from nativepopulations, 8% of the N accumulated by first season plants, 45% of the N of second season plants and 68% of the N of fourth season plants were estimated to be derived from symbiosis. Average annual returns of N to the ecosystem were estimated at 3.9 kg/ha, probably more than half of this from N2 fixation. Progressive death of plants in the populations gave the greatest return ( 1.9 kg N per ha per yr), the remainder from litter (1 kg N per ha per yr) and shed seed ( 1 kg N per ha per yr).


Heredity ◽  
2003 ◽  
Vol 92 (3) ◽  
pp. 242-248 ◽  
Author(s):  
J D Karron ◽  
R J Mitchell ◽  
K G Holmquist ◽  
J M Bell ◽  
B Funk

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