A test of the reproductive assurance hypothesis in Ipomoea hederacea : does inbreeding depression counteract the benefits of self‐pollination?

2021 ◽  
Author(s):  
Ruth Delgado‐Dávila ◽  
Silvana Martén‐Rodríguez
2019 ◽  
Vol 124 (5) ◽  
pp. 869-881 ◽  
Author(s):  
Laura S Hildesheim ◽  
Øystein H Opedal ◽  
W Scott Armbruster ◽  
Christophe Pélabon

Abstract Background and Aims To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. Methods We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. Key Results Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. Conclusions In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.


2005 ◽  
Vol 92 (11) ◽  
pp. 1871-1877 ◽  
Author(s):  
H. M. Hull-Sanders ◽  
M. D. Eubanks ◽  
D. E. Carr

Botany ◽  
2009 ◽  
Vol 87 (11) ◽  
pp. 1110-1115 ◽  
Author(s):  
Rosane G. Collevatti ◽  
Raquel Estolano ◽  
Silmara F. Garcia ◽  
John D. Hay

In self-compatible plants, the reduction in brood size may be caused either by inbreeding depression, resource limitation, maternal regulation of offspring quality, or by sibling rivalry. We studied seed abortion in Caryocar brasiliense Camb. (Caryocaraceae), a Neotropical tree species, to verify whether seeds sired by self-pollination are aborted. Fruits were sampled from 23 mother trees to estimate seed set and proportion of aborted seeds. Ripened and aborted seeds from 18 mother trees were genotyped using 10 microsatellite loci together with mother trees and all nearby adults (83 adults) to determine the pollen donor by assignment test. From the 541 seeds, 190 were aborted and the mean number of aborted seeds per fruit was 0.627 (SD = 0.807). Proportion of aborted seeds was different among mother trees and among fruits within mother trees. All but three aborted seeds were sired by self-pollination and selfed seeds were aborted in fruits harbouring both selfed and outcrossed seeds. Aborted outcrossed seeds were sired by pollen donors closely related to mother trees. Our results strongly support that seed abortion in C. brasiliense may be the outcome of inbreeding depression and sibling rivalry when selfed and outcross pollinated ovules compete.


Botany ◽  
2014 ◽  
Vol 92 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Isabel Marques ◽  
David Draper ◽  
José María Iriondo

Small fragmented populations often exhibit reduced plant–pollinator interactions and scarce outcrossing opportunities. In this context, mixed-mating systems can be advantageous since selfing can provide reproductive assurance, but they may also carry relevant costs such as those involved in inbreeding depression. This study examines the advantages and costs of selfing in Narcissus serotinus L., a mixed-mating geophyte that currently occurs in several fragmented populations in Portugal, that resulted from the construction of the largest European dam. Observation of pollinators revealed that cross-pollination is less frequent in small than in large populations. Manual self-pollinations significantly increased fruit and seed set in small-size populations, also suggesting limited insect pollination. The existence of selfing may provide reproductive assurance in small-size populations of N. serotinus where outcrossing pollination is reduced. Although floral biology and experimental pollinations showed that N. serotinus is capable of autonomous selfing, four of the six fitness traits studied showed significant inbreeding depression in all populations. The high levels of inbreeding depression found in N. serotinus suggest that the initial reproductive assurance advantage of selfing may be counterbalanced by lower survival of the resulting individuals and a decrease in the evolutionary potential of the populations.


2005 ◽  
Vol 2 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Craig I Peter ◽  
Steven D Johnson

Mating success in plants depends largely on the efficiency of pollen dispersal. For hermaphrodite plants, self-pollination, either within or among flowers, can reduce mating opportunities because of pollen and ovule discounting and inbreeding depression. Self-pollination may be particularly detrimental in plants such as orchids and asclepiads that package each flower's pollen into one or more pollinia which, together with accessory structures, comprise a pollinarium. Darwin proposed that physical reconfiguration of pollinaria serves as a mechanism for reducing the likelihood of self-pollination. To be effective, the time taken for pollinarium reconfiguration would need to exceed that spent by a pollinator on a plant. We investigated pollinarium reconfiguration (including pollinarium bending, pollinium shrinking and anther cap retention) in 19 species and found a strong positive relationship between reconfiguration time and the duration of pollinator visits. Reconfiguration times were also consistently longer than pollinator visit times. These results provide strong support for Darwin's idea that this mechanism promotes cross-pollination.


2013 ◽  
Vol 280 (1766) ◽  
pp. 20131336 ◽  
Author(s):  
N. T. Jones ◽  
B. C. Husband ◽  
A. S. MacDougall

How plants respond to climatic perturbations, which are forecasted to increase in frequency and intensity, is difficult to predict because of the buffering effects of plasticity. Compensatory adjustments may maintain fecundity and recruitment, or delay negative changes that are inevitable but not immediately evident. We imposed a climate perturbation of warming and drought on a mixed-mating perennial violet, testing for adjustments in growth, reproduction and mortality. We observed several plasticity-based buffering responses, such that the climatic perturbation did not alter population structure. The most substantial reproductive adjustments, however, involved selfing, with a 45% increase in self-pollination by chasmogamous flowers, a 61% increase in the number of cleistogamous flowers that produced at least one fruit and an overall 15% increase in fruit production from selfed cleistogamous flowers. Reproductive assurance thus compensated for environmental change, including low pollinator visitation that occurred independently of our climate treatment. There was also no immediate evidence for inbreeding depression. Our work indicates that plants with vegetative and reproductive flexibility may not be immediately and negatively affected by a climatic perturbation. The stabilizing effects of these reproductive responses in the long term, however, may depend on the implications of significantly elevated levels of selfing.


Hoehnea ◽  
2020 ◽  
Vol 47 ◽  
Author(s):  
Inara Carolina da Silva-Batista ◽  
Cristiana Koschnitzke ◽  
Claudia Petean Bove

ABSTRACT (Reproductive assurance in three Neotropical species of Podostemaceae: strategies of self-pollination and the first report of apomixis). The aspects of reproductive assurance of the Lophogyne lacunosa (Gardner) C.P.Bove & C.T.Philbrick, Podostemum weddellianum (Tul.) C.T. Philbrick & Novelo, and Tristicha trifaria (Bory ex Willd.) Spreng. were investigated and, the mechanisms correlated to the flower morphology and floral biology. The mating system of L. lacunosa was also described, as well as the first report of apomixis in Podostemaceae. The reproductive assurance strategies used by L. lacunosa were autonomous competitive self-pollination, wind pollination, and apomixis. This species has floral attributes that ensure the dispersion of pollen by wind and its capture by the stigmas. Podostemum weddellianum and Tristicha trifaria presented autonomous competitive self-pollination before and during anthesis, respectively; both lack floral attributes for wind pollination. Considering that these species can be found in the same running water environment and that they are not phylogenetically close related, it was concluded that the different reproductive strategies are related to their evolutionary lineages.


2019 ◽  
Vol 11 (16) ◽  
pp. 68
Author(s):  
Jackson da Silva ◽  
Andréia Rodrigues Ramos ◽  
Deoclecio Jardim Amorim ◽  
Maurício Dutra Zanotto ◽  
Maria Márcia Pereira Sartori

Oil of castor bean despite its wide range of use, still present a relevant deficit in the Brazilian market. This deficit could be softened or extinguished with increased productivity, in which the genetic aspect has a great contribution. The most productive genotypes are the hybrid varieties, however for obtaining the hybrids pure lineages are required which have appropriate agronomic characteristics and that express the minimum of inbreeding depression. Thus, the objective of this research was to evaluate the inbreeding depression of castor bean progenies, from the cultivar FCA-PB, resulting from three types of pollination. The experiments were implanted in design in randomized blocks, in the 30 × 3 factorial scheme, being 30 progenies and 3 types of pollination (free, cross and self-pollination), in 2 environments (São Manuel and Araçatuba) and in 2 crops (2004/2005 and 2005/2006), with three replications. Inbreeding depression was estimated under the grain productivity variable. It was observed that cross-pollination presented grain productivity close to 2500 kg ha-1, in which the lowest coefficient of inbreeding was determined, zero (0). Opposed It self-pollination, in which resulted in lower productivity, around 2000 kg ha-1, and the highest inbreeding coefficient being of 0.77. The reflection of the coefficient of inbreeding on productivity presents inversely proportional behavior, ie, the measure that increases the coefficient of inbreeding decreases the grain yield.


2002 ◽  
Vol 50 (5) ◽  
pp. 627 ◽  
Author(s):  
S. J. Wooller ◽  
R. D. Wooller

Differential exclusion of vertebrates and invertebrates from the inflorescences of Banksia media R.Br. on the south coast of Western Australia showed the species to be partially self-compatible. Access by invertebrates increased fruit set and additional access by vertebrates resulted in even greater fruit set. Honeyeater birds and marsupial nectarivores were abundant and widespread in the study area and most carried the pollen of Banksia media while it flowered. However, although B. media had the floral characteristics attributed to vertebrate pollination, self-pollination and pollination by insects clearly also play major roles in seed production. Banksia media regenerates solely from seed released after fire and we suggest that its mixed mating strategy is a compromise between inbreeding depression and risk of elimination from areas prone to occasional fires.


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