Floral biology and late-acting self-incompatibility in Jacaranda racemosa (Bignoniaceae)

Breeding-system studies have been conducted with 38 of the approximately800 species of Bignoniaceae, and self-incompatibility was found in 31 of these. In species for which the site of self-incompatibility barrier was studied, self-pollinated flowers consistently failed to develop into fruits, even though pollen tubes grew down to the ovary and penetrated most of the ovules. In this study, we have investigated the floral biology and the breeding system in Jacaranda racemosa Chamisso, with hand-pollination experiments and the histology of post-pollination events. Flower anthesis lasted 1–3 days, and although the frequency of flower visitation was extremely low, natural pollination seemed to be effected mainly by medium-sized bees. Because the conspicuous staminodium favours eventual pollination by small bees, a possible role of the staminodium in the increase of potential pollinators is suggested. Hand-pollinations indicated that J. racemosa is a self-sterile species. Histological analysis of post-pollination events indicated the occurrence of a kind of late-acting self-incompatibility in which the processes of ovule penetration, fertilisation and endosperm initiation were slower in selfed than in crossed pistils. Until the time of self-pollinated pistil abscission, no signs of endosperm malfunction or proembryo development were observed in selfed pistils. Therefore, inbreeding depression is an unlikely explanation for self-sterility in J. racemosa.

Download Full-text

The role of floral biology and breeding system on the reproductive success of the narrow endemic Petrocoptis viscosa rothm. (Caryophyllaceae)

Biological Conservation ◽

10.1016/s0006-3207(01)00108-2 ◽

2002 ◽

Vol 103 (2) ◽

pp. 125-132 ◽

Cited By ~ 35

Author(s):

Luis Navarro ◽

Javier Guitián

Keyword(s):

Reproductive Success ◽

Breeding System ◽

Floral Biology ◽

Narrow Endemic

Download Full-text

Reproductive ecology and isolation ofPsittacanthus calyculatusandP. auriculatusmistletoes (Loranthaceae)

PeerJ ◽

10.7717/peerj.2491 ◽

2016 ◽

Vol 4 ◽

pp. e2491 ◽

Cited By ~ 12

Author(s):

Sergio Díaz Infante ◽

Carlos Lara ◽

María del Coro Arizmendi ◽

Luis E. Eguiarte ◽

Juan Francisco Ornelas

Keyword(s):

Breeding System ◽

Tree Species ◽

Floral Biology ◽

Host Tree ◽

Sympatric Populations ◽

Trait Divergence ◽

Ecological Isolation ◽

Hand Pollination ◽

Host Tree Species ◽

Seed Dispersers

BackgroundRelationships between floral biology and pollinator behavior are important to understanding species diversity of hemiparasiticPsittacanthusmistletoes (c. 120 species). We aimed to investigate trait divergence linked to pollinator attraction and reproductive isolation (RI) in two hummingbird-pollinated and bird-dispersedPsittacanthusspecies with range overlap.MethodsWe investigated the phylogenetic relationships, floral biology, pollinator assemblages, seed dispersers and host usage, and the breeding system and female reproductive success of two sympatric populations ofP. calyculatusandP. auriculatus, and one allopatric population ofP. calyculatus. Flowers in sympatry were also reciprocally pollinated to assess a post-mating component ofRI.ResultsHummingbird assemblages differed betweencalyculatuspopulations, while allopatric plants ofcalyculatusopened more but smaller flowers with longer lifespans and produced less nectar than those in sympatry. Bayesian-based phylogenetic analysis indicated monophyly forcalyculatuspopulations (i.e. both populations belong to the same species). In sympatry,calyculatusplants opened more and larger flowers with longer lifespans and produced same nectar volume than those ofauriculatus; populations shared pollinators but seed dispersers and host usage differed between species. Nectar standing crops differed between sympatric populations, with lower visitation incalyculatus. Hand pollination experiments indicated a predominant outcrossing breeding system, with fruit set after interspecific pollination two times higher fromcalyculatustoauriculatusthan in the opposite direction.ConclusionsGiven the low genetic differentiation betweencalyculatuspopulations, observed trait divergence could have resulted from changes regarding the local communities of pollinators and, therefore, expected divergence for peripheral, allopatric populations. UsingRIestimates, there were fewer heterospecific matings than expected by chance inP. calyculatus(RI4A= 0.629) as compared toP. auriculatus(RI4A= 0.20). When considering other factors of ecological isolation that affect co-occurrence, theRI4Cvalues indicate that isolation by hummingbird pollinators was less effective (0.20) than isolation by host tree species and seed dispersers (0.80 and 0.60, respectively), suggesting that host usage is the most important ecological isolation factor between the two species. Accordingly, the absolute and relative cumulative strength values indicated that the host tree species’ barrier is currently contributing the most to maintaining these species in sympatry.

Download Full-text

Floral Morphology and Breeding System of Three Species of Eucalyptus, Section Bisectaria (Myrtaceae)

Australian Journal of Botany ◽

10.1071/bt9920249 ◽

1992 ◽

Vol 40 (3) ◽

pp. 249 ◽

Cited By ~ 30

Author(s):

MF Ellis ◽

M Sedgley

Keyword(s):

Breeding System ◽

No Reduction ◽

Floral Morphology ◽

Self Incompatibility ◽

Floral Structure ◽

Transmitting Tissue ◽

Self Pollination ◽

Low Levels ◽

Ovule Penetration ◽

Stigma Morphology

Aspects of the breeding system, floral morphology and pistil cytology were studied in three trees each of E. spathulata, E. cladocalyx and E. leptophylla. E. spathulata and E. leptophylla were found to be highly self incompatible, setting very low levels of seed from controlled self pollination. E. cladocalyx trees ranged from self compatible to self incompatible. Reductions were seen in both the number of capsules and the numbers of seeds per capsule, from self pollination. The mechanism of self incompatibility was investigated in the pistil by following the success of cross and self pollinations with fluorescence microscopy. In E. cladocalyx and E. leptophylla no reduction in ovule penetration was seen from self pollination while in E. spathulata a significant reduction was seen in two trees but not the third, indicating that the post-zygotic mechanism of self incompatibility operates in all three species, and with mixed pre-zygotic and post-zygotic mechanisms in E. spathulata. Floral architecture differed between the three species in the structure of the inflorescence units, flower morphology, and anther, pollen and ovule numbers per flower. Pistil cytology was similar for all three species but differed in the length of the stylar canal, degree of sclerotinisation, stigma morphology and volume of transmitting tissue. The implications of floral structure and of the location and extent of outcrossing control are discussed in relation to seed genotypes and seed output.

Download Full-text

The Effect of Partial Self‐Incompatibility on the Breeding System of Campanula rapunculoides L. (Campanulaceae) under Conditions of Natural Pollination

International Journal of Plant Sciences ◽

10.1086/321928 ◽

2001 ◽

Vol 162 (5) ◽

pp. 1081-1087 ◽

Cited By ~ 10

Author(s):

Sara V. Good‐Avila ◽

Francis Frey ◽

Andrew G. Stephenson

Keyword(s):

Breeding System ◽

Self Incompatibility ◽

Natural Pollination

Download Full-text

Selective Fruit Abortion in Grevillea barklyana (Proteaceae)

Australian Journal of Botany ◽

10.1071/bt9930499 ◽

1993 ◽

Vol 41 (5) ◽

pp. 499 ◽

Cited By ~ 24

Author(s):

F Harriss ◽

RJ Whelan

Keyword(s):

Breeding System ◽

Fruit Set ◽

Pollen Tubes ◽

The Other ◽

Limited Resources ◽

Pollination Experiments ◽

Cross Pollination ◽

Hand Pollination ◽

Fruit Abortion ◽

Natural Pollination

The breeding system of Grevillea barklyana F. Muell. ex Benth. was studied using experimental hand pollinations. Fruit set was generally low (less than 5%), and equivalent for autogamy, self-pollination, outcross-pollination and inflorescences left exposed to natural pollination. Pollen tubes were produced in only a low proportion of flowers in the autogamy treatment, with few pollen tubes per flower and short pollen tubes in styles at both 24 and 48 h after anthesis. Selfing and cross-pollination produced equal numbers of pollen tubes in an equivalent and high proportion of flowers (ranging from 40% to 80%). However, pollen tubes resulting from selfing were shorter than from outcrossing after 24 and 48 h. Hand pollination experiments in which half of the flowers on inflorescences were pollinated with self pollen and the other half with outcross pollen generally produced a slightly skewed pattern of fruit set, with a higher proportion of the outcrossed flowers setting fruit. The following processes could contribute to the selective development of outcrossed fruit in this self-compatible species: (1) pollen tubes from outcrossed pollinations reach ovules before those growing from self pollen; (2) fruits that start to develop first obtain first call on limited resources; (3) fruits that are initiated later abort when other fruits on an inflorescence are developing.

Download Full-text

Do s genes or deleterious recessives control late-acting self-incompatibility in Handroanthus heptaphyllus (Bignoniaceae)? A diallel study with four full sib progeny arrays

Annals of Botany ◽

10.1093/aob/mcab031 ◽

2021 ◽

Author(s):

Marta B Bianchi ◽

Thomas R Meagher ◽

Peter E Gibbs

Keyword(s):

Genetic Control ◽

Inbreeding Depression ◽

Fruit Set ◽

Genetic Model ◽

Pollen Tubes ◽

Self Incompatibility ◽

Significant Difference ◽

Partial Embryo ◽

Ovule Penetration ◽

S Genes

Abstract Background and Aims Genetically controlled self-incompatibility (SI) mechanisms constrain selfing and thus have contributed to the evolutionary diversity of flowering plants. In homomorphic gametophytic SI (GSI) and homomorphic sporophytic SI (SSI), genetic control is usually by a single multi-allelic locus S. Both GSI and SSI prevent self pollen tubes reaching the ovary and so are pre-zygotic in action. In contrast, in taxa with late-acting self-incompatibility (LSI), rejection is often post-zygotic, since self-pollen tubes grow to the ovary where fertilization may occur prior to floral abscission. Alternatively, lack of self fruit set could be due to early-acting inbreeding depression (EID). The aim of our study was to investigate mechanisms underlying lack of selfed fruit set in Handroanthus heptaphyllus in order to assess the likelihood of LSI versus EID. Methods We employed four full sib diallels to study the genetic control of LSI in Handroanthus heptaphyllus using a precociously flowering variant. We also used fluorescence microscopy to study the incidence of ovule penetration by pollen tubes in pistils that abscised following pollination or initiated fruits. Key Results All diallels showed reciprocally cross-incompatible full-sibs (RCI), reciprocally cross compatible full-sibs (RCC), and non-reciprocally compatible full-sibs (NRC) in almost equal proportions. There was no significant difference between the incidence of ovule penetrations in abscised pistils following self- and cross-incompatible pollinations, but those in successful cross pollinations were around twofold greater. Conclusions A genetic model postulating a single S locus with four s alleles, one of which, in the maternal parent, is dominant to the other three, will produce RCI, RCC and NRC situations each at 33 %, consistent with our diallel results. We favour this simple genetic control over an early-acting inbreeding depression (EID) explanation since none of our pollinations, successful or unsuccessful, resulted in partial embryo development, as would be expected under a whole genome EID effect.

Download Full-text

Pollination ecology of Caryocar brasiliense (Caryocaraceae) in Central Brazil cerrado vegetation

Journal of Tropical Ecology ◽

10.1017/s0266467400007173 ◽

1993 ◽

Vol 9 (2) ◽

pp. 199-211 ◽

Cited By ~ 55

Author(s):

Rogério Gribel ◽

John D. Hay

Keyword(s):

Breeding System ◽

Fruit Set ◽

Seed Set ◽

Floral Biology ◽

Cerrado Vegetation ◽

Central Brazil ◽

Glossophaga Soricina ◽

Caryocar Brasiliense ◽

Anoura Geoffroyi ◽

Phyllostomus Discolor

ABSTRACTThe floral biology, breeding system and pollination of Caryocar brasiliense were studied in the cerrado vegetation of Central Brazil. The large, yellowish-cream, brush-like flowers are pollinated mainly by glossophagine bats (Glossophaga soricina and Anoura geoffroyi). Three non-glossophagine bats (Phyllostomus discolor, Vampyrops lineatus and Carollia perspicillata) and two short probosisced hawk moths (Erinyis ello and Pseudosphinx tetrio) may also act as occasional pollinators. Caryocar brasiliense is self-compatible although it sets significantly more fruits when crossed than when selfed. The natural fruit set (fruit/flower ratio) and seed set (seed/ovule ratio) are 3.1% and 1.0% respectively. Most of the fruits and seeds are formed through the action of the flower visitors, despite the fact that about 20% of the non-visited flowers receive self pollen on at least one stigma.

Download Full-text