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

1992 ◽  
Vol 40 (3) ◽  
pp. 249 ◽  
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.

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

2006 ◽  
Vol 54 (3) ◽  
pp. 315 ◽  
Author(s):  
Nelson S. Bittencourt ◽  
João Semir
Keyword(s):  
Breeding System ◽  
Histological Analysis ◽  
Floral Biology ◽  
Self Incompatibility ◽  
Flower Visitation ◽  
Hand Pollination ◽  
Natural Pollination ◽  
Ovule Penetration ◽  
Incompatibility Barrier

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.

Embryology of Eucalyptus Spathulata and E. platypus (Myrtaceae) Following Selfing, Crossing and Reciprocal Interspecific Pollination

1996 ◽  
Vol 44 (6) ◽  
pp. 661 ◽  
Author(s):  
M Sedgley ◽  
L Granger
Keyword(s):  
Pollen Tube ◽  
Embryo Development ◽  
Bright Field ◽  
Cross Pollination ◽  
Self Pollination ◽  
Bright Field Microscopy ◽  
Low Levels ◽  
Pollen Tube Penetration ◽  
Ovule Penetration

Embryology of Eucalyptus spathulata Hook. and E. platypus Hook. (subgenus Symphyomyrtus, section Bisectaria) was investigated by bright field microscopy to determine the cause of ovule failure at 2 months following selfing, crossing and reciprocal interspecific pollination. Eucalyptus spathulata retained more capsules and produced more seeds following cross- than self-pollination, whereas there was no difference between selfing and crossing for E. platypus. Both species produced seeds following interspecific pollination, but germination was low. Highest ovule penetration by a pollen tube, and ovule growth at 2 months, was observed following crossing of E. spathulata and following interspecific pollination of E. platypus. Most self-pollinated ovules of both species were degenerating and were either unfertilised or had undivided zygotes and free nuclear endosperm. Muticellular pro-embryos were more common in cross-pollinated and interspecific pollinated ovules than following selfing. It was concluded that ovule degeneration of E. spathulata and E. platypus following selfing resulted from low levels of pollen tube penetration and fertilisation, and that in those ovules which were fertilised, the zygote generally failed to divide. Degeneration following cross-pollination of E. spathulata also resulted from failure of the zygote to divide, and in E. platypus additional reasons were low levels of pollen tube penetration and fertilisation, and lack of cellularisation of the endosperm. Ovule degeneration of both species following interspecific pollination included failure of the zygote to divide, but in E. spathulata it also resulted from slower embryo development and reduced cellularisation of the endosperm.

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

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.

scholarly journals Cytological Observation and Transcriptome Comparative Analysis of Self-Pollination and Cross-Pollination in Dendrobium Officinale

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 432
Author(s):  
Yaling Chen ◽  
Benchang Hu ◽  
Fantao Zhang ◽  
Xiangdong Luo ◽  
Jiankun Xie
Keyword(s):  
Pollen Tubes ◽  
The Self ◽  
Dendrobium Officinale ◽  
Self Incompatibility ◽  
Related Gene ◽  
Cytological Observation ◽  
Lectin Receptor ◽  
Cross Pollination ◽  
Self Pollination ◽  
Medicinal Value

Dendrobium officinale is a rare and traditional medicinal plant with high pharmacological and nutritional value. The self-incompatibility mechanism of D. officinale reproductive isolation was formed in the long-term evolution process, but intraspecific hybridization of different germplasm resources leads to a large gap in the yield, quality, and medicinal value of D. officinale. To investigate the biological mechanism of self-incompatibility in D. officinale, cytological observation and the transcriptome analysis was carried out on the samples of self-pollination and cross-pollination in D. officinale. Results for self-pollination showed that the pollen tubes could grow in the style at 2 h, but most of pollen tubes stopped growing at 4 h, while a large number of cross-pollinated pollen tubes grew along the placental space to the base of ovary, indicating that the self-incompatibility of D. officinale may be gametophyte self-incompatibility. A total of 63.41 G basesum of D. officinale style samples from non-pollinated, self-pollination, and cross-pollination by RNA-seq were obtained, and a total of 1944, 1758, and 475 differentially expressed genes (DEGs) in the comparison of CK (non-pollinated) vs. HF (cross-pollination sample), CK vs. SF (self-pollination sample) and SF vs. HF were identified, respectively. Forty-one candidate genes related to self-incompatibility were found by function annotation of DEGs, including 6 Ca2+ signal genes, 4 armed repeat containing (ARC) related genes, 11 S-locus receptor kinase (SRK) related genes, 2 Exo70 family genes, 9 ubiquitin related genes, 1 fatty acid related gene, 6 amino acid-related genes, 1 pollen-specific leucine-rich repeat extensin-like protein (LRX) related gene and 1 lectin receptor-like kinases (RLKs) related gene, showed that self-incompatibility mechanism of D. officinale involves the interaction of multiple genes and pathways. The results can provide a basis for the study of the self-incompatibility mechanism of D. officinale, and provide ideas for the preservation and utilization of high-quality resources of D. officinale.

Pollen flow in distylous populations of Amsinckia (Boraginaceae)

1976 ◽  
Vol 54 (22) ◽  
pp. 2530-2535 ◽  
Author(s):  
Fred R. Ganders
Keyword(s):  
Pollen Flow ◽  
Progeny Testing ◽  
Self Incompatibility ◽  
Disassortative Mating ◽  
Pollen Loads ◽  
Self Pollination ◽  
Incompatibility System ◽  
Total Pollen

Stigmatic pollen loads were analyzed from naturally pollinated pin and thrum form flowers of Amsinckia douglasiana and A. vernicosa var. furcata. Pin stigmas captured more total pollen than thrum stigmas. Pins experienced either net self-pollination or random pollination. Thrum stigmas experienced significant disassortative pollination. Comparing pollen loads from intact and emasculated thrum flowers of A. douglasiana indicated that self-pollination and geitonogamy were relatively unimportant in the pollination of the thrum form. The level of disassortative pollination of A. vernicosa var. furcata does not appear to be high enough to account for the level of disassortative mating observed by progeny testing, suggesting that this species may possess an incomplete stylar self-incompatibility system such as has been reported in A. grandiflora.

scholarly journals Floral morphology and anatomy of Dalechampia alata Klotzsch ex Baill. (Euphorbiaceae), with emphasis on secretory structures

2016 ◽  
Vol 76 (1) ◽  
pp. 233-244 ◽  
Author(s):  
F. M. Martins ◽  
I. L. Cunha-Neto ◽  
T. M. Pereira
Keyword(s):  
Light Microscope ◽  
Chemical Nature ◽  
Floral Morphology ◽  
Staminate Flower ◽  
Ovary Wall ◽  
Transmitting Tissue ◽  
Secretory Structures ◽  
First Report ◽  
Meristematic Activity ◽  
Secretory Glands

Abstract The morphology and anatomy of the flower of Dalechampia alata, as well as the chemical nature of the exudates secreted in the inflorescence were studied using light microscope. This is the first report showing the presence of colleters in the genus Dalechampia. In the staminate flower occur a group of small secretory glands. The histochemical results indicate that the substance secreted from the glands is lipidic and resinuous in nature, while in the colleters it consists of polysaccharides and lipid-rich substances. The ovule of D. alata are anatropous, subglobose and bitegmic. It presents obturator, micropyle occluded by nucellar beak and meristematic activity in the ovary wall. The secretion produced in the stigmatic and transmitting tissue consists of polysaccharides.

scholarly journals Interaction Between Ploidy, Breeding System, and Lineage Diversification

2019 ◽  
Author(s):  
Rosana Zenil-Ferguson ◽  
J. Gordon Burleigh ◽  
William A. Freyman ◽  
Boris Igić ◽  
Itay Mayrose ◽  
...  
Keyword(s):  
Breeding System ◽  
Whole Genome Duplication ◽  
Genome Duplication ◽  
Whole Genome ◽  
Self Incompatibility ◽  
Evolutionary Pathway ◽  
Diversification Rates ◽  
Extinction Rates ◽  
Biological Hierarchy ◽  
Lineage Diversification

AbstractIf particular traits consistently affect rates of speciation and extinction, broad macroevolutionary patterns can be understood as consequences of selection at high levels of the biological hierarchy. Identifying traits associated with diversification rate differences is complicated by the wide variety of characters under consideration and the statistical challenges of testing for associations from comparative phylogenetic data. Ploidy (diploid vs. polyploid states) and breeding system (self-incompatible vs. self-compatible states) have been repeatedly suggested as possible drivers of differential diversification. We investigate the connections of these traits, including their interaction, to speciation and extinction rates in Solanaceae. We show that the effect of ploidy on diversification can be largely explained by its correlation with breeding system and that additional unknown factors, alongside breeding system, influence diversification rates. These results are largely robust to allowing for diploidization. Finally, we find that the most common evolutionary pathway to polyploidy in Solanaceae occurs via direct breakdown of self-incompatibility by whole genome duplication, rather than indirectly via breakdown followed by polyploidization.

scholarly journals The synstigma turns the fig into a large flower

2020 ◽  
Vol 195 (1) ◽  
pp. 93-105
Author(s):  
Simone P Teixeira ◽  
Marina F B Costa ◽  
João Paulo Basso-Alves ◽  
Finn Kjellberg ◽  
Rodrigo A S Pereira
Keyword(s):  
Pollen Tube ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Live Cells ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Floral Structure ◽  
Transmitting Tissue ◽  
Transmission Electron ◽  
Large Flower

Abstract The synstigma is a structure formed by clusters of two to several stigmas, whether in the same or between different flowers. Although rare in angiosperms, synstigmas are found in c. 500 out of the c. 750 Ficus spp. (Moraceae). This floral structure is associated with fig-fig wasp pollinating mutualism. The synstigma structure and pollen tube pathways were studied in six Ficus spp. from Ficus section Americanae to test the hypothesis that the synstigma allows pollen grains deposited on a stigma to emit pollen tubes that can grow laterally and fertilize surrounding flowers. Syconia containing recently pollinated stigmas were collected and dissected, and the stigmas were processed for analyses with light and scanning and transmission electron microscopy. The arrangement of the synstigmas across species can be spaced or congested, with the number of stigmas per synstigma ranging from two to 20. Contact between the stigmas in a synstigma occurs by the intertwining of the stigmatic branches and papillae; their union is firm or loose. The pollen tube grows through live cells of the transmitting tissue until reaching the ovule micropyle. Curved pollen tubes growing from one stigma to another were observed in five out of the six species studied. The curvilinear morphology of pollen tubes probably results from competition by pollen between the stigmas composing a synstigma via chemotropic signals. The synstigma appears to be a key adaptation that ensures seed production by flowers not exploited by the fig wasps in actively pollinated Ficus spp.

Floral structure in Thismia (Thismiaceae: Dioscoreales): new insights from anatomy, vasculature and development

2020 ◽  
Author(s):  
Maxim S Nuraliev ◽  
Sophia V Yudina ◽  
Ekaterina A Shepeleva ◽  
Ba Vuong Truong ◽  
Thi Xuyen Do ◽  
...  
Keyword(s):  
Distal Part ◽  
Floral Development ◽  
Floral Morphology ◽  
Reproductive Organs ◽  
Floral Structure ◽  
Interspecific Differences ◽  
Precise Understanding ◽  
Floral Vasculature ◽  
General Appearance ◽  
Comprehensive Study

Abstract Thismia is characterized by an exceptionally complicated floral morphology that is currently not understood properly. In the taxonomic literature, descriptive rather than morphological terms are often applied to parts of the flower in Thismia, relating to the general appearance of the floral organs instead of their precise homologies. Precise understanding of the floral structure is complicated by the rarity of Thismia spp. and the paucity of appropriate material. Here we provide a comprehensive study of reproductive organs of three Thismia spp. (T. annamensis, T. javanica and T. mucronata) including the first investigation of inflorescence architecture and early floral development in Thismiaceae. We found a hitherto unknown diversity of the reproductive shoots in the genus, manifested in the number of floral prophylls (two or three, in contrast to a single prophyll in the vast majority of monocots) and in the branching plane resulting in two distinct inflorescence types, a drepanium and a bostryx. We report the non-acropetal sequence of initiation of floral whorls (with stamens being the last elements to initiate), never previously described in monocots, and the gynoecium composed of completely plicate carpels, also a rare feature for monocots. Floral vasculature is relatively uniform in Thismia, but significant interspecific differences are found in tepal innervation, including the number of tepal traces; some of these differences are not immediately related to the external tepal morphology. We argue that the annulus, which acts as a roof of the hypanthium, possesses an androecium nature and represents congenitally fused bases of stamen filaments. We describe the stamens as laminar structures, which are also shortly tubular in the distal part of the supraconnective with the adaxial tubular side forming a skirt-like appendage. Finally, the placentas, which are column-like when mature, are initially parietal, becoming secondarily similar to free-central placentas through schizogenous separation from the ovary wall.

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