Pollen Germination, Pollen Tube Growth, Fruit Set, and Seed Development in Schlumbergera truncata and S. ×buckleyi (Cactaceae)

The reproductive biology of Schlumbergera truncata (Haworth) Moran and S. xbuckleyi (T. Moore) Tjaden was examined in a series of experiments. At anthesis, pollen grains are spherical, 54 to 62 μm in diameter, and tricellular. The receptive surface of the stigma is densely covered with elongated papillae and is devoid of exudate during the period of flower opening. When compatible pollen was applied to mature stigmas, germination occurred between 20 and 30 minutes after pollination and pollen tubes penetrated the stigma surface between 30 and 40 minutes after pollination. Pollen tubes exhibited a nonlinear pattern of growth in the upper two-thirds of the style, and the maximum rate of growth (≫1.9 mm·h-1) occurred between 12 and 18 hours after pollination. Full seed set was attained between 32 and 48 hours after pollination. Genotypic variation in the time required to achieve full seed set was partly attributable to differences in stylar length. Seeds were fully mature 6 months after pollination, but delaying fruit harvest until 8 months after pollination did not affect seed germination.

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Two groups of Arabidopsis receptor kinases preferentially regulate the growth of intraspecies pollen tubes in the female reproductive tract

10.1101/2020.03.17.995555 ◽

2020 ◽

Author(s):

Hyun Kyung Lee ◽

Daphne R. Goring

Keyword(s):

Pollen Tube ◽

Reproductive Tract ◽

Cell Communication ◽

Pollen Grains ◽

Pollen Tubes ◽

Female Reproductive Tract ◽

Wild Type ◽

Knockout Mutant ◽

Receptor Kinases ◽

Compatible Pollen

SummaryIn flowering plants, continuous cell-cell communication between the compatible male pollen grain/growing pollen tube and the female pistil is required for successful sexual reproduction. In Arabidopsis thaliana, the later stages of this dialogue are mediated by several peptide ligands and receptor kinases that guide pollen tubes to the ovules for the release of sperm cells. Despite a detailed understanding of these processes, a key gap remains on the nature of the regulators that function at the earlier stages. Here, we report on two groups of A. thaliana receptor kinases, the LRR-VIII-2 RK subclass and the SERKs, that function in the female reproductive tract to regulate the compatible pollen grains and early pollen tube growth, both essential steps for the downstream processes leading to fertilization. Multiple A. thaliana LRR-VIII-2 RK and SERK knockout mutant combinations were created, and several phenotypes were observed such as reduced wild-type pollen hydration and reduced pollen tube travel distances. As these mutant pistils displayed a wild-type morphology, the observed altered responses of the wild-type pollen are proposed to result from the loss of these receptor kinases leading to an impaired pollen-pistil dialogue at these early stages. Furthermore, using pollen from related Brassicaceae species, we also discovered that these receptor kinases are required in the female reproductive tract to establish a reproductive barrier to interspecies pollen. Thus, we propose that the LRR-VIII-2 RKs and the SERKs play a dual role in the preferential selection and promotion of intraspecies pollen over interspecies pollen.

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The consequences of mixed pollination on seed set in Vaccinium corymbosum

Canadian Journal of Botany ◽

10.1139/b91-304 ◽

1991 ◽

Vol 69 (11) ◽

pp. 2448-2454 ◽

Cited By ~ 7

Author(s):

S. P. Vander Kloet

Keyword(s):

Key Words ◽

Seed Set ◽

Vaccinium Corymbosum ◽

Viable Seed ◽

Maturation Time ◽

Embryo Abortion ◽

Berry Ripening ◽

Time Required ◽

Compatible Pollen ◽

Berry Maturation

Self pollen of Vaccinium corymbosum germinates as well as outcross (compatible) pollen from the same population and more rapidly than compatible pollen from more distant populations. When a mixture of self and compatible pollen, either from the same or incontiguous populations, is applied to the stigma, the time required for berry ripening is significantly reduced compared with compatible pollen alone, although seed set also decreases significantly. Adding compatible pollen from different pollen donors significantly increased seed set but also increased the time for berry maturation by 5 days. Self pollen in conjunction with compatible pollen resulted in a 50% loss of viable seed production and an 8% gain in berry maturation time. Self-pollination resulted in embryo abortion in V. corymbosum. Key words: pollination, Vaccinium, seed set, outcrossing.

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The effect of pollination intensity and incompatible pollen on seed set in Turnera ulmifolia (Turneraceae)

Canadian Journal of Botany ◽

10.1139/b84-175 ◽

1984 ◽

Vol 62 (6) ◽

pp. 1298-1303 ◽

Cited By ~ 98

Author(s):

Joel S. Shore ◽

Spencer C. H. Barrett

Keyword(s):

Regression Analysis ◽

Seed Set ◽

Pollen Grains ◽

The Self ◽

Time Intervals ◽

Pollination Experiments ◽

Controlled Pollination ◽

Incompatible Pollen ◽

Turnera Ulmifolia ◽

Compatible Pollen

Controlled pollination experiments were performed on the self-incompatible distylous herb Turnera ulmifolia L. to investigate the effects of pollination intensity and large amounts of incompatible pollen on seed set. In the first experiment, known numbers of compatible pollen grains ranging from 1 to 100 were applied to stigmas of the floral morphs. In both morphs, increasing amounts of pollen generally resulted in increased levels of seed set, although considerable variance was observed at all pollination intensities. Approximately two to seven pollen grains are required to produce a single seed and more than 95 grains are required to achieve maximum seed set in T. ulmifolia. Regression analysis of the seed set data failed to detect a difference in the response of the floral morphs to pollination intensity. In the second experiment, known proportions of compatible and incompatible pollen were applied to stigmas at various time intervals. Most treatments involving mixtures of compatible and incompatible pollen had no significant effect on seed set when compared with the controls. Clogging was only observed in the long-styled morph when one anther of compatible pollen was applied to stigmas 1.5 and 3.0 h after pollination with five anthers of incompatible pollen. The clogging of stigmas by incompatible pollen seems unlikely to have played a major role in the evolution and maintenance of distyly in Turnera ulmifolia.

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Identification of a role for an E6-like 1 gene in early pollen-stigma interactions in Arabidopsis thaliana

10.1101/623686 ◽

2019 ◽

Cited By ~ 1

Author(s):

Jennifer Doucet ◽

Christina Truong ◽

Elizabeth Frank-Webb ◽

Hyun Kyung Lee ◽

Anna Daneva ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Seed Set ◽

Biological Function ◽

Fiber Development ◽

Orthologous Genes ◽

Fusion Construct ◽

Pollen Hydration ◽

Stigma Surface ◽

Stigmatic Papillae ◽

Compatible Pollen

AbstractIn Arabidopsis, successful pollen-stigma interactions are dependent on rapid recognition of compatible pollen by the stigmatic papillae located on the surface of the pistil and the subsequent regulation of pollen hydration and germination, and followed by the growth of pollen tubes through the stigma surface. Here we have described the function of a novel gene, E6-like 1 (E6L1), that was identified through the analysis of transcriptome datasets, as one of highest-expressed genes in the stigma, and furthermore, its expression was largely restricted to the stigma and trichomes. The first E6 gene was initially identified as a highly-expressed gene during cotton fiber development, and related E6-like predicted proteins are found throughout the Angiosperms. To date, no orthologous genes have been assigned a biological function. Both the Arabidopsis E6L1 and cotton E6 proteins are predicted to be secreted, and this was confirmed using an E6L1:RFP fusion construct. To further investigate E6L1’s function, one T-DNA and two independent CRISPR-generated mutants were analyzed for compatible pollen-stigma interactions, and pollen hydration, pollen adhesion and seed set were mildly impaired for the e6l1 mutants. This work identifies E6L1 as a novel stigmatic factor that plays a role during the early post-pollination stages in Arabidopsis.Key MessageWe describe a function for a novel Arabidopsis gene, E6-like 1 (E6L1), that was identified as a highly-expressed gene in the stigma and plays a role in early post-pollination stages.

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A quantitative and structural comparison of Citrus pollen tube development in cross-compatible and self-incompatible gynoecia

Canadian Journal of Botany ◽

10.1139/b86-337 ◽

1986 ◽

Vol 64 (11) ◽

pp. 2548-2555 ◽

Cited By ~ 13

Author(s):

Tracy L. Kahn ◽

Darleen A. DeMason

Keyword(s):

Pollen Tube ◽

Pollen Tubes ◽

Citrus Paradisi ◽

Structural Comparison ◽

Stigma Surface ◽

Incompatible Pollination ◽

Compatible Cross ◽

Incompatible Cross ◽

Compatible Pollinations ◽

Compatible Pollen

Pollen tube development in Orlando tangelo (Citrus paradisi Macf. × C. reticulata Blanco.) was compared within and between cross-compatible pollinations of Orlando pollen on Dancy tangerine (C. reticulata Blanco.) stigmas and self-incompatible pollinations on Orlando tangelo stigmas. Orlando and Dancy gynoecia were morphologically similar but differed slightly in stigma, style, and ovary lengths. Orlando pollen tube development was studied 1, 3, 6, 9, and 12 days after both cross- and self-pollination to record the number of pollen tubes at each of five levels: stigma surface, upper style, lower style, ovary, and entrance into ovules. In the incompatible cross (self-pollinated Orlando), the stigma was the primary region of pollen tube arrest. In the compatible cross (Orlando pollen on Dancy), some pollen tubes penetrated ovules between 9 and 12 days after cross pollination; however, other pollen tubes were arrested in the stigma. Pollen tubes that successfully penetrated ovules in the compatible cross differed morphologically from pollen tubes arrested in both the compatible and incompatible situations. Successful compatible pollen tubes were straight with thin-walled tips and regularly spaced callose plugs behind the growing tips. Many pollen tube abnormalities associated with the self-incompatible pollination of Orlando were also present among arrested pollen tubes from the compatible cross.

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455 PB 326 PISTIL INFLUENCE ON GROWTH OF POLLEN TUBES OF P. X DOMESTICUM

HortScience ◽

10.21273/hortsci.29.5.496e ◽

1994 ◽

Vol 29 (5) ◽

pp. 496e-496

Author(s):

Mary Stuart ◽

Pablo Jourdan

Keyword(s):

Male Gametophyte ◽

Genotypic Variation ◽

Pollen Grains ◽

Pollen Tubes ◽

Female Fertility ◽

Low Fertility ◽

High Fertility ◽

Poor Seed ◽

Germinated Pollen ◽

Germination And Growth

The regal pelargonium (P. x domesticum) is generally characterized by low fertility and poor seed set. In studys designed to assess factors that contribute to low fecundity in this crop we have examined genotype interactions among various cultivars and have identified lines that differ in degree of male and female fertility. The objective of this study was to examine genotypic variation, other than self-incompatibility, of P. x domesticum pistils in supporting the development of the male gametophyte. Variation in pollen germination and growth was assessed after crossing either a male of high fertility or a mate of poor fertility to nine different selections of varying female fertility. Styles were harvested 2 hours after pollination and examined using fluorescence microscopy to determine the number of germinated pollen grains on the stigma and the number of pollen tubes growing down the style. Female selections displayed large differences in their ability to support pollen tubes. Styles from different females pollinated with the same male varied in average number of pollen tubes from 30 to 2.

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Pollen Wall Proteins: Pollen-Stigma Interactions in Ragweed and Cosmos (Compositae)

Journal of Cell Science ◽

10.1242/jcs.12.2.421 ◽

1973 ◽

Vol 12 (2) ◽

pp. 421-443 ◽

Cited By ~ 1

Author(s):

R. B. KNOX

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Pollen Grains ◽

Pollen Tubes ◽

Pollen Wall ◽

Stigma Surface ◽

Cosmos Bipinnatus ◽

Stigmatic Papillae ◽

Scanning Electron

The release of wall-held materials from the pollen of ragweed (Ambrosia tenuifolia) and Cosmos bipinnatus on to the stigma surface has been followed. When fresh stigmas were viewed by scanning electron microscopy, a fluid material was observed coating pollen grains, pollen tubes and adjacent stigmatic papillae. This fluid contained pollen-wall antigens, including the allergen Antigen E, detected by immunofluorescence, and proteins, lipids and carbohydrates detected by cytochemical methods. In Cosmos, the fate of the antigens was much the same after both compatible and incompatible matings. In incompatible matings, pollen tubes were blocked with a polysaccharide considered to be callose. Callose particles appeared on neighbouring stigmatic papillae, and adjacent stigmatic hairs accumulated callose internally. This reaction may be an important one for the incompatibility response.

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Characterization of the role of several COPI complex isoforms during the early acceptance of compatible pollen grains in Arabidopsis thaliana

10.1101/427534 ◽

2018 ◽

Author(s):

Daniel A. Cabada Gomez ◽

M. Isabella Chavez ◽

Emily Indriolo

Keyword(s):

Pollen Tube ◽

Seed Set ◽

Contact Point ◽

Pollen Grains ◽

Retrograde Transport ◽

Pollen Grain ◽

Knock Out ◽

Pollen Tube Penetration ◽

Compatible Pollen

AbstractCOPI is a seven subunit coatomer complex, consisting of α, β, β′, γ, δ, ε, and ξ; in A. thaliana, COPI is necessary for retrograde transport from the Golgi to the Endoplasmic Reticulum, Golgi maintenance, and cell-plate formation in plant cells. Vesicle recruitment to the pollen contact point is required for pollen hydration and pollen tube penetration. To determine what other aspects of trafficking may be involved in the stigmatic papillae acceptance of compatible pollen, knock-out lines of several isoforms of the COPI complex were characterized in their roles during compatible pollination. Isoforms that were studied included α1-COPI, β-COPI, β′-COPI, γ-COPI and ε-COPI. Each mutant line was characterized in regards to pollen grain adherence, pollen tube penetration, and seed set. Of the mutant lines examined, α1-copi had the strongest phenotype with issues with compatible pollen grain adherence, tube germination and reduction in seed set while other lines had milder but visible retardation in compatible pollen acceptance. The data presented here are the first study of the role of the COPI complex in compatible pollinations and that certain subunit isoforms are required for compatible pollen acceptance.

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Reproductive Biology of Clethra alnifolia

HortScience ◽

10.21273/hortsci.41.3.567 ◽

2006 ◽

Vol 41 (3) ◽

pp. 567-570

Author(s):

Sandra M. Reed

Keyword(s):

Seed Set ◽

Pollen Tubes ◽

Self Incompatibility ◽

Stigma Receptivity ◽

Flower Opening ◽

Lack Of Information ◽

Incompatibility System ◽

Self Compatibility ◽

Pollen Shed ◽

The Relationship

Breeding efforts in Clethra alnifolia L., an ornamental shrub native to the Eastern U.S., are hindered by a lack of information on the reproductive behavior of this species. The objective of this study was to evaluate self-compatibility, time of stigma receptivity, and the relationship between time of pollen shed and stigma receptivity in C. alnifolia. Stigma receptivity and changes in floral morphology were monitored over a 7-day period beginning at flower opening. Pollen germination and pollen tube growth in styles were examined following self- and cross-pollinations using fluorescence microscopy. Seed set and germination were compared following self- and cross-pollinations. Anthers began to dehisce in `Hummingbird' and `Ruby Spice' the day after flowers opened, but stigmas did not become fully receptive to pollen until 2 days later. An increase in the length of pistils was observed following flower opening. Maximum elongation of pistils occurred at approximately the same time stigmas became receptive and could be utilized as an indicator of receptivity. While self-pollen tubes appeared to grow slightly slower than cross-pollen tubes, there was no indication of a self-incompatibility system acting at the stigmatic or stylar level in C. alnifolia. Self-pollinations of `Hummingbird' and `Ruby Spice' produced fewer seeds than did cross-pollinations of these cultivars. Germination of all seed obtained from this study was too poor to allow a comparison of germination rates of the self- and cross-pollinated seed. However, because a few self-progeny were obtained, emasculation is recommended when making controlled pollinations. The presence of a late acting self-incompatibility system or early-acting inbreeding depression was proposed as being responsible for the lower seed set following self-pollination.

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Laboratory Exercise on the Segregation of Flower Color and Related Genes Using Salpiglossis sinuata

HortScience ◽

10.21273/hortsci.33.3.555b ◽

1998 ◽

Vol 33 (3) ◽

pp. 555b-555

Author(s):

Chiwon W. Lee

Keyword(s):

Phenotypic Expression ◽

Pollen Grains ◽

Flower Color ◽

Segregation Ratio ◽

Crop Breeding ◽

Flower Opening ◽

Pigmentation Pattern ◽

Laboratory Exercise ◽

Demonstration Plant ◽

Corolla Color

Velvet flower (Salpiglossis sinuata, Solanaceae) can be used as an excellent demonstration plant for horticultural crop breeding classes. Salpiglossis produces large trumpet-like flowers exhibiting an assortment of corolla color and pigmentation pattern. The pistil is large (3 to 4 cm long) with a sticky stigmatal tip and anthers can be easily emasculated prior to anthesis. The large pollen grains are shed in tetrads, which can be separated and individually placed on the stigma. It takes 8 to 9 weeks from seeding to blooming, with a prolific flowering cycle repeated in flushes. Numerous seeds (about 750/capsule) are obtained in 3 weeks after self- or cross-pollination. The influences of three genes that control flower color and pigmentation pattern can be conveniently demonstrated with their dominant and recessive alleles. The R gene controls flower color with red (RR or Rr) being dominant over yellow (rr) flower color. The D gene controls the density of pigmentation with solid (DD or Dd) color being dominant over dilute (dd) color. Corolla color striping is controlled by the St gene with striped (stst) being recessive to non-striped (StSt or Stst) pattern. For example, by using diploid lines of genotypes RRDD (red, solid), RRdd (red, dilute), or rrdd (yellow, dilute) and their crosses, students can easily learn a dominant phenotypic expression in the F1 hybrid and the digenic 9:3:3:1 segregation ratio in the F2 progeny. Another gene (C) that controls flower opening can also be used to show its influence on cleistogamous (closed, self-pollinated, CC or Cc) versus normal chasmogamous (open-pollinated, cc) corolla development. In addition, the induction and use of polyploid (4X, 3X) plants in plant breeding can be effectively demonstrated using this species.

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