Citrus pollen tube development in cross-compatible gynoecia, self-incompatible gynoecia, and in vitro

The route of 'Orlando' tangelo (Citrus paradisi Macf. × C. reticulata Blanco) pollen tubes was traced and compared in self-incompatible pollinations and cross-compatible pollinations with 'Dancy' tangerine (C. reticulata Blanco). In both crosses, 'Orlando' pollen germinated in the stigmatic exudate and grew between the papillae on the stigma surface and inter-cellularly between the parenchymatous cells until reaching a stylar canal by 3 days. However, in the incompatible pollination, irregular deposition of callose occurred in the pollen tube walls as early as 1 day after pollination. By day 6, pollen tubes were in the upper portion of the ovary in the compatible pollination, whereas most pollen tubes from the incompatible pollination were still in the upper style. 'Orlando' pollen tube growth rate decreased substantially by day 3 in both the self-incompatible pollination and in vitro but increased rapidly after day 3 in the compatible combination. The generative cell divided between 1 and 3 days after pollination in the compatible cross. Generative cell division was observed by day 3 in only a few pollen tubes in the incompatible cross and in cultured tubes. Compatible pollen tubes grew slowly for the first 3 days after pollination, during which time generative cells divided and then grew rapidly until fertilization. In contrast, incompatible pollen tubes showed morphological features indicative of an incompatibility reaction by 1 day after pollination and grew slowly for a period of 6 days, and then ceased growth.

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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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The RSS system of unidirectional cross-incompatibility in maize. 2. Cytology

Genome ◽

10.1139/g92-083 ◽

1992 ◽

Vol 35 (4) ◽

pp. 560-564

Author(s):

Abdul Rashid ◽

Peter A. Peterson

Keyword(s):

Pollen Tube ◽

Female Parent ◽

Pollen Tubes ◽

Pollen Grain ◽

Maize Pollen ◽

Transmitting Tract ◽

Incompatible Pollination ◽

Recessive Genes ◽

Maize Genetics ◽

Incompatibility Reaction

In 1975, a number of genetic lines discovered in our maize genetics nursery in Ames, Iowa, showed unidirectional cross-incompatibility. Later, it was found that this unidirectional cross-incompatibility is controlled by three recessive genes. One locus (cif) controls the incompatibility reaction in the female tissue and the other two (cim1 and cim2) control the incompatibility reaction in the pollen grain. The cross is incompatible only when the female parent is homozygous recessive for the cif and the male parent is homozygously recessive for the cim1 as well as the cim2 locus. Cytological studies of this unidirectional cross-incompatibility show that the site of the incompatibility reaction occurs after the entry of the pollen tubes into the transmitting tract of the incompatible silks. Between 12 and 24 h after pollination, the incompatible pollination is characterized by the swelling and bursting of pollen tubes at the tip, after which pollen tube growth stops.Key words: maize, pollen tube, cross-incompatibility.

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Localization of actin in pollen tubes of Ornithogalum virens L.

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1999.014 ◽

2014 ◽

Vol 68 (2) ◽

pp. 97-102

Author(s):

Małgorzata Stępka ◽

Fabricio Ciampolini ◽

Mauro Cresti ◽

Maria Charzyńska

Keyword(s):

Pollen Tube ◽

Actin Filaments ◽

Laser Scanning ◽

Higher Plants ◽

Generative Cell ◽

Pollen Tubes ◽

Confocal Laser ◽

Vegetative Nucleus ◽

Ornithogalum Virens

The germinating pollen grain (in vivo on the stigma or in vitro in germination medium) forms a pollen tube which transports the vegetative nucleus and generative cell/two sperm cells participating in the process of double fertilization. The growth of the tube and the transport of organelles and the cells occur due to two major motor systems existing in the pollen tubes of higher plants: the tubuline-dynein/kinesin and the actin-myosin system. In pollen tubes of Ornithogalum virens the actin filaments were labelled with TRITC-phalloidin (2 µg/ml) in the PIPES buffer and the 10% sucrose, without the fixative and DMSO. Omission of the fixative and permeabilizing agent (DMSO) allowed better preservation of the structure, and the "fluorescence" of actin was observed in living pollen tubes. Observations in CLSM (confocal laser scanning microscope) showed that actin is distributed in the vicinity of the cell membrane. This could support the view that actin filaments and the plasmalemma form the pollen tube cortex along which the cytoplasmic movement of organelles, and cell transport occurs.

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Protein Analysis of Pollen Tubes after the Treatments of Membrane Trafficking Inhibitors Gains Insights on Molecular Mechanism Underlying Pollen Tube Polar Growth

The Protein Journal ◽

10.1007/s10930-021-09972-x ◽

2021 ◽

Vol 40 (2) ◽

pp. 205-222

Author(s):

Monica Scali ◽

Alessandra Moscatelli ◽

Luca Bini ◽

Elisabetta Onelli ◽

Rita Vignani ◽

...

Keyword(s):

Pollen Tube ◽

Actin Cytoskeleton ◽

Membrane Trafficking ◽

Tip Growth ◽

Male Gametophyte ◽

Pollen Tubes ◽

Structural Features ◽

Two Dimensional Gel Electrophoresis ◽

Depth Analysis

AbstractPollen tube elongation is characterized by a highly-polarized tip growth process dependent on an efficient vesicular transport system and largely mobilized by actin cytoskeleton. Pollen tubes are an ideal model system to study exocytosis, endocytosis, membrane recycling, and signaling network coordinating cellular processes, structural organization and vesicular trafficking activities required for tip growth. Proteomic analysis was applied to identifyNicotiana tabacumDifferentially Abundant Proteins (DAPs) after in vitro pollen tube treatment with membrane trafficking inhibitors Brefeldin A, Ikarugamycin and Wortmannin. Among roughly 360 proteins separated in two-dimensional gel electrophoresis, a total of 40 spots visibly changing between treated and control samples were identified by MALDI-TOF MS and LC–ESI–MS/MS analysis. The identified proteins were classified according to biological processes, and most proteins were related to pollen tube energy metabolism, including ammino acid synthesis and lipid metabolism, structural features of pollen tube growth as well modification and actin cytoskeleton organization, stress response, and protein degradation. In-depth analysis of proteins corresponding to energy-related pathways revealed the male gametophyte to be a reliable model of energy reservoir and dynamics.

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Hyperoside promotes pollen tube growth by regulating the depolymerization effect of actin-depolymerizing factor 1 on microfilaments in okra

Horticulture Research ◽

10.1038/s41438-021-00578-z ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Biying Dong ◽

Qing Yang ◽

Zhihua Song ◽

Lili Niu ◽

Hongyan Cao ◽

...

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Germination ◽

Pollen Tubes ◽

Tube Growth ◽

Actin Depolymerizing Factor ◽

Specific Mechanism ◽

Promoting Effect ◽

New Research

AbstractMature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2–3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.

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Prunus necrotic ringspot virus Early Invasion and Its Effects on Apricot Pollen Grain Performance

Phytopathology ◽

10.1094/phyto-97-8-0892 ◽

2007 ◽

Vol 97 (8) ◽

pp. 892-899 ◽

Cited By ~ 24

Author(s):

Khalid Amari ◽

Lorenzo Burgos ◽

Vicente Pallas ◽

María Amelia Sanchez-Pina

Keyword(s):

Developmental Stages ◽

Generative Cell ◽

Pollen Grains ◽

Growth Zone ◽

Pollen Tubes ◽

Climatic Conditions ◽

Pollen Grain ◽

Ringspot Virus ◽

Prunus Necrotic Ringspot Virus

The route of infection and the pattern of distribution of Prunus necrotic ringspot virus (PNRSV) in apricot pollen were studied. PNRSV was detected both within and on the surface of infected pollen grains. The virus invaded pollen during its early developmental stages, being detected in pollen mother cells. It was distributed uniformly within the cytoplasm of uni- and bicellular pollen grains and infected the generative cell. In mature pollen grains, characterized by their triangular shape, the virus was located mainly at the apertures, suggesting that PNRSV distribution follows the same pattern as the cellular components required for pollen tube germination and cell wall tube synthesis. PNRSV also was localized inside pollen tubes, especially in the growth zone. In vitro experiments demonstrated that infection with PNRSV decreases the germination percentage of pollen grains by more than half and delays the growth of pollen tubes by ≈24 h. However, although PNRSV infection affected apricot pollen grain performance during germination, the presence of the virus did not completely prevent fertilization, because the infected apricot pollen tubes, once germinated, were able to reach the apricot embryo sacs, which, in the climatic conditions of southeastern Spain, mature later than in other climates. Thus, infected pollen still could play an important role in the vertical transmission of PNRSV in apricot.

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Immunochemical and immunocytochemical identification of a myosin heavy chain polypeptide in Nicotiana pollen tubes

Journal of Cell Science ◽

10.1242/jcs.92.4.569 ◽

1989 ◽

Vol 92 (4) ◽

pp. 569-574

Author(s):

X.J. Tang ◽

P.K. Hepler ◽

S.P. Scordilis

Keyword(s):

Pollen Tube ◽

Nuclear Envelope ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Immunofluorescence Microscopy ◽

Generative Cell ◽

Pollen Tubes ◽

Nuclear Surface ◽

Common Pattern ◽

Western Blots

A myosin heavy chain polypeptide has been identified and localized in Nicotiana pollen tubes using monoclonal anti-myosin antibodies. The epitopes of these antibodies were found to reside on the myosin heavy chain head and rod portion and were, therefore, designated anti-S-1 (myosin S-1) and anti-LMM (light meromyosin). On Western blots of the total soluble pollen tube proteins, both anti-S-1 and anti-LMM label a polypeptide of approximately 175,000 Mr. Immunofluorescence microscopy shows that both antibodies yield numerous fluorescent spots throughout the whole length of the tube, often with an enrichment in the tube tip. These fluorescent spots are thought to represent vesicles and/or organelles in the pollen tubes. In addition to this common pattern, anti-S-1 stains both the generative cell and the vegetative nuclear envelope. The different staining patterns of the nucleus between anti-S-1 and anti-LMM may be caused by some organization and/or anchorage state of the myosin molecules on the nuclear surface that differs from those on the vesicles and/or organelles.

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Pollen tube incompatibility reaction on the stigma in selfpollinated Sinapis alba L.

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.017 ◽

2014 ◽

Vol 65 (1-2) ◽

pp. 101-105 ◽

Cited By ~ 1

Author(s):

Renata Śnieżko ◽

Krystyna Winiarczyk

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Pollen Grains ◽

Pollen Tubes ◽

Sinapis Alba ◽

Pollen Grain ◽

Tube Growth ◽

Sinapis Alba L ◽

Growth Changes ◽

Incompatibility Reaction

After selfpollination of Sinapis alba L. pollen tubes growth is inhibited on the stigma. The pollen grains germinate 3-4 hours after pollination. The pollen give rise to one or more pollen tubes. They grow along the papillae. In the place of contact between the papilla and pollen tube the pellicula is digested. Then the direction of pollen tube growth changes completely. Pollen tubes grow back on the exine of their own pollen grain, or turn into the air. The pollen tubes growth was inhibited in 6-8 hours after selfpollination. After crosspollination usually there is no incompatibility reaction.

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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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Tradescantia bracteata pollen in vitro: pollen tubes development and mitosis

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1977.047 ◽

2015 ◽

Vol 46 (4) ◽

pp. 587-598 ◽

Cited By ~ 9

Author(s):

E. Lewandowska ◽

M. Charzyńska

Keyword(s):

Pollen Tube ◽

Generative Cell ◽

Metaphase Plate ◽

Pollen Grains ◽

Neutral Red ◽

Generative Nucleus ◽

Mitotic Spindles ◽

Germinating Pollen ◽

Vacuolar System

About 90 per cent of Tradescantia bracteata pollen germinates in vitro after 15 min. Mitosis starts in the pollen tube after about 3 h. The mitotic trans-formations of chromosomes within the generative nucleus are not synchronized. They involve succesively the linearly arranged chromosomes in the elongated generative nucleus. In metaphase the chromosomes are arranged tandem-like linearly along the pollen tube. The chromatides translocate in anaphase from various distances to the poles in a plane parallel to the metaphase plate. This suggests that chromosomes have individual mitotic spindles and that coordination of the chromosome transformations in the generative cell is much less strict than in a typical somatic mitosis. Starch is the storage material of pollen grains. In the vegetative cytoplasm of mature pollen grains minute reddish-orange vesicular structures are visible after staining with neutral red. They do not fuse with the vacuoles proper arising in germinating pollen grains to form the vacuolar system of the pollen tube.

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