Isolation of Sperms from the Pollen Tubes of Flowering Plants during Fertilization

In flowering plants, pollen grains germinate on the pistil and send pollen tubes down the transmitting tract toward ovules. Previous genetic studies suggested that the ovule is responsible for long-range pollen tube guidance during the last phase of a pollen tube's journey to the female gametes. It was not possible, however, to unambiguously identify the signaling cells within an ovule: the haploid female gametophyte or the diploid sporophytic cells. In an effort to distinguish genetically between these two possibilities, we have used a reciprocal chromosomal translocation to generate flowers wherein approximately half the ovules do not contain a functional female gametophyte but all ovules contain genotypically normal sporophytic cells. In these flowers, pollen tubes are guided to the normal but not to the abnormal female gametophytes. These results strongly suggest that the female gametophyte is responsible for pollen tube guidance, but leave open the possibility that the gametophyte may accomplish this indirectly through its influence on some sporophytic cells.

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The LI-rings in pollen tubes

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.012 ◽

2014 ◽

Vol 65 (1-2) ◽

pp. 65-68

Author(s):

H. Q. Zhang ◽

H. F. Linskens

Keyword(s):

Cell Wall ◽

Monoclonal Antibodies ◽

Confocal Laser Scanning Microscopy ◽

Laser Scanning ◽

Pollen Tubes ◽

Arabinogalactan Proteins ◽

Flowering Plants ◽

Laser Scanning Microscopy ◽

Confocal Laser Scanning ◽

Confocal Laser

Monoclonal antibodies, which recognize the specific epitopes for pectins and arabinogalactan proteins, in connection with confocal laser scanning microscopy demonstrated the presence of a ring-like structure in the cell wall of pollen tubes of flowering plants.

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Cysteine-rich peptides promote interspecific genetic isolation in Arabidopsis

Science ◽

10.1126/science.aau9564 ◽

2019 ◽

Vol 364 (6443) ◽

pp. eaau9564 ◽

Cited By ~ 24

Author(s):

Sheng Zhong ◽

Meiling Liu ◽

Zhijuan Wang ◽

Qingpei Huang ◽

Saiying Hou ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Tube ◽

Reproductive Isolation ◽

Gene Family ◽

Pollen Tube Growth ◽

Pollen Tubes ◽

Flowering Plants ◽

Tube Growth ◽

Genetic Isolation ◽

Tube Emergence

Reproductive isolation is a prerequisite for speciation. Failure of communication between female tissues of the pistil and paternal pollen tubes imposes hybridization barriers in flowering plants. Arabidopsis thaliana LURE1 (AtLURE1) peptides and their male receptor PRK6 aid attraction of the growing pollen tube to the ovule. Here, we report that the knockout of the entire AtLURE1 gene family did not affect fertility, indicating that AtLURE1-PRK6–mediated signaling is not required for successful fertilization within one Arabidopsis species. AtLURE1s instead function as pollen tube emergence accelerators that favor conspecific pollen over pollen from other species and thus promote reproductive isolation. We also identified maternal peptides XIUQIU1 to -4, which attract pollen tubes regardless of species. Cooperation between ovule attraction and pollen tube growth acceleration favors conspecific fertilization and promotes reproductive isolation.

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Expression of the cell cycle in sperm of Arabidopsis: implications for understanding patterns of gametogenesis and fertilization in plants and other eukaryotes

Development ◽

10.1242/dev.126.5.1065 ◽

1999 ◽

Vol 126 (5) ◽

pp. 1065-1075 ◽

Cited By ~ 2

Author(s):

W.E. Friedman

Keyword(s):

Cell Cycle ◽

Higher Plants ◽

Generative Cell ◽

Pollen Grains ◽

Pollen Tubes ◽

Flowering Plants ◽

S Phase ◽

Flowering Plant ◽

Sperm Nuclei

The relationship between developmental events and the cell cycle was examined in sperm of Arabidopsis thaliana. Sperm of Arabidopsis rapidly enter the S (synthesis) phase of the cell cycle after inception from mitosis of the generative cell. Sperm in pollen grains within anthers continue to synthesize DNA, and at the time of pollination, contain approximately 1.5C DNA. Following pollination, sperm continue through the S phase of the cell cycle during pollen tube growth. By the time pollen tubes reach the ovary, sperm nuclei contain approximately 1.75C DNA. Just prior to double fertilization, sperm nuclei within embryo sacs contain the 2C quantity of DNA. These data indicate that molecular programs associated with the G1-S transition and the S phase of the cell cycle are expressed in sperm cells of developing pollen grains and pollen tubes in Arabidopsis. This pattern of prefertilization S phase activity in the sperm of a flowering plant stands in marked contrast to all other non-plant eukaryotes (from ciliates to yeast to sea urchins to mammals) where sperm remain in G1 during development, prior to the initiation of gametic fusion. In addition, when patterns of cell cycle activity in sperm of Arabidopsis and other flowering plants are compared, developmental analysis reveals that heterochronic alterations (changes in the relative timing of ontogenetic events) in cell cycle activity are a central cause of the diversification of patterns of gametogenesis in higher plants. Finally, comparative analysis of the patterns of cell cycle activity in Arabidopsis and other angiosperms may be used to predict which flowering plants will be amenable to development of successful in vitro fertilization techniques.

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