scholarly journals Arabinogalactan proteins (AGPs) related to pollen tube guidance into the embryo sac in Arabidopsis

2008 ◽  
Vol 3 (7) ◽  
pp. 455-456 ◽  
Author(s):  
Sílvia Coimbra ◽  
Brian Jones ◽  
Luís Gustavo Pereira
Keyword(s):  
Pollen Tube ◽  
Embryo Sac ◽  
Arabinogalactan Proteins ◽  
Pollen Tube Guidance

scholarly journals Spatio-Temporal Distribution of Cell Wall Components in the Placentas, Ovules and Female Gametophytes of Utricularia during Pollination

2021 ◽  
Vol 22 (11) ◽  
pp. 5622
Author(s):  
Bartosz Jan Płachno ◽  
Małgorzata Kapusta ◽  
Piotr Świątek ◽  
Krzysztof Banaś ◽  
Vitor F. O. Miranda ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Female Gametophyte ◽  
Embryo Sac ◽  
Temporal Distribution ◽  
Arabinogalactan Proteins ◽  
Central Cell ◽  
Nutritive Tissue ◽  
Pollen Tube Guidance ◽  
Micropylar Canal

In most angiosperms, the female gametophyte is hidden in the mother tissues and the pollen tube enters the ovule via a micropylar canal. The mother tissues play an essential role in the pollen tube guidance. However, in Utricularia, the female gametophyte surpasses the entire micropylar canal and extends beyond the limit of the integument. The female gametophyte then invades the placenta and a part of the central cell has direct contact with the ovary chamber. To date, information about the role of the placenta and integument in pollen tube guidance in Utricularia, which have extra-ovular female gametophytes, has been lacking. The aim of this study was to evaluate the role of the placenta, central cell and integument in pollen tube pollen tube guidance in Utricularia nelumbifolia Gardner and Utricularia humboldtii R.H. Schomb. by studying the production of arabinogalactan proteins. It was also determined whether the production of the arabinogalactan proteins is dependent on pollination in Utricularia. In both of the examined species, arabinogalactan proteins (AGPs) were observed in the placenta (epidermis and nutritive tissue), ovule (integument, chalaza), and female gametophyte of both pollinated and unpollinated flowers, which means that the production of AGPs is independent of pollination; however, the production of some AGPs was lower after fertilization. There were some differences in the production of AGPs between the examined species. The occurrence of AGPs in the placental epidermis and nutritive tissue suggests that they function as an obturator. The production of some AGPs in the ovular tissues (nucellus, integument) was independent of the presence of a mature embryo sac.

Pollination in Arabidopsis Thaliana

1998 ◽  
Vol 4 (S2) ◽  
pp. 1180-1181
Author(s):  
K. Lennon ◽  
E. Lord
Keyword(s):  
Pollen Tube ◽  
Cell Communication ◽  
Embryo Sac ◽  
Pollen Grain ◽  
Secretory Cells ◽  
Higher Plant ◽  
Transmitting Tissue ◽  
Pollen Tube Guidance ◽  
Complex Processes ◽  
Communication Events

In flowering plants, pollination and the process of fertilization are complex processes involving a series of cell-to-cell communication events. Though details of the progression of the pollen tube through the pistil, beginning with germination of the pollen grain on the stigma and culminating with delivery of the sperm cells to the embryo sac, are well established for several higher plant species, the mechanisms involved have yet to be elucidated. It has been shown that the transmitting tissue, which coincides with the path of pollen tubes in the gynoecium, is composed of highly secretory cells characterized by an extensive extracellular matrix (ECM). The actual roles that this ECM plays in pollination are currently unknown, although functions proposed include mechanical and/or chemotropic pollen tube guidance as well as pollen tube nutrition.

scholarly journals Paving the Way for Fertilization: The Role of the Transmitting Tract

2021 ◽  
Vol 22 (5) ◽  
pp. 2603
Author(s):  
Ana Marta Pereira ◽  
Diana Moreira ◽  
Sílvia Coimbra ◽  
Simona Masiero
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Current Knowledge ◽  
Embryo Sac ◽  
Tube Growth ◽  
Signaling Cascades ◽  
Secretory Cells ◽  
Transmitting Tract ◽  
Specialized Tissue

Angiosperm reproduction relies on the precise growth of the pollen tube through different pistil tissues carrying two sperm cells into the ovules’ embryo sac, where they fuse with the egg and the central cell to accomplish double fertilization and ultimately initiate seed development. A network of intrinsic and tightly regulated communication and signaling cascades, which mediate continuous interactions between the pollen tube and the sporophytic and gametophytic female tissues, ensures the fast and meticulous growth of pollen tubes along the pistil, until it reaches the ovule embryo sac. Most of the pollen tube growth occurs in a specialized tissue—the transmitting tract—connecting the stigma, the style, and the ovary. This tissue is composed of highly secretory cells responsible for producing an extensive extracellular matrix. This multifaceted matrix is proposed to support and provide nutrition and adhesion for pollen tube growth and guidance. Insights pertaining to the mechanisms that underlie these processes remain sparse due to the difficulty of accessing and manipulating the female sporophytic tissues enclosed in the pistil. Here, we summarize the current knowledge on this key step of reproduction in flowering plants with special emphasis on the female transmitting tract tissue.

Overgrowth of Pollen Tubes in Embryo Sacs of Rhododendron Following Interspecific Pollinations

1986 ◽  
Vol 34 (4) ◽  
pp. 413 ◽  
Author(s):  
EG Williams ◽  
V Kaul ◽  
JL Rouse ◽  
BF Palser
Keyword(s):  
Pollen Tube ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Egg Cell ◽  
Interspecific Crosses ◽  
Main Body

Frequent overgrowths of pollen tubes within the embryo sac are characteristic of a number of interspecific crosses in the genus Rhododendron (Ericaceae). The combined techniques of sectioning, squashing and whole-ovule clearing have confirmed that in ovules showing this phenomenon the pollen tube fails to terminate growth and release sperms on entry into a synergid; instead it continues to grow beyond the synergid and egg cell, often filling the main body of the embryo sac with a coiled and distorted mass. Such ovules fail to develop further. The occurrence and possible causes of this error syndrome are discussed.

scholarly journals Arabidopsis HAP2 (GCS1) is a sperm-specific gene required for pollen tube guidance and fertilization

Development ◽  
2006 ◽  
Vol 133 (23) ◽  
pp. 4761-4769 ◽  
Author(s):  
K. von Besser ◽  
A. C. Frank ◽  
M. A. Johnson ◽  
D. Preuss
Keyword(s):  
Pollen Tube ◽  
Specific Gene ◽  
Pollen Tube Guidance

Ultrastructural Aspects of the Self-Incompatibility Mechanism in Lycopersicum Peruvianum Mill

1973 ◽  
Vol 12 (2) ◽  
pp. 403-419 ◽  
Author(s):  
D. DE NETTANCOURT ◽  
M. DEVREUX ◽  
A. BOZZINI ◽  
M. CRESTI ◽  
E. PACINI ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Tube Wall ◽  
Degradation Mechanism ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Weak Reaction ◽  
General Hypothesis ◽  
Incompatible Pollen ◽  
Compatible Pollen

The experimental results obtained show that the tip of the incompatible pollen tube bursts open after the outer-wall has considerably expanded in the intercellular spaces of the conducting tissue and the inner-wall has disappeared and numerous particles have accumulated in the tube cytoplasm. These particles, which measure approximately 0.2 µm in diameter and give a weak reaction to the test of Thiéry, differ in many respects from the vesicles normally present in compatible pollen tubes growing through the style; they appear to resemble, in some cases, the spheres which are discharged by the compatible pollen tubes after they have reached the embryo-sac. It is considered that these observations support the current belief that the tube wall is the site of action for the incompatibility proteins and suggest that self-incompatibility is not a passive process resulting from lack of growth stimulation but an active event which leads to the destruction of the incompatible pollen tubes. The degradation mechanism involved appears similar to the one which enables the compatible pollen tube to release its contents in the degenerated synergid and presents some analogies with the lytic process taking place in virus-infected cells. The general hypothesis is presented that the particles observed in the cytoplasm of self-incompatible pollen tubes consist of a mixture of incompatibility proteins and of basic constituents of the tube wall.

scholarly journals The Central Cell Plays a Critical Role in Pollen Tube Guidance in Arabidopsis

2007 ◽  
Vol 19 (11) ◽  
pp. 3563-3577 ◽  
Author(s):  
Yan-Hong Chen ◽  
Hong-Ju Li ◽  
Dong-Qiao Shi ◽  
Li Yuan ◽  
Jie Liu ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Critical Role ◽  
Central Cell ◽  
Pollen Tube Guidance
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