Abstract
To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen, we removed the pollen wall by freeze-fracturing before treating the resultant pollen protoplasts by conventional immunofluorescence procedures. Results reveal that axial bundles of microtubules are present in the generative cell of both inactivated and activated pollen grains. Microtubules are not present in the vegetative cells of inactivated pollen, but they are present in the vegetative cells of activated pollen grains. Microtubule nucleation occurs in the vegetative cell cortex. Subsequently, the microtubules grow as branching arrays through most of the vegetative cell cortex except at the apertures where they form localized converging or criss-cross patterns. Eventually, in a germinated pollen grain, the microtubules form network-like arrays through most of the pollen grain and a collar of short arrays at the base of the pollen tube. It is suggested that the role of vegetative cell microtubules in pollen germination is indirect through their mediation of the conformational changes in actin organization that are essential for pollen germination.
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Claims 8
Claim · model-written summary
Axial microtubule bundles are present in the generative cell of both inactivated and activated pear pollen.
- Taxon
- pear
_Poirier_Fleurs_et_feuilles.jpg?width=60)
Pyrus communise0 - Organ / stage
- generative celle1
- Outcome
- axial bundles of microtubulese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Poirier_Fleurs_et_feuilles.jpg?width=500)
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e1“Results reveal that axial bundles of microtubules are present in the generative cell of both inactivated and activated pollen grains”
Claim · model-written summary
Microtubules are absent from vegetative cells of inactivated pear pollen but present in vegetative cells of activated pollen.
- Taxon
- pearPyrus communise0
- Organ / stage
- vegetative cellse2
- Outcome
- Microtubulese2
- Qualifier
- inactivated pollene2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e2“Microtubules are not present in the vegetative cells of inactivated pollen, but they are present in the vegetative cells of activated pollen grains”
Claim · model-written summary
Microtubule nucleation occurs in the vegetative cell cortex of pear pollen.
- Taxon
- pearPyrus communise0
- Organ / stage
- vegetative cell cortexe3
- Outcome
- Microtubule nucleatione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e3“Microtubule nucleation occurs in the vegetative cell cortex”
Claim · model-written summary
Microtubules grow as branching arrays through most of the vegetative cell cortex.
- Taxon
- pearPyrus communise0
- Organ / stage
- vegetative cell cortexe4
- Outcome
- branching arrayse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e4“Subsequently, the microtubules grow as branching arrays through most of the vegetative cell cortex except at the apertures where they form localized converging or criss-cross patterns”
Claim · model-written summary
At the apertures, vegetative cell microtubules form localized converging or criss-cross patterns.
- Taxon
- pearPyrus communise0
- Outcome
- localized converging or criss-cross patternse4
- Qualifier
- at the aperturese4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e4“Subsequently, the microtubules grow as branching arrays through most of the vegetative cell cortex except at the apertures where they form localized converging or criss-cross patterns”
Claim · model-written summary
In germinated pear pollen grains, microtubules form network-like arrays through most of the grain.
- Taxon
- pearPyrus communise0
- Organ / stage
- pollen graine5
- Outcome
- network-like arrayse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e5“Eventually, in a germinated pollen grain, the microtubules form network-like arrays through most of the pollen grain and a collar of short arrays at the base of the pollen tube”
Claim · model-written summary
A collar of short microtubule arrays forms at the base of the pear pollen tube.
- Taxon
- pearPyrus communise0
- Organ / stage
- base of the pollen tubee5
- Outcome
- a collar of short arrayse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e5“Eventually, in a germinated pollen grain, the microtubules form network-like arrays through most of the pollen grain and a collar of short arrays at the base of the pollen tube”
Claim · model-written summary
Vegetative cell microtubules are suggested to act indirectly on pollen germination by mediating actin conformational changes.
- Taxon
- pearPyrus communise0
- Outcome
- pollen germinatione6
- Qualifier
- indirect through their mediation of the conformational changes in actin organizatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To study microtubule organization in germinating pear (Pyrus communis L., cv., Bartlett) pollen”
e6“It is suggested that the role of vegetative cell microtubules in pollen germination is indirect through their mediation of the conformational changes in actin organization that are essential for pollen germination”