Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biology of the Cell 79 (1993), S. 125-132 
    ISSN: 0248-4900
    Keywords: Nicotiana tabacum ; acetylated α-tubulin ; confocal laser scanning microscope ; microtubules ; pollen tube growth ; tyrosinated α-tubulin
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-2048
    Keywords: Kinesin ; Nicotiana ; Organelle movement ; Pollen tube
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In plant cells, microtubule-based motor proteins have not been characterized to the same degree as in animal cells; therefore, it is not yet clear whether the movement of organelles and vesicles is also dependent on the microtubular cytoskeleton. In this work the kinesinimmunoreactive homologue from pollen tubes of Nicotiana tabacum L. has been purified and biochemically characterized. The protein preparation mainly contained a polypeptide with a relative molecular weight of approx. 100 kDa. This polypeptide bound to animal microtubules in an ATP-dependent manner and it further copurified with an ATPase activity fourfold-stimulated by the presence of microtubules. In addition, the sedimentation coefficient (approx. 9S) was similar to those previously shown for other kinesins. Immunofluorescence analyses revealed a partial co-distribution of the protein with microtubules in the pollen tube. These data clearly indicate that several properties of the kinesin-immunoreactive homologue are similar to those of kinesin proteins, and suggest that molecular mechanisms analogous to those of animal cells may drive the microtubule-based motility of organelles and vesicles in plants.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Planta 133 (1976), S. 35-40 
    ISSN: 1432-2048
    Keywords: Pollen tube ; Style ; Callose ; Petunia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Petunia pollen tubes growing in the style there appear to be two ways of callose deposition. The first one is callose deposition outside the plasma membrane as a distinct layer closely appressed to the cell wall. The second one is callose deposition within the cytoplasm as distinct callose grains, leading to the formation of callose plugs. This second way is accompanied by a characteristic ultrastructure of the cytoplasm, namely strong electron-density of the plasma matrix, partial absence of the plasma membrane and the absence of plastids and dictyosomes. For both ways of callose deposition a mechanism is proposed and the function of callose plugs is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-2048
    Keywords: Lycopersicum ; Pollen activation ; Pollen tube ; Self-incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract No differences have been observed “in vivo” between Lycopersicum peruvianum compatible and incompatible pollen during activation and pollen tube emission and organization, that is until 4 h and 30 min after pollination. During pollen activation the main events are the setting free of rough endoplasmic reticulum (RER) cisterns which were “stacked” in the mature pollen, the increase in the number of polysomes, and a great activity of the dictyosomes. Immediately after germination of the vegetative nucleus and the generative cell move into the tube, the generative cell diviting to form the male gametes; the tube then becomes organized in four zones. This series of changes is similar to what has already been observed “in vitro” except that in vitro the generative cell remains undivided and the whole process from seeding to tube organization takes 3 h instead of 4 h and 30 min after pollination, as it does in vivo. Our findings are compatible with the main models of the tube inhibition mechanism proposed till now.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-2145
    Keywords: Key words Cell fusion ; Gamete interaction ; In vitro polygamy ; Nicotiana tabacum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In vitro polygamy was studied mainly by using isolated sperm and central cells of tobacco in order to elucidate the mechanism that might be involved in preventing in vivo polygamy. In 17.5% 4000 M.W. polyethylene glycol, only when two sperm cells were made close enough to each other and adhered to a female cell simultaneously was polygamy possible. If one sperm cell fused with the egg or central cell, within 30 min another sperm cell could not fuse with the same egg or central cell. Similar phenomena were found in selected single somatic cell fusion. When more than two protoplasts adhered to each other simultaneously, fusion was always successful; after two protoplasts fused, within 30 min the fusion products could not fuse with another protoplast under the same conditions. This comparative study revealed this characteristic to be shared by both sexual and somatic cell fusion. However, after cytoplasm reorganization was complete in the fusion product, it was possible for the fusion product to fuse with the third protoplast. This indicates that the obstruction to additional fusion was present only during a certain period after the preceding fusion under certain condition. The possible reason for the effect is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 4 (1991), S. 104-109 
    ISSN: 1432-2145
    Keywords: High humidity and temperature stress ; Nicotiana tabacum ; Tobacco ; Pollen viability ; Vigour ; Semi-vivo technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Responses of pollen grains of Nicotiana tabacum to high humidity (95% RH, 4 h) and temperature (38°/45° C, 4 h) stresses were investigated. Pollen grains were subjected to only RH or only temperature, or to both of these stresses. Their viability was assessed on the basis of the fluorochromatic reaction (FCR) test, and vigour was assessed on the basis of the time taken for in vitro germination as well as on the emergence of pollen tubes through the cut end of semi-vivo implanted styles. None of the stress conditions affected pollen viability and high RH or high temperature stress did not individually affect pollen vigour. However, pollen vigour was markedly affected when both the stresses were given together. Pollen grains subjected to high RH at 38° C took a longer time to germinate in vitro and the pollen tubes emerged later from the cut end of the semi-vivo styles; division of the generative cell was also delayed. Pollen grains subjected to high RH at 45° C failed to germinate in vitro, but did germinate on the stigma. Many pollen tubes subjected to this treatment showed abnormalities, and the growth of pollen tubes in the pistil was much slower than that observed in other treatments. Pollen samples subjected to all of the stress conditions were able to induce fruit and seed set. The implications of these results on the relationship between the FCR test and viability, and between viability and vigour, especially in stressed pollen, are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 12 (1999), S. 67-70 
    ISSN: 1432-2145
    Keywords: Key words Cytoskeleton ; Cytoskeleton proteins ; Cytoskeleton function ; Pollen tube ; Embryo sac
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Sexual reproduction in plants is intimately connected to the activity of the cytoskeletal apparatus in reproductive cells. Because of the ease with which the pollen tube can be studied, it has become a model for studying many aspects of cell physiology related to the cytoskeleton, such as movement of organelles and vesicles and cell division. However, information about cytoskeletal proteins is still insufficient for determining cytoskeletal functions during reproduction, especially in terms of cell-cell interactions. One reason may be that cytological and biochemical research on the cytoskeleton of pollen and the embryo sac has not been complemented by sufficient research activity at genetic and molecular levels, and few laboratories are currently involved in this work. This might be because of problems in identifying appropriate applied applications of the work that might attract more investigation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 9 (1996), S. 59-64 
    ISSN: 1432-2145
    Keywords: Motor proteins ; Pollen tube ; Tip growth ; Organelle movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of pollen tubes is characterized by an intense cytoplasmic streaming, during which the movements of smaller organelles (like secretory vesicles) and larger ones (including the generative cell and vegetative nucleus) are precisely coordinated. A well-characterized cytoskeletal apparatus is likely responsible for these intracellular movements. In recent years both microfilament and microtubule-based motor proteins have been identified and assumed to be the translocators of the several organelle categories. Their precise function during pollen tube growth is not yet clear, but apparently an actomyosin-based system is mainly responsible for pollen tube elongation. On the other hand, microtubules and microtubule-based motors have been thought to play a role in the maintenance of cell polarity. Both cytoskeletal systems (and their respective motor activities) could cooperate to ensure a precise regulation of pollen tube growth.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 2 (1989), S. 137-141 
    ISSN: 1432-2145
    Keywords: Humidity ; Temperature stress ; Nicotiana tabacum ; Pollen germination ; Pollen membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The prolonged exposure of pollen Nicotiana tabacum to high humidity at both room temperature and 38° C did not affect membrane integrity as revealed by the fluorochromatic reaction (FCR) test, but did affect pollen vigour. At room temperature germination was not affected, although tube growth was reduced; at 38° C, there was both a reduction in tube growth and delayed germination. When the pollen was subjected to 1 h hydration followed by 1 h desiccation (up to a maximum of four cycles) at room temperature, a reduction in the FCR, germination and tube length after each desiccation treatment was observed. Subsequent hydration fully restored the FCR, but only partially restored germination and tube growth. At 38° C, however, FCR, germination, and tube growth were drastically reduced. The implications of these results on the relationship between FCR and germinability, the responses of pollen exposed to humidity and temperature stress in the field, and on pollen storage are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 9 (1996), S. 59-64 
    ISSN: 1432-2145
    Keywords: Key words Motor proteins ; Pollen tube ; Tip growth ; Organelle movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The growth of pollen tubes is characterized by an intense cytoplasmic streaming, during which the movements of smaller organelles (like secretory vesicles) and larger ones (including the generative cell and vegetative nucleus) are precisely coordinated. A well-characterized cytoskeletal apparatus is likely responsible for these intracellular movements. In recent years both microfilament- and microtubule-based motor proteins have been identified and assumed to be the translocators of the several organelle categories. Their precise function during pollen tube growth is not yet clear, but apparently an actomyosin-based system is mainly responsible for pollen tube elongation. On the other hand, microtubules and microtubule-based motors have been thought to play a role in the maintenance of cell polarity. Both cytoskeletal systems (and their respective motor activities) could cooperate to ensure a precise regulation of pollen tube growth.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...