Library

X
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
    Recent progress on sperm characterization in flowering plants (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 80 (1990), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The organization, isolation and physiology of the angiosperm male gamete has recently emerged as an area of special interest. Detailed in vivo studies have revealed: (1) that the functional unit of male reproduction is a‘male germ unit,’composed of two sperm cells and a physically associated vegetative nucleus; (2) that the two sperm cells are often cytoplasmically dimorphic, and (3) that some sperm cells appear to undergo preferential fertilization, preferentially fusing with either the egg or the proendospermaric central cell. Male gamete isolation has provided enrichments of up to 107 cells ml–1, with sperm integrity and viability demonstrated by the flunrochromatic reaction and ATP levels. Although results from biochemical and hybridoma antibody characterization are still preliminary, they indicate that sperm cells possess polypeptide expression patterns that are different from those of surrounding cells. These findings suggest the existence of an independent developmental program in the angiosperm male gamete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1990.tb05695.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Plant cells which aid in pollen digestion within a beetle's gut (1990)
    Springer
    Oecologia 82 (1990), S. 424-426 
    Details
    ISSN: 1432-1939
    Keywords: Scarabaeidae ; Palmae ; Pollination ; Brachysclereids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The peach palm, Bactris gasipaes H.B.K., in Costa Rica, possesses unusual trichomes on the inflorescence epidermal surface. Certain cells of the trichome possess a thick, highly lignified cell wall and are consumed by the beetle Cyclocephala amazona L. before it ingests pollen from the same inflorescence. Chemical analyses show the trichome to possess no nutritive value. The thick-walled trichome cells pass intact through the beetle's digestive system, while ingested pollen is crushed. We suggest that the specialized plant cells function as gastroliths in the beetle's digestive tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317493
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Entrapment of long-distance transported pollen grains by various moss species in coastal Victoria Land, Antarctica (1993)
    Springer
    Polar biology 13 (1993), S. 81-87 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In northern Victoria Land (continental Antarctica, between 72° and 76°S, 162° and 169°E), 18 moss samples have been collected and analysed for the presence of pollen. In turfs and cushions of 8 different moss species, at least 27 pollen taxa could be identified. The pinus-type pollen and those of grasses were very common. More than 60% of the total grains were damaged or could not be identified. There is evidence that the Antarctic continent could act as a sink for wind-transported pollen from sub-Antarctic islands or from plants (native or cultivated) in South America, Australia, New Zealand and South Africa. However, the pollen concentration in air (⩽ 1 pollen grain/100 m3) and its entrapment rate on moss (about 0.12 grain/cm2/year) result in a very low pollen density in these plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238539
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The kinesin-immunoreactive homologue from Nicotiana tabacum pollen tubes: Biochemical properties and subcellular localization (1993)
    Springer
    Planta 191 (1993), S. 496-506 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00195751
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Pollen viability and pollen vigor (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 38-42 
    Details
    ISSN: 1432-2242
    Keywords: High temperature and humidity stress ; In vitro germination ; Pollen grains ; Storage ; Viability and vigor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Investigations were carried out to correlate pollen viability, assessed on the basis of a fluorochromatic reaction (FCR) test, with pollen vigor, assessed on the basis of the time taken for in vitro germination in pollen grains subjected to high humidity (〉95% RH) and temperature (38 °C) or storage stress of Nicotiana tabacum, Agave sp., Tradescantia virginiana, and Iris sp. Both high RH and temperature, as well as storage stresses, affected pollen vigor before affecting pollen viability. The results are discussed in the light of available data on the viability and vigor of stressed pollen and of aged seeds. The need for consideration of pollen vigor, particularly in stored pollen, the inadequacy of the methods presently used, and some of the methods suitable to assess pollen vigor are elaborated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Responses of tobacco pollen to high humidity and heat stress: viability and germinability in vitro and in vivo (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 104-109 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00196495
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The microtubule cytoskeleton and the rounding of isolated generative cells ofNicotiana tabacum (1992)
    Springer
    Sexual plant reproduction 5 (1992), S. 64-71 
    Details
    ISSN: 1432-2145
    Keywords: Generative cell ; Isolation ; Microtubules ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Upon squashing of the pollen grain, the isolated generative cell ofNicotiana tabacum looses its spindle shape to become spherical; this phenomenon is independent of the sucrose concentration used. The time necessary for this change can vary from 1 min (0% sucrose) to 20 min (30% sucrose). The microtubular cytoskeleton was studied by means of immunofluorescence and electron microscopy. Just after isolation, 5 to 15 clearly visible bundles in microtubules organized in a basket-like structure are present. After 15 min in medium with 15% sucrose, the microtubular cytoskeleton disappears, and a diffusely spread tubulin can be observed. Neither the addition of 10–20 μM taxol to the medium, nor the omission of Ca2+ to the medium has any effect on the changes in cell shape and loss of microtubular bundles after isolation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00714559
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Secretory tapetum of Brassica oleracea L.: polarity and ultrastructural features (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 28-35 
    Details
    ISSN: 1432-2145
    Keywords: Tapetal cells ; Brassica oleracea L ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of the secretory, binucleate tapetum of Brassica oleracea in the micro spore mother cell (MMC) stage through to the mature pollen stage is reported. The tapetal cells differentiate as highly specialized cells whose development is involved in lipid accumulation in their final stage. They start breaking down just before anther dehiscence. Nuclei with dispersed chromatin, large nucleoli and many ribosomes in the cytoplasm characterize the tapetal cells. The wall-bearing tapetum phase ends at the tetrade stage. The dissolution of tapetal walls begins from the inner tangential wall oriented towards the loculus and proceeds gradually along the radial walls to the outer tangential one. The plasmodesmata transversing the radial walls between tapetal cells persist until the mature microspore, long after loss of the inner tangential wall. After wall dissolution, the tapetal protoplasts retain their integrity and position within the anther locule. The tapetal cell membrane is in direct contact with the exine of the microspores/pollen grains and forms tubular evaginations that increase its surface area and appear to be involved in the translocation of solutes from the tapetal cells to the microspores/ pollen grains. The tapetal cells exhibit a polarity expressed by spatial differentiation in the radial direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194568
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Cytochemical immunolocalization of the abundant pistil protein Sk2 in potato (Solanum tuberosum) (1994)
    Springer
    Sexual plant reproduction 7 (1994), S. 164-168 
    Details
    ISSN: 1432-2145
    Keywords: Immunolocalization ; Pistil protein (Sk2) ; Solanum tuberosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sk2 protein is the most abundant member of the pistil-specific proteins of Solanum tuberosum. Sk2 protein has been localized by use of a polyclonal antibody (anti-Sk2) in the pistils of four clones of Solanum tuberosum. In the stigmas Sk2 protein accumulates to a high level in the cytoplasm of the internal secretory cells underlying the papillae one day prior to anthesis. In styles, the intercellular matrix of the transmitting tissue cells is intensely labelled by anti-Sk2. Sk2 protein is present in all four clones and shows the same labelling pattern. The possible role of the Sk2 protein in pollen tube growth is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228489
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructural features of pollen tubes of Endymion non-scriptus modified by cytochalasin D (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 73-80 
    Details
    ISSN: 1432-2145
    Keywords: Pollen-tube structure ; Intracellular movement ; Tip-growth mechanism ; Cytochalasin effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cytochalasins, known as inhibitors of various processes involving motility in plant and animal cells, induce far-reaching structural changes in the cytoplasm and walls of pollen tubes without destroying the capacity for subsequent growth in normal media. The fine structure of tubes of Endymion non-scriptus modified by cytochalasin D suggests that the changes all stem directly or indirectly from the interruption of the longrange cyclosis along the tube axis, which is sustained throughout the period of normal growth. The elimination of this movement breaks down the the pattern of flow responsible for the sorting-out process that maintains the characteristic zonation of organelles and other inclusions at the apex of the extending tube, and leads gradually to re-distribution of the vacuoles and membranes in the vegetative cell, the disposition of which is normally correlated with the longitudinally oriented flow pathways. Random local migrations of organelles and other inclusions of greater amplitude than is to be expected from Brownian movement continue in the tubes in the presence of cytochalasin D, indicating that the motility system is not wholly destroyed. Following the interruption of concerted axial movement, the polysaccharide wall-precursor bodies (P-particles), normally inserted into the wall mainly in the apical part of the tube during tip growth, gradually become dispersed throughout the tube and are incorporated in the wall at random, entering even into the intine of the parent pollen grain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00196491
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...