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  • Female gametophyte  (1)
  • cone abortion  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Postpollination-prezygotic ovular secretions into the micropylar canal inPseudotsuga menziesii (Pinaceae) (1996)
    Springer
    Journal of plant research 109 (1996), S. 147-160 
    Details
    ISSN: 1618-0860
    Keywords: Female gametophyte ; Integument ; Ovule ; Pseudotsuga ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ovular morphology was examined ultrastructurally inPseudotsuga menziesii to determine the effects of the ovule on pollen development. Vesicles containing lipid-like substances traverse cell walls of the inner epidemis of the integument and release their contents at the integument surface to form the integumentary membrane. A major aqueous secretion from the integument into the micropylar canal is proposed to occur by the movement of the integumentary membrane and its invaginations towards the center of the micropylar canal. The cellular degeneration of the nucellar apex results from the breakdown of vacuoles. After this degeneration, electron-dense substances move from the prothallial cells of the female gametophyte towards the nucellus, and many morphological changes in the nucellus, prothallial cells, and micropylar canal take place simultaneously. We interpret these changes to result from another major secretion from the prothallial cells. Egg cytoplasm appears to disorganize for a short time. Simultaneously, substantial amounts of electron dense-substances in the prothallial cells and lipid-like substances in surface cell walls of the female gametophyte move towards the nucellus as components of the third major secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02344540
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Seasonal occurrence of potential ice-nucleating bacteria on Douglas fir foliage and seed cones (1990)
    Springer
    New forests 4 (1990), S. 55-61 
    Details
    ISSN: 1573-5095
    Keywords: Pseudotsuga menziesii ; cone abortion ; seed orchard ; pollination ; ice nucleation ; bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Total bacteria and fluorescent Pseudomonas populations were monitored on buds, conclets and foliage in a Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard in April 1986 and between October 1986 and May 1987, over periods that spanned two pollination seasons. Seasonal variation in bacterial numbers was observed, with the highest levels occurring in the late winter and early spring. Bacterial populations active in ice nucleation were found. Bacterial numbers during pollination were higher in 1986 than in 1987. Conclet abortion at pollination was also higher in 1986 (55%) than in 1987 (11%). A relationship may exist between bacterial populations and conelet abortion at pollination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00119590
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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