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
    ISSN: 1432-2145
    Keywords: Wheat pollen ; Chemical hybridizing agents ; Male sterility ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Phenylcinnoline carboxylate compounds SC-1058 and SC-1271 cause complete male sterility in wheat when applied at suitable dosages at the pre-meiotic stage of anther development. Anthers from treated and untreated plants were compared using light and electron microscopy from the pre-meiotic stage through the formation of nearly mature pollen. Overall anther development is gradually slowed in treated plants and pollen development is generally arrested in the late prevacuolate or early vacuolate microspore stage, although the first pollen mitosis does sometimes occur. The sporopollenin-containing exine walls are thinner, and show abnormally developed foot and tectum layers with sparse connecting baculi. Microspore cytoplasm degenerates and the cells eventually collapse. At the early, prevacuolate, free microspore stage treated tapetal cells hypertrophy, expanding into the locule. They contain abnormally large vacuoles that appear to form from the fusion of secretory vesicles, and some vacuoles contain electrondense deposits. The sporopollenin-containing orbicular wall and Ubisch bodies are retarded in their development and are structurally deformed. Acetolysis of whole anthers and of thick sections shows that the sporopollen-in-containing structures of treated materials are greatly reduced in thickness and are less rigid than in the control. We conclude that application of these compounds causes interference with the secretory function of tapetal cells which supplies sporopollenin cell-wall polymers to the exine of the microspores and to the tapetal orbicular wall and associated Ubisch bodies. Interference with the tapetal secretion of other nutrients required for microspore development is strongly suggested.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 4 (1991), S. 235-243 
    ISSN: 1432-2145
    Keywords: Male sterility ; Pollen ; Anther ; Gameto cides ; Chemical hybridizing agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Several unrelated compounds are known to selectively inhibit the development of the male gametophyte. When applied at suitable dosages to plants at the appropriate stages of anther development, these substances block the formation of fertile pollen. The affected stage of pollen development is characteristic of the specific chemical structure of the compound, ranging from effects on microspore meiosis to the formation of pollen defective in the ability to germinate or fertilize. The range of effects mediated by these substances, and by known male-sterile mutants, indicates that microspore development has several critical phases that are particularly sensitive to fatal inhibition. We propose that chemical inhibitors of pollen development deserve attention as tools for elucidating the regulation of pollen development.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 26 (1990), S. 122-128 
    ISSN: 1040-452X
    Keywords: Mouse ; Placenta ; Pregnancy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Antiviral activity has been found in conceptus and placental tissues in numerous species, including mice, pigs, sheep, cattle and humans. In sheep and cattle, the antiviral activity is due to an interferon alpha (IFN-α), but in other species the nature of the protein(s) responsible for placental activity is unknown. The objectives of this study were to determine if the constitutive antiviral activity associated with the mouse conceptus is produced as early as the peri-implantation period, and to determine if the activity is due to an IFN-α or -β. Conceptus and placental tissue explants released antiviral activity from Day 4 through at least Day 16 of gestation as measured in an agar overlay bioassay employing CHO cells challenged with vesicular stomatitis virus. This activity was neutralized by antiserum against MuIFN-α/β. The same antiserum failed, however, to immunoprecipitate radiolabeled proteins from medium collected from Day 4 blastocysts cultured in the presence of L-[35S]-methionine. S1 nuclease analysis of placental RNA and screening of ectoplacental cone and extraembryonic ectoderm cDNA libraries with MuIFN-α and -β probes failed to detect IFN related mRNAs, even under relatively non-stringent conditions of hybridization. Thus, while antiviral activity is produced by peri-implantation conceptuses in several diverse mammalian species, it does not appear to be due to a conserved type of IFN in all these species.
    Additional Material: 4 Ill.
    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...