Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Physiological and Environmental Aspects of Ascospore Discharge in Gibberella zeae (Anamorph Fusarium graminearum)

Frances Trail, Haixin Xu, Rachel Loranger and David Gadoury
Mycologia
Vol. 94, No. 2 (Mar. - Apr., 2002), pp. 181-189
DOI: 10.2307/3761794
Stable URL: http://www.jstor.org/stable/3761794
Page Count: 9
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Physiological and Environmental Aspects of Ascospore Discharge in Gibberella zeae (Anamorph Fusarium graminearum)
Preview not available

Abstract

We investigated ascospore discharge in the perithecial fungus, Gibberella zeae. In a wind tunnel study that simulated constant rain and varying day and night lengths, the rate of ascospore release was approximately 8-30% greater under light than in complete darkness. Under constant light, ascospore discharge occurred at maximal rates at relative humidity levels greater than 92%. When perithecia were placed under conditions of high external osmolarity, ascospore discharge was significantly reduced. Ascospores were discharged from asci along with droplets of fluid, the epiplasm, from within the ascus. Analysis of discharged epiplasmic fluid by GC-MASS Spectrometry revealed that mannitol was the major simple sugar component of the fluid. Activity of mannitol dehydrogenase, which catalyzes the conversion of fructose to mannitol, was higher in protein extracts from mature perithecia than in extracts from vegetative tissue. Several inhibitors of K+ and Ca++ ion channels inhibited ascospore discharge, which suggested that ascospore discharge resulted from the buildup of turgor pressure generated by ion fluxes and mannitol accumulation.

Page Thumbnails

  • Thumbnail: Page 
181
    181
  • Thumbnail: Page 
182
    182
  • Thumbnail: Page 
183
    183
  • Thumbnail: Page 
184
    184
  • Thumbnail: Page 
185
    185
  • Thumbnail: Page 
186
    186
  • Thumbnail: Page 
187
    187
  • Thumbnail: Page 
188
    188
  • Thumbnail: Page 
189
    189