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Sexual Crosses with the Mucoromycete Phycomyces blakesleeanus
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Phycomyces: growth responses of the sporangium

D L Johnson1, R I Gamow

  • 1Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80302.

Plant Physiology
|June 1, 1972
PubMed

Insights

During Phycomyces blakesleeanus development, growth shifts from elongation to spherical sporangium formation (stage II). This growing sporangium acts as a sensory receptor, responding to light and humidity.

Area of Science:

  • Mycology
  • Developmental Biology
  • Biophysics

Background:

  • The fungus Phycomyces blakesleeanus exhibits distinct developmental stages.
  • Sporangiophore elongation is a key growth phase, followed by sporangium formation.

Purpose of the Study:

  • To investigate the growth dynamics and sensory responses during Phycomyces blakesleeanus sporangium development (stage II).
  • To model the regulatory mechanisms controlling sporangium size.

Main Methods:

  • Observation of sporangiophore development in Phycomyces blakesleeanus.
  • Analysis of growth redirection from cylindrical elongation to spherical formation.
  • Characterization of sensory responses (light and humidity) of the developing sporangium.

Main Results:

  • During stage II, Phycomyces blakesleeanus sporangiophore growth ceases elongation and redirects resources to form a spherical sporangium.
  • The growing sporangium functions as a sensory receptor and effector, exhibiting responses to light and humidity.
  • A model for the regulation of ultimate sporangium size was proposed.

Conclusions:

  • Sporangium formation in Phycomyces blakesleeanus represents a significant geometric shift in growth, not a cessation of growth.
  • The developing sporangium integrates environmental cues (light, humidity) to modulate its growth and size.
  • The study provides insights into the biophysical mechanisms governing fungal development and size determination.

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