Abstract
Morphology of urediospores of stem rust of wheat, including shape, size and exterior adornment, has been investigated considering possible aerodynamic properties. This study included live and killed urediospores in an unhydrated and hydrated state. Density, mass measurements and physical counts of these materials were also compared. Observations of the urediospores include: a. Distribution of inner contents is reasonably homogeneous. Live urediospores possess a small amount of granular cytoplasm and one to several lipid globules. Killed urediospores possess only granular cytoplasm and lack the lipid globules. b. Live urediospores (unhydrated or hvdrated) are more dense and have a greater mass than do killed urediospores. Physical counts of killed urediospores per gram are greater than those of live urediospores in either the unhydrated or hydrated state. c. Live urediospores exhibit a characteristic bending and depression in the region of the germ pore. These characteristics are more pronounced in the killed urediospores. Hydration decreases the depression in both live and killed urediospores. d. Exterior adornment of urediospores consists of minute echinulae (curved spines) which may function in electrostatic or aerodynamic properties. e. Shape, bending, central thickness and external spines suggest possible aerodynamic properties of urediospores including a rotary motion which would permit greater long range travel.
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Orr, G.F., Tippets, W.C. Morphology and other physical characteristics of urediospores possibly related to aerodynamics and long range travel. Mycopathologia et Mycologia Applicata 48, 143–159 (1972). https://doi.org/10.1007/BF02063054
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DOI: https://doi.org/10.1007/BF02063054