Summary
The water expulsion vacuole ofPhytophthora palmivora was studied with the light microscope after the motility of the spores had been slowed by using a low Ca2 + medium. For transmission electron microscopy, the zoospores were prepared using freeze substitution. The water expulsion vacuole consisted of a central vacuole that collapsed and emptied its contents to the external medium. The central vacuole was surrounded by a series of interconnected vacuoles that are called the surrounding vacuole. The surrounding vacuole and the central vacuole were always associated with coated pits. The vesicles found in the region between the central and surrounding vacuole were exclusively coated vesicles. Consistent changes in the organization of the water expulsion vacuole led us to conclude that, as the central vacuole collapses, the surrounding vacuole is transformed and becomes the new central vacuole. No evidence was obtained for contraction of the central vacuole. The processes involved in membrane recycling during the functioning of the water expulsion vacuole are discussed.
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Abbreviations
- WEV:
-
water expulsion vacuole
- CT:
-
central vacuole
- SU:
-
surrounding vacuole
- MV:
-
multivesicular body
- SS:
-
smooth spherical vacuole
- dH2O:
-
distilled water
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Cho, C.W., Fuller, M.S. Observations of the water expulsion vacoule ofPhytophthora palmivora . Protoplasma 149, 47–56 (1989). https://doi.org/10.1007/BF01623982
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DOI: https://doi.org/10.1007/BF01623982