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[1] [4] Once conditions become more favorable for growth, the akinete can then germinate back into a vegetative cell. [5] Increased light intensity, nutrients availability, oxygen availability, and changes in salinity are important triggers for germination. [5] In comparison to vegetative cells, akinetes are generally larger.
Once a heterocyst has formed it cannot revert to a vegetative cell. Certain heterocyst-forming bacteria can differentiate into spore-like cells called akinetes or motile cells called hormogonia, making them the most phenotypically versatile of all prokaryotes.
Over the winter Gloeotrichia forms dormant cells called akinetes that germinate and begin to form colonies when temperatures begin to increase. [7] As these cells grow, they uptake nutrients like P. However, they generally uptake more nutrients than they need and store it for later use for when they migrate to the nutrient deplete epilimnion.
In harsh conditions, A. circinalis form spore-like cells called akinetes. Akinetes are resistant to low temperature, desiccation , and darkness. Often, akinetes will hibernate in sediment until environmental conditions allow germination and re-growth.
Their cell size varies from less than 1 μm in diameter (picocyanobacteria) up to 100 μm (some tropical forms in the genus Oscillatoria) [39] [40] [41] Filamentous forms exhibit functional cell differentiation such as heterocysts (for nitrogen fixation), akinetes (resting stage cells), and hormogonia (reproductive, motile filaments). These ...
During the winter, Aphanizomenon flos-aquae persists as akinetes deep in the layers of sediment. [7] These dormant cyanobacterial cells will last all season until the water temperature rises again in the spring. During the springtime, the akinetes go through a recruitment phase as they germinate and disperse into the water column. [7]
These akinetes can persist in sediment for long periods of time, and are able to germinate once water temperatures rise to the appropriate level. [2] The bacteria prefers temperatures ranging from 25–30 °C, light intensity of 80–121 μmol m-2 s-1, and a max salinity concentration of 4 g L-1 NaCl.
An akinete spore is large, non-motile, and thick walled, the wall of which is fused to that of the parent cell. Akinetes thick cell walls are enriched in food materials. Both aplanospores and akinetes are able to withstand unfavourable habitual conditions (cold, winter months or nutrient poor waters) and remain dormant under these conditions.