What is akinetes reproduction?
One of the methods through which vegetative reproduction exists in Nostoc is akinetes. Akinetes are resting pores formed to tide over adverse conditions such as dryness. Hence, they maintain perennation (live for more than one year). Any vegetative cell can develop into an akinete.
What is the function of akinetes?
Akinetes are spore-like non-motile cells that differentiate from vegetative cells of filamentous cyanobacteria from the order Nostocales. They play a key role in the survival and distribution of these species and contribute to their perennial blooms.
What is the difference between akinetes and Heterocyst?
Akinetes (Greek “akinetos”) are motionless, spore-like resting cells that differentiate from vegetative cells and serve in perennation. Akinetes are larger (sometimes up to 10-fold) than vegetative cells, and heterocysts possess thickened cell wall and a multilayered extracellular envelope (Adams and Duggan, 1999).
Are akinetes reproductive structures?
Akinetes are ellipsoidal to cylindrical, appearing above basal heterocytes and developing from a vegetative portion of the trichome. Reproduction occurs via hormogonia (sometimes with aerotopes), which are released from the end of the filament after the end hair has separated.
What is meant by akinetes?
Definition of akinete in certain algae. : a thick-walled single-celled nonmotile asexual resting spore formed by the thickening of the parent cell wall, corresponding to the chlamydospore of many fungi, and usually germinating directly into a new filament — see aplanospore.
How is akinetes formed?
Akinetes are formed under unfavorable conditions, such as nutrient starvation, low light, and low temperature. Akinetes are resting cells, which can survive under harsh environmental conditions.
Where are akinetes found?
Akinetes are dormancy cells commonly found among filamentous cyanobacteria, many of which are toxic and/or nuisance, bloom-forming species. Development of akinetes from vegetative cells is a process that involves morphological and biochemical modifications.
How akinetes are formed?
What do you mean by akinetes?
What are akinetes and hormogonia?
Hormogonia are motile filaments of cells formed by some cyanobacteria in the order Nostocales and Stigonematales. They are formed during vegetative reproduction in unicellular, filamentous cyanobacteria, and some may contain heterocysts and akinetes.
How are akinetes formed?
How do hormogonia reproduce?
Hormogonia is a part of a filament of a cyanobacterium that detaches and grows by cell division into a new filament. Cyanobacteria mostly multiply by asexual means like binary fission, small fragments (hormogones), hormospores, akinetes, endospores, etc. Common cyanobacteria are-Nostoc, Anabaena, Oscillatoria, etc.
What is the mode of reproduction of Oscillatoria?
Oscillatoria reproduces by fragmentation, facilitated by dead cells which separate a filament into separate sections, or hormogonia, which then grow. Oscillatoria uses photosynthesis to survive and reproduce.
How are hormogonia formed in Oscillatoria?
These organisms undergo reproduction through the process of fragmentation. We should note that fragmentation is the process that forms shorter filaments and these filaments get separated as fragments and grow as new younger ones. The broken filaments produced by oscillatoria are referred to as hormogonia.
What method of asexual reproduction is used by Oscillatoria and Anabaena?
Reproduction is by fragmentation in which dead concave cells (separation disks) separate sections of the filament (hormogonia).
Does Oscillatoria have Akinetes?
End cells are rounded, capitate, and with a calyptra. Filaments tremble and oscillate. Heterocysts: Absent. Akinetes: Absent.
How does Oscillatoria reproduce?
Does Oscillatoria have akinetes?
Does Scytonema fix nitrogen?
The crusts dominated by Stigonema species were fixing 0.3 g N m(-2) (ethylene production rate, 1.10 g C2H4 m(-2)) and crusts dominated by Nostoc and Scytonema were fixing 1.3 g N m(-2) (4.10 g C2H4 m(-2)). Keywords: Subpolar Urals; biological soil crusts; mountain tundra cyanobacteria; nitrogen fixation.
What are different modes of reproduction found in Oscillatoria?
Reproduction in Oscillatoria: Oscillatoria reproduces only by the vegetative method. Reproduction by the formation of zoospores or by gametes is unknown. Each filament does not grow indefinitely in length, but regularly breaks up into short fragments, called hormogones, each containing 2, 3 or several cells.