''Chlorokybus'' is a multicellular (sarcinoid) genus of basal
green algae
The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...
or
charophyte
Charophyta () is a paraphyletic group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision. The terrestrial plants, the Embryophyta emerged deep within Charophyta, possibly from terres ...
. It has been classified as the sole member of the family Chlorokybaceae,
which is the sole member of the order Chlorokybales,
in turn the sole member of the class Chlorokybophyceae.
It grows on soil and rock surfaces,
[ and is rare.][
]
Description
''Chlorokybus'' is a microalga
Microalgae or microphytes are microscopic algae invisible to the naked eye. They are phytoplankton typically found in freshwater and marine systems, living in both the water column and sediment. They are unicellular species which exist individu ...
forming sarcinoid, cubical packets of two to eight cells. Each cell contains a single chloroplast
A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...
which contains a central pyrenoid
Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...
surrounded by grains of starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...
, as well as another pyrenoid (called the pseudopyrenoid) near the edge of the chloroplast which lacks starch grains. Mature packets produce a layer of mucilage surrounding the cells.[
''Chlorokybus'' reproduces asexually by forming ]autospore
Autospores are a type of spores that are produced by algae to enable asexual reproduction and spread. They are non-motile and non-Flagellated cell, flagellated Aplanospore, aplanospores that are generated within a parent cell and have the same sha ...
s. The autospores can also differentiate into zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion in aqueous or moist environments. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Certain zoospores are ...
s, which have two flagella
A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...
. Zoospores can form groups of up to 32 cells. Zoospores swim to a new location and then settle, retracting their flagella and creating a new vegetative cell.[
]
Taxonomy
''Chlorokybus atmophyticus'' was once thought to be the only species in the genus.[
''Chlorokybus'' was placed in a new class, order and family. The new class Chlorokybophyceae was basal within the charophytes.][
Within the genus, the species were related as shown in the cladogram:][
]
References
External links
The Delwiche Lab: Molecular Systematics
{{Taxonbar, from=Q860872
Charophyta
Charophyta genera