''Haplotaenium'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
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 ...
, specifically of the
Desmidiaceae
The Desmidiaceae are one of four family (biology), families of Charophyta, charophyte green algae in the order (biology), order Desmidiales (desmids).See the National Center for Biotechnology Information, NCBI]webpage on Desmidiaceae Data extrac ...
.
[See the National Center for Biotechnology Information, NCBIbr>webpage on Haplotaenium]
Data extracted from the Species are widespread in acidic, oligotrophic
freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...
s.
''Haplotaenium'' consists of solitary, cylindrical cells; the cell consists of two identical halves, called semicells. The semicells are joined at the middle of the cell, where there is a slight constriction called an isthmus. Semicells are slightly swollen at the base and smoothly truncate at the apex. The
cell wall
A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...
is smooth or covered in fine pores. Each semicell has one
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 is axially located, and with a central row of 2–15
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 ...
s; terminal
vacuole
A vacuole () is a membrane-bound organelle which is present in Plant cell, plant and Fungus, fungal Cell (biology), cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water ...
s are absent. The nucleus is located at the isthmus.
[
''Haplotaenium'' reproduces asexually and sexually. Asexual reproduction involves cell division at the isthmus, where the two semicells separate and each grow a new semicell. Sexual reproduction involves ]conjugation
Conjugation or conjugate may refer to:
Linguistics
*Grammatical conjugation, the modification of a verb from its basic form
*Emotive conjugation or Russell's conjugation, the use of loaded language
Mathematics
*Complex conjugation, the change o ...
; the resulting zygote
A zygote (; , ) is a eukaryote, eukaryotic cell (biology), cell formed by a fertilization event between two gametes.
The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individ ...
s are globose and smooth, or with conical projections.[
''Haplotaenium'' was split off from '' Pleurotaenium''; it differs from the latter genus in having axial chloroplasts and lacking apical vacuoles.][ It is also similar to '' Docidium'', from which it differs in lacking a ring or row of granules/teeth at the base of the semicells.]
References
External links
*
AlgaTerra database
Index Nominum Genericorum
Desmidiaceae
Charophyta genera
{{green algae-stub