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The life cycle of Gonyostomum semen (Raphidophyceae)

Cronberg, Gertrud LU (2005) In Phycologia 44(3). p.285-293
Abstract
Gonyostomum semen (Raphidophyceae) is today one of the most common flagellates in humic lakes ill Sweden and appears regularly in 30% of these lakes. The first mass development of this alga was recorded in 1948 in Lake Helgasjon, South Sweden. In this paper the life cycle of Gonyostomum is described for the first time. During the winter Gonyostomum survived as resting cysts on the surface of the bottom sediment. In spring (April to May) meiosis took place in the cysts, and on excystment two haploid gametes appeared. After a period of mobility, the gametes formed pairs. The gametes then fused, and a new diploid Gonyostomum cell developed. The vegetative stage of Gonyostomum, which was seen during the summer period (May-October), is thus the... (More)
Gonyostomum semen (Raphidophyceae) is today one of the most common flagellates in humic lakes ill Sweden and appears regularly in 30% of these lakes. The first mass development of this alga was recorded in 1948 in Lake Helgasjon, South Sweden. In this paper the life cycle of Gonyostomum is described for the first time. During the winter Gonyostomum survived as resting cysts on the surface of the bottom sediment. In spring (April to May) meiosis took place in the cysts, and on excystment two haploid gametes appeared. After a period of mobility, the gametes formed pairs. The gametes then fused, and a new diploid Gonyostomum cell developed. The vegetative stage of Gonyostomum, which was seen during the summer period (May-October), is thus the diploid phase. During this period normal, longitudinal cell division took place. Under unfavourable conditions, temporary cysts Could be formed. Cyst formation started from the centre of the cell, which swelled and became spherical. This was a thin-walled, temporary cyst, which was mobile and, like ordinary cells, had one flagellum protruding forward and one trailing behind. The temporary cysts could accumulate and settle in large clusters where the flagella were lost or had become invisible. When favourable conditions reappeared, the temporary cysts divided and formed two new gametes. In autumn, when the water temperature decreased to below about 10 degrees C, the temporary cysts went into dormancy and became resting cysts. The cyst wall thickened, and a brown body appeared within the cyst. Below 4-6 degrees C no vegetative cells were found. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Phycologia
volume
44
issue
3
pages
285 - 293
publisher
International Phycological Society
external identifiers
  • scopus:19444374894
ISSN
0031-8884
language
English
LU publication?
yes
id
6875463d-6961-4aea-9eb1-5067313b8c82 (old id 146477)
date added to LUP
2007-06-28 12:52:17
date last changed
2017-10-29 04:20:26
@article{6875463d-6961-4aea-9eb1-5067313b8c82,
  abstract     = {Gonyostomum semen (Raphidophyceae) is today one of the most common flagellates in humic lakes ill Sweden and appears regularly in 30% of these lakes. The first mass development of this alga was recorded in 1948 in Lake Helgasjon, South Sweden. In this paper the life cycle of Gonyostomum is described for the first time. During the winter Gonyostomum survived as resting cysts on the surface of the bottom sediment. In spring (April to May) meiosis took place in the cysts, and on excystment two haploid gametes appeared. After a period of mobility, the gametes formed pairs. The gametes then fused, and a new diploid Gonyostomum cell developed. The vegetative stage of Gonyostomum, which was seen during the summer period (May-October), is thus the diploid phase. During this period normal, longitudinal cell division took place. Under unfavourable conditions, temporary cysts Could be formed. Cyst formation started from the centre of the cell, which swelled and became spherical. This was a thin-walled, temporary cyst, which was mobile and, like ordinary cells, had one flagellum protruding forward and one trailing behind. The temporary cysts could accumulate and settle in large clusters where the flagella were lost or had become invisible. When favourable conditions reappeared, the temporary cysts divided and formed two new gametes. In autumn, when the water temperature decreased to below about 10 degrees C, the temporary cysts went into dormancy and became resting cysts. The cyst wall thickened, and a brown body appeared within the cyst. Below 4-6 degrees C no vegetative cells were found.},
  author       = {Cronberg, Gertrud},
  issn         = {0031-8884},
  language     = {eng},
  number       = {3},
  pages        = {285--293},
  publisher    = {International Phycological Society},
  series       = {Phycologia},
  title        = {The life cycle of Gonyostomum semen (Raphidophyceae)},
  volume       = {44},
  year         = {2005},
}