摘要:

SUMMARYThe distribution of the rare filamentous green alga Ctenocladus Borzi was examined on a world‐wide basis. All the collection sites are restricted to specific inland habitats. Most of these locations are in arid regions of North America with a few scattered sites in Peru, Sicily, and Siberia. This alga has been referred to 2 genera, eitherCtenocladusorLochmiopsisWoronochin&Popova, for the past 45 years. Based on field observations, laboratory cultures, and herbarium material,Lochmiopsisis considered synonymous withCtenocladus.The response of vegetative cell dimensions to seasonal changes (i.e., osmotic potential and temperature) in 3 saline habitats in British Columbia was also investigated. Results from the study, along with laboratory dilutions of natural saline waters, showed that cell dimensions arc not valid criteria for separating species ofCtenocladusas proposed by some authors. ConsequentlyCtenocladusis considered a monotypic genus with physiological variants responding to seasonal environmental condition

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02365.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYTwo new species ofChlamydomonas, C. surtseyiensisandC. archibaldii, are described as is their sexual reproduction which occurs in clonal culture.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02366.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYNet phytoplankton samples were collected weekly for 13 months at points above and below sewage effluents. Sixty‐three genera and 130 taxa were identified: diatoms, 19 genera, 44 taxa; greens, 31 genera, 67 taxa; blue‐greens, 6 genera, 8 taxa. Downstream from the sewage effluents the number of taxa was unchanged but the number of organisms was definitely increased. This increase was most pronounced for green and blue‐green algae, and least for diatoms. The seasonal distribution of algae was that usually seen in waters of the North Temperate Zone. The particular taxa and number of taxa found were those of productive waters but not typical of heavily polluted w

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02367.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA study concerning the colonization of glass slides by diatoms was conducted in Prater's Creek, Pickens County. S. C., to observe qualitatively and quantitatively the responses of the periphytic community to current velocities for varied lengths of time. Over short time periods (1, 2 and 4 weeks) diatoms seemed to adhere best at slow current velocities. Over longer periods (6 weeks) growth, of the initial colonizers seemed to be the density governing factor; consequently, the highest diatom densities developed at the higher current, velocities. The interaction of time and current resulted in a reversal of the diatom deposition phenomenon.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02368.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYThe existence of sexuality in dinoflagellates has long been controversial. Events described as the differentiation and release of isogametes and sexual fusion in cultures ofNoctiluca miliariswere studied with the light microscope. In cultures fed. twice weekly withDunaliellasp., kept under a 12‐hr day, 12‐hr night light regime at 25–30 ft‐c and held at 18 C, certain vegetative cells, termed gametocyte mother cells, were observed to undergo what is interpreted as meiosis. This was followed by several synchronous mitotic divisions occurring at 45‐min to 1‐hr intervals and. resulting in the production of up to 1024 mature uniflagellated isogametes attached on the surface of the gametocyte mother cell body. After several hours gametes now seen swimming freely in the media were observed to fuse and form zygotes. One zygote subsequently became vacuolated and eventually differentiated into a small but reasonably typical vegetative cell. The life cycle ofN. miliarisappears thus to be of the diplontic type. The taxonomic relationships betweenNoctilucaand other mesocaryotic dinoflagellates ar

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02369.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYPseudochlorococcumgen. nov. and 2 new species,P. typicumandP. polymorphum, are described and their physiological attributes are compared. In addition, 12 physiological strains ofP. typicumare characterized.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02370.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYSphaeridiothrix compressawas found in a. saline pond in central Kansas in 1966. Studies in culture have shown that it reproduces readily by zoosporogenesis when grown in media of 12–21 ppt (%0) total salt. Its taxonomic position in the Chrysophyceae and synonymy withS. globulosa, S. brunea, andChrysodictyon indicumare discussed. This is the first report ofSphaeridiothrixin the Western Hemisphere, and the first account of zoosporogenesis in the genu

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02371.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYSome aspects of thecal morphology inCeratium hirundinellaare redescribed by means of scanning electron microscopy. The internal anatomy of the cell has been clearly revealed for the first time in serial sections examined by transmission electron microscopy. An unusual sulcus, termed the sulcul aperture, has been found to open into a large ventral chamber which extends toward the center of the cell. The 2 flagella are inserted at one side of the ventral chamber. The ultrastructure of the flagellar canals and root systems arc described in detail. A microtubular strand has been found to run from near the nucleus to near the flagellar bases but not to conned with either. The fine structure of the theca, trichocysts, nucleus, and chloroplasts is basically similar to that of other dinoflagellates. Food vacuoles are reported. These contain material thought to be undergoing digestion. It is suggested that the food particles enter the cell by way of the ventral chamber, which is lined only by membranes, unlike the rest of the cell, which is covered by thick plates. The new findings are discussed in relation to the earlier work on the species and to the fine structure of oilier dinoflagellates.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02372.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA new centric diatom,Microsiphona potamosgen. et sp. nov. (family Coscinodiscaceae), is described from the Little Miami River, Cincinnati, Ohio, where it occurred at cell densities ranging from 29 to 20,140/ml in surface grab samples during the period May 18–December 14, 1966, contributing an average of 11% and a maximum of 35% of the centric diatoms. This species has been observed in grab samples from rivers throughout the United States.The cells are 3–4 μ in diameter, 4–8 μ long, and contain 2 to several plate‐like chromatophores. They occur singly, or arc held together in short chains by the old girdle bands and by numerous apiculi that connect the opposing valves of adjacent daugh

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02373.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYInformation on the life history and development ofThuretellopsis peggianaKylin (Cryptonemiales) has been obtained additional to that first given by Kylin in 1925. Culture studies showed the life history to consist of morphologically dissimilar gametangial and tetrasporangial phases. Examination of plants from, field material indicated carposporophyte development similar to that described by Kylin. Spermatangia were found in field‐collected material also bearing carpogonial branches. Monosporangia were observed on field and cultural material of gametangial plants and on tetrasporangial plants in culture. A crustose tetrasporangial phase arose in culture from germinating carpospores under a photoperiod of 16– hr and formed tetrasporangia under a photoperiod of 9–hr. Germination of tetraspores yielded plants similar in morphology to gametangial plants collected in the field. The present study of the life history ofT. peggianaand its crust, which has some similarity toErythrodermis allenii, complements previous observations on the relationship betweenHalarachnion ligulatumandCruoria rosea(Gigartinales). Observations on the arrangement of carpogonial and. auxiliary cell branches suggest the need for very close scrutiny of characters in cultured mat

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02374.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY