摘要:

Reproductive structures inAntithamnion antarcticumKylin (Rhodophyceae: Ceramiaceae) are described for the first time. Tetrasporangia are cruciately divided and sessile, replacing first- or second-order branchlets of major and minor whorl-branches. Spermatangia are cut off in whorls by spermatangial mother cells, which in turn are produced in whorls by distal cells of ordinary first- or second-order branchlets of major and minor whorl-branches. Procarps are produced by the basal cell of non-reduced major whorl-branches at least 10 cells below the apical cell of an indeterminate axis, 1 or 2 per axis. Gonimolobe initials apparently arise directly from the auxiliary cell. Carposporophyte development does not suppress further growth of the axis, but no additional procarps are formed. Carposporophytes are naked.

ISSN:0007-1617    

DOI:10.1080/00071618000650011

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

In the presence of chloramphenicol the main peptidic inclusions of exponentially growingAnabaenacells changed from carboxysomes to cyanophycin. Prolonged chloramphenicol treatment removed both carboxysomes and cyanophycin, leaving only polyphosphate bodies. Polyphosphate bodies were common to senescent, nitrogen deficient and chloramphenicol-treated cells, but absent from exponentially growing cells. All three inclusions were present in senescent cells from aged cultures. Cyanophycin can be simply and reproducibly distinguished from osmiophilic inclusions by its strong reaction to uranyl acetate.

ISSN:0007-1617    

DOI:10.1080/00071618000650021

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Dense populations ofScenedesmus quadricauda(Turp.) Bréb. (up to 1118 μg chlorophyll per 1) were recorded in the hypolimnion of a hypertrophic pond (Priest Pot, English Lake District) throughout the summer of 1978. Cell concentrations increased exponentially with depth to a maximum at the sediment surface. Although theScenedesmuscells maintained an operational photosynthetic apparatus, they occurred below the 1% light level in anoxic water. Samples from the hypolimnion could not fix carbon by cyclic photophosphorylation and their capacity for non-cyclic photophosphorylation was extremely low by comparison with surface populations. Thus the biomass accumulation in the hypolimnion could not be explained by photosynthetic production there.

ISSN:0007-1617    

DOI:10.1080/00071618000650031

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Hypolimnetic levels of isocitrate lyase (an inducible enzyme common to certain bacteria and heterotrophic algae) in Priest Pot deviated by up to two orders of magnitude from a general relationship between activities of this enzyme and bacterial concentration established for surface waters of the English Lake District. Water column activities of isocitrate lyase in Priest Pot were highly correlated withScenedesmuspopulations but were uncorrelated with numbers of either filamentous or non-filamentous bacteria. Dark acetate uptake by bottom water populations was predominantly (> 88%) by the microbial fraction trapped by an 8 μm filter. Uptake was light-stimulated in either the presence or absence of DCMU. Wavelengths of 675 nm (photosystem II light) and 710 nm (photosystem I light) were equally effective in promoting acetate transport. Light of 800 nm (in vivo peak for absorbance by bacteriochlorophyll) had no effect on uptake. These findings strongly support the hypothesis thatScenedesmuspopulations in the bottom waters of Priest Pot were heterotrophically active.

ISSN:0007-1617    

DOI:10.1080/00071618000650041

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Eight unialgal strains ofSirogonium sticticum(J. E. Smith) Kütz. were studied to compare their conjugation response. These strains were cultured in soil-water medium with a light intensity of 3,500–4,000 1x on a 16:8 h light-dark cycle at 20° ± 1°C. Chlorophyll content was used as an indirect measurement of growth to determine the phase of the growth cycle in which conjugation is initiated. Time in weeks to mating competency among the strains ranged from 3 to 6 weeks. This followed the end of log-phase growth from 0 to 2 weeks based on weekly observations. Variation in the intensity of conjugation was related to the duration of the sexual response. This duration ranged from 2 weeks, resulting in less than 0·1% sexual cells, to 7 weeks with 5·3% sexual cells.

ISSN:0007-1617    

DOI:10.1080/00071618000650051

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Eight species of freshwater plankton algae were fed to three species of duck. No viable cells of any of the algal species were found in faeces from Australian white-eye or tufted duck. Growth of the diatomAsterionella formosawas found in two cultures inoculated from the faeces of mallard and the significance of this result in relation to the dispersal of algae by ducks is discussed.

ISSN:0007-1617    

DOI:10.1080/00071618000650061

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

During an excursion to Scotland in June 1976, the algal vegetation in 15 saltmarshes was investigated. Eighty-one taxa were reported with certainty, one of which,Anacystis montana(Lightf.) Dr et D. can be added to the list of British marine algae. The algal vegetation of the marshes along the Solway Firth has a composition similar to that found in the Wadden area and is characterized by a richness inVaucheriacommunities. In the marshes of Argyllshire and in the Ross and Cromarty/Moray area a combination of the following algal communities predominated, viz. ofRhizoclonium riparium, ofBostrychia scorpioides, ofFucus vesiculosusecadmuscoidesand ofRivularia nitida.

ISSN:0007-1617    

DOI:10.1080/00071618000650071

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Chondria dasyphylla, Hymenoclonium serpens(Rhodophyta) andBryopsis lyngbyei(Chlorophyta) are reported for the first time in Norway from several localities in Vest-Agder county on the south coast.C. dasyphyllais reported from two localities situated in sheltered fjords.H. serpensis growing mostly epizoic on ascidians; in July-September often in close connection withBonnemaisonia asparagoides. B. lyngbyeitypically grows on vertical rock in surf channels on exposed localities.

ISSN:0007-1617    

DOI:10.1080/00071618000650081

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The chlorococcalean alga,Echinosphaeridium nordstedtiiLemm. has been rediscovered in a lake in Ontario, Canada, nearly 80 years after its first and only report from Sweden. Its rediscovery discounts suggestions recently made in the taxonomic literature that the description ofE. nordstedtiiwas based on an abnormalGolenkinia. Echinosphaeridiumis shown to be a valid genus differing fromGolenkinia, mainly in the structure of its spines which are broadly triangular at their bases.

ISSN:0007-1617    

DOI:10.1080/00071618000650091

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Strains of infraspecific taxa ofMicrasterias mahabuleshwarensisfrom several Australian localities cross freely producing viable zygospores. Anisogamous conjugation takes place inside a common mucilage investment. There is no conjugation tube. The zygospore has three walls. The germination vesicle escapes by hinging open an undifferentiated operculum of the exospore bearing 2 to 3 fork-tipped spines. Cleavage produces 4, 3 or 2 gones.

ISSN:0007-1617    

DOI:10.1080/00071618000650101

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor