摘要:

AbstractNo abstract available.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-1.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractA comparative study of the effects of light quality on the growth and phycobiliprotein (PBP)/chlorophyllafluorescence quotients for two strains of cryptophytes, the bloom-forming cyanobacteriumOscillatoria(Tychonema)bourrellyiLund and a non-PBP-containing green alga,Euglenasp., is described.Oscillatoria bourrellyiLund (Cyanobacteria) was able to sustain a high growth rate regardless of the light quality.CryptomonasCCAP 979/67 exhibited only weak chromatic adaptation compared with the cyanobacterium, and inCryptomonasCCAP 979/62 chromatic adaptation was even weaker. Thus the possession of PBPs does not seem to provide cryptophytes with a distinct advantage in terms of growth in chromatic light and it is possible that cryptophytes use PBPs mainly as a nitrogen reserve.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-22.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractGrowth and development of cultured skeleton-bearing and naked stages of the heterokont flagellateDictyocha speculumEhrenberg (Silicoflagellata, Dictyochophyceae) were examined. The bloom-forming naked stage is easily cultivated and shows optimum growth at salinities of 15–25%, within a temperature range of 11–15°C. A maximum growth rate of 1 division/24 h was found in cultures. The skeleton-bearing stage is difficult to maintain in culture: growth is slow and dense cultures were never obtained. The salinity optimum of this stage as deduced from field data is somewhat higher than that observed for the naked stage, whereas the temperature requirements are similar. Multinucleate cells occurred in cultures of the naked stage. Cells analogous to the multinucleate cells were derived from the skeleton-bearing cells and subsequently observed to transform into naked cells. The multinucleate cells are possibly resting stages. Measurements of the DNA content of the skeleton-bearing and the naked cells showed equivalent ploidy levels in both. It has not been possible to demonstrate a toxic effect for the naked stage in laboratory experiments. Fish-kills in Denmark in 1983, associated with a bloom ofD. speculum, were therefore most likely caused by the generation of anoxic conditions.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-29.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThe marine red algaDudresnaya okiensissp. nov. (Dumontiaceae, Rhodophyta) is described from the Sea of Japan. It is a deep-water species with the following characters: terete, radially branched thallus, with annulations in young branches, hexagonal crystals in axial cells, hairs, distinct primary axes, cylindrical outer cortical cells, rhizoids up to 36μm in diameter and bearing cortical laterals, carpogonia once or twice obliquely divided, and an isomorphic alternation of generations; lacking indeterminate-axis primordia, a mucilage coat around the carpogonial and auxiliary-cell filaments, and distinctly cleft cystocarps; and with gonimoblast initials that may or may not be recurved around their auxiliary-cell filament.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-40.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThe Everglades National Park, a World Heritage site, is showing the first signs of nutrient impacts caused by intensive agricultural farming north of the Park. Investigations have shown that sediments in the Park are advectively accumulating phosphorus. At the study site, median total phosphorus concentration inflows have increased from 7 to 12μg 1−1and the TN: TP ratio has decreased from 250 to 120 over a 12-year period. Periphyton diatom mean diversity and taxon numbers are increasing in association with increased amounts of sediment phosphorus.Cymbella pusillaGrunow andAnomoeoneis vitrea(Grunow) Ross were generally predominant at less impacted far-field stations but yielded in predominance toNitzschia palea(Kützing) W. Smith,Fragilaria vaucheriae(Kützing) Petersen var.capitellata(Grunow) Patrick, andCymbella microcephalaGrunow at phosphorus-enriched near-field stations. Two non-predominant indicators of phosphorus enrichment,Gomphonema parvulumKützing andNitzschia amphibiaGrunow, showed a response to increased sediment phosphorus along the transect. These diatom community responses are the forerunner of undesirable changes experienced in the upper everglades where cattails (Typhaspp.) replaced sawgrass (Cladium jamaicenseCrantz).

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-48.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractA tiny species ofPyramimonas,P. mantoniaesp. nov. (Prasinophyceae, Chlorophyta), is described from Australian, New Zealand and Danish waters. Belonging to the subgenusVestigiferathe new species differs from all described species of this subgenus in the presence of two types of flat‘box’scales, instead of box and crown scales. Thin sections ofP. mantoniaeandP. mitraMoestrup et Hill have enabled construction of a model of the flagellar scale layers showing the arrangement of the individual scales in advanced prasinophytes.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-59.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractSeveral pigment mutants of the red microalgaPorphyridiumsp. were isolated after induced mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine (NNG). The mutants were screened on agar plates incubated at 150μmol photons m−2s−1for clones that did not show red pigmentation. After two weeks of incubation, three green or greenish-yellow mutants, C-12, 0-10 and F-11, were chosen for further characterization. The mutation frequency of these mutants ranged between 5×10−6and 8×10−6, their phenotypic pigmentation was stable over many consecutive transfers, and no reversion to the wild phenotype was observed. The reversion frequency was estimated to be less than 3×10−8. The most striking feature of the mutants was their low phycoerythrin content. When the mutants were cultured under conditions of high photon flux density (300μmol photons m−2s−1) no phycoerythrin was detected in cells of mutants D-10 and F-11, while mutant C-12 produced about 25% of the phycoerythrin found in the wild type cells. However, when cultured at a low photon flux density (40μmol photons m−2s−1) all mutants produced phycoerythrin, although at a level that ranged between 5 and 30% of that of the wild type. Similarly, during growth at high photon flux density, the chlorophyll content of the mutants was lower than that of the wild type. Under conditions of low photon flux density the chlorophyll values in mutant cells were higher than those found at high photon flux density and were comparable with those of the wild type. No significant difference was found between the phycocyanin content of the mutants and that of the wild type. The growth rate of all mutants was found to be similar to that of the wild type. However, when the mutants were cultured at high photon flux density, the cell biomass of two of them (D-10 and C-12) was lower than that of the wild type. This could be partially attributed to the reduced amount of cell wall polysaccharide in these mutants. Two of the mutants (C-12 and F-11) showed similar or slightly higher photosynthetic performance compared with the wild type, on a per cell basis, while all three had higher Pmax values and mutant F-11 had a higherαvalue when normalized to the chlorophyllαlevel.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-68.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractNo abstract available.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-73.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractNo abstract available.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-76.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractNo abstract available.

ISSN:0031-8884    

DOI:10.2216/i0031-8884-32-1-77.1

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor