摘要:

SUMMARYSampling of benthic algae from selected sites in the Metolius River was carried out at regular intervals between April 15, 1967 and March 9, 1968 to determine the species composition of the communities. With the exception of the sampling site at the headwaters and the site immediately downstream, the benthic community of the Metolius River is described as a Cladophora–Achnanthes–Spirogyra community, with species of these 3 genera predominating on a year‐round basis. The community described for the headwaters and the sampling site immediately downstream was composed primarily of Nitzchia palea and Cymbella cistula. Of the approximately 60 species of algae which were identified, only 9 showed a definite seasonal distribution, the remaining species being found on a year‐roun

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01516.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYGood collections ofVacuolaria virescensCienkowski made from a pond in Forsyth County, North Carolina, marks the first recorded appearance of large numbers of this rare genus in the United States. The abundance of this material permitted a careful study of the gross morphology, nuclear structure, organelles, reproduction, and cyst formation, as well as of the ecology of the flagellates. Definitive descriptions ofVacuolaria virescensandV. viridis(Dang.) Senn by European authors are inconsistent and contradictory. Characteristics earlier attributed to each of these species have been found in the American, taxon. Indications are that the taxa described belong to the same species,V. virescens.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01517.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYThe nuclear cytology of 9 strains ofSirogoniumis described. The interphase nucleus contains 1–3 nucleoli, a nucleolar‐organizing track, and many (>100) chromocenters. During the division cycle the nucleoli are transformed into a nucleolar substance which becomes associated with the chromosome and is transported through mitosis on the chromosomes. All strains possess minute dot chromosomes varying in length at metaphase from 0.5 to 1.5 μ; satellite chromosomes are 2.5–3.5 μ long. The number of chromosomes varies from 48 ± 2 to 100 ± 2. No evidence of centromeric activity was

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01518.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYConjugating filaments ofSpirogyrawere examined with both light and electron microscopes. Initially 2 or more filaments ofSpirogyrawere attached by mucilagenous material. Papillae appeared first in one filament and then in adjacent positions on the other filament. Subsequent growth of papillae separated the conjugating filaments; wall microtubules disappeared in papillae as they elongated. Golgi activity then increased markedly only in the male filament; mucilage production by these Golgi coincided with contraction of the male gamete from its cell wall and may be responsible for its subsequent migration. The end walls separating papillae dissolved to form the conjugation tube, allowing gamete union. The male protoplast then migrated through the tube and further cytoplasmic condensation formed an elliptical‐shaped zygote. During the migration phase, zygote wall formation was initiated and numerous active Golgi apparently contributed material to it. Early zygote maturation was characterized by rapid wall formation and an increase in lipid droplet

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01519.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYControlled environment culture studies have disclosed thatPikea californicahas a life history with morphologically dissimilar gametangial and tetrasporangial phases. The effects of light intensity and photoperiod on tetrasporogenesis, cell division, and, cell elongation in the tetrasporangial phase ofP. californicaare discussed.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01520.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYThe procedure described is applicable to 11 mutant strains ofC. reinhardiDangeard. In general, freezing resulted in 3‐log loss of viable cells. Nevertheless, the phenotypic response of the recovered viable cells to selected media was the same as before freezing. There was no further reduction in viability after 6–17 months storage at liquid N2temperatu

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01521.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYA new forma ofPeridinium penardii(Lemm.) Lemm. (Dinophyceae) is described from Clear Lake, California, based upon the morphology of a theca. The formacalifornicumJavorn. is believed to be a connecting link betweenP. penardiiandP. berolinenseLemm. A nomenclatural survey of the species, as well as a key to its formae, are given.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01522.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYCytokinesis essentially similar to that of vascular plants occurs inUlothrix, an unbranched filamentous green alga. Plasmodesmata, similar to those of vascular plants, but different from those of many other algae, are also present. Cell plate formation and plasmodesmata also occur inStigeoclonium, a branched green alga.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01523.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYSpirulina major Kütz.was observed with the electron microscope and compared at the ultrastructural level with a species ofArthrospira.The presence, of crosswalls which develop by progressive ingrowth from peripheral walls was demonstrated inS. major.Since cellular septation is not consistent with the generally accepted characters of the genusSpirulina, a taxonomic shift may be indicated

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01524.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY

摘要:

SUMMARYFilaments ofZygnemawere blended 3 min in a buffered sucrose solution, and a pyrenoid‐rich cell fraction was obtained by filtration through a 10‐μ filter. The filtrate was placed on a 35%/40%/50% (wt/wt) discontinuous sucrose density gradient and was spun at approximately 50,000 × g for 1/2–1 hr. Pyrenoids, which were collected at the 40%/50% interface, appeared with light microscopy to be firm, intact, spherical, colorless refractive bodies. Althoughin situpyrenoids stained with propionocarmine, isolated pyrenoids would not stain, indicating a change in the chemical properties of pyrenoids during the isolation pr

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1971.tb01525.x

出版商:Blackwell Science Inc    

年代:1971

数据来源: WILEY