摘要:

SUMMARYA species ofZygogoniumforms extensive dark purple mats in Yellowstone National Park in acidic habitats adjacent to thermal areas. These mats range up to 6 cm in thickness and up to 3000 m2in areal extent. Temperatures in the mats varied from 20–31 C and pH varied from 2.4–3.1. These mats form on soil in areas where a moist surface is created by the presence of small acidic springs or seeps. The effect of light, temperature, and pH on photosynthesis was studied in the field by use of14CO2. Photosynthesis increased in rate up to full sunlight; light inhibition was not observed. Temperature optimum for photo‐synthesis was 25 C. A broad pH optimum was found between 1.0 and 5.0. TheZygogoniummats have a high water holding capacity and create a moist habitat in whichEuglenaandChlamydomonasdevelop. The mats also serve as repositories for the eggs of the brine flyEphydra bruesiand both larvae and adults of this fly probably consumeZygogoniumfilaments as their main food s

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02600.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYWhenScenedesmusculture 16, a soil organism with numerous long spines, was grown in axenic culture in a dilute laboratory medium (with approximately 30 mg/liter total salts), spines were not formed. In this medium the organism resembledS. bijugatus,whereasS. longusandS. abundanscolonies were typically formed in more concentrated media.Spines were formed on daughter colonies upon transfer to the dilute medium plus additional Fe EDTA or Ca EDTA. No other individual components of the medium did this. Spineless colonies were healthy and green with a well‐defined chloroplast, provided the culture was transferred often.In addition to the absence of spines, cultures in the dilute medium had a linear arrangement of cells within a colony, along with terminal cells 20% shorter than median cells. With 4‐celled spiny colonies all cells were the same length and were alternately arran

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02601.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYA new species, Platysiphonia decumbens, belonging to the Sarcomenia group (Rhodophyta, Ceramiales), is described from Puget Sound, Washington. Reproductive thalli are described and illustrated, and the growth of this alga in culture is correlated with observations made on field material. The limits of the genus Platysiphonia Børgesen are broadened to include this species. The relationship of Platysiphonia to Sarcomenia Sonder is discussed

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02602.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYUltrastructural investigations of the development and structure of pseudocilia inTetraspora lubricaandSchizochlamys sp.have disclosed interconnections between cytoptasmic microtubules and pseudo‐cilial basal bodies heretofore unreported. Connections between elements of the basal bodies and the proximal connecting fibers are also described. The possible significance of the interconnections in correlating structure and function of these organelles is discusse

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02603.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYThe vitamins p‐aminobenzoic acid, thiamine, biotin, nicotinamide, andB12were tested for their ability to stimulate growth. Only vitaminB12was required. Urea and NaNO2supported excellent growth, although sodium nitrite, ammonium nitrate, and the Casamino acids supported only fair growth. Platydorinagrew aerobically in the absence of an exogenous source of carbon; however a carbon source was required for anaerobic growth. Of 25 carbon compounds examined, isocitrate supported anaerobic growth in the light equalling the aerobic controls. Growth did not occur aerobically or anaerobically in the dark with any carbon source examined. Growth was excellent at pH values in excess of 7.0. Growth at pH 10.0 was 4 times that at 7.0 in strain I.U. 850 and twice that at 7.0 in strain Kan‐3E. Growth was accelerated with the increase in temperatures but this increase may well be due to the increased intensity of light to which the cultures were exposed at the higher terperatu

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02604.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYIn culture tetraspores of the sporophyte(Trailliella intricata)ofSonnemaisonia hamiferagave rise to male gametophytes only. In the Gulf of St. Lawrence tetrasporangia occur annually during the autumn, but mature gametophytes have not been recorded. However, gametophytes with antheridia were found during the winter on the Atlantic coast of Nova Scotia. Both phases are capable of vegetative propagation, and this is probably the usual method of reproduction in nature.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02605.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYFrom previously published data, 73 characteristics of 17 species of Chlorococcum were compiled. Comparisons of character states of each character were made, and simple matching coefficients were calculated for each species by following the procedure of Sokal&Michener. From a data matrix of the matching coefficients, a phenogram was constructed according to the unweighted pair group method of Sokal&Sneath. Arithmetic averages were used in transferring data from one matrix to another. The frequency of each character state was calculated, and the character states of the highest frequency (the modes) were used to describe a “typical”Chlorococcumspecies. Comparisons were made between the “typical”Chlorococcumspecies and each of the 17 species studied. Simple matching coefficients were also calculated from these comparisons. All of the species had a relatively high affinity for the data of the calculated “typical”. Suggestions are made about the use of a “typical” taxonomic unit, and questions are raised about the taxonomic relationship among species of the genusTetracystisand the ge

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02606.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYDividing and nondividing cell populations ofChaetoceros costatumPavillard were placed in light; nondividing populations were also placed in the dark, and one population was killed by formalin. No difference in203Hg uptake was seen in nondividing cells in the light and dark, while cells accumulated about 2 times as much203Hg as living cells, presumably by surface adsorption. Dividing cells in light accumulated203Hg longer than did nondividing cells, indicating the possibility of some active uptake of Hg.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02607.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYThe fine structure of 10 lichens was examined. A comparison was made of the storage products of the algal symbiont(Trebouxia) in situin the desiccated and hydrated states of the lichens. All theTrebouxiaphycobionts, with the exception of that inUsnea strigosa,had lipid‐containing globules in the pyrenoid. The globules were present in both the hydrated and desiccated conditions. Trebouxiain the hydrated condition contained starch granules in the chloroplast as well as the lipid‐containing globules in the pyrenoid. The cell wall ofTrebouxiaconsists of an outer electron‐dense layer and an inner electron‐light layer. Fungal haustoria(inLecanora rubina)rupture the outer layer of the algal cell wall and invaginate the inner layer. A thick polysaccharide fibrillar material surrounds the fungal cells. Many bacteria were observed within this material. Septa and lomasomes are described. Ellipsoidal bodies, which appear to be an integral and unique part of the lichen fungal ultrastructure, were observed associated with membrane p

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02608.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYDividing cells of Spirogyra sp. were examined with both the light and electron microscopes. By preprophase many of the typical transverse wall micro‐tubules disappeared while others were seen in the thickened cytoplasmic strands. Microtubules appeared in the polar cytoplasm at prophase and by prometaphase they penetrated the nucleus. They were attached to chromosomes at metaphase and early anaphase, and formed a sheath surrounding the spindle during anaphase; they were seen in the interzonal strands and cytoplasmic strands at telophase. The interphase nucleolus, containing 2 distinct zones and chromatinlike material, fragmented at prophase; at metaphase and anaphase nucleolar material coated the chromosomes, obscuring them by late anaphase. The chromosomes condensed in the nucleoplasm at prophase, moving into the nucleolus at prometaphase. The nuclear envelope was finally disrupted at anaphase during spindle elongation; at telophase membrane profiles coated the reforming nuclei. During anaphase and early telophase the interzonal region contained vacuoles, a few micro‐tubules, and sometimes eliminated n ucleolar material; most small organelles, including swollen endoplasmic reticulum and tubular membranes, were concentrated in the polar cytoplasm. Quantitative and qualitative cytological observations strongly suggest movement of intact wall rnicrotubules to the spindle at preprophase and then back again at teloph

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1969.tb02609.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY