摘要:

SUMMARYReproductive, vegetative, anatomical, and depth distribution keys are presented for the saxicolous crustose corallines of the northwestern North Atlantic. The 3 species ofLithothamniumin the region are named, whileLithothamnium lemoineaeis described as a new species.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02385.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYPlanktonic blue‐green algae are known to be always associated with bacteria. Earlier work has shown that the addition of a bacteria‐assimilable carbon source to a normal Zehnder‐Gorham culture medium (No. 11) will produce enhanced growth of these algae when atmospheric CO2has become the limiting factor. In new work, phosphate‐rich culture media were diluted so that they simulated nutrient levels found in the Great Lakes, e.g., Lake Erie. At these low concentrations and when atmospheric CO2was not available in a sufficient supply, the addition of sucrose to either a 1/100 or a 1/1000 diluted Z‐G, medium (10 mg or 2 mg of sucrose, respectively) also produced enhanced, growth of the tested blue‐green algae. The stimulation of algal growth was apparently due to an increased bacterial production of CO2and possibly other carbon compounds approaching the composition of the CO2molecule. The literature suggests that during vigorous algal growth in lakes, atmospheric CO2will be severely limiting. Productive lakes always contain nonliving organic matter. The presence of bacteria‐assimilable matter is probably one of the important factors leading t

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02386.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYVolvox pocockiaeis described as the second species in the section Janetosphaera. The somatic protoplasts are connected by cytoplasmic strands approximately the same diameter as flagella, and the construction of the spheroid is identical to that ofV. aureus.Asexual reproduction by the division of gonidia differs from that inV. aureusin the enlargement of the gonidium prior to its division to form the embryo. Sexual reproduction is very similar to that inV. spermatosphaera, a species in the section Merrillosphaera without cytoplasmic connections. Dwarf males are formed in the posterior end of the parental spheroid, and, as inV. spermatosphaera, the dwarf males are composed exclusively of androgonidia with no sterile somatic cells. Females are facultatively asexual spheroids, the gonidia of which function as eggs. The single biflagellate zoospore produced by the germinating zygote undergoes cleavage to form a germling spheroid. The differentiation of gonidia in the asexual embryo and in the germling spheroid is evident only after inversion and enlargement of the spheroid have begun.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02387.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYTechniques are compared for the evaluation of nutrient sources in which the potential nutrients are in contact with algae over their entire culture period versus relatively short‐term exposure tests. Different nitrogen and phosphorus compounds were shown to be utilized in darkness as well as in light and were equally available at pH 7 and 9. The availability of relatively insoluble nutrients–iron‐phosphorus compounds and teeth for phosphorus, hair for nitrogen iron pyrites for iron, and marble for carbon–indicates that in many cases the equilibrium between soluble and insoluble forms allows algae to compete successfully with insoluble forms for nutrients. Apparently, factors other than mere insolubility prevent algae from obtaining available nitrogen or phosphorus from phosphate rock or lake muds. Live algae or aquatic weeds with adequate or surplus nitrogen or phosphorus were shown to not share their nutrients with nitrogen‐ or phosphorus‐limited algae, whereas the nutrients of killed algae or aquatic weeds were readily used by nutrient‐limited algae. The facts–(1) that live algae and aquatic weeds do not share their adequate or surplus nutrients with nutrient‐limited algae and (2) that lake muds do not provide readily available nitrogen or phosphorus–indicate that once lake waters are stripped of available nutrients by plant production, further plant production will depend upon nutrients from continuous sources of nutrients, such as w

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02388.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA revision of several of the Myrionemataceae described by Setchell&Gardner in 1922 from the Pacific Coast of North America has been undertaken. Collections at different seasons, on different substrates, and comparisons with the types and isotype material, as well as culture studies, show that many of these species are merely different stages of a few algae. Twenty‐seven species or forms have been grouped into 4 species and several changes of genus have been made. Life histories observed are simple, generally asexual except forHecatonema streblonematoides, which shows a“Microsyphar”‐like game

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02389.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYCladophora pygmaeais described from Quick's Hole, Elizabeth Islands, southern Cape Cod, Massachusetts; the alga was known previously from several northern European localities. The morphology and ecology of the Massachusetts plants are given and compared with those of European populations of this species.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02390.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA laboratory phenomenon involving autostimulation of growth by filtrates of the green algaHormotila blennistais described, and stimulation attributed primarily to the secretion of organic metabolites. Filtrates obtained from actively growing cultures 1 through 4 weeks old showed maximum growth rate stimulation values in excess of 100%. Stimulatory properties of filtrate were heat labile, were not closely controlled by the starting pH within the limits normally encountered in culture, and did not result from depletion of essential nutrients. Concomitant with growth rate stimulation, filtrates characteristically extended the lag phase of culture growth.H. blennistafiltrate can support bacterial growth and selectively stimulate or inhibit 2 planktonic green algae. It was suggested that extracellular organic products secreted byH. blennistaduring active growth could be of survival value to the organism, and could also play regulatory roles among other microorganisms in nature.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02391.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA number of boreal‐subarctic crustose corallines were kept in natural seawater tanks at temperatures ranging from 0 to 19 C and, using fluorescent lamps at light intensities, ranging from 7 to 750 lux with periods of 8 and 14 hr/day. The resultant growth rates as a function of temperature and light are presented and discussed in relation to the ecology of the plants.All of the Lithothamnieae studied had growth maxima at temperatures from 9 to 15 C. Growth in these species showed little light dependence below 4–6 C, but had a strong light dependence at higher temperatures. The oneLithophyllumspecies examined gave a flatter growth‐temperature curve than the Lithothamnieae and showed little light dependence.The effects of temperature variation, salinity, and current on growth rates were also examined and are discussed. It was found to be especially important in studying growth rates of crustose corallines to allow time for growth stabilization following temperature change. In general, growth was found to exhibit a hysteresis effect, increased rates with the raising of temperatures 5–10 C and decreased rates with lowering tempe

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02392.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYProduction of ammonia by urea‐grownChlorella ellipsoideawas investigated. Ammonia was produced during the stationary growth phase in cultures with urea as sole nitrogen source and glucose as supplementary carbon source. Ammonia was produced only in medium containing excess urea and limiting amounts of glucose. Ammonia production was accompanied by increase in pH.In cultures with nitrate as sole nitrogen source and glucose as supplementary carbon source, growth and pH changes were similar to those in urea‐glucose medium, but no ammonia was detected.Cultures grown in urea‐acetate medium were similar to those grown in urea medium without additional organic carbon source. No ammonia was produced under these circumstances and growth was significantly lower than that achieved in glucose‐supplemented cultures.C. ellipsoideaevidently produces an enzyme or enzyme system which forms ammonia from urea. This organism was reportedly urease‐free because previous workers did not detect ammonia formation from urea. Our findings indicate that special circumstances are required to produce detectable amounts of ammonia from urea. These findings are in agreement with a recent report of urea‐splitting, cofactor‐requiring enzyme in cell‐free extra

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02393.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY

摘要:

SUMMARYPhycobiliprotein aggregates, found at the outer surfaces of the chloroplast lamellae ofBatrachospermum virgatum, do not look like isolated globular granules, or thin discs, as reported in different algae by other authors. The aggregates appear as long cylinders of constant thickness, perhaps composed of subunits which are not distinguishable.On a single lamella (or thylakoid) the cylinders are always parallel to one another and this parallelism may persist through several successive lamellae. However, this pattern may change according to variations in the orientation of the lamellae; in tangential and oblique sections, the phycobiliprotein cylinders frequently take the shape of chevrons.In addition, arrays of tubular structures bearing phycobilin aggregates at their outer surfaces are also seen. These “tubes” probably originate from dilated short or fragmented thylako

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1970.tb02394.x

出版商:Blackwell Science Inc    

年代:1970

数据来源: WILEY