摘要:

SUMMARYThe half‐saturation constant(K8)for growth and the maximum growth rate (μmax) were determined for 2 clones ofThalassiosira pseudonana (=Cyclotella nana)under conditions in which external silicon concentrations controlled growth. The estuarine clone (3H) had a higher half‐saturation constant and maximum growth rate(K8=0.98 μM Si; μmax= 3.6 divisions/day) than the clone from the Sargasso Sea(K8=0.19 μM Si; μmax= 2.1 divisions/day). TheK8values for each clone are such that the silicate levels found at certain times in both the Sargasso Sea and the coastal regions are rate limiting to growth, hence can be of significance to plant production and to species succession. The yield data are consistent with the concept that growth rate and cellular silicon content vary together in silicon‐limite

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04086.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYA far‐red effect exists in 4 marine phytoplankton species: the diatomDitylum brightwelli, the coccolithophoridCoccolithus huxleyi, the green flagellateDunaliella tertiolecta, and the dinoflagellatePyrocystis lunula.The effect is reversible and is manifested through a change in cell division rate. Cultures of algae which received 30‐min far‐red (FR) light (750 nm) prior to the dark period were compared to controls which received, no FR. Reversal of the FR effect was studied by exposing experimental cultures to 30 min FR followed by 5‐min red (R) light (650 nm) prior to the dark period. Controls received only FR. Cultures were exposed to light at 6 different enumerated wavelengths between 460 and 750 nm. A decrease in division rate runs evident only with light at 750 nm. These results give evidence for the presence of the phytochrome system in these phytoplankton

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04087.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe red algaSmithora naiadumis normally found only as an epiphyle on the sea grassesPhyllospadix scouleriandZostera marina.I used32P and14CO2to examine the chemical communication between host and alga. Both32P and the product of14CO2light fixation moved from the host to the alga. Reverse movement between host and epiphyte was also demonstrated. Part of this transfer occurred through the plant and part occurred by leakage from the host into the medium and subsequent uptake by the alga. Although plants were initially labeled in the light, transfer of14C was light independent.Transfer of14C‐labeled products between host and epiphyte was also shown forPunctaria orbiculataandZ. marina;forMicrodadia coulterionGrateloupia doryphora, and betweenGonimophyllum skottsbergiiandBotryoglossum ruprechtiana.Epiphyte‐host associations do not require a penetrating rhizoid for an exchange of the isotopes tested. By their proximity alone, epiphytic flora are apparently capable l exchanging products before these are diluted by the

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04088.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYUltrastructural examination of platinum‐carbon replicated trichomes or wall fragments of 3Oscilatoriaspecies readily displayed the fibrillar components of the presumed motility system. These fibrils had a lateral organization as well as longitudinal continuity and wavelike distortions, which are consistent with the hypothesized movement mechanism. The fibrils were sensitive to proteolytic enzymes but resistant to hydrolytic agents, suggesting a protein composition. The fibrils and motility were unaffected by cytochalasin

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04089.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYA cluster analysis and a principal components analysis were performed to examine the degree to which the diatom flora of Yaquina estuary can be partitioned into discrete associations and to relate the composition of the flora to selected physical properties of the estuary. The species composition of the diatom flora during the winter was more closely associated with salinity and intertidal exposure them in the summer. A cluster of freshwater taxa obtained for the winter data was the most conspicuous diatom association defined by the cluster analysis. Although taxa within a cluster had more similar distributions than taxa from different clusters, there was considerable variation in the distributions of marine and brackish water taxa within a multispecies cluster.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04090.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYAlgal succession on artificial reefs constructed of tires has been studied over a 26‐mo period. Filamentous algae,ie, Calothrix crustacea, Feldmannia indica, andSphacelaria tribuloides, are the primary colonizers; the fleshy brown alga,Dictyota bartayresii, appears soon after.Lobophora variegatais the only alga present which occurs seasonally. Low light penetration through the silly lagoon water and selective browsing by herbivorous fishes favor the blue‐greensCalothrix crustaceaandMicrocoleus lyngbyaceusto be the dominant algae in the climax community which, occurs within a 1‐year p

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04091.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYAn empirical relation relating specific growth, rate in steady state systems to nutrient status with respect to more than one nutrient simultaneously is proposed, based on 3 experimentally verifiable postulates: (1) that uptake depends on the external substrate concentration; (2) that growth depends on the interval substrate concentration; and (3) in a steady state system specific rate of uptake (in the absence of significant, excretion) is necessarily the product of the specific growth rate and internal substrate concentration. The implications of this model are discussed in particular in respect to the concept of luxury consumption and Liebig's law of minimum. Some aspects of uptake in transient situations are also discussed.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04092.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYWhenDunaliella tertiolecta, previously adapted to medium containing 0.5 M NaCl, is transferred to higher salinities, there is a lag in growth, suggesting an adaptation period. Since there is no significant difference in the Na+content of cells grown between 0.5 and 3.5 M NaCl, a mechanism for Na+extrusion or exclusion is indicated.Increasing the salinity of cell suspensions stimulates an incorporation of H+by the cells, suggesting an H+/Na+exchange. Cells adapted to higher salinities have, increased carbonic anhydrase activity, suggesting that increased CO2or HCO3−transport may be required at higher salinities.Growth, ofD. tertiolectaat salinities above 2.5 M requires continuous illumination; therefore a light‐driven H+/Na+exchange accompanied by a HCO3−influx is pro

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04093.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYSeveral different stages of the development of unilocular zoidocysts of small brown algae—Elachista fucicola, Hecatonema streblonematoides, Pylaiella littoralis—are observed by electron microscopy.1. A slow growing phase is seen, during which nuclei and pheoplasts become associated by pairs and divide together, vacuoles and physodes are excreted through the plasmalemma, and Golgi bodies liberate vesicles with fibrillar material identical to the growing cell wall fibers. Mitochondria and Golgi bodies are concentrated under the very sinuous plasmalemma.2. A very short spatial reorganization phase follows, during which organelles disperse between the nuclei‐pheoplast pairs, cleavage vesicles appear, and flagella start developing. New pyrenoids formde novo.3. The latter phase is followed by a longer maturation phase. Cleavage vesicles fuse and separate zoids grow as flagella. Mastigonemes formed in the endoplasmic reticulum are finally found in vesicles of a special Golgi body at the base of the anterior flagellum. They are liberated in parallel rows at the base of the already developed flagella by these Golgi's vesicles, and attach, on the flagella by an unknown process. Excretion of a mucilaginous substance takes place as the stigmas formde novo.4. The ripe, swollen zoidocysts burst open, liberating the whole gelatinous mass. Naked zoids swim and settle on a substrate, retracting their flagella before excreting a new cell

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04094.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY

摘要:

SUMMARYProteins from 7 species of chlorosarcinacean algae representing 4 genera were studied with starch and disc gel electrophoresis and immunology to determine biochemical relationships. Migration patterns of enzymes and serological reactions indicated that 4 species ofChlorosarcinopsiswere closely related, whereasFriedmannia israeliensis, Fasciculochloris boldii, andChlorosarcina longispinosawere more diverse. Malate dehydrogenase, glutamate dehydrogenase, nonspecific alpha esterases, and peroxidase (using pyrogallol as the hydrogen donor) were present in all 7 species. No peroxidase activity occurred with benzidine. Leucine aminopeptidase was obvious in only 2 species. A single distinct band of general protein inF. israeliensisandC. longispinosasuggested the presence of homogenous reserve protein. The 7 species exhibited serological affinity to 4 isolates ofProtosiphonrepresenting diverse morphology within the genus. The data are discussed relative to current knowledge of comparative morphology of chlorosarcinacean algae.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1973.tb04095.x

出版商:Blackwell Science Inc    

年代:1973

数据来源: WILEY