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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gametophytes of 9 laminarian species (4 from southern California, and 5 from central California, USA) became fertile in the unicellular stage (female gametophytes) or in a few-celled stage (male gametophytes), when appropriate temperatures and a sufficiently high quantum irradiance in the blue part of the spectrum were supplied. Vegetative growth, leading to the formation of filamentous gametophytes was light-saturated at relatively low irradiances (4 W m-2; equivalent to about 2 nE cm-2 sec-1 or an illuminance of 1000 lux), whereas 2 to 3 times this irradiance in continuous fluorescent cool white light was needed to induce the majority of the gametophytes to become fertile. An illuminance of 8300 lux did not inhibit the development of the gametophytes from southern Californian species. Egregia menziesii exhibited an exceptionally low quantum demand for induction of fertility. Gametophytes of species from central and southern California differed in regard to their temperature optimum for growth (12°C in the former, 17°C in the latter) and their upper temperature limit for reproduction (17°C in the former, 20°C in the latter).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 102 (1989), S. 557-564 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fertile Macrocystis pyrifera (L.) C. Ag. and Pterygophora californica Rupr. were collected in California, USA in 1987 to 1988. Spores of the kelps exhibited both positive and negative chemotaxis to a variety of chemical nutrients. Chemotaxis was measured by counting the number of spores that swam into flattened capillary tubes with the chemical relative to the number that swam into control tubes. Video-motion-analysis also showed that P. californica spores swam towards a nitrogen source more often than they swam away. Similar chemotactic effects were observed in both 2 and 8 h-old preparations. M. pyrifera spores swam towards nitrate, ammonium (1 to 90 μM), glycine, aspartate iron (1 μm), boron, cobalt, and manganese. Negative chemotaxis was elicited by ammonium (1 000 μM) and iron (45 μM). Neither phosphate nor zinc had significant effects. P. californica spores were attracted by nitrate, ammonium, phosphate, and boron. Negative chemotactic effects were recorded with iron (45 μM) and manganese. Iron (1 μM), cobalt, and zinc had no effect. It is suggested that chemotactic behavior is an adaptation which allows the kelp spores to find and settle in microhabitats suitable for gamatophytic growth and reproduction.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 107 (1990), S. 297-304 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract FertilePterygophora californica Rupr. andMacrocystis pyrifera (L.) C.Ag. were collected in California, USA, from 1987 to 1989. Settlement activity of the spores was stimulated by nutrients, but this was not constant over time. Nutrients had no effect on the settlement ofP. californica spores between 2 and 18 h after sunrise, but settlement activity was stimulated by a nutrient mixture between 20 and 24 h after sunrise (14 to 18 h after release). Settlement activity inM. pyrifera spores was unaffected at 2 to 3 h after release, but settlement activity was significantly stimulated from 5 to 12 h after release. A variety of individual nutrients significantly stimulated settlement in 8 to 9 h oldM. pyrifera spores: ammonium, nitrate, glycine, phosphate, manganese-EDTA (18µM), borate, ferrous iron-EDTA, and ferric iron-EDTA. Spores also settled readily in unenriched artificial seawater, and nutrient-stimulated settlement rates were usually ≤150% of the unenriched control levels. Neither EDTA alone, cobalt-EDTA, nor manganese-EDTA (2µM) had significant effects onM. pyrifera spore settlement. The effects of time and of several individual nutrients on spore settlement activity are different from previously reported chemotactic effects of nutrients onP. californica andM. pyrifera spores. It is suggested that nutrient settlement-stimulation is mechanistically different from nutrient chemotaxis. However, like chemotaxis, settlement stimulation is probably an adaptation which increases the likelihood of spore settlement in microhabitats suitable for subsequent growth and reproduction of gametophytes.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Ultrasructure Research 37 (1971), S. 532-543 
    ISSN: 0022-5320
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Aquaculture 57 (1986), S. 203-210 
    ISSN: 0044-8486
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1335
    Keywords: Antiretroviral activity ; Marine algae ; Avian myeloblastosis virus ; Reverse transcriptase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An aqueous extract from the marine red alga, Schizymenia pacifica has been tested in a cell free system for its effect on reverse transcriptase from avian retrovirus (avian myeloblastosis virus), and mammalian retrovirus (Rauscher murine leukemia virus). The extract inhibited reverse transcriptase from both these retroviruses but showed almost no effect, if any, on the activity of cellular DNA polymerase alpha and RNA polymerase II in vitro. Consequently it is unlikely to have an adverse effect on the growth of cultured cell. The inhibitory activity of the extract was stable over a relatively wide pH range (pH 1–11) and was not lost after pronase digestion. Inhibitory activity of the extract was lost after boiling at 100°C in 0.67 N HCl, and after treatment with 100 mM NaIO4. The active principle in the extract has an apparent molecular weight in excess of 100 000 daltons. This new reverse transcriptase inhibitor is probably a polysaccharide.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 35 (1979), S. 433-435 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 221 (1991), S. 91-106 
    ISSN: 1573-5117
    Keywords: agarophyte ; cultivation ; Gelidium ; growth ; hydrodynamics ; mariculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gelidium fronds were grown in the sea under a variety of experimental conditions: on rigid, damped and tensioned test farms of various designs, in calmer and more turbulent habitats, at various depths, with and without commercial fertilizer supply. Initially, the effectiveness of a given cultivation strategy was based on the survival and growth of the fronds, here termed ‘bio-assay’ mariculture. Ambient seawater temperature, nutrient availability, hydrodynamics and other environmental parameters were measured periodically. In-the-sea irrigation of test plants with commercial fertilizers was apparently effective, at least with some farm designs, and when ambient nutrient levels were low. Under optimal conditions, achieved through experimental manipulation of farm design, specific growth rates of over 2% per day were recorded. However, considerable variation in growth rates and in plant performances was observed. It was not always possible to correlate these variations with design modifications or other experimental parameters. In view of these findings, we have reviewed our initial ‘bio-assay’ approach, namely the assumptions about the design and operation of farm structures and their interactions with the water and the fronds. Methods were developed to quantify these interactions. We advocate a quantitative, ‘hydrodynamic’ approach in developing an effective cultivation strategy for gelidioid algae and are optimistic about progressing from test-to-commercial scale farms in the near future.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied phycology 4 (1992), S. 255-265 
    ISSN: 1573-5176
    Keywords: Kelp farming ; hydrodynamics ; flow ; nutrient-uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A better understanding of water motion effects on nutrient uptake by marine crop plants should make it possible to farm the sea more effectively. Farms in China, Japan and the Philippines now grow plants on slack lines or nets that move with passing waves and currents. Nutrient uptake rates are increased onLaminaria farms in China by adding nitrogen-containing fertilizer. In contrast, forests of the giant kelp,Macrocystis grow in California at low nutrient levels without fertilization. The giant kelp, compared as a structure with the slack Chinese farms, has float-supported, spring-like stipes that stretch and recoil as waves pass. This motion seems likely to enhance flow over the thallus surface. In thus study we modified flow around kelp blades in a water tunnel in the laboratory by changing orifice plates, and flow around Chinese-style long-line farms in the sea by tightening them under various sea conditions. Our measurements suggest that if marine farms were designed and operated to increase water movement over the plants being grown, their rates of nutrient uptake, and growth would increase.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 116-117 (1984), S. 456-462 
    ISSN: 1573-5117
    Keywords: seaweed ; kelp ; light ; growth ; biomass production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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