摘要:

ABSTRACTThe coenocytic algaValonia macrophysaKützing was selected for an investigation of nuclear synchrony in the order Siphonocladales. Light microscopy reveals that nuclear synchrony is evident as patches of nuclei dividing simultaneously. Flow cytometry was utilized for the first time with a macroalga for cell‐cycle analysis. Results indicate that nuclei in the entire cell exhibit a high degree of synchrony throughout the cell cycle. Also it appears that cells within a clonal culture are synchronous with each other, in their progression through the cell cycle. The advantages of using flow cytometry for cell‐cycle analysis of coenocytic algae include the rapid collection of quantitative data on relative DNA content for a large number of nu

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00068.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe lipid profile of seven species of unicellular eukaryotic microalgae grown under controlled conditions was studied with emphasis on the hydrocarbons and the fatty acids as part of a search for oil‐producing algae. Green, slow‐growing colonies ofBotryococcus brauniiKutz contained the highest lipid content of 45% based on the organic weight, with an increase to 55% under nitrogen deficiency and with no effect of sodium chloride stress.Ankistrodesmussp. Thomas,Dunaliellaspp.,Isochrysissp.,Nannochlorissp. Thomas, andNitzschiasp. Chapman contained an average of 25% lipids under nitrogen sufficient conditions. Nitrogen deficiency resulted in significant increase in the lipid content in all species butDunaliellaspp., which produced a higher content of carbohydrates. Significant low amounts of acyclic hydrocarbons were detected only inBotryococcus brauniiKutz and not in the other algae. The major hydrocarbon fractions in nitrogen deficientBotryococcus brauniiKutz,Dunaliella salinaThomas,Isochrysisspp. andNannochlorissp. Thomas were cyclic and branched polyunsaturated components which were identified as various isoprenoid derivatives. The polar lipid composition of glycolipids and phospholipids of all species investigated was fairly typical of photosynthetic eukaryotic algae. Fatty acid composition was species specific, with changes occurring in the relative amounts of individual acids of cells cultivated under different conditions and growth phases. All species synthesized C14:0, C16.0, C18:1, C18:2 and C18:3 fatty acids; C 16:4 inAnkistrodesmussp. Thomas; C18:4 and C 22.6 inIsochrysissp.; C16:2, C16:3 and C20:5 inNannochlorissp. Thomas; C16:2, C16:3 and C20:5 inNitzschiasp. Chapman. Nitrogen deficiency and salt stress induced accumulation of C18:1 in all treated species and to a lesser extent inBotryococcus brauniiKutz. The low production of hydrocarbons under optimal growth conditions and the high production of hydrocarbons under limited growth conditions cannot support the notion that microalgae can be utilized as biosolar energy converters for the production of liquid fuel, but point to the availability of a variety of neutral and polar lipid produ

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00072.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTA biogeographical survey of the freshwater brown algaHeribaudiella fluviatilis(Areschoug) Svedelius was conducted in southern British Columbia (Canada) and northern Washington (U.S.A.). Surveys of 121 reaches on streams and rivers revealed 25 populations, including the first record for the U.S.A. A strongly noncoastal distribution provides no evidence of a marine‐based source for its distribution in the region. Streams withHeribaudiellatypically have a: current velocity greater than 1.0 m · s−1; rocky substrata; range of width from 1.7–60 m; broad range of Ca concentration; and, ranged from heavily shaded to fully open location. Although once thought rare in North America, it was fairly widespread in the region and often abundant within a given sampling site. Biogeographic and ecological data suggest thatHeribaudiellamay be a common, but often overlooked, component of the flora of

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00081.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTGiffordia onslowensissp. nov. is described from the North Carolina continental shelf. This alga is distinct in having upper filaments which are profusely branched, with branches borne at the tops of cells at narrow angles, and lower filaments which are sparsely branched, with branches borne at the middle of cells at wide angles. It is somewhat intermediate betweenAcinetosporaandGiffordiabecause of the morphology of the lower branches. Morphological variability ofGiffordiain culture is numerically documented and similarities betweenGiffordiaspp. andAcinetosporain culture are interpreted as artifacts of altered or incomplete development. It is concluded thatAcinetospora, Giffordia,andEctocarpusshould be retained as separate genera.

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00094.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTSeveral demographic features were examined in the field over a period of eleven months for the subtidal algaCystoseira osmundacea(Turner) C. Agardh at two localities near Monterey, California. This species showed a restricted distribution with depth, with peak average numbers of 3–4 plants per m2occurring at 6–8 m and forming a dense canopy on the surface of the sea. Below 10 m depth, there was a decline in the abundance of plants and also in the proportion of plants which bore seasonal fronds and reproductive tissue.Macrocystis pyrifera(L.) C. Agardh plants were also common at both localities. There was a negative correlation between the presence of this species andC. osmundaceaat a scale of 1 m2, but no correlation at 4, 9, and 25 m2.Cohorts ofC. osmundaceawere mapped and tagged at one locality. The plants had markedly seasonal growth, with the greatest elongation of fronds occurring between March and June. Dense surface canopies and reproductive tissue were present during the summer months of June–August. These seasonal fronds were shed during September, leaving small perennial holdfasts and fronds.Plants were strictly dioecious, and there was a one‐to‐one ratio of male to female plants at both localities. Length‐dry weight relationships showed that the largest plants had over 80% of their weight invested in seasonal fronds (vegetative plus reproductive tissue).Recruits ofC. osmundaceaat one locality appeared during September–November only in areas cleared to bare substratum. There was 15% survival of recruits between November and the following May, while 98% of the original mapped cohort survived for the 11 months

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00099.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTTwo new species are recognized in the rhodomelacean genusTayloriellaKylin:T. divaricatasp. nov. andT. abyssalissp. nov. These two taxa are distributed in the northeastern North Pacific, the former ranging from Amchitka Island in the Aleutians through southcentral Alaska to northern British Columbia, and the latter ranging also from Amchitka Island through southcentral Alaska and British Columbia into northern Washington. A characteristic of these two species shared with the type ofTayloriellais that the abaxial lateral always overtops the monopodially developed axes in every order of branching. The laterals have little congenital fusion with the parent axes. A common feature in these two species is that the laterals are terminated in a relatively long monosiphonous portion (usually 6 or 7 cells). The relationship ofTayloriellatoPterosiphoniaandPterosiphoniellais discussed.

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00107.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe organization of two types of nontubular mastigonemes associated with the anterior flagellar surface of the phagotrophic biflagellatePeranema trichophorum(Ehrenberg) Stein is described from studies of thin sections, negative‐stained and shadow‐cast preparations of both intact and isolated, detergent‐treated flagella. Long mastigonemes form a unilateral, spiral array of tufts which curve toward the distal end of the flagellum, while two short mastigoneme ribbons form unequal halves of a bilateral array parallel to the flagellar long axis. Each ribbon is composed of individual overlapping fan‐shaped tiers of short mastigonemes interlinked by fine fibrils. A model proposed forPeranemamastigonemes is similar to recent models of mastigoneme organization in

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00114.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTPeranema trichophorum(Ehrenberg) Stein, a colorless phagotrophic euglenoid flagellate, has a typically euglenoid microtubular root complement. Striated root components, relatively uncommon in euglenoids, are connected to the basal bodies and to a microtubular root.The flagellar system ofPeranemaconsists of three unequal microtubular roots which extend anteriorly beneath the reservoir membrane, and narrow‐band striated roots (periodicity = 29–33 nm) which connect one of the four basal bodies to the movable rodorgan of the feeding apparatus. An inter basal body striated fiber forms a three‐way connection between one particular microtubular root, a flagellar basal body, and the striated roots. A striated fibril (periodicity = 18–25 nm), which may be an extension of the striated root system, extends beneath the reservoir membrane. Associated with the striated fibril and the striated roots are cisternae of smooth endoplasmic re

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00125.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe blue‐green algaSynechococcus linearis(Naeg.) Kom. was grown in P‐ and N‐limited chemostats over a range of potentially limiting irradiances in order to determine the combined effects of light and nutrient limitation on some aspects of the composition and metabolism of this alga. Over a narrow range of low irradiances, simultaneous limitation of growth rate by light and either N or P was shown. This simultaneous limitation of growth rate by a nutrient and a physical factor can be explained by the ability of an increased supply of one to compensate in part for a decreased supply of the other. At all irradiances, the internal concentration of the limiting nutrient increased with increasing dilution rate, and the results could be fitted to the Droop relationship. With decreasing irradiance, the internal concentration of the limiting nutrient increased. There appeared to be little or no effect of light on the minimum internal concentration of P but that of N increased with decreasing light. Both chlorophyllaand biliprotein per unit particulate C increased with increasing dilution rate and decreasing irradiance. The critical N/P ratio increased with decreasing light as the N requirement of N‐limited cells increased faster than did the P requirement of P‐limited cells. The composition of exponentially growing cells in complete medium varied much less with light. Neither dilution rate nor irradiance during growth had a great effect on saturated rates of P or N uptake or alkaline phosphatase activity. Calculated assimilation ratios increased with light and dilution rate. The role of the flexibility of nutrient composition in adaptation to adverse conditions and the implications of the results for the use of physiological indicators of nutrient status are

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00134.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY

摘要:

ABSTRACTThe fine structure of released, attached, and germinating carpospores ofPorphyra variegata(Kjellm.) Hus is described. Adhesive vesicles, formed during sporogenesis and discharged upon settling of the spore, produced a layer of adhesive mucilage around the spore and filled a deep imagination on the spore's ventral side. The mucilage layer was punctured by the emergence of a germ tube. Both spore and germ tube were lined by newly deposited cell wall. Germination was accompanied by vacuolation and starch mobilization. The morphological development of the sporeling was not noticeably influenced by the great variability of the timing, location, and orientation of septum formation. The attached carpospore possessed a plastid like that of gametophyte cells: stellate with one large central pyrenoid and no peripheral encircling thylakoids. Cells of mature vegetative cells of the conchocelis had plastids that were elongate and parietal and had multiple pyrenoids and encircling thylakoids. Most stages in the transition between the two forms of plastids occurred during carpospore germination.

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1985.00146.x

出版商:Blackwell Science Inc    

年代:1985

数据来源: WILEY