摘要:

ABSTRACTSix different isolates ofOchlochaeteThwaites ex Harvey have been studied under identical culture conditions. All the isolates show open branching, a character previously ascribed specifically toO. hystrixThwaites ex Harv. sensu stricto, and all form hairs on rounded cells in the central part of the thallus, a character hitherto attributed only toO. feroxHuber. Consequently, separation of these two entities on the species level is untenable. The plant described by Huber is referred toO. hystrixvar. ferox(Huber) var. nov. The type material of Chaetobolus gibbus Rosenvinger is similar to one of the isolates studied and is included inO. hystrix.Quadriflagellate zoospores have been observed in all the isolates, and in one of them also biflagellate swarmers.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02436.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTAn ultrastructure study of mitosis and cytokinesis in the sessile sporangium ofTrentepohlia aurea(L.) Mart, was made to clarify the phylogenetic position of the alga. Mitosis was closed and centric at late anphase with cytokinesis involving the production of cleavage membranes by dictyasames between the numerous, well‐separated daughter nuclei. Neither phycoplast nor phragmoplast microtubules were observed during cytokinesis. The lack of phycoplast microtubules and the presence of multilayered structures in flagellated cells suggestTrentepohliais phylogenetically related to those green algae thought to have given rise to the land plants. The primitive type of mitosis and the lack of microbodies suggest that the ancestors ofTrentepohliamay have branched off from this line relatively earl

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02437.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe mechanism of photosynthetic carbon dioxide fixation in the green flagellateDunaliella tertiolectaButcher varies during growth in batch culture. Evidence for this change comes from three sources: i) algae from the stationary phase incorporated a greater proportion of the fixed carbon into amino arids and protein than did cells from the mid‐exponential phase; ii) the activity of phosphoenolpyruvate carboxylase relative to that of ribulose‐1, 5‐di‐phosphate carboxylase increased with age in batch culture; and, iii) cells from the stationary phase appeared to utilize the bicarbonate ion as the substrate for photosynthesis, whereas those from mid‐exponential phase appeared to utilize fire carbon dioxide. These data suggest that a change of photosynthetic mechanism can occur within a single species of alga, depending on its physiologi

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02438.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe growth dry weight, fatty acid weight and fatty acid composition of two clones ofThalassiosira pseudonanaHasle&Heimdal were measured under several growth conditions. Determinations of total cellular fatty acids were made using chemical ionization mass spectrometry. Both clones had the same fatty acids, dominated by C14:0, C16:0, C16:1, C16:3, C16:4, C18:4 and C20:5, though in different relative amounts. Fatty acids typically represented 5–10% the dry weight of a cell during log Phase growth and up to 22% during stationary Phase. The C16 fatty acids of both clones changed as the cultures aged, though much more markedly in the Sargasso Sea done (13–1) than in the estuarine one (3H). The C16:0 and C16:1 acids of both clones declined sharply in the dark and were replenished in the light. Cells maintained in constant illumination, but with no cell division. produced large quantities of these acids. Cells of done 13–1 treated with polychlorinated biphenyl (PCB) initially grew more slowly than control cells, weighed more, and had higher relative amounts of C16:0 and C16:1. Fatty acid studies may provide useful indicators of ecologically important energy reserves and membrane adaptations in the

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02439.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe rarely studied large diatomStictocyclus stictodiscus (Grun.) R. Ross has been investigated by light and electron microscopy. Confusion over the classification of this diatom has been reduced, and it has been assigned to a new family, Stictocyclaceae, though the relationship of this to the overall classification of centric diatoms is still not clear.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02440.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTSeasonal variations in nitrate and organic nitrogen content along the wing and midrib ofAlaria esculenta(L.) Grev. lamina have been compared with the NO3‐cycle in the sea and yearly growth pattern of the blade. Throughout the year, organic N is highest in blade meristem, while NO3‐distribution is less consistent. NO3‐in blades reaches a peak in March (ca. 25–28 μM), whereas maximum relative accumulation, 3,300X ambient seawater level, occurs in October. Content of NO3‐and organic N in the blade decreases in concert with the decline of seawater NO3‐in April. The three periods of rapid blade growth are not correlated with a specific organic N content in the blade meristem. Laboratory experiments suggest that low NO3‐and elevated seawater temperature are not the major factors retardingAlariablade growth during summer and early

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02441.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe taxonomic status ofCryptoglena pigraEhrb., interpreted from observations based on bright‐field microscopy, has been uncertain. Examination with the electron microscope of a clone ofC pigraisolated by E. G. Pringsheim reveals certain features which, collectively, are distinctly euglenoid: periplast associated with muciferous bodies and subpellicular microtubules; canal and reservoir with microtubules; one flagellum with a swelling and emergent through a canal, and a second flagellum without a swelling and nonremergent; stigma (eyetpot) closely apprrssed to but not part of the chloroplast; nucleus with permanently condensed chromosomes attached to the inner nuclrar membrane; mitochondria with disc‐shaped cristae constricted at the base; chloroplast with thylakoids often in triplets; and paramylon grains in the cytoplasm. Unlike most euglenoids, C. pigrapossesses a single chloroplast that in transverse thin sections is U‐s

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02442.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe heated biuret‐Folin method for determining protein consistently measures 90% of the total nitrogen of filtered algae samples as protein‐N without the need of mechanical disruption as long as the heating period in biuret is 100 min at 100 C. Data indicate this protein assay measures total protein on all species tried and for naturally occurring mixtures of species plus detritus. Dilute algal suspensions with as little as 0.05 μg‐atom particulate protein N.liter‐1can he concentrated by fltration on glass fiber filters to 1.0 μg‐atom particulate protein‐N per filter, the optimal amount of sample for a 5 ml volume of biuret. The filtered algae samples can be stored for several weeks frozen before assaying,

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02443.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTSpatial studies of colonization and succession of soil algae and chemical analyses of the various soils on the cinde cone of Kilauea Iki in Hawaii Volcanoes National Park, Hawaii are outlined. There is a positive correlation between the diversity and quantity of soil algae with nutrient levels and organic matter accumulation in each locale. Three distinct edaphic‐biotic zones existing in this area are differentially revealed by the soil chemical composition, quantity and diversity of soil algae, and as evident variations in higher plant growth and colonization. Varying colonization and successional phases of higher plant growth around standing and fallen tree snags killed by volcanic activity also reflect variations in the soil algal flora. These variations appear largely as a function of differential water interception, absorption, and retention as well as differential accumulation of organic matter, and the initiation of various biogeochemical cycle

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02444.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTTranslocation patterns in the giant kelp, Macrocystis integrifoliaBory, were investigated in situ using14C tracer; sources and sinks were identified. Export was first detected after 4 h of labeling; experiments were routinely 24 h continuous14C application. Mature blades exported14C to young blades on the same frond and on younger fronds, as well as to sporophylls and frond initials at the bases of the fronds. Blades2 m from the apex exported exclusively downwards. Carbon imported by frond initials, young fronds, and sporophylls in fall may partly be stored for growth in early spring. No translocation was seen in very young plants until one blade (secondary frond initial) bad been freed from the apical blade; this blade exported to the apical blade for a time, but imported when it began to develop into a frond. The second and third formed blades on the primary fronds (sporophylls also exported when<0.3 m from the apex, and later stopped. Frond initials and sporophylls on later‐formed fronds did not export at all. The translocation pattern inM. integrifoliadiffers from that previously reported inM. pyriferain seasonal change and in distances from the apex at which the changes take pl

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1978.tb02445.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY