摘要:

SUMMARYSpecies separation in the genusLaurencia(Rhodomelaceae, Rhodophyta) is complicated by the high degree of morphological variation within the species. Chemical investigations on a worldwide basis of over 15 species indicate that 1 or more of the halogenated natural products synthesized byLaurenciaare unique to each species. Our chemical investigations ofLaurencia pacifica, as presently understood from the Gulf of California, indicate that more than 1 species had been included under this name. Thin layer chromatographic (TLC) comparisons of the halogenated components of 3 recognizable forms of“L. pacifica”were completed. The results revealed 3 distinct forms, with halogenated products unique to each form. In each form the observed chemical characters had been previously isolated and identified and could now be positively assigned to their algal source. Comparisons were also conducted withL. pacifica Kylin(1941) from the type locality of the species, La Jolla, California, and revealed that it contained another halogenated product different from those isolated from the Gulf species.We conclude that 3 species of Laurenciahave been elucidated in the Gulf of California and these are separate fromL. pacificaKylin. Each species can be distinguished by its characteristic array of halogenated compounds. Comparative thin layer chromatography of the lipid components of morphologically similarLaurenciaspecies should prove to be a useful new taxonomic

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1975.tb02755.x

出版商:Blackwell Science Inc    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe brown algaAscophyllum nodosumis not a major source of organic carbon for its epiphytic red algaPolysiphonia lanosa.Plants pulse‐labeled for 24–25 hr with NaH14CO3were examined for exudation and translocation. The maximum amount of radioactive carbon compounds lost fromA. nodosumduring this experimental period was less than 0.3% of the total14C fixed by the alga, and of this amount, only 5% could, have moved through the frond. The remaining fraction of the14C lost from the thallus was released into the water.The total exudate fromA. nodosumwas collected for 1 week in a series of flasks of filtered seawater changed at 12‐hr intervals corresponding with the beginning of the light and dark periods, respectively. During 7 days at 15 C only 1.5% of the total14C originally fixed had been released as radioactive organic carbon, whereas at 5 C, 0.6% of the total14C fixed was found in the medium. No significant difference in the rate of exudation of organic14C was observed in light or darkness. After fractionation of the exudate it was found that only 10% of the radioactivity in these exudates was composed of organic acids or amino acids.P. lanosa, on the other hand, is perfectly capable of fixing its own carbon. The photosynthetic rates measured by H14CO3uptake confirm the observations of Bidwell: 3.96 mg CO2/g/hr (0.09 m mole/

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1975.tb02756.x

出版商:Blackwell Science Inc    

年代:1975

数据来源: WILEY

摘要:

SUMMARYCell division inPyramimonas parkeaeis described and compared with some other green algae. The first indication of mitosis is division of the chloroplast, accompanied by growth of a prominent microbody, followed by replication of the 4 basal bodies. Also closely timed with this is the replication of the Golgi and other components of the basal body complex. Two basal body complexes separate, each taking a position at either pole of the nucleus which has migrated to a characteristic position just beneath the plasmalemma of a broadened and flattened flagellar pit. Cytokinesis is accomplished by the fusion of ducts and vesicles with the simultaneous release of scales to the newly formed exterior. Cells swim throughout division.

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1975.tb02757.x

出版商:Blackwell Science Inc    

年代:1975

数据来源: WILEY

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1975.tb02758.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY