Portal de Periódicos da CAPES

Apolar Embryos of Fucus Resulting from Osmotic and Chemical Treatment

1970; Wiley; Volume: 57; Issue: 1 Linguagem: Inglês

10.2307/2440384

1537-2197

John G. Torrey, Esra Galun,

Marine and coastal plant biology

American Journal of BotanyVolume 57, Issue 1 p. 111-119 Article APOLAR EMBRYOS OF FUCUS RESULTING FROM OSMOTIC AND CHEMICAL TREATMENT John G. Torrey, John G. Torrey The Biological Laboratories, Harvard University, Cambridge, MassachusettsSearch for more papers by this authorEsra Galun, Esra Galun The Biological Laboratories, Harvard University, Cambridge, MassachusettsPermanent address: Weizmann Institute of Science, Rehovoth, Israel.Search for more papers by this author John G. Torrey, John G. Torrey The Biological Laboratories, Harvard University, Cambridge, MassachusettsSearch for more papers by this authorEsra Galun, Esra Galun The Biological Laboratories, Harvard University, Cambridge, MassachusettsPermanent address: Weizmann Institute of Science, Rehovoth, Israel.Search for more papers by this author First published: 01 January 1970 https://doi.org/10.1002/j.1537-2197.1970.tb09795.xCitations: 13 This research was supported in part by the Maria Moors Cabot Foundation for Botanical Research, Harvard University, and in part by the Public Health Service Research grant GM-08145 to JGT. The authors are indebted to Mrs. Joan Miller and Mr. Harry L. Phillips, Jr., for competent technical assistance. Most of the research was conducted at the Mount Desert Island Biological Laboratory, Salisbury Cove, Maine. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Embryos of the brown alga Fucus vesiculosas L. were grown as populations in glass petri dishes in seawater at 15 C in continuous low-intensity unilateral fluorescent illumination for periods up to 2 weeks. A quantitative estimate of increase in nuclear number was made from acetocarmine squash preparations of samples taken at 12-or-24 hr intervals. Over the period of 2-6 days embryos showed a doubling time of about 12-18 hr. Under normal seawater culture conditions each embryo formed a single rhizoid. When grown in seawater supplemented with sugar concentrations above 0.4 m, Fucus embryos developed as multicellular spherical embryos lacking rhizoids. In 0.6 m sucrose-seawater, 97% of the embryos were apolar at 2 days; only 37% were apolar at 4 days, many having recovered from the sucrose inhibition. Some embryos remained apolar after growth in 0.6 m sucrose for 2 weeks. Nuclear counts showed that sucrose-seawater markedly inhibited the rate of cell division. Other sugars including D-glucose, D-fructose, D-galactose and the sugar alcohol D-mannitol were also effective. When apolar embryos grown in sucrose-seawater were returned to seawater, embryo growth resumed at the normal seawater rate, judged from nuclear counts. Such embryos formed multiple rhizoids, varying from two to eight rhizoids per embryo, which developed on the embryo quadrant or half away from the unilateral light. Each of the multiple rhizoids originated from a single small cell in the periphery of the multicellular spherica embryo. Thus the rhizoid-forming stimulus apparently had been subdivided among a number of the cells of the apolar embryos. The implications of this finding are discussed. Attempts to produce multiple rhizoids by treatment of embryos with indoleacetic acid or 2,4-dichlorophen-oxyacetic acid failed. However, embryos treated with 10−4 M or 5 × 10−5 m 2,3,5-triiodobenzoic acid formed 40 and 30% multiple rhizoids, respectively, suggesting that some chemical, perhaps hormonal, mechanism is involved in polarization and rhizoid initiation in Fucus embryogenesis. Citing Literature Volume57, Issue1January 1970Pages 111-119 RelatedInformation