title: Impact of UV radiation on the early development of the giant kelp (Macrocystis pyrifera) gametophytes.
abstract: The mechanisms and dose-response of UV action on the early development of Macrocystis pyrifera (L.) C. Agardh gametophytes were investigated. Post-release, zoospores undergo germination, germ tube elongation, DNA synthesis, nuclear division and translocation, which were followed for 41 h under laboratory conditions. The spores were exposed to UV radiation before germination (3 h post-release) or before nuclear division (20 h post-release). Biologically effective UV-B doses (BEDDNA300 nm) higher than those used in the experiments are needed for a 50% inhibition in germination (BED50 > 1600 J m-2). Nuclear division/translocation was more sensitive to UV radiation. When the spores were cultured in the dark, UV exposure at both 3 and 20 h post-release resulted in a dose-responsive inhibition of nuclear division/translocation (BED50 64 and 86 J m-2). Culturing in the light indicated recovery in the spores that were irradiated at 3 h post-release (BED50 356 J m-2), whereas no light-dependent recovery occurred within 41 h of culture when irradiated at 20 h post-release (BED50 80 J m-2). The results present a possible mechanism of UV inhibition in early life stages of the giant kelp, suggesting that environmentally relevant UV-B levels can perturb or delay the development and recruitment of the gametophytes by inhibiting nuclear events.
authors.affiliation: University of California at Davis, Bodega Marine Laboratory, CA, USA. pshuovin@jyu.fi
authors.forename: P S
authors.initials: PS
authors.lastname: Huovinen
authors.forename: A O
authors.initials: AO
authors.lastname: Oikari
authors.forename: M R
authors.initials: MR
authors.lastname: Soimasuo
authors.forename: G N
authors.initials: GN
authors.lastname: Cherr
mesh_terms: D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism; D004261:DNA Replication; D012624:Seaweed / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D014466:Ultraviolet Rays