title: Gravitropism and phototropism in protonemata of the moss Pohlia nutans (Hedw.) Lindb.
abstract: The gravitropism of protonemata of Pohlia nutans is described and compared with that of other mosses. In darkness, protonemata showed negative gravitropism. Under uniform illumination they grew radially over the substrate surface, whereas unilateral illumination induced positive phototropic growth. Gravitropism was coupled with starch synthesis and amyloplast formation. Protonematal gravitropic growth is more variable than the strict negative gravitropism of Ceratodon chloronema.
authors.affiliation: Institute of Ecology of the Carpathians, National Academy of Science of Ukraine, L'viv 290000, Ukraine.
authors.forename: O T
authors.initials: OT
authors.lastname: Demkiv
authors.forename: E L
authors.initials: EL
authors.lastname: Kordyum
authors.forename: O R
authors.initials: OR
authors.lastname: Kardash
authors.forename: O Y
authors.initials: OY
authors.lastname: Khorkavtsiv
mesh_terms: D019068:Bryopsida / Q000166:cytology / Q000254:growth & development* / Q000528:radiation effects*; D003624:Darkness; D006112:Gravitation; D018522:Gravitropism / Q000502:physiology*; D008027:Light; D008029:Lighting; D018524:Phototropism / Q000502:physiology*; D018087:Plastids / Q000502:physiology