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High rates of extracellular superoxide production in bryophytes and lichens, and an oxidative burst in response to rehydration following desiccation
Author(s) -
Minibayeva Farida,
Beckett Richard Peter
Publication year - 2001
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.0028-646x.2001.00256.x
Subject(s) - desiccation , lichen , extracellular , desiccation tolerance , botany , biology , superoxide , biochemistry , enzyme
Summary• The mechanism of extracellular superoxide radical (O 2 · − ) formation and the role of the oxidative burst in response to desiccation stress is reported here in bryophytes and lichens from habitats of contrasting water availability. • Rates of extracellular production of O 2 · − radicals were measured, before and after desiccation stress, by the oxidation of epinephrine to adrenochrome, determined spectrophotometrically. • Several desiccation‐sensitive lichens and bryophytes that grow in very wet microhabitats produced O 2 · − extracellularly at high rates, even when they were not stressed. In addition, some species showed a powerful burst of O 2 · − production during rehydration following desiccation. Production of high levels of O 2 · − and the existence of an inducible oxidative burst was best developed in cyanobacterial lichens, a hornwort and the two thalloid liverworts tested. Extracellular production of O 2 · − was almost absent from all mosses tested, a leafy liverwort, a filmy fern and from desiccation‐tolerant lichens. • Patterns of O 2 · − production are discussed in terms of their possible role as a defence against pathogenic fungi and bacteria.