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Angiosperm Flora of India

Extracellular superoxide production, viability and redox poise in response to desiccation in recalcitrant Castanea sativa seeds

Publication Type:Journal Article
Year of Publication:2010
Authors:ROACH, THOMAS, Beckett, RP, MINIBAYEVA, FARIDAV, COLVILLE, LOUISE, WHITAKER, CLAIRE, CHEN, HONGYING, BAILLY, CHRISTOPHE, Kranner, I
Journal:Plant, Cell & Environment
Volume:33
Issue:1
Date Published:2010
ISBN Number:1365-3040
Keywords:Castanea sativa, Germination, glutathione, hydrogen peroxide, peroxidase, phenolic acid, reactive oxygen species, Seed, superoxide
Abstract:

Reactive oxygen species (ROS) are implicated in seed death following dehydration in desiccation-intolerant ‘recalcitrant’ seeds. However, it is unknown if and how ROS are produced in the apoplast and if they play a role in stress signalling during desiccation. We studied intracellular damage and extracellular superoxide (O2·−) production upon desiccation in Castanea sativa seeds, mechanisms of O2·− production and the effect of exogenously supplied ROS. A transient increase in extracellular O2·− production by the embryonic axes preceded significant desiccation-induced viability loss. Thereafter, progressively more oxidizing intracellular conditions, as indicated by a significant shift in glutathione half-cell reduction potential, accompanied cell and axis death, coinciding with the disruption of nuclear membranes. Most hydrogen peroxide (H2O2)-dependent O2·− production was found in a cell wall fraction that contained extracellular peroxidases (ECPOX) with molecular masses of ∼50 kDa. Cinnamic acid was identified as a potential reductant required for ECPOX-mediated O2·− production. H2O2, applied exogenously to mimic the transient ROS burst at the onset of desiccation, counteracted viability loss of sub-lethally desiccation-stressed seeds and of excised embryonic axes grown in tissue culture. Hence, extracellular ROS produced by embryonic axes appear to be important signalling components involved in wound response, regeneration and growth.

URL:http://dx.doi.org/10.1111/j.1365-3040.2009.02053.x
Short Title:Plant, Cell & Environment
Taxonomic name: 
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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith