Format

Send to

Choose Destination
See comment in PubMed Commons below
Plant Physiol. 2009 Aug;150(4):1855-65. doi: 10.1104/pp.109.139204. Epub 2009 Jun 3.

In vivo cell wall loosening by hydroxyl radicals during cress seed germination and elongation growth.

Author information

1
University of Freiburg, Faculty of Biology, Institute for Biology II, Botany/Plant Physiology, D-79104 Freiburg, Germany.

Abstract

Loosening of cell walls is an important developmental process in key stages of the plant life cycle, including seed germination, elongation growth, and fruit ripening. Here, we report direct in vivo evidence for hydroxyl radical ((*)OH)-mediated cell wall loosening during plant seed germination and seedling growth. We used electron paramagnetic resonance spectroscopy to show that (*)OH is generated in the cell wall during radicle elongation and weakening of the endosperm of cress (Lepidium sativum; Brassicaceae) seeds. Endosperm weakening precedes radicle emergence, as demonstrated by direct biomechanical measurements. By (3)H fingerprinting, we showed that wall polysaccharides are oxidized in vivo by the developmentally regulated action of apoplastic (*)OH in radicles and endosperm caps: the production and action of (*)OH increased during endosperm weakening and radicle elongation and were inhibited by the germination-inhibiting hormone abscisic acid. Both effects were reversed by gibberellin. Distinct and tissue-specific target sites of (*)OH attack on polysaccharides were evident. In vivo (*)OH attack on cell wall polysaccharides were evident not only in germinating seeds but also in elongating maize (Zea mays; Poaceae) seedling coleoptiles. We conclude that plant cell wall loosening by (*)OH is a controlled action of this type of reactive oxygen species.

PMID:
19493972
PMCID:
PMC2719145
DOI:
10.1104/pp.109.139204
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center