1. J Plant Physiol. 2010 Mar 15;167(5):382-92. Epub 2009 Dec 3.

Mucilage and polysaccharides in the halophyte plant species Kosteletzkya
virginica: localization and composition in relation to salt stress.

Edmond Ghanem M, Han RM, Classen B, Quetin-Leclerq J, Mahy G, Ruan CJ, Qin P,
Pérez-Alfocea F, Lutts S.

Groupe de Recherche en Physiologie Végétale, Université catholique de Louvain
(UCL), Croix du Sud 5 Bte 13, 1348 Louvain-la-Neuve, Belgium.
Michel.Ghanem@uclouvain.be

Mucilage is thought to play a role in salinity tolerance in certain halophytic
species by regulating water ascent and ion transport. The localization and
composition of mucilage in the halophyte Kosteletzkya virginica was therefore
investigated. Plants were grown in a hydroponic system in the presence or absence
of 100mM NaCl and regularly harvested for growth parameter assessment and
mucilage analysis with the gas liquid chromatography method. NaCl treatment
stimulated shoot growth and biomass accumulation, had little effect on shoot and 
root water content, and reduced leaf water potential (Psi(w)), osmotic potential 
(Psi(s)) as well as stomatal conductance (g(s)). Mucilage increased in shoot,
stems and roots in response to salt stress. Furthermore, changes were also
observed in neutral monosaccharide components. Levels of rhamnose and uronic acid
increased with salinity. Staining with a 0.5% alcian blue solution revealed the
presence of mucopolyssacharides in xylem vessels and salt-induced mucilaginous
precipitates on the leaf abaxial surface. Determination of ion concentrations
showed that a significant increase of Na(+) and a decrease of K(+) and Ca(2+)
simultaneously occurred in tissues and in mucilage under salt stress. Considering
the high proportion of rhamnose and uronic acid in stem mucilage, we suggest that
the pectic polysaccharide could be involved in Na(+) fixation, though only a
minor fraction of accumulated sodium appeared to be firmly bound to mucilage.


PMID: 19962213 [PubMed - indexed for MEDLINE]