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The Arabidopsis ‐related halophyte Thellungiella halophila : boron tolerance via boron complexation with metabolites?
Author(s) -
LAMDAN NETTA LI,
ATTIA ZIV,
MORAN NAVA,
MOSHELION MENACHEM
Publication year - 2012
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02447.x
Subject(s) - halophyte , arabidopsis , boron , arabidopsis thaliana , botany , chemistry , biology , biochemistry , salinity , ecology , gene , organic chemistry , mutant
Tolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila , an Arabidopsis thaliana ‐related ‘extremophile’ plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 1–10 m m B applied ([B] ext ) to Thellungiella and Arabidopsis grown in hydroponics, the steady‐state accumulated B concentration ([B] int ) in the root was below [B] ext , and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B] int was higher in Arabidopsis than in Thellungiella , suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot‐accumulated [B] int (about 10 to 40 m m B in ‘shoot water’), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B] ext = 5 m m , the summed shoot concentration of the potentially B‐binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B] int , but in Thellungiella it was over twofold higher than [B] int , and therefore likely to allow appreciable 1:2 boron–metabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism.