Characterization of quaternary ammonium compounds in Flourensia xerophytic communities and response to UV - B radiation
As part of ongoing studies aimed at characterizing molecular components involved in the ecophysiological adaptations of native xerophytic plants from central Argentina, we demonstrated the presence of compatible solutes in Flourensia campestris [FC] and Flourensia oolepis [FO], specifically glycine betaine [GB] through TLC, LC, 1H NMR and 13C-NMR. GB content [leaves: 38 plus or minus 7 umolg-1 DW; adult plants greater than seedlings], and distribution [capitula greater than vegetative leaves greater than reproductive leaves greater than shoots greater than roots] were similar to other quaternary ammonium compound [QAC] accumulators. Flourensia seedlings from both species protected from UV-B exposure - a major abiotic stress in these natural environments - showed a significant increase of GB in the leaves [p less than 0.01] and a significant decrease in the roots [p less than 0.05]. In FC and FO xerophytic shrub-dominated communities QACs were detected for the first time in 41 percent of co-occurring species [N=39], 14 of 28 natives [50 percent] and 2 of 11 exotics [18 percent], being GB in natives only [57 percent of QAC accumulators]. GB may be considered as a chemotaxonomical character for the genus Flourensia, since it was also detected in Flourensia hirta, Flourensia niederleinii, Flourensia riparia, Flourensia fiebrigii, Flourensia macroligulata and Flourensia heterolepis. Our controlled UV-B experiments, set up in the same natural environment where these species grow, clearly show that solar UV-B - and therefore oxidative stress - is involved in regulating GB contents and within-plant distribution in FC and FO seedlings. The findings in Flourensia co-occurring native species suggest that QACs accumulation may be considered as a community-specific ecophysiological trait in these xerophytic environments.
| Main Authors: | , , , , , , |
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| Format: | Texto biblioteca |
| Language: | spa |
| Subjects: | ABIOTIC STRESSES, ADAPTATION, AMMONIUM COMPOUND, ARGENTINA, BIOACCUMULATION, BIOCHEMICAL COMPOSITION, COEXISTENCE, ECOPHYSIOLOGY, ENVIRONMENTAL STRESS, GLYCINE BETAINE, NATIVE SPECIES, PHYTOCHEMISTRY, PLANT COMMUNITY, SHRUB, ULTRAVIOLET B RADIATION, UV-B, , |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=47046 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= |
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