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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Changes in pectins of the Xylopodium of Ocimum nudicaule from dormancy to sprouting

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Author(s):
Márcia Regina Braga [1] ; Nicholas C. Carpita [2] ; Sonia M. C. Dietrich [3] ; Rita de Cássia L. Figueiredo-Ribeiro [4]
Total Authors: 4
Affiliation:
[1] Instituto de Botânica. Seção de Fisiologia e Bioquímica de Plantas - Brasil
[2] Purdue University. Department of Plant Pathology - Estados Unidos
[3] Instituto de Botânica. Seção de Fisiologia e Bioquímica de Plantas - Brasil
[4] Instituto de Botânica. Seção de Fisiologia e Bioquímica de Plantas - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Brazilian Journal of Plant Physiology; v. 18, n. 2, p. 325-331, 2006-06-00.
Abstract

The thickened underground organ of Ocimum nudicaule is a tuber-like structure (xylopodium) that is dormant in winter and sprouts at the beginning of the spring. Changes in content of cell wall polysaccharides were shown to occur from dormancy to sprouting. Pectic polysaccharides of O. nudicaule were analyzed in relation to composition, molecular mass, and linkage structure in these two phenological phases. The pectin content was 33 % lower during sprouting when compared to dormancy. Changes were also observed in the molecular mass of the pectin fraction from dormancy to sprouting. Galacturonic acid was the predominant sugar, suggesting the presence of a homogalacturonan as the main pectic polysaccharide. A decrease in the acidic polysaccharides, homogalacturonans and rhamnogalacturonan I, equally accounted for the decrease in the pectin composition upon sprouting. These acidic carbohydrates were predominantly detected in the cell walls of the phellogen region of the xylopodium, suggesting catabolism of the cell walls of this tissue during bud flushing. These results suggest that variations in the content and in the molecular mass of pectins, in addition to changes in their composition and structure could be related to storage function as well as cell wall extension growth, both required for the sprouting of new buds in the xylopodium of O. nudicaule. (AU)

FAPESP's process: 98/05124-8 - Conservation and sustainable use of the plant biodiversity from the cerrado and Atlantic Forest: the storage of carbohydrates and their role on the adaptation and maintainance of plants in their natural environment
Grantee:Marcos Silveira Buckeridge
Support Opportunities: BIOTA-FAPESP Program - Thematic Grants