| Texto completo | |
| Autor(es): |
Kretzschmar, Fernanda dos Santos
[1]
;
Marinho Aidar, Marcos Pereira
[1]
;
Salgado, Ione
[2]
;
Braga, Marcia Regina
[1]
Número total de Autores: 4
|
| Afiliação do(s) autor(es): | [1] Inst Bot Secao Fisiol & Bioquim Plantas, BR-01061970 Sao Paulo - Brazil
[2] Univ Estadual Campinas, Inst Biol, Dept Bioquim, BR-13083970 Campinas, SP - Brazil
Número total de Afiliações: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ENVIRONMENTAL AND EXPERIMENTAL BOTANY; v. 65, n. 2-3, p. 319-329, MAR 2009. |
| Citações Web of Science: | 15 |
| Resumo | |
Increased atmospheric pollutants including carbon dioxide (CO(2)) and nitric oxide (NO) have a large impact on vegetation, with detrimental or beneficial influences on plant growth and metabolism. Here, we evaluated the effect of an elevated CO(2) atmosphere on the production of soybean defensive secondary chemicals induced by NO and a fungal elicitor. We hypothesized that an excess of carbon may alter the production of specific flavonoids that were previously shown to be induced by NO in soybean cotyledons. Pots containing soybean seeds (Glycine max {[}L] Merr.) were submitted to 380 and 760 mu mol mol(-1) of atmospheric CO(2) in open-top chambers. After nine days, plantlets grown under these conditions were assessed for biochemical and physiological parameters. Defense-related flavonoids were evaluated in detached cotyledon diffusates elicited with two different NO donors and with the beta-glucan elicitor from Phytophthora sojae. A CO(2)-enriched atmosphere stimulated initial growth, photosynthetic assimilation, and an altered C/N ratio in soybean plantlets resulting in allocation of precursors into different branches of the phenylpropanoid pathway in the cotyledons. Under elevated CO(2), the biotic elicitor caused accumulation of phytoalexins (glyceollins) as the natural end products of the phenylpropanoid pathway. In contrast, elevated CO(2) combined with NO resulted in an increase of intermediates and diverted end products (daidzein-127%, coumestrol-93%, genistein-93%, luteolin-89% and apigenin-238%) with a concomitant increase of 1.5-3.0 times in the activity of enzymes related to their biosynthetic routes. These observations point to changes in the pool of defense-related flavonoids that are related to increased carbon availability in soybeans. This may alter the responsiveness of soybean plants to pathogens when they are grown in CO(2) atmospheric concentrations close to those predicted for the upcoming several decades. (C) 2008 Elsevier B.V. All rights reserved. (AU) | |
| Processo FAPESP: | 05/04139-7 - Carboidratos de plantas tropicais como moduladores de processos ecofisiológicos e indicadores de respostas a estresses ambientais |
| Beneficiário: | Marcia Regina Braga |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |