Photosynthetic gas exchange and antioxidative system in common bean plants infected by Colletotrichum lindemuthianum and supplied with silicon

• Autor(a) principal: Polanco,Leonora R.
• Data de Publicação: 2014
• Outros Autores: Rodrigues,Fabrício A., Nascimento,Kelly J. T., Cruz,Maria F. A., Curvelo,Carmen R. S., DaMatta,Fábio M., Vale,Francisco X. R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Tropical plant pathology (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1982-56762014000100005
• topic: Colletotrichum lindemuthianum; antioxidative enzymes; foliar disease; mineral nutrition; photosynthesis

This study investigated the effects of silicon (Si) on the resistance of common bean plants to anthracnose caused by Colletotrichum lindemuthianum. The plants were grown in a nutrient solution containing 0 (control) or 2 mM Si (+Si) and both photosynthesis and antioxidative metabolism levels were evaluated. The Si concentrations in the leaf tissues of +Si plants increased by 33% in comparison to those of control plants. Anthracnose severity was reduced by 34% in +Si plants in comparison to control plants. The net carbon assimilation rate, stomatal conductance to water vapor and transpiration rate values were significantly higher in +Si plants than in control plants. The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) tended to be higher in +Si plants than in control plants. The hydrogen peroxide concentration was significantly lower in +Si plants than in control plants. In conclusion, the Si supply was associated with lower anthracnose severity and up-regulation of antioxidant enzymes, which in turn might be associated with better gas exchange in +Si plants. The impaired photosynthetic performance in +Si plants was associated with stomatal limitations, whereas in control plants those impairments likely reflected dysfunctions at the level of biochemical reactions involved in CO2 fixation.