In this work we have analysed two pear rootstocks (cv. Conference and BA29) showing different susceptibility to carbonate in the soil with the aim to identify other mechanisms than Fe uptake involved in their different performance in the field. Under our experimental conditions (+Fe, -Fe and +FeBic), the presence of bicarbonate caused significant differences in root elongation, which was affected only in quince. The mechanisms involved in the growth of plant organs are still poorly understood, however the idea that the cell wall modifications underlying tissue growth are affected by ROS production, has recently received some support. Staining of freshly cut cross-sections demonstrated that O2- and H2O2 were preferentially accumulated in roots of both genotypes under Fe deficiency and in BA29 also in +FeBic treatment. To investigate the biochemical behaviour bearing the hystochemical evidences, the main enzymes involved in ROS production/scavenging, such as superoxide dismutase and peroxidase, have been analysed. In general, though other activities could not be excluded, data obtained in –Fe treatment suggest that the high levels of ROS could be a consequence of an overproduction and, at the same time, of a scarce capacity to detoxification this dangerous species. An important aspect of this work comes from the behaviour of bicarbonate-treated plants. In fact only in quince roots, the presence of bicarbonate negatively affected the enzymes tested, resulting in the marked ROS accumulation also detected in these roots. Furthermore, to verify whether the presence of ROS in the apoplast could be associated to cell wall plasticity modification, the specific role of PODs in the lignification process was clarified by using syringaldazine. The histochemical analysis was performed in the presence of safranina/fast green reagents. Both syr-POD increase and deposits consistent with an increased process of lignification were revealed in particular in +FeBic BA29. We suggest that in this genotype the lignification could be a consequence of senescence induction correlated to root biomass decrease, not only to a specific response to bicarbonate toxicity. In any case, in these roots mineral nutrition could be impaired, generating susceptibility to Fe deficiency condition. In pear genotype, the allocation of new biomass to the organs that are involved in acquiring resources that are scarce, could assure growth of new roots to increase soil exploration and Fe uptake.
|Titolo:||Bicarbonate-induced changes in oxidative stress responses in relation to different degree of susceptibility of two pear rootstocks|
DONNINI, SILVIA (Primo)
|Data di pubblicazione:||26-giu-2010|
|Settore Scientifico Disciplinare:||Settore AGR/13 - Chimica Agraria|
|Citazione:||Bicarbonate-induced changes in oxidative stress responses in relation to different degree of susceptibility of two pear rootstocks / S. Donnini. ((Intervento presentato al 15. convegno International Symposium on Iron Nutrition and Interactions in Plants tenutosi a Budapest nel 2010.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|