Browsing by Author "Diaz, I."
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- Fe deficiency induction in Poncirus trifoliata rootstock growing in nutrient solution changes its performance after transplant to soilPublication . Gama, Florinda; Saavedra, Teresa; Diaz, I.; del Carmen Campillo, M. D.; de Varennes, A.; Duarte, Amílcar; Pestana, M.; Correia, P. J.The absence of iron (Fe) in the nutrient solution induces several physiological and morphological adaptations in the roots of Poncirus trifoliata, a citrus rootstock, thereby modifying its overall nutritional status. Whether these changes are advantageous when plants are transplanted to calcareous soils needs to be assessed. To achieve this objective a two-phase experiment was established, first in nutrient solution (phase I) then in pots containing different soils (phase II). In phase I, P. trifoliata L. Raf. plants were grown in Hoagland’s solution with 120 M of Fe (Fe120 treatment) or without (Fe0 treatment). At the end of phase I (87 days), Fe-chlorotic plants had less chlorophyll in apical younger leaves, root tips were swollen and their FC-R activity was enhanced, typical responses to Fe-stress. Chlorotic plants had less Fe compared to control plants, but accumulated more Cu and Zn. In contrast the root to shoot ratio (dry weight) and the amounts of macronutrients were not affected by Fe chlorosis. In phase II, plants of both treatments were transplanted to pots containing a calcareous (C) or a non-calcareous (nC) soil resulting in four treatments: Fe0nC, Fe120nC, Fe0C and Fe120C. From the end of phase I until the end of the experiment (353 days), the calcareous soil negatively affected the overall nutritional balance in both Fe0 and Fe120 treatments. Apparently, the ability to change metal homeostasis in particular Cu, as a Fe-stress response was maintained in plants grown in non-calcareous soil. Moreover, the previous induction of physiological and morphological adaptations to Fe depletion alleviated the iron chlorosis symptoms caused by soil carbonates. These results may point to the utilization of internal stress signalling as a tool to cope with different soil conditions.
- Sustainable bioethanol production using agro-industrial by-productsPublication . Pardão, J.; Diaz, I.; Raposo, Sara; Manso, Teresa; Lima-Costa, Maria EmíliaThis work aimed to evaluate a sustainable bioethanol production by a laboratorial isolate strain of Saccharomyces cerevisiae, along with the use of agro-industrial by-products as carbon source. The effect of several carbon sources and their concentrations was studied using carob pod extract (CPE) and beet molasses (BM) and compared with glucose and sucrose as conventional carbohydrates at different concentrations, 15, 20 and 30 g/l.No significant difference was found between maximum ethanol production obtained with CPE, BM, glucose and sucrose fermentations profiles. It was obtained values of 10.65 g/l and 10.5 g/l ethanol, respectively for sucrose and CPE at 30g/l, which can be improved using higher substrate concentration.