Browsing by Author "Ferreira, S."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Alleviation of salt stress using exogenous proline on a citrus cell linePublication . Lima Costa, Maria Emília; Ferreira, S.; Duarte, Amílcar; Ferreira, A. L.Salinity constitutes an important abiotic problem since ancient times, world-wide, for it leads to a decrease in productivity of crops with agronomic value. Under salt stress conditions, plant cells develop strategies to cope with Na+ and Cl-, including exclusion and compartmentalisation, induction of antioxidant enzymatic systems and compatible solutes accumulation, such as proline. The precise function of this osmolyte still remains unclear. Proline may act on osmotic adjustment, as a free radical scavenger, protecting enzymes and avoiding DNA damages. It has been also suggested the role of proline in prevention of lipid peroxidation and as a signalling/regulatory molecule. A salt-sensitive Citrus sinensis ‘Valencia late’ cell line has a smaller growth rate and accumulates proline in the presence of NaCl (>200 mM). The addition of external proline to this cell line was evaluated in terms of cell metabolism. A positive influence on the relieve of salt stress symptoms due to the presence of exogenous proline 5 mM and 100 mM NaCl was obtained, with increased growth of this salt sensitive citrus cell line.
- Born small, die young: Intrinsic, size-selective mortality in marine larval fishPublication . Garrido, Susana; Ben-Hamadou, Radhouan; Santos, A. Miguel P.; Ferreira, S.; M A Teodosio; Cotano, U.; Irigoien, X.; Peck, M. A.; Saiz, E.; Re, P.Mortality during the early stages is a major cause of the natural variations in the size and recruitment strength of marine fish populations. In this study, the relation between the size-at-hatch and early survival was assessed using laboratory experiments and on field-caught larvae of the European sardine (Sardina pilchardus). Larval size-at-hatch was not related to the egg size but was significantly, positively related to the diameter of the otolith-at-hatch. Otolith diameter-athatch was also significantly correlated with survival-at-age in fed and unfed larvae in the laboratory. For sardine larvae collected in the Bay of Biscay during the spring of 2008, otolith radius-at-hatch was also significantly related to viability. Larval mortality has frequently been related to adverse environmental conditions and intrinsic factors affecting feeding ability and vulnerability to predators. Our study offers evidence indicating that a significant portion of fish mortality occurs during the endogenous (yolk) and mixed (yolk /prey) feeding period in the absence of predators, revealing that marine fish with high fecundity, such as small pelagics, can spawn a relatively large amount of eggs resulting in small larvae with no chances to survive. Our findings help to better understand the mass mortalities occurring at early stages of marine fish.