Browsing by Autor "Isa Grilli"

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Ageing in embryos from wheat grains stored at different temperatures: oxidative stress and antioxidant response
(CSIRO Publishing, 2011) Carmelina Spanò; Stefania Bottega; Roberto Lorenzi; Isa Grilli
In the present work we studied oxidative stress as an important cause of seed deterioration during ageing in embryos from durum wheat grains stored at room temperature and at low temperature (10°C). The protective role of low temperature on seed viability was confirmed. The increase of hydrogen peroxide content during dry storage was strongly correlated with the decrease of germinability. Ascorbate and glutathione showed a good correlation with grain germinability and significantly increased upon imbibition, in particular in embryos from viable grains. Ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX) and catalase (CAT) were studied quantitatively (enzymatic assays). APX, GR, and GPX were also studied qualitatively by native PAGE. The enzymes were active in dry, still viable, embryos whereas no activity was detected in non-viable embryos. With the exception of APX, all enzymatic activities decreased upon imbibition. The study of grains stored in different conditions indicated a negative correlation between the efficiency of the antioxidant enzymatic machinery and the age of the grain. The differences detected in differently stored materials confirmed that both germination parameters and the length of storage period are important in determining grain condition.
Morpho-physiological plasticity contributes to tolerance of Calluna vulgaris in an active geothermal field
(CSIRO Publishing, 2013) Gianni Bartoli; Stefania Bottega; L. M. C. Forino; Monica Ruffini Castiglione; A. M. Tagliasacchi; Isa Grilli; Carmelina Spanò
Geothermal alteration fields are very prohibitive environments, limiting vegetation establishment and growth. In the present study, the ecological specialisation of the pioneer plant Calluna vulgaris (L.) Hull was investigated, assuming that its ability to survive in geothermal habitats derives from a fine regulation of morpho-physiological traits. Mature leaves of C. vulgaris were sampled from plants close to a fumarole (near), and from plants living at a distance of some metres (intermediate) or ~1 km (distant) from a fumarole. Along the sampling sites, a gradient of soil-pH and temperature values occurred, with near plants facing the highest soil temperature and the lowest soil pH. A regulation of constitutive morpho-anatomical and physiological traits in response to different stress levels occurred. A progressive reduction of leaf exposed surface and hair density and mucilages, combined with a gradual increase of oxidative stress levels, of phenols and ascorbate, was observed from distant to near plants. Near plants showed an increase in stomatal density and in lignin and cuticle thickness, and the highest activity of ascorbate peroxidase. Except for high glutathione concentrations, in distant plants antioxidant machinery was consistently less active. The apparent morphological and physiological plasticity demonstrated in the present research contributed to the capability of these plants to tolerate the prohibitive, highly changing environmental conditions of the geothermal field.