Cristina Vettori

... and dispersal-vicariance analyses indicated that the ancestral area of speciation of Castanea ... Jaynes (1975) hypothesizes that chestnut arose in China, and, accordingly, the native Chinese species ... migrations during the Tertiary period of the two species should have originated ...

ABSTRACT The aim of this study was to develop a cryogenic procedure for the conservation of an ancient Citrus collection, maintained at the botanical garden of the "Villa Medicea di Castello" in Florence, Italy. The collection was initiated by Cosimo I de' Medici in the 16th century, and it includes more than 600 accessions, conserved mainly in big earthenware basins. An effective procedure of seed dehydration and direct immersion in liquid nitrogen was developed for a sample of five polyembryonic Citrus accessions, i.e., C. aurantium 'Foetifera', C. volkameriana, C. lumia 'Pyriformis', C. sinensis and the hybrid C. aurantium x C. parodisi. The initial seed moisture content was between 33 and 55%. Seed dehydration was performed in open Petri dishes, exposed to sterile air flow. All the accessions showed adaptability to seed cryopreservation, after the seeds were appropriately dehydrated between 25 (C. lumia) and 15% (C. aurantium x C. paradisi). Maximum post-freezing germinability ranged from 27 (C. aurantium) to 100% (C. aurantium x C. paradisi). In general, one seedling per seed was obtained after the dehydration/cryopreservation procedure. Molecular analysis showed the nucellar origin of seedlings. Only in C. volkameriana the occasional development of zygotic embryos was pointed out.

The effect of UV radiation on the survival of and transduction by phage PBS1 of Bacillus subtilis, free or adsorbed on the clay minerals montmorillonite (M) and kaolinite (K), was studied. After free or clay-associated phage (approximately 10(7) PFU.mL-1) was irradiated with UV light (254 nm) for 0, 1, 2, 5, 10, and 30 min and then allowed to infect B. subtilis FB300 (thiB4 metA29 argF4 Rfmr), the phage was titered, and Met+ transductants were enumerated on selective media. After 1 min of irradiation, the titer of free and clay-associated phage decreased significantly (approximately 1.6 times for free phage, and approximately 4.9 and 6.8 times for M and K, respectively), whereas the transduction frequency increased significantly (approximately 3 times for free phage and approximately 1.4 and 2.2 times for M and K, respectively). The titer and transduction frequency of clay-associated phage remain essentially constant between 1 and 10 min of irradiation, whereas the titer of free phage decreased by approximately 1 order of magnitude after 5 min of irradiation. When free phage was irradiated for 10 min, the titer and transduction frequency decreased by approximately 2 and 0.5 orders of magnitude, respectively, whereas 30 min of irradiation was necessary to obtain comparable decreases with clay-associated phage. These results indicated that phages are protected to some extent from UV radiation when adsorbed on clay minerals.

The fine-scale assessment of both spatially and non-spatially distributed genetic variation is crucial to preserve forest genetic resources through appropriate forest management. Cryptic within-population genetic structure may be more common than previously thought in forest tree populations, which has strong implications for the potential of forests to adapt to environmental change. The present study was aimed at comparing within-population genetic structure in European beech (Fagus sylvatica L.) plots experiencing different disturbance levels. Five plot pairs made up by disturbed and undisturbed plots having the same biogeographic history were sampled throughout Europe. Overall, 1298 individuals were analyzed using four highly polymorphic nuclear microsatellite markers (SSRs). Bayesian clustering within plots identified 3 to 11 genetic clusters (within-plot θ ST ranged from 0.025 to 0.124). The proportion of within-population genetic variation due to genetic substructuring (F CluPlot = 0.067) was higher than the differentiation among the 10 plots (F PlotTot = 0.045). Focusing on the comparison between managed and unmanaged plots, disturbance mostly explains differences in the complexity of within-population genetic structure, determining a reduction of the number of genetic clusters present in a standardized area. Our results show that: i) genetic substructuring needs to be investigated when studying the within-population genetic structure in forest tree populations, and ii) indices describing subtle characteristics of the within-population genetic structure are good candidates for providing early signals of the consequences of forest management, and of disturbance events in general.

... Parole chiave: Fagus sylvatica; diversità genetica; bosco vetusto; trattamenti selvicolturali. ... to the presence of a series of successional of structural and descriptive phases of biomass repartition. ... del legno morto in soprassuoli non gestiti: il caso di “Bosco Pennataro”, Alto Molise. ...

... Fusi P., Ristori G., Calamai L. and Stotzky G. (1989) Adsorption and binding of protein on "clean" (homoionic) and "dirty" (coated with Fe oxyhydroxides) montmorillonite, illite and kaolinite. ... Graham JB and Istock CA (1978) Genetic exchange in Bacillus subtilis in soil. ...

... and 0.1 ml of serial 10-fold dilutions of the heated supernatants was plated on a semi-selective medium of Nutrient Agar (NA, 1.5% agar; Difco) containing 5 μg ml −1 of polymyxin B sulfate and 4 μg ml −1 of penicillin G, to facilitate the selection of B. thuringiensis ([Saleh et al ...

Culturable bacteria were isolated from seeds, embryos and contaminated in vitro cultures of ash (Fraxinus excelsior L., F. ornus L. and F. angustifolia L.) and were identified using morphological and molecular analyses. Fourteen morphologically distinct isolates were recovered from seeds of Fraxinus spp. 16S rDNA sequencing categorised these isolates into ten separate genera. Three strains isolated from contaminated in vitro cultures, Pantoea agglomerans, Staphylococcus succinus and Aerococcus viridans, were used for comparative analysis with isolates from seeds. Antibiotic sensitivity testing of the isolated contaminants, including phytotoxicity of antibiotics on in vitro cultures of ash, was also investigated. Phytotoxic effects on explants immersed in ampicillin or cultured on medium containing ampicillin were negligible, however tetracycline, either alone or in combination with other antibiotics, had phytotoxic effects. We conclude that ampicillin is a suitable antibiotic to limit the growth of contaminating bacteria during the in vitro culture of ash.

... By P. SALEHI SHANJANI1, C. VETTORI2, R. GIANNINI2 and RA KHAVARI-NEJAD3 (Received 21st May 2003) 1) Dr. PARVIN SALEHI SHANJANI, Member of scientific board at Forest Research Division Research Institute of Forests and Rangelands, PO Box 13185-116, Tehran ...