31,176 research outputs found
Dalla teoria alle buone prassi. Formare per promuovere intercultura. L’esperienza del Master all’Università di Foggia
No full textQuesto volume raccoglie i contributi di quasi tutti i coordinatori della prima edizione dei Master in “Organizzazione e gestione delle istituzioni scolastiche in contesti multiculturali”. Si tratta di un’iniziativa nata all’interno del progetto FAMI 740, finanziato dal Fondo Asilo Migrazione e Integrazione (FAMI), in collaborazione con il Ministero dell’Interno quale Autorità responsabile per l’Italia.
Il contributo a firma Loiodice-Altamura riporta teoria e pratica del master realizzato presso l'Ateneo foggiano
Root histogenesis in herbaceous and woody explants cultured in vitro. A critical review
No full textCompetence, determination and root meristemoid organization are key steps in adventitious rooting. A direct and indirect pattern of root formation may be present in both herbaceous and woody systems. The pattern is indirect when competence is achieved during the culture; it is direct when competent cells are present in the tissues at explanting time. Both processes may be activated in the same (herbaceous or woody) explant, and by the same tissue. A coordinated reactivation to division of cell types not directly involved in the rooting process may occur in the woody cuttings. In general, determination occurs before meristemoid formation; however, the ab initio root identity of the meristemoid has been debated. Examples of herbaceous and woody systems showing one or both rooting patterns are described. Studies on mutations affecting the specification of root meristem and on genes involved in cell cycle regulation could contribute to understanding adventitious rooting
Auxin, photoperiod and putrescine affect flower neoformation in normal and rolB-transformed tobacco thin cell layers
No full textAuxin, photoperiod and putrescine are factors involved in the control of the reproductive phase of the flowering process in planta. The aim of this study was to investigate whether auxin is able, in the absence of other exogenous hormones, to stimulate flower neoformation in Nicotiana tabacum L, thin cell layers excised from flowering plants, whether an interaction exists between the hormone and the length of the light treatment per day, and whether exogenous putrescine interferes with auxin and light in the realization of the flowering programme. Since tissues transformed with rolB gene show an increased binding capacity of auxin, the response of rolB-explants was compared with that of the wild type. Thin cell layers from floral branches were cultured in the presence of a wide range (0-10 mu M) of indoleacetic acid alone, under various phototreatments (continuous darkness, 8 h light/day, and 16 h light/day). Floral, vegetative and rooting responses were favoured in the transgenic explants. Flower neoformation was stimulated by long days and by exogenous auxin (1 mu M). In rolB-thin cell layers flowering also occurred in the most unfavourable culture conditions (i.e. continuous darkness combined with either hormone-free medium or 10 mu M auxin). Long days and 1 mu M auxin also favoured caulogenesis, though to a lesser extent than flower neoformation. Rhizogenesis occurred in rolB-explants only and was induced by exogenous auxin and favoured by continuous darkness, In both wild type and rolB-explants, exogenous putrescine (1 mM) reduced flower neoformation in the presence of 1 mu M auxin and long days. (C) Elsevier, Paris
Responsabilità professionale: un ulteriore fardello per il medico
No full textACTA MEDICA MEDITERRANE
Transition from absolute to quantitative short-day control in Nicotiana tabacum cv. Maryland Mammoth
No full textThe response in vitro of thin cell layers, excised from different stem regions of Nicotiana tabacum cv. Maryland Mammoth plants at various developmental stages, was studied under different photoperiodic treatments. The aim was to determine at which stage of plant development, and in which region of the stem, the absolute short‐day requirement, indispensable for the induction of the flowering process in this genotype, becomes quantitative and whether it remains short‐day. The explants were cultured on a medium suitable for flower neoformation, and were exposed for 30 days to the following treatments: continuous darkness, 8 h light/16 h dark per day, 16 h light/8 h dark per day, and continuous light. The first flowers on explants were observed from plants that were still in the vegetative state, but whose apex showed an accelerated production of axillary vegetative buds, as observed histologically. These explants were excised from the first 10 internodes below the first node with a leaf ≥ 5 cm in length (apical site), and produced flowers only under short‐day treatment. When the apical dome initiated the organization of the terminal flower, the apical site explants developed flowers under both short‐day and long‐day treatments. At the same stage, explants from the 15th to the 20th internode below the first leaf ≥ 5 cm in length also formed flowers, but only under short‐day. When the plant showed a complete inflorescence, flowers were also present on explants from the most basal stem internodes and from the inflorescence branches. At this stage, flower neoformation occurred under all treatments; however, under short‐day the number of explants showing flowers not associated with vegetative buds on the same sample greatly exceeded that observed under other treatments, as did the mean number of flowers per explant (except the basal regions). In conclusion, in the post‐inductive phases of the flowering process, the photoperiodic requirement of this genotype is always short‐day. The superficial tissues of the stem require either absolute or quantitative short‐day treatment, depending on their position on the stem and the stage of evolution of the flowering process in the terminal apex
Agrobacterium rhizogenes rolB and rolD genes: regulation and involvement in plant development
No full textRol genes belong to the T-DNA which is transferred by Agrobacterium rhizogenes into plant cells. Each of these genes affects plant development and is regulated by the host. In this review, after a brief historical background, the most intriguing aspects of past and current research on rolB and rolD genes are highlighted and discussed
Maria Bersani
No full textLa voce illustra la biografia e l'apporto letterario dato da Maria Bersani alla letteratura per l'infanziaThe headword explains the biography and the contribution of the author Maria Bersani to the children's literatur
Unsaturated lipids change in olive tree drupe and seed during fruit development and in response to cold-stress and acclimation
No full textThe olive tree is a plant of economic value for the oil of its drupe. It is a cultigen complex composed of genotypes with differences in cold-hardiness. About 90% of the oil is stored in oil bodies (OBs) in the drupe during the oleogenic phase. Phenols and lipids contribute to oil quality, but the unsaturated fatty acid (FA) fraction is emerging as the most important for quality, because of the very high content in oleic acid, the presence of ω6-linoleic acid and ω3-linolenic acid, and the very low saturated FA content. Another 10% of oil is produced by the seed. Differences in unsaturated FA-enriched lipids exist among seed coat, endosperm, and embryo. Olive oil quality is also affected by the environmental conditions during fruit growth and genotype peculiarities. Production of linoleic and α-linolenic acids, fruit growth, fruit and leaf responses to low temperatures, including cuticle formation, and cold-acclimation are related processes. The levels of unsaturated FAs are changed by FA-desaturase (FAD) activities, involving the functioning of chloroplasts and endoplasmic reticulum. Cold induces lipid changes during drupe and seed development, affecting FADs, but its effect is related to the genotype capability to acclimate to the cold
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