A method for adventitious shoot regeneration from leaves of micropropagated peach shoots has been developed. Apices were excised from in vitro shoot cultures of a seed-derived (juvenile) genotype (P16Cl5) and mature genotypes (Babygold 6, 842 Standard, San Giorgio and Yumyeong). Apices were cultured 21 days in the dark on a medium supplemented with 6-benzyladenine and α-naphthaleneacetic acid and then transferred to an auxin-free medium and incubated in the light for 21 days. The first four apical leaves were excised from these apices and cultured in the same way. During the dark incubation period, leaves developed a callus at the petiolar base. Adventitious shoots appeared on this callus after transfer to auxin-free medium and culture under light conditions. The morphogenic ability of the callus was maintained for several months.

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To determine the optimum conditions for Agrobacterium-mediated gene transfer, peach explants including cotyledons, embryonic axes and hypocotyl slices from non-germinated seeds and epicotyl internode slices from germinating seeds were exposed to Agrobacterium-mediated transformation treatments. The GUS (uidA) marker gene was tested using two different A. tumefaciens strains, three plasmids and four promoters [CaMV35s, (Aocs)3AmasPmas (''super-promoter''), mas-CaMV35s, and CAB]. GFP was tested with six A. tumefaciens strains, one plasmid (pLC101) and the doubleCaMV35s (dCaMV35s) promoter. The CaMV35s promoter produced more GUS expression than the CAB promoter. A. tumefaciens strains EHA105 and LBA4404 harboring the same plasmid (pBIN19) differed in their effects on GUS expression suggesting an interaction between A. tumefaciens strain and plasmid. A combination of A. tumefaciens EHA105, plasmid pBIN19 and the CaMV35s promoter produced the highest rates of transformation in peach epicotyl internodes (56.8%), cotyledons (52.7%), leaves (20%), and embryonic axes (46.7%) as evaluated by the percentage of explants expressing GUS 14 days after co-cultivation. GFP expression under the control of the dCaMV35s promoter was highest for internode explants but only reached levels of 18-19%. When GFP-containing plasmid pCL101 was combined with each of five A. tumefaciens strains the highest levels of transformation were 20-21% (internode and cotyledons, respectively). When nine peach genotypes were co-cultivated with A. tumefaciens strain EHA105 and GFP-containing plasmid pCL101 the highest levels of transformation were 26-28% (cotyledons and internodes, respectively). While GFP represents a potentially useful transformation marker that allows the non-destructive evaluation of transformation, rates of GFP transformation under the conditions of this study were low. It will be necessary to optimize expression of this marker gene in peach.Abbreviations: BA -benzyladenine; CAB -chlorophyll a/b binding protein promoter; CaMV35s -cauliflower mosaic virus promoter; GUS -beta-glucuronidase; LB -Luria Broth base; NPTII -neomycin phosphotransferase

AIM A randomised field trial was conducted to evaluate a school-based programme to prevent tobacco use in children and adolescents. SUBJECT AND METHODS Five hundred and thirty-four children and three hundred and eight adolescents were randomly select to receive or not receive the prevention programme. The prevention programme included: a) health facts and the effect of smoking; b) analysis of the mechanisms to start smoking; c) refusal skills training to deal with the social pressures to smoke. A questionnaire was administered before the intervention programme and two years later. RESULTS The prevalence rates of smoking in both group of children and adolescents resulted to be increased at the end of the study. Anyway, the difference of smoking prevalence between intervention and control group was statistically significant only for children group (from 18.3% to 18.8% for the intervention group, and from 17.8 % to 26.9% in the control group) (p = 0.035). As regards reasons that induced to start smoking, there was a significant increase of the issue "Because smokers are fool" (p = 0.004 for children; p < 0.001 for adolescents) and "Because smokers are irresponsible" (p ≤ 0.001 for both children and adolescents) in the experimental groups. CONCLUSION The results suggest that a school-based intervention programme on children and adolescent tobacco use, based on the development of cognitive and behavioural aspects, can be effective. After one year of intervention, smoking prevalence was significantly lower in children belonging to intervention group than in children not randomised to intervention. Targeting young children before they begin to smoke can be a successful way of prevention. AbstractAIM A randomised field trial was conducted to evaluate a school-based programme to prevent tobacco use in children and adolescents.SUBJECT AND METHODS Five hundred and thirty-four children and three hundred and eight adolescents were randomly select to receive or not receive the prevention programme. The prevention programme included: a) health facts and the effect of smoking; b) analysis of the mechanisms to start smoking; c) refusal skills training to deal with the social pressures to smoke. A questionnaire was administered before the intervention programme and two years later. RESULTSThe prevalence rates of smoking in both group of children and adolescents resulted to be increased at the end of the study. Anyway, the difference of smoking prevalence between intervention and control group was statistically significant only for children group (from 18.3% to 18.8% for the intervention group, and from 17.8 % to 26.9% in the control group) (p = 0.035). As regards reasons that induced to start smoking, there was a significant increase of the issue "Because smokers are fool" (p = 0.004 for children; p < 0.001 for adolescents) and "Because smokers are irresponsible" (p ≤ 0.001 for both children and adolescents) in the experimental groups. CONCLUSIONThe results suggest that a school-based intervention programme on children...

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