The System Of In Vitro Culture And Shoot Regeneration From Leaves Of Strawberry Cultivars

The stable, efficient plant regeneration system is the prerequisite to success for transformation with Agrobacterium tumefaciens. In this study, the shoot tips isolated from 'Toyonoka' , 'Zoji' , and 'Shuang20' were used as explants. By means of the orthogonal experiment design, analysis of variance and multiple comparisons, the factors including genotypes, basic media, plant growth regulators ,dark periods, AgNO3 concentrations and antibiotics were analyzed and the ideal regeneration system of strawberry (Fragaria ananassa Duch.) by leaf explants was established. The results were as follows:(1)'Toyonoka' was the species of larger shoot regeneration caliber than 'Zoji' and ' Shuang 20' . Through the analysis of regeneration rate, shoots per leaf and the quality of adventitious shoots, the optimal initiation medium for shoot regeneration of each cultivar was respectively as follows:For 'Toyonoka' , shoot regenerated best on MS supplemented with 2.0 mg?L-1 TDZ and 0.8 mg ?L-1 IBA with regeneration rate of 75.67%. For 'Zoji', 8.33% leavesgave rise to shoots on the MS medium containing 2.0 mg昄-1 BA plus 0.4 mg昄-1IBA.(2)CTK played an important role in the shoot regeneration from the leaves of strawberry. TDZ was more effective than BA in inducing shoot regeneration from leaves of strawberry cv. 'Toyonoka' .(3)To compare the effects of four basic media, MS , AS , WPM and QL, on the shoot regeneration from the leaves of strawberry cv. 'Toyonoka' , MS with high salt and N concentrations was more benefitial to the shoot regeneration than the otherswith low or middle salt and N concentrations.(4) Two weeks of dark treatment increased the shoot regeneration rate from 71.67% to 90.09%. However, with the extension of dark periods, the shoot regeneration rate decreased.(5)On the best combination of plant growth regulators for shoot regeneration, theaddition of AgNO3 varied from 2.5 mg L-1 to 10.0 mg L to the medium could nothelp to stimulated shoot regeneration, but it changed the cell differentiational direction in somewhat.(6)Four antibiotics were evaluated for their effects on the producing of adventitious shoot from leaves of strawberry cv. 'Toyonoka' . Exposure to 10.0mg ?L kanamycin, 25.0 mg ?L neomycin or 50.0~100.0 mg ?L ampicillinabsolutely inhibited the shoot regeneration from the leaves of strawberry cv. 'Toyonoka' , in comparison with antibiotic-free medium. The addition of 25.0-50.0mg ?L-1 cefotaxime was of little harmfulness in adventitious shoots production, butmore than 50.0 mg L cefotaxime inhibited adventitious bud regeneration.