Studies On High Efficient Regeneration From Strawberry Leaves And Cyto-histological Observation

Factors affecting the high efficient regeneration of adventitious shoots were studied by using leaves of in vitro cultured shoots of widely used strawberry cultivars "Allstar" and "New star", including genotypes, basal media, culture conditions of subculture shoots, methods of inoculation, the length of darkness, light intensity and plant growth regulators. The high efficient regeneration system of adventitious shoots was established. The critical concentration of kanamycin and cyto-histological observation was examined. Main achievements were as follows:1. Regeneration efficencies were same on the basal medium of MS and MS+B5. It indicated the influence of B5 organic matters on induction of leaf disks was not substantial for the two cultivars.2. Cutting the leaf into two parts was an appropriate way of inoculation. Regeneration efficencies were same when the adaxial surface and abaxial surface were kept in contact with the media surface for the two cultivars.3. For "Allstar", newly and fully unfolded young leaves from subculture shoots cultured for 30 to 35 days under 2000 Lx light intensity were most responsive to regeneration. For "Newstar", a period of darkness from 10 to 20 days was necessary to the high efficient regeneration system of adventitious shoots.4. TDZ combined with NAA increased regeneration efficiency dramatically. For the two cultivars of "Allstar" and "New star", the optimal shoot regeneration media was MS supplemented with 1.0~1.5mg/L TDZ and 0.05 mg/L NAA.5. Kanamycin was proved to be an efficient inhibitor for regeneration of strawberry leaves. For "Allstar", the critical concentration of 50mg/L kanamycin could be used to choose transplanted shoots.6. For "Allstar", cyto-histological observations suggested that adventitous shoots originated from epidermal or subepidermal cells near vascular tissue. The original formation of adventitious shoots happened from 4 to 8 days after inoculation.