Effects of the Ice Bath Time after Heat Shock and the Incubation Time on the Efficiency of Chemical Transformation Method

[Objective] The aim of the research was to study the effect of the ice bath time after heat shock and the incubation time on the transformation efficacy,and to establish a simple and quick transformation method.[Method]Competent cells were prepared with two buffer solutions;with the ice bath time after heat shock and the recovery time as the variables,the relationship between these two factors and transformation efficacy was studied.[Result]The transformation efficacy was the best when the ice bath time was 2 min and the recovery time was 30 or 40 min;when the ice bath time and the recovery time was 0 min,a certain amount of transformants still could be obtained.[Conclusion]The ice bath time after heat shock and the recovery time had certain impact on transformation efficacy,but they were not the decisive factors.Therefore,in the general transformation experiment,these two steps could be omitted.

In vitro morphogenic response of leaf sheath of Phyllostachys bambusoides

Nodal segments from secondary branches of saplings of Phyllostachys bambusoides were inoculated in MS medium to assess the in vitro morphogenic response of leaf sheath through the induction to callogenesis by Picloram（4-amino-3,5,6-trichloropicolinic acid） at different concentrations of carbohydrate under the same conditions with presence or absence of luminosity.In our experiment,secondary explants were kept in MS medium containing 8.0 mg·L-1 of Picloram for the callus formation.Calluses were transferred in MS medium supplemented with sucrose,fructose and glucose（control,2%,4% and 6%）.Results show that Picloram induced the callogenesis in leaf sheath.The secondary embryogenesis was formed in yellow-globular callus.The sucrose as carbohydrate source in the absence of light was more efficient to induce rhizogenesis.Glucose was more efficiency in the presence of light.Callogenic induction and further embryogenesis evidenced the competence and determination of leaf sheath cells.

Responses of the Host Plant Tissues to Gall Induction in Aspidosperma spruceanum Müell.Arg.(Apocynaceae)

The ontogenetic characterization of the leaf galls induced in the internervural region and in the second and third order veins of A. spruceanum Müell Arg. (Apocynaceae) aims to evaluate the distinct levels of cell reaction during the process of gall formation, and the relation between external gall morphology and the oviposition sites. The ground system had the most remarkable alterations, namely, the non differentiation of palisade parenchyma in both leaf sides, the hyperplasia of the spongy parenchyma and the neoformation of fibersclereids, a cell type not observed in non galled leaves. Changes of the feeding sites inside the larval chamber reveal distinct levels of cell competence to respond to the insects stimuli and explain the variations in the shape of the larval chamber.