Preliminary Study On⁶⁰Co-γ Irradiation Of Gerbera Jamesonii

In this experiment, the callus, shoot tips and tube plantlet of Gerbera jamesonii were used as materials for different Co-y ray doses. Callus, shoot tips and tube plantlets were treated as following doses:0Gy、5Gy、10Gy、15Gy、20Gy、30Gy. OGy was used as control. The irradiation sensitivity of different materials was studied. In order to analyze the influence of different irradiation doses on the growth and mutation, the main characteristic and mutation of regeneration plants were observed. Finally, using SRAP molecular markers technology identified the mutant plants. The main research contents and results were as follows:1. Effect of different doses on callus, shoot tips and tube plantlets. Results showed that under the low irradiation doses of5Gy, the injury of materials was not apparent. It had a promoting influence on the growth of shoot tips. When irradiation doses were higher, different irradiation materials susceptibility to irradiation from high to low in turn was:callus> shoot tip> tube plantlet. Under the dosage of15Gy, the irradiation treatment of callus differentiation rate was45.9%, the rooting rate was61.5%, so the15Gy is the suitable irradiation doses for callus; Under the dosage of20Gy, the irradiation treatment of shoot tip budding rate was45.0%, the rooting rate was56.4%, so20Gy is the suitable irradiation doses for shoot tips; under the dosage of30Gy, survival rate of tube plantlet was76.25%, the rooting rate was36.67%, so30Gy is the suitable irradiation doses for tube plantlets.2. Effect of irradiation treatment on transplanting survival rate and growth condition of regeneration plants. Source from callus regeneration plants (M-1) transplanting survival rate was higher than the source of shoot tip regeneration plants (M-2). Plant height and crown of M-1rises with the increase of radiation doses, processing of5Gy,10Gy plants height and crown breadth were smaller than controls, and processing of15Gy,20Gy plants height and crown breadth were greater than the controls; On the other side, M-2plants height and crown breadth decreased with the increase of irradiation doses. The plants grow very slow.3. The influence of different irradiation doses of M-1flowering. Flower diameter increases with the increase of irradiation doses, the diameter of15Gy、20Gy plants were greater than controls; Peduncle lengths were decreased with the increase of doses, from5Gy to20Gy, the peduncle lengths shortened from34.32cm to29.23cm, the control was35.48cm; Pedicel diameter increases with the increase of irradiation doses, from5Gy to20Gy, pedicel diameter increased from0.81cm to0.95cm, the control was0.76cm. There were no big differences with low doses processing plants and control on beginning flowering date. But the processing of15Gy plant beginning flowering date was earlier25days than control; the processing of20Gy plant beginning flowering date was delayed25days.4. The main mutation types of the leaves and flowers. Mutation types of leaves are as follows:leaf thickening, pinnate division decrease, pointy edges, foliar distortion fold; Mutation types of follows are as follows:widen ligulate flower petals, split at the top, or ligulate flower petals curling, narrowed, ligulate flowers by2-3rounds down to1-2rounds, color becomes shallow. The types of mutation plants had little relevance with the irradiation doses.5. SRAP analysis of mutant plants. Using SRAP technology,8of random primers were choose to amplify the DNA of mutation plants.8primers were amplified out of54bands,34bands were polymorphism bands, the polymorphism rate was62.9%. Results show that after irradiation, the plants have varying degrees of changes in gene sequences.