Effect Of Ultrasonic Treatment On Protocorm-Like Bodies Morphogenesis And Its Physiological And Biochemical Characteristics Of Oncidium

Oncidium belong to the Orchidaceae family. It was one kind of very beautiful plant favored by international flower markets doubly in recent years. The effect of ultrasonic on plants growth has become one of the important topics recently. It was showed by many researches that lower strength and frequencies of ultrasonic treatment can strengthen some plants' metabolizes process, increase cell membrane permeation property and selectivity, and have advantage to DNA's synthesize and synchronize of the cell period. For the instant needs of the Oncidium seedlings on the market relative to the shortage of the production ability, and for the purpose of further exploring the influence of Ultrasonic on the growth of cells theoretically, Oncidium PLBs and in vitro plantlets were treated with different frequencies for different time to study the effects on morphilogical characteristic and physiological and biochemical characteristics. It has important meaning for promote the production of Oncidium. The results of Experiments were as follows:Tissue culture jar was more suitable for being the ultrasonic treatment vessel than flask in proliferation culture because the average proliferation rate of PLBs was increased about 24.2%. The average proliferation rate of 25kHz ultrasonic treated PLBs groups was higher than the 40kHz ultrasonic treated PLBs groups 23.4%. The effect of 25kHz ultrasonic treatment for 3min was most notable as the average proliferation rate of PLBs was higher than control group about 49.5%. The average number of developed shoots of 25kHz ultrasonic treated PLBs-groups was higher than the 40kHz ultrasonic treated PLBs groups 28.3%. The effect of 25kHz ultrasonic treatment for 6min was most notable as the average number of developed shoots of PLBs was higher than control group about 98.8%. The average roots length and number of 25kHz ultrasonic treated groups was higher than the 40kHz ultrasonic treated groups 10.1% and 13.6%. The effect of 25kHz ultrasonic treatment for 3min was most notable as the average roots length and number was higher than control group about 75.0% and 37.5%.The effect of Ultrasonic on the protecting enzymes activity (SOD, POD, CAT) of Oncidium was notability. The protecting enzyme activity of 25kHz ultrasonic treated 3min PLBs group was higher than other groups in proliferation culture; the protecting enzyme activity of 25kHz ultrasonic treated 6min PLBs group was higher than other groups in differentiation culture; the protecting enzyme activity of 25kHz ultrasonic treated 3min PLBs group was higher than other groups in rooting culture. These results were consistent with the effect of ultrasonic on promoting the proliferation, differentiation and rooting of Oncidium. The inducing of protecting enzymes activity was influenced synthetically by ultrasonic, culture medium and other environmental factors.The content of MDA,soluble sugar and soluble protein in oncidium were influenced synthetically by ultrasonic, culture medium, physiological state of plant and other environmental factors. The lowest MDA content in proliferation, differentiation and rooting culture appeared in 25kHz ultrasonic treated for 6min and 3min groups, and also the highest soluble sugar and soluble protein content. These results were consistent with the activity change of protecting enzymes and the morphilogical characteristic of Oncidium induced by ultrasonic. The MDA content was decreased by ultrasonic. The trend of content change of soluble sugar and soluble protein were opposite.The results of SDS-PAGE showed that the protein content of Oncidium treated with ultrasonic by 3-4min were higher than others. Histology characters showed that the granulose became fewer but the amount of parenchyma cell with eyeable nucleolus became larger and partial cell walls were thickened in Oncidium treated with ultrasonic. This may be related to the effect of ultrasonic promoting the proliferation, differentiation of Oncidium PLBs. Ultrasonic treatment for long of time exceed the cell bearing limit would induce damnification to cells.