Effect Of Stress On The Metabolism Of Dendrobium Candidum & Primary Study In Molecular Biology

Nowadays, the effect of environmental factors on the growth of plant has become one of the hot researches in plant physiology and biological physics. In terms of finding out some researches on. the process in which how environment affect botanic metabolism, how plant would receive the stress signals and how these signals induce the expression of genes of plant regulated metabolic pathway, we cannot receive some satisfactory outcomes. Dendrobium candidum is a rare and endangered Chinese herbal medicine. It mainly contains polysaccharide and total dendrobine that can improve the capacity of immunity and delay the cell aging. As the relevant research work indicated, with variations of environmental factors, the pathway of photosynthesis of Dendrobium candidumcovld change foundationally between CAM and C3 pathway which affect the content of polysaccharide etc. For the purpose of further exploring the influence of stress on the botanic metabolism theoretically and of finding a new way in the breeding and the improvement of plant varieties in application, in this paper, using sound wave stimulation as a loading manner and the young plant of Dendrobium candidum as materials, we analyzed the influence of stress on the botanic metabolism basing on the content of metabolism product and the differential gene expression of Dendrobium candidum under the stress, at the same time researched preliminary on the relationship between stress and botanic metabolism. Then the main contents and the results of the research are as follow:To begin with, the influence of sound wave stimulation on the content of metabolism product of Dendrobium candidum had been examined, and the results showed that, under the frequency of 1000Hz and the intensity of 100dB, the polysaccharide formation would get the most obvious acceleration, but small impact on the total dendrobine.Secondly, through investigation, we noted that the normal photosynthesis and respiration were notable influenced by sound wave. The result indicated that the changes between CAM and C3 pathway of photosynthesis of Dendrobium candidum could are possibly induced in the effects of the sound wave on the plant, the CO2 uptake rate are enhanced and improved the content of polysaccharide.Thirdly, we measured and analyzed the differential expression of the chrysanthemum gene responded to the sound wave. The results showed that the yieldrate of total RNA is larger in the treated group than that in the control group, and the differential expression gene can be detected. With the total RNA extracted from the treated group and the control group, mRNA reverse transcription differential display PCR(DDRT-PCR) is applied to screen out the differential expression gene fragments induced by the sound wave. Differential expression gene fragments are isolated by the polypropylene acyl gel electrophoresis and be re-amplified. The five bands (SA5, SA8, SC3, SC8, CC7) can be seen from the agarose gel. Northern dot hybridization is used to further confirm whether the screening bands are induced by the sound wave or not. The results revealed that after the SA5, SG3 and CC7 hybridized with total RNA of the treated group and the control group, they were developed clearly on the film in the treated group only, however, the SC3 was not, which indicted that the SC3 was fake positive. And SA8 were developed clearly on the film both treated group and the control group. CC7 was an inhabitation expression band. The molecular weight of SA5, SG3 and CC7 were approximately 370bp, 410bp and 500bp respectively. These imply the influence of stress on the metabolism of Dendrobium candidum are possibly controlled by the differential genes.