The Effect Of Exogenous Ethylene On Growth And Alkaloid Accumulation In Catharanthus Roseus

Catharanthus roseus contains more than100kinds of alkaloids, of which there are many species also has medicinal hotspot, such as vinblastine which has anticancer effect and vindoline, a drop of lowering blood pressure and blood lipid effect, especially anticancer role has been scientists and medical researchers target. Studies have shown that vinblastine cannot be produced by cell culture in vitro synthesis in plants; therefore, exploring methods of alkaloid rise in Catharanthus roseus has important significance. Ethylene is a plant hormone, which has a certain effect to metabolism regulation on plant itself. In this paper, using different concentrations of ethephon in Catharanthus roseus seedlings, we observe effect of ethylene on physiological metabolism of Catharanthus roseus phenotype, especially medicinal active ingredient effect of alkaloids and related gene expression. The main results as follow:1、The effect of different concentrations of ethephon on morphology and biomass in Catharanthus roseus had significant influence. Inhibition of Catharanthus roseus plant height and root length, and increase of stem diameter, root weight and root shoot ratio with ethylene concentration rising could be more and more obvious. To biomass:5μM～45μM ethephon made biomass per plant increased;60μM and100μM ethephon made biomass per plant reduced.2、The effect of different concentrations ethephon on ROS and antioxidases in Catharanthus roseus leaves had significant influence. Overall, ethephon could decrease the level of ROS and promote the content of various antioxidases in Catharanthus roseus leaves, in which the contents of various antioxidases were highest under60μM ethephon and the level of ROS was lowest.3、The effect of different concentrations ethephon on photosynthesis characteristics in Catharanthus roseus leaves had significant influence. Net photosynthetic rates were increase under5μM～45μM ethephon, and5μM and15μM ethephon made transpiration rate declined which benefited to water conservation;60μM and100μM ethephon made net photosynthetic rate of descent which was caused by non stomatal factors. To photosynthetic pigment,5μM～45μM ethephon increased the contents of chlorophyll, and carotenoid also increased;60μM and100μM ethephon made chlorophyll content decreas-ed, and carotenoid content increased significantly.4、The effect of different concentrations ethephon on the contents of three kinds of alkaloid including vindoline, catharanthine and vinblastine in Catharanthus roseus leaves had significant influence. The contents of vindoline and catharanthine were decreased under ranging from5μM to45μM ethephon, contents of vinblastine were gradually increase; 5、ethephon the contents of three alkaloids were significantly elevated under60μM and100μM ethephon.6、The effect of different concentrations ethephon on gene expression related to alkaloid synthesis catalyzed enzyme and peroxidase in Catharanthus roseus leaves had significant influence. Expressions of gene str and dat were "down then up" with ethephon concentration elevating. In12hours and24hours, expressions of gene str and dat were gradually decreased under5μM～45μM ethephon, but60μM and100μM ethephon could make the expression quantity to rise significantly. Overall, prx expression quantities with Ethephon concentration was increased, which60μM ethephon made expression level highest.7、Correlation analysis of the alkaloid content and genes expression was carried out. The results showed that the correlation between vindoline content and the expression of dat related to enzymes which catalyzed vindoline synthesis was significantly. In addition, the correlation between catharanthine content and the expression of prx related to enzymes which catalyzed catharanthine synthesis was significantly.