Abstract:
Catharanthus roseus, as a medicinal plant, contains more than 100 terpenoid indole alkaloids(TIAs), including vinblastine and vincristine which focus on anti-cancer effects. In order to study the comprehensive influence of exogenous ethylene on growth, physiology, and terpenoid indole alkaloid accumulations,
C.roseus seedlings were cultured as experimental material and contrasted the data of biomass, growth rate of root and stem, photosynthetic parameter and alkaloid contents with or without ethephon treatment, and the correlations between these indexes were analyzed. The ethylene release amount and the expression of
erf(ethylene-response factor) gene were increased under exogenous ethylene treatment. Ethephon inhibited biomass, longitudinal growth but promoted lateral thickening growth of stem; in addition, net photosynthetic rate(
Pn) and stomatal conductance(
Gs) were decreased leading from non-stomatal factor. The biosynthesis of four alkaloids including strictosidine(STR), catharanthine(CAT), vindoline(VIN) and vinblastine(VINB) were accelerated in ethephon-treatment group, and the expression of key enzyme genes(
str and
CrPRX) were up-regulated by ethephon. By correlation analysis, we found that relationships among alkaloid contents, growth indexes and photosynthetic parameters were significant and photosynthetic parameters were significant. It were positive relation between three alkaloids including CAT, VIN, VINB and stem diameter(SD)(
P < 0.05). On the contrary, there was a significantly negative relations between these three alkaloids and biomass(B), height(H), root length(RL), net photosynthetic rate(
Pn)(
P < 0.05). Our study will provide useful information for mechanism research of exogenous ethylene regulating TIAs biosynthesis in
C.roseus.