Ecophysiological Characteristics Of Phytohormone In Different Plant Life Cycle Forms In Catharanthus Roseus

The endogenous hormones (GA₃, IAA, ABA and ZR) of Catharanthus roseus by ELISA analysis, the ecophysiological characteristics of phytohormone and hormonal balance in different plant life cycle forms of C. roseus were studied in this paper. By dynamic changes of endogenous hormones, we discussed the regulatory effect of hormone and the significance of hormonal balance in different plant life cycle forms of C. roseus.The parameters of the vegetative growth, the clonal reproduction and the sexual reproduction of the natural, fertilizable, drought stress and pruning stress conditions were analyzed by the principal component analysis (PCA), and the life cycle forms are determine by score proportion of PCA. The results showed that by contrast with normal condition(V_0.492309S_0.390092C_0.117599), the life cycle form of fertilizable condition (V_0.599322S_0.396201C_0.004477) was V form in the mass, that of drought stress condition(V_0.368282S_0.458116C_0.173603) was S form, and that of pruning stress conditions (V_0.484328S₀C_0.515672) was C form in the mass. In three typical plant life cycle forms, the content of endogenous GA₃ and IAA were both high but that of ABA was low in the fertilizable condition(V form);and the content of GA₃ and IAA were low but that of ABA was high in drought stress condition(S form);three endogenous hormones were all very high in pruning stress condition(C form), because under the heavy pruning stress all energy supports to clone reproduction.In flowering differentiation (transforming from Vegetative growth to sexual reproduction), GA₃ played an inhibition role while IAA and ABA played a promotion role. Under 28℃ and 40℃, the ratios of endogenous hormones GA₃/ABA and IAA/ABA were all decline, it suggested that the vegetative growth was inhibited, and the sexual reproduction transformation was suitable in 40℃ than 28℃. Under 2 and 6 illuminations, the ratios of endogenous hormones GA₃/ABA and IAA/ABA were all decrease which restrained the plant vegetative growth. The decreasing tendency of GA₃ and IAA was found, and ABA increased in excised drought stress condition, this may contribute to transform from V to S form. The ratios of endogenous GA₃/ABA and IAA/ABA were increase with the treatment of endogenous hormones rapidly affected by the exogenous hormone and dip in exogenous GA₃, the development of plant trended to vegetative growth, and the ratios of endogenous GA3/ABA and IAA/ABA were decline with dipped in ABA,, it favors to sexual reproduction. it can improve the growth of node by exogenous GA₃ on leaves, while improving plant resistance and promoting abloom by exogenous ABA.