Poster: Hormones

Abs # 626: Allelopathic properties of narciclasine and its mode of action

Presenter:	Wong, Chi-Fai
Authors	Wong, Chi-Fai  (A)   Wong, Yum-Shing  (A)
Affiliations:	(A): The Chinese University of Hong Kong

Narciclasine (NCS) is an alkaloid isolated from the bulbs of Narcissus tazetta L. In our previous studies, we first reported the inhibitory effects of NCS on various growth and developmental processes in plants including seed germination, cotyledon expansion and chlorophyll synthesis. Most current research on NCS focuses on its chemical synthesis and potential use as anticancer drug, and very limited information is available on its physiological role and mode of action. In this research we demonstrated NCS's allelopathic properties by inhibiting seedling growth of both dicot and monocot species. NCS at 10^-6M significantly inhibited root growth of mung bean and maize seedlings. These inhibitory effects were concentration-dependent. However, NCS did not affect Narcissus cell growth. In cell culture, NCS (10^-4M) inhibited callus growth of carrot and tobacco but not Narcissus. Anti-mitotic activity of NCS was observed using shallot root tip smear technique. The number of shallot root tip meristematic cells undergoing mitotic division (including prophase, metaphase, anaphase and telophase) was reduced from 56% in the control to 38% when treated with 10^-4M NCS for 1 h. The mode of action of NCS as protein synthesis inhibitor was tested. Results showed that NCS inhibited in vitro translation in both wheat germ and rabbit reticulocyte lysate systems. (Supported by CUHK Research Committee Direct Grant to YSW)