Advances of research on allelopathic potencial of terpenoids in plants

Terpenoids widely exist in higher plants as volatile oil,especially in Compositae family.They have the largest variety of plant secondary metabolization products and are classified into monoterpene,diterpene,sesquiterpene,triterpene and polyterpene according to their structures.Terpenoids are one of the main types of allelochemicals,of which monoterpene and sesquiterpene have stronger bioactivities.The synthesized terpenids are mainly released from plants into soil through volatilization or root exudation and disturb the growth and development of neighboring plants and selfish.Currently,the allelopathy on terpenoids had received increased attention in plant ecology field in China and abroad.This paper made a systematic discussion on the distribution of trpenoids,accumulation characteristic,releasing pathways in plants and its impact factors,etc.And it analyzed the allelopathic mechanism of trpenoids and summarized the research progress in this area in recent years.The paper considered that the trpenoids played a special role on allelopathic activity and exhibited a stronger inhibitory even though the concentration was lower.The complicated allelopathy of terpenoids may be due to their wide varieties.Moreover,many factors all influenced the releasing of terpenoids.Finally,the paper pointed out some key problems in current researches and also made a prospect for the research trends in the future on the allelopathy of terpenoids.It is suggested that further study should be focused on the collecting method of terpenoid allelochemicals and the influences of transformed medium such as soil or air on allelopathic activity.In addition,it is effective and feasible to study allelopathic mechanism of terpenoids through the solution of discipline-crossing.