ALLELOPATHIC EFFECT OF β-CEMBRENEDIOL AND ITS MODE OF ACTION: INDUCED OXIDATIVE STRESS IN LETTUCE SEEDLINGS
β-cembrenediol((1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol), shown to be one of the most important allelochemicals of tobacco in our previous studies, effectively inhibited the root and shoot elongation of receptor plants in a concentration-dependent manner. However, its mechanism of action remains unclear. Seedlings of lettuce (Lactuca sativa) were now treated with β-cembrenediol to clarify its mode of action. Results showed that β-cembrenediol significantly inhibited the seeding growth and reduced fresh weight of L. saiva. The compounds effectively arrested cell division and caused cell death. Exposure to β-cembrenediol induced overproduction of reactive oxygen species. Moreover, increased levels of malondialdehyde, proline and hydrogen peroxide, and decreased in chlorophyll content indicated lipid peroxidation and induction of oxidative stress. These results suggested that β-cembrenediol caused oxidative damage through enhanced generation of ROS, as indicated by increased lipid peroxidation, disruption of membrane integrity and impacted mitosis, ultimately resulted in growth inhibition of the receptor plant.