Abstract:

To study the response mechanisms of Lolium perenne and Poa pretensis to allelochemicals stress in Wedelia trilobata, seeds and seedlings of the two plants were treated with extracts from Wedelia trilobata in different concentrations, and the germination rates (Gr), germination energies (Ge), germination indexes (Gi) of seeds and growth characters of seedlings were compared between the two plants. The results showed that when the extract concentration was 0.01 g/mL, Gr, Ge and Gi of Lolium perenne seeds were not influenced while these indexes of Poa pretensis seeds all increased, then these indexes of the two plant seeds all decreased when further raise of the extract concentration. With the increase of extract concentration, radicel length of Lolium perenne decreased more rapidly than that of Poa pretensis, and number of the two plant seedlings capable of generating one or two secondary roots declined gradually, the embryo length of Lolium perenne seedlings tended to be reinforced first then descended abruptly, whereas Poa pretensis seedlings showed a gradually reduced growth tendency. As the results showed, Poa pretensis could adaptively respond to the low stress under the allelochemicals in Wedelia trilobata by increasing Gr, Ge and Gi, whereas compensatory growth of embryo was responsible for the adaptive response of Lolium perenne.