Determination of allelopathic potentials in plant species in Sino-Japanese floristic region by sandwich method and dish pack method

The Sino-Japanese Floristic Region appears as one of the major centers of development of higher plants. This region have been relevant for the study of evolution and systematics of many flowering plants. The taxonomic richness of endemic plant species in this region have survived several years of extreme climate conditions. Endemic mountainous plant species that have survived extreme climate conditions are of allelopathic and medicinal interest. For this reason, 251 plant species collected from the Sino-Japanese Floristic Region were screened for allelopathic plant species. Sandwich method and dish pack method were respectively used to screen plant leaf leachates and volatile materials with lettuce ( Lactuca sativa CV. Great Lakes 366) as receptor plant. Among the 84 species that showed inhibitory effect on lettuce radicle elongation in our sandwich bioassay, Photinia glabra showed complete inhibition of lettuce radicle elongation (0% radicle elongation). In the dish pack bioassay, Photinia glabra , Liquidambar styraciflua , and Cinnamomum camphora (90.6%, 61.4%, and 50.2% respectively) were among the nine species that were observed with strong inhibitory effect on lettuce radicle growth. On the other hand, nine other species promoted lettuce radicle growth when compared to the control. Aesculus turbinata and Quercus gilva were the species with the highest growth stimulatory effect (33.0% and 16.1% respectively). We hereby present Photinia glabra as an allelopathic candidate species for both leachate and volatile compounds.