Allelopathic activity of camphor released from camphor tree (Cinnamomum camphora)

The allelopathic activity of camphor tree (Cinnamomum camphora Sieb.) was studied to determine the behaviour of allelochemicals released from the leaf powder into air and soil in laboratory. Growth of rice seedlings, as a receiver plant, was inhibited in soil incorporated with the leaf powder and in sea sand applied with the soil water from the leaf powder-incorporated soil. (+)-Camphor was detected in soil water from the soil incorporated with the leaf powder and was considered an allelochemical released from camphor tree. The phytotoxic activity of leaf powder and of (+)-camphor in soil coincided with the concentration of (+)-camphor in soil water. It was suggested that the allelopathic activity of (+)-camphor in soil treated with the leaf powder was principally induced by (+)-camphor which was released from the leaf powder into the soil and additionally by absorption of (+)-camphor from the air through the stomata.