Propagation characteristics and method of appropriate management of invasive alien species Iris pseudacorus L.

To establish a proposal for a guiding principle supporting appropriate management of Iris pseudacorus L., which had been used as an important vegetation bank species until the Invasive Alien Species Act, this study investigated propaga-tion characteristics. The seed in which seed coat cracked germinated earlier, and it was shown that their cumulative germination percentage was high even under 30 °C constant conditions. When the fresh weight of the rhizome cut pieces in the spring became greater than 15 g, the individual plant flowering rate increased gradually. Individuals of more than 30 g achieved a flowering rate higher than 76 %. The flow-ering rate was highest for individual plants that had two green leaves, but it became progressively lower for increas-ing numbers of green leaves：non-flowering individuals grew better than flowering individuals. In the 0 cm height scape-cutting treatment, no significant difference was found in the numbers of flowers and fruits the next year. In the 5 cm height top-cutting treatment, the flowers and fruits in the next year were significantly fewer.

研究紹介(Research Reports)