Research Interests †

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1. Phylogeography of Pantropical Plants with Sea Drifted Seeds †

Almost all flowring plants can not move by themselves, but they cast their seeds or fruits by several ways to attain new domain. The geographic distance attained by seed dispersal are generally limited because of the media, such as, winds, water, animal, etc., so that the distribution areas of plants itself are mostly limited. This is the reason that we meet lots of endemic plants, even if we visit a certain mountain area in Honshu Isl. of Japan. -- The dispersal range is mostly limited in Plants.--
ipomoea.jpg

However, some plants have really wide distribution on the earth, and Pantropical Plants with Sea Drifted Seeds (PPSDS) are one of the plants that have most intriguing distribution areas. Ipomoea pes-caprae (Convolvulaceae), Canavalia rosea (Leguminosae), and Hibiscus tiliaceus (Malvaceae) are the top three member of PPSDS that are perhaps less than 6 species in total. PPSDS are littoral plants that have very wide distribution range in tropics. The three species and their close allies have almost overlapping distribution range in the coastal areas of tropical to subtropical area on the earth. Imagine this. How can a plant species that grow in the beautiful sandy beach of Rio de Janeiro can interact with the one in Okinawa Isls. in Japan? The geographic distance between the two localities is about 20,000km! This is the problem we are currently working on. We focus on these three species and collect materials from their populations in tropics world wide, and to reveal the level of gene flow than are maintained by Sea-Drifted seeds. Our goal is to figure out the level of recurrent gene flow by sea-drifted seeds, to maintain the unity of a species in the distribution area around the earth in tropics.