Bruguiera gymnorrhiza is an ecologically and somewhat economically important mangrove tree species. We isolated 10 polymorphic microsatellite loci from B. gymnorrhiza using a dual-suppression polymerase chain reaction (PCR) technique. These loci provided microsatellite markers with polymorphism of two to five alleles per locus within 216 individuals from nine natural populations of B. gymnorrhiza on Iriomote Island, the Sakishima Islands, Japan. The expected and observed heterozygosities ranged from 0.220 to 0.720 and from 0.104 to 0.447, respectively.

Betula platyphylla var. japonica is a typical pioneer tree species in the secondary succession in northern Japan. We describe the cloning and characterization of 13 polymorphic, codominant microsatellite loci isolated from this species. These polymorphic loci had 2–8 alleles per locus and a range of expected heterozygosities from 0.050 to 0.808.

Salix reinii Franch. et Savat., a crawl shrub, is one of the most dominant pioneer trees on the southeastern slope of Mt. Fuji, on which an early stage of the volcanic desert succession has been underway since the last eruption in 1707. To investigate the population genetic structure within and among patches of S. reinii, seven polymorphic microsatellite markers were developed by an enrichment procedure. The multiple banding patterns amplified by developed microsatellite markers showed the polyploidy in S. reinii growing on the southeastern slope of Mt. Fuji.

Interactive competition of Pisolithus tinctorius (Pers.) Coker et Couch with an unidentified species Tanashi 01 and Suillus luteus (L.: Fr.) S. F. Gray was investigated using a rhizobox. Pinus densiflora Sieb. et Zucc. was used as the host plant and mycelia were distinguished by hyphal color. The speed of mycelial spread differed between the fungi; P. tinctorius and Tanashi 01 grew faster than S. luteus . A P. tinctorius mycorrhizal seedling and a Tanashi 01 mycorrhizal seedling were transplanted on opposite sides of the rhizobox. The mycelia and mycorrhizae of P. tinctorius were overgrown by Tanashi 01 hyphae and development of P. tinctorius was gradually inhibited. The areas occupied by mycelia and mycorrhiza of P. tinctorius decreased by 52% and 37%, respectively, 154 days after transplantation relative to that at 91 days. In the overlap area of P. tinctorius and Tanashi 01, the latter fungus infected new root tips emerging from P. tinctorius mycorrhiza, which lacked a mantle of P. tinctorius hyphae, and formed a composite mycorrhizal structure. P. tinctorius mycorrhizae were progressively replaced by Tanashi 01 mycorrhizae. Mycelial spread of P. tinctorius and S. luteus were naturally inhibited but there was no interaction in mycorrhizal formation.