Development of microsatellite markers for Dryobalanops aromatica (Dipterocarpaceae), a tropical emergent tree in Southeast Asia

Eight polymorphic microsatellite markers were developed in Dryobalanops aromatica, an emergent tree in tropical rain forests in Southeast Asia, using an enriched library method. For the assessment of microsatellite variation, 36 individuals from a natural population were analysed. The number of alleles per locus ranged from three to 16, with observed heterozygosity of 0.056–0.833 and expected heterozygosity of 0.054–0.882. These microsatellite markers will be useful for studies of population genetics, reproductive ecology and regeneration dynamics of D. aromatica.     

Sprouting traits and population structure of co-occurring Castanopsis species in an evergreen broad-leaved forest in southern China

The role of sprouting in regeneration was compared betweenfour co-occurring Castanopsis species in an evergreen broad-leavedforest in southern China. We considered the largest stem of an individualto be the main stem, while all of the other stems were consideredto be sprouts. To evaluate the degree of dependence on sproutingin the regeneration of each species, we measured the ratio of thenumber of all sprouts to the number of main stems in a population. The ratio was 4.3 in Castanopsis fordii and > 1in Castanopsis fabri and Castanopsis carlesii, althoughit was < 1 in Castanopsis fargesii. The ratioof the number of all sprouts to the number of main stems in a populationwas represented by the product of two factors of sprouting ability:the proportion of sprouting individuals among all individuals andthe number of sprouts per sprouting individual. The proportion ofsprouting individuals among all individuals differed significantlyamong the four species, while the number of sprouts per sproutingindividual did not. Specific variations in sprouting traits werein agreement with the population structure of each species. Specieswith fewer small individuals in the size distribution had a higherratio than species with L-shaped distribution. Furthermore, specieswith a clumped distribution had a larger ratio than species thatwere randomly distributed. These results suggested that specieswhose recruitment by seedlings was temporally and spatially restrictedwere relatively more dependent on sprouting in the regeneration. The specific gradient of sprouting ability and the relative dependencyon sprouts to maintain a population can enhance the coexistenceof these four congeneric species.