Hyun-Deok Son’s research while affiliated with Korea Environment Institute and other places

Due to substantial population decline, the Korean orchid P. scolopendrifolia is considered endangered and highly threatened. Like many endangered species, it is vulnerable to biological and anthropogenic threats that can lead to the loss of genetic diversity and, ultimately, extinction. Therefore, the assessment of genetic diversity and population genetic structure is imperative for conservation. In this study, we newly developed 15 polymorphic microsatellite markers. Analyses of genetic diversity and population genetic structure that included 182 samples from 11 populations were conducted using microsatellite markers and four noncoding regions of chloroplast DNA. Our study revealed a relatively low level of genetic diversity (Ho = 0.529, He = 0.356), albeit harboring with private alleles based on microsatellite genotyping data, and high haplotype diversities based on chloroplast DNA sequences data. The results of STRUCTURE and PCoA based on microsatellite genotyping data showed population differentiations. An AMOVA based on chloroplast DNA sequence data further corroborated these conclusions, indicating about 70% of variations found among populations. Low genetic diversity and divergence among the population might have been caused by factors, such as asexual reproduction, demographic events (bottleneck and population expansion), geographic isolation, and low gene flow. The development and implication of conservation strategies and management of P. scolopendrifolia are proposed based on these results.

We investigated the pollinators of Centipede's foot orchid (Cleisostoma scolopendrifolium) at five locations in southern Korea. Only one species of megachilid bee (Megachile yasumatsui) was observed at three of the sites (Mokpo, Haenam, and Wando). We assumed that the megachilid bee worked as a sole pollinator of C. scolopendrifolium based on the visiting behavior of the bees the attached pollinia. Fruits were observed at the three locations that bees visited: 74% fruit set at Mokpo, 59% at Wando, and 31% at Haenam. By contrast, at two of the locations where megachilid bees did not visit the plants (Naju and Jindo), there were no fruits set. The differences in fruit set rates at the three orchid populations where bees were observed appear to be related to bee abundance and flower visitation rate rather than to differences in flower abundance. The pollination interaction between C. scolopendrifolium and megachilid bees appears to involve sexual deception since only male bees were attracted to the flowers. The underlying mechanism involved in this interaction needs investigation.

We determined the complete chloroplast genome sequence of two individuals of Pelatantheria scolopendrifolia, an endangered orchid species in Korea. The total chloroplast genome size of Mokpo (MG752972) and Naju (MG752973) population was 146,971 bp and 146,848 bp, respectively. The chloroplast genome contained 106 genes, including 72 protein-coding genes, 30 tRNA genes, and four rRNA genes. Variation in gene contents and structures was not found between two individuals. We found truncated or deleted ndh genes in P. scolopendrifolia. Phylogenetic analysis, based on the whole chloroplast genome sequences of 25 species of Orchidaceae, showed that P. scolopendrifolia was most closely related to Gastrochilus fuscopunctatus.

We investigated the flora of Jang-do (Isl.), an island of the Heuksan archipelago, located in Heuksan-myeon, Shinan-gun, Jeollanam-do and discussed the remarkable plants found there. Thirteen-field trips (total 27 days) were completed from May of 2004 to May of 2013. As a result, we identified the distribution of 423 taxa in Jang-do (Isl.), comprising 104 families, 285 genera, 335 species, 78 varieties and 10 forms. There are a total of 95 taxa of floristic regional indicator plants. The floristic regional indicators are as follows; four taxa of level V such as Impatiens furcillata, four taxa of level IV such as Hosta yingeri, 14 taxa of level III such as Ophioglossum vulgatum, 5 taxa of level II, and 58 taxa of level I. In addition 10 red data plants, 2 vulnerable species (VU) including Calanthe striata for. sieboldii, and 4 least concern species (LC) like Ardisia crenata, 2 not evaluated species (NE) such as Hosta yingeri, were found in the investigated area. An unrecorded species, Fragaria (Rosaceae), was found in a forest of Jang-do (Isl.) for the first time in Korea.

During the course of the execution of the project entitled Distribution Research of Rare Plants, we found the habitats of two rare ferns with obscure and/or extremely restricted distribution ranges, as previously unreported habitats. A subantarctic fern reported on Hamgyeong-do and Gangwon-do, Dryopteris coreano-montana Nakai, was found on Mt. Ibam in Jangseong-gun, Jeollanam-do. A subtropical fern reported south of Jeju-do, Dryopteris decipiens (Hook.) Kuntze, was newly found on Mt. Cheongwan of Jangheung-gun in Jeollanam-do.