Selection of Restoration Material for Abies koreana Based on Its Genetic Diversity on Mt. Hallasan

The restoration of damaged or disrupted forests with genetically appropriate restoration planting material that can adapt to future environmental conditions will ensure the conservation of forest genetic resources. Abies koreana is endemic to the Republic of Korea, with declining populations under current environmental changes. In this study, we examined the genetic diversity of its largest population growing on Mt. Hallasan to determine the sampling size of planting material from the population that will ensure 95% coverage of alleles in the population. We evaluated the genetic diversity and spatial genetic structure of three subpopulations of A. koreana on Mt. Hallasan. A total of 456 samples were evaluated using 10 microsatellites. The observed heterozygosity and expected heterozygosity were 0.538 and 0.614 at the population level, respectively. The differences among the subpopulations accounted for 4% of the total variance. Intervals between individuals of the sample to be extracted were based on the two-target distance (5 and 10 m) inferred from the spatial genetic structure. Through random sampling methods considering the target distance, we showed that genetic diversity can be captured by obtaining at least 35 individuals in the population of A. koreana on Mt. Hallasan.

Explant, Medium and Plant Growth Regulator (PGR) Affect Induction and Proliferation of Callus in Abies koreana

Korean fir (Abies koreana E.H. Wilson) is a unique Pinaceae tree species endemic in Korea. In recent years, it is believed that climate change has caused many of them to die. Therefore, it has become extremely important to protect and preserve this tree species. In this study, the possibility of callus induction using different explants, media, and plant growth regulators (PGRs) was studied. After the dormancy period in May 2020, needles and stem segments that grew from the leaf buds as the explants were collected from one-year-old shoots. The explants were disinfected and subsequently transferred to culture media supplemented with different combinations of auxins and cytokinins. These explants were cultured in the dark in a culture room with a 16 h photoperiod, day/night temperature of 24/18 °C, and 80% relative humidity. After 8 weeks, significant differences were observed in the callus induction and proliferation, as affected by the explant type, basic medium, and PGR. The stem segments were more suitable as the explants for callus induction than needles were. Furthermore, fluffy calli suitable for differentiating the regeneration buds were observed on the calli induced from stem segments. The Murashige and Skoog (MS) medium was the most effective of the three media used in this study, namely MS, Douglas fir cotyledon revised (DCR), and Quoirin and Lepoivre (LP) media, with the highest callus induction ratio of stem segments being 100.0%. The highest fresh callus weight was also observed on the MS medium (819.3 mg). Moreover, the PGR combinations of α-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and 6-benzylaminopurine (6-BA) consistently exerted a positive influence on callus induction throughout this study. In addition, the advantages of these two kinds of PGR were reflected in callus proliferation. The callus proliferation ratio reached 1,147.6% as compared to the initial fresh weight, with a high concentration of 2,4-D (3.0 mg·L−1). In conclusion, the MS medium was optimal for callus induction on the stem segment explants, and 2,4-D promoted callus induction as well as an increased proliferation ratio of callus in A. koreana.

The Role of Aging and Wind in Inducing Death and/or Growth Reduction in Korean Fir (Abies Koreana Wilson) on Mt. Halla, Korea

The purpose of this study was to investigate the role of strong winds and aging in the death and/or decline in the growth of Korean fir on Mt. Halla in Korea. Bangeoreum (BA-S), Jindalrebat (JD-E), and Youngsil (YS-W) on the southern, eastern, and western slopes of Mt. Halla (ca. 1600 and 1700 m a.s.l.) were selected for the study. The site chronologies were established using more than 10 living Korean firs at each site. Additionally, to date the years and seasons of death of standing/fallen dead Korean firs, 15/15, 14/15, and 10/10 trees were selected at BA-S, JD-E, and YS-W, respectively. After adjusting the age with the period of growth up to the sampling point, the oldest Korean fir found among the living trees was 114 years old at JD-E and the oldest fir among the dead trees was 131 years old at JD-E. Besides this, most of the trees at BA-S and JD-E were found to have died between 2008 and 2015, and at irregular intervals between 1976 and 2013 at YS-W. Also, the maximum number of trees, that is, 62.7% died between spring and summer, followed by 20.9% between summer and autumn, and 16.4% between autumn of the current year and spring of the following year. Abrupt growth reductions occurred at BA-S and JD-E, and have become more significant in recent years, whereas at YS-W, the abrupt growth reduction and recovery occur in a cyclic order. The intensity and frequency of the typhoons increased from 2012, and this trend was in-line with the increased number of abrupt growth reductions at BA-S and JD-E. Therefore, the typhoons of 2012 are considered as the most likely influencing factor in death and/or growth reduction in Korean firs. In contrast, the decline in the growth of the Korean firs located on the windward slope (YS-W) showed a relationship with winds stronger than 25–33 m/s.

A new species of Anurophorus (Collembola: Isotomidae) from South Korea, with notes on its molecular data

A new species, Anurophorus hallaensis sp. nov. was collected from the withered leaves of Korean fir (Abies koreana Wilson), which is distributed at higher than 1,300 m in altitude on Mt. Hallasan (Jeju Island, South Korea). The morphology and two partial gene regions of this species are described herein. Anurophorus hallaensis sp. nov. showed the same formulas of macrochaetae and sensilla on thoracic segment II to abdominal segment IV as those exhibited by A. laricis Nicolet and A. palearcticus Potapov; however, this new species can be distinguished from them by the number of knobbed hairs on ventral side of legs. Partial DNA sequences of the mitochondrial Cytochrome c Oxidase subunit I (COI) gene and ribosomal DNA (28S rDNA) were used as DNA barcodes to distinguish between A. hallaensis sp. nov. and closely related congeners. The results of the present study indicate that the COI and rDNA are useful for species discrimination within the genus Anurophorus. An identification key to the Korean species of Anurophorus is provided.