• Research in Plant Disease
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• v.28 no.4
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• pp.231-236
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• 2022

Oxypetalum coeruleum, commonly known as Tweedia, is a perennial herbaceous plant of the Apocynaceae family native to southern Brazil and Uruguay. Tweedia plants are grown as one of the most popular ornamental flowers for floral arrangement in Korea. In May 2021, several tweedia plants in a single greenhouse in Gimje, Jeollabuk-do were found to show virus-like symptoms including necrotic rings, vein-clearing, chlorotic mottle, and mosaic on the leaves, and necrosis on the stems. Here, we have identified tomato spotted wilt virus (TSWV) in symptomatic tweedia leaves by applying high-throughput RNA sequencing. In the result, a single infection by TSWV was verified without mixed infections of different virus species. To confirm the presence of TSWV, a reverse transcription polymerase chain reaction was performed with a specific primer set to the N gene of TSWV. The complete genomic sequence of L, M, and S segments of TSWV 'Oxy' isolate were determined and deposited in GenBank under accession numbers LC671525, LC671638, and LC671639, respectively. In the phylogenetic tree analysis by maximum likelihood method, 'Oxy' isolate showed a high relationship with TSWV 'Gumi' isolate from Gerbera jamesonii in Gyeongsangbuk-do, Korea; for all three RNA segments. To our knowledge, this is the first report of TSWV infection of O. coeruleum in Korea.

• Korean Journal of Environment and Ecology
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• v.38 no.3
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• pp.310-323
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• 2024

The purpose of this study was to understand the vegetation structure and ecological characteristic of Bulgapsan(Mt.) Provincial Park by setting up and surveying 64 plots(100m²). The analysis using the TWINSPAN and DCA techniques found seven community groups: Pinus densiflora-Quercus variabilis community, P. densiflora-P. rigida-Q. serrata community, Q. variabilis-Carpinus tschonoskii community, Q. aliena-Q. variabilis-Cornus controversa community, Q. aliena-Platycarya strobilacea community, Broad-leaved miced community and Q. variabilis community. The result of vegetation community structure analysis showed that P. densiflora community and deciduous Quercus spp. community were in competition, and succession to Quercus spp. community was expected. In the case of other broad-leaved forests, the current status is expected to be maintained. But continuous monitoring is required in areas where Neolitsea sericea and Cephalotaxus appear, which grow naturally in warm temperate forest and southern temperate vegetation zone. Species diversity by communities are confirmed to be highest at 2.6654 in the actively competitive P. densiflora-P. rigida-Q. serrata community, and the lowest in the Deciduous broad-leaved forests community at 1.2548. The results of the tree rings and annual growth analysis showed that dominant trees had an average age of more than 37~87 years. Among them, N. sericea designated as a natural monument was 48~56 years old.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.46-52
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• 2009

Deposition of atmospheric N that is depleted in $^{15}N$ has shown to decrease N isotope ratio ($^{15}N/^{14}N$,expressed as ${\delta}^{15}N$) of forest samples such as tree rings, foliage, and total soil-N. However, its effect on ${\delta}^{15}N$ of mineral soil-N which is biologically active N pool has never been tested. In this study, ${\delta}^{15}N$ of mineral N($NH{_4}^+$ and $NO_3{^-}$) in forest soils from organic and two depths of mineral soil layers (0 to 20 cm and 20 to 40cm depth) of Pinus densiflora stands located at two distinct areas (rural and industrial areas) in southern Korea was analyzed to investigate if there is any difference in ${\delta}^{15}N$ of mineral N between these areas. We also evaluated potential N loss of the study sites using ${\delta}^{15}N$ of mineral N. Across the soil layers, the ${\delta}^{15}N$ of $NH{_4}^+$ ranged from +8.9 to +24.8‰ in the rural area and from +4.4 to +13.8‰ in the industrial area. Soils from organic layer (+4.4‰) and mineral layer between 0 and 20 cm (+13.8‰) of industrial area showed significantly lower ${\delta}^{15}N$ of $NH{_4}^+$ than those of rural area (+8.9 and +24.3‰, respectively), probably indicating the greater contribution of $^{15}N$-depleted $NH{_4}^+$ from atmospheric deposition to forest in the industrial area than in the rural area. Meanwhile, ${\delta}^{15}N$ of $NO_3{^-}$ was not different between the rural and industrial areas, probably because ${\delta}^{15}N$ of $NO_3{^-}$ is more likely to be altered by the N loss that causes $^{15}N$ enrichment of the remaining soil N pool. Compared with the ${\delta}^{15}N$ of soil mineral N reported by other studies (from -10.9 to +15.6‰ for $NH{_4}^+$ and -14.8 to +5.6‰ for $NO_3{^-}$), the ${\delta}^{15}N$ observed in our study was substantially high, suggesting that the study sites are more subject to the N loss. It was concluded that $NH{_4}^+$ rather than $NO_3{^-}$ can conserve the ${\delta}^{15}N$ signature of atmospheric N deposition in forest ecosystems.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.43-52
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• 2017

This study was fulfilled to verify the durations of cambial activity and analyze the associations of degree days and precipitation with the initiation of cambial activity and intra-annual wood formation for Pinus koraiensis and Chamaecyparis pisifera planted at Mt. Worak, respectively, by monitoring of their intra-annual cambial activities. And more, the reason was also analyzed why the DBH of Chamaecyparis pisifera known as planted in the same year could be classified as two groups (CPL: ${\phi}30cm$, CPS: ${\phi}15cm$). The intra-annual cambial activity was monitored using mini-cores (${\phi}2mm$) and they were collected in 2-week interval between April and October. However, between April and May and between middle September and October expected as the initiation and cessation of the cambial activity, respectively, it was fulfilled in 1-week interval. The average number of tree rings for PK (30) was less than CPS (37) and CPL (38), whereas the average ring width of PK (4.12 mm) was wider than CPS (1.84 mm) and CPL (3.97 mm). In the comparison of ring widths between CPL and CPS, CPL was 2.13 mm wider than CPS, however, excepting CPS 1 (0.83 mm), the average ring widths of CPS 2 (2.42 mm) and CPS 3 (2.73 mm) in the last 3 years were close to the average of CPL (2.71 mm). The initiation of cambial activity for PK was between 1 and 21 April, which was 1 week earlier than CPL and CPS (excepting CPS 1) and the cessation was between 1 and 22 September. The longest growing season therefore was 157.3 days (${\pm}3.3$) and it was longer than CPL ($145.7{\pm}6.6days$) and CPS ($148.0{\pm}15.1days$). In CP groups there were wide variations for the cessation of cambial activity and also there were the meaningful linear relationship between the growing seasons and the ring widths (r = 0.69, p < 0.064). The cambial activity in PK was initiated when degree days were between 99 and 134 and in CPS (excepting PCS 1) and CPL between 134 and 200. Excepting CPS 3, the false ring was observed in all samples collected on 21 July when drought stress was high due to low precipitation from June to the beginning of July.