• 식물분류학회지
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• 제32권3호
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• pp.293-299
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• 2002

새로이 명명된 완도호랑가시나무(Ilex $\times$ wandoensis C. F. Miller & M. Kim hybrid nov.)는 전남 완도군 완도에서 채집하였다. 완도호랑가시나무는 호랑가시나무(I. cornuta Thunb.)와 감탕나무(I. integra Thunb.)의 자연교잡을 통해 형성된 분류군이다. 따라서 가시형 엽연과 평평한 표면을 가진 신분류군은 사각형으로 뒤틀린 엽연에 강한 가시형 거치와 볼록한 표면을 가진 호랑가시나무와 전연이며 평평한 표면을 가진 감탕나무의 중간형질을 가지고 있다. 또한 완도호랑가시나무는 소교목이고 1.0-1.4cm의 엽병을 가진 점에서 관목이고 0.4-0.6cm의 엽병을 가진 호랑가시나무와 키가 큰 교목이고 1.5-2.0cm의 엽병을 가진 감탕나무와 뚜렷이 구별이 된다.

• 식물분류학회지
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• 제47권3호
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• pp.189-195
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• 2017

Aruncus L. is a small genus which is distributed in the circumpolar regions of the Northern Hemisphere, including Europe, Asia, and North America. In Korea, there are two taxa, A. dioicus var. kamtschaticus and A. aethusifolius. Aruncus aethusifolius is a species endemic to Korea, occurring only on Jeju Island. An important characteristic of Aruncus is dioecy. However, there is some controversy regarding the sexuality of this genus, and little is known about A. aethusifolius. To characterize the sexuality of A. aethusifolius and to provide insight into the evolution of its sexual system, we investigated natural populations and herbarium specimens of A. aethusifolius. The results indicate that the species has carpellate, staminate, and bisexual flowers. Carpellate flowers are always borne on separate individuals, and staminate flowers are borne either on separate individuals or mixed with bisexual flowers on the same individuals. The sexuality of A. aethusifolius is defined as polygamo-dioecious. The polygamo-dioecious type is also found in A. dioicus var. dioicus and A. dioicus var. kamtschaticus and thus may be a general condition in Aruncus.

• Journal of Forest and Environmental Science
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• 제38권4호
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• pp.275-283
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• 2022

A study was designed to investigate the pattern of sexual dimorphism in a plantation of Garcinia kola. Twenty trees were randomly selected for the study and have been observed to flower regularly. A total of 100 inflorescence were randomly collected from the crown of each tree and 500 flowers randomly assessed within the period of four (4) flowering seasons. Floral sex assessment was done visually and with a hand magnifying lens; floral morphometric measurements (i.e. pedicel and perianth length and breadth), inflorescence length, and breadth) was taken using a veneer caliper; number of flowers per inflorescence and inflorescence per twig was counted; while, data analysis was conducted on excel using analysis of variance and pairwise t-test comparison. Four floral sexes were identified in the G. kola plantation studied which were unisexual male flowers, unisexual female flowers, cosexual unisexual male flowers, and cosexual hermaphrodite flowers. Three tree sexes were identified viz: inconstant male, invariant female, and cosexual trees. The plantation was significantly sexually dimorphic in floral sex and phenotypic traits (i.e. pedicel and perianth size), and as well as sexually dimorphic in tree sex and reproductive phenotypic traits (i.e. inflorescence size, number of inflorescences per twig, and number of flower bud per inflorescence). The sexual system of the plantation was therefore trioecious with features suggestive of evolving dioecy through the gynodioecious pathway.

• Journal of Plant Biotechnology
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• 제50권
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• pp.207-214
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• 2023

Lindera obtusiloba (Lauraceae) is a dioecious tree that is widely distributed in the low-altitude montane forests of East Asia, including Korea. Despite its various pharmacological properties and ornamental value, the genetic diversity and population structure of this species in Korea have not been explored. In this study, we selected 6 nuclear and 6 chloroplast microsatellite markers with polymorphism or clean cross-amplification and used these markers to perform genetic diversity and population structure analyses of L. obtusiloba samples collected from 20 geographical regions. Using these 12 markers, we identified a total of 44 alleles, ranging from 1 to 8 per locus, and the average observed and expected heterozygosity values were 0.11 and 0.44, respectively. The average polymorphism information content was 0.39. Genetic relationship and population structure analyses revealed that the natural L. obtusiloba population in Korea is composed of 2 clusters, possibly due to two different plastid genotypes. The same clustering patterns have also been observed in Lindera species in mainland China and Japan.

• Journal of Ecology and Environment
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• 제41권8호
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• pp.223-234
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• 2017

Background: Spatial structure of plants in a population reflects complex interactions of ecological and evolutionary processes. For dioecious plants, differences in reproduction cost between sexes and sizes might affect their spatial distribution. Abiotic heterogeneity may also affect adaptation activities, and result in a unique spatial structure of the population. Thus, we examined sex- and size-related spatial distributions of old-growth forest of dioecious tree Torreya nucifera in extremely heterogeneous Gotjawal terrain of Jeju Island, South Korea. Methods: We generated a database of location, sex, and size (DBH) of T. nucifera trees for each quadrat ($160{\times}300m$) in each of the three sites previously defined (quadrat A, B, C in Site I, II, and III, respectively). T. nucifera trees were categorized into eight groups based on sex (males vs. females), size (small vs. large trees), and sex by size (small vs. large males, and small vs. large females) for spatial point pattern analysis. Univariate and bivariate spatial analyses were conducted. Results: Univariate spatial analysis showed that spatial patterns of T. nucifera trees differed among the three quadrats. In quadrat A, individual trees showed random distribution at all scales regardless of sex and size groups. When assessing univariate patterns for sex by size groups in quadrat B, small males and small females were distributed randomly at all scales whereas large males and large females were clumped. All groups in quadrat C were clustered at short distances but the pattern changed as distance was increased. Bivariate spatial analyses testing the association between sex and size groups showed that spatial segregation occurred only in quadrat C. Males and females were spatially independent at all scales. However, after controlling for size, males and females were spatially separated. Conclusions: Diverse spatial patterns of T. nucifera trees across the three sites within the Torreya Forest imply that adaptive explanations are not sufficient for understanding spatial structure in this old-growth forest. If so, the role of Gotjawal terrain in terms of creating extremely diverse microhabitats and subsequently stochastic processes of survival and mortality of trees, both of which ultimately determine spatial patterns, needs to be further examined.

• Journal of Ecology and Environment
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• 제35권2호
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• pp.111-122
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• 2012

The sex ratio and spatial structure of different sexes are major components that affect the reproductive success and population persistence of dioecious plants. The differential reproductive costs between male and female plants are often believed to cause a biased sex ratio and spatial segregation of the sexes through slower growth and/or lower female survivorship. In this study, we examined the sex ratio and spatial structure of one population of $Torreya$ $nucifera$ trees in Jeju Island, Korea. We also tested the effects of the current tending actions in relation to tree vitality. At the population level, the sex ratio of the 2,861 trees was significantly biased toward males; however, it also showed considerable variation among different diameter at breast height classes and across habitats according to terrain level (from upper to lower). In 1999, before tree management (tending) began, among the ecological traits examined, only climber coverage correlated with tree vitality. Intensive tending such as climber removal since 1999 clearly enhanced the vitality of the majority of trees, but its effects were more conspicuous in medium-sized trees than in small ones, in upper terrain trees than those in other terrains, and in females than in males. Both male tree domination in small and large trees and tending effects on females are likely to reflect the effects of female reproductive costs regarding growth and/or survivorship. Spatial segregation between males and females was not observed in $T.$ $nucifera$. Habitat heterogeneity created by the forest's rocky ground and its implications regarding sex ratios and spatial structure require further studies.

• 식물분류학회지
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• 제42권2호
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• pp.126-140
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• 2012

국내에 분포하는 나자스말속(Najas L.) 분류군의 형태적 변이를 파악하고 각 분류군의 식별형질을 검토하기 위하여 32개 정량형질을 이용하여 주성분분석을 수행하였다. 나자스말속의 분류군에서 잎의 너비, 엽초의 모양, 엽연의 거치수, 약실의 수, 한 줄에 배열하는 종자의 그물눈 수와 길이의 비 등이 유용한 식별형질로 파악되었다. 자웅이주인 민나자스말(N. marina)은 잎과 줄기, 수꽃과 암꽃, 열매가 대형으로서 자웅동주인 다른 분류군들과 뚜렷하게 구분되었다. 자웅동주인 분류군들 중에서 나자스말(N. graminea), 실나자스말(N. gracillima), 동아나자스말(N. orientalis)은 영양 형질에 의하여 식별이 가능하지만, 톱니나자스말(N. minor)과 큰톱니나자스말(N. oguraensis)은 수꽃에 있는 약실의 수에 의해서만 구분되었다.

• 한국자원식물학회지
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• 제28권4호
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• pp.400-410
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• 2015

Juniperus chinensis (Cupressaceae) is a valuable woody plant resource, but this rare plant is only distributed in restricted regions in Korea. In this study, we surveyed the geographic distribution regions, variation of sex ratio and the dynamics of natural populations of J. chinensis. in order to establish conservation strategies for the sustainable conservation of this important resource tree. The 17 natural populations of J. chinensis are restrictively distributed in the shore cliffs of (1) Ulleungdo island, (2) Gyeongju-si to Gangneung-si of the eastern coast, the riverside cliff along (3) Donggang-river of Jungsun-gun and Pyeongchang-gun and (4) branch of Nakdonggang-river in Uiseong-gun. The populations in Ulleungdo island showed continuous population distribution of over 200 individuals, but populations in other regions had discontinuous population distribution of under 200. The population of J. chinensis surveyed in Korea was estimated in ca. 3,200 individuals. The sex ratio (male/female) among populations of J. chinensis was diverse with variation from 0.46~1.67 range, but showed no significance. The sex ratio of the total individuals by species level was 0.74, and the percentage of female tree was significantly higher than the male. The results of dynamics analysis within population among regions showed that seedlings and saplings of J. chinensis in three regions surveyed were continuously regenerating. The distribution of DBH class showed a stable population structure of inverse J shape graph, but fragmentation and decrease in populations because of invading broad-leaved shrubs and trees from the surroundings were concerned. Further studies, and in situ and ex situ conservation strategies for the sustainable conservation on natural populations of this rare resources woody plant, J. chinensis in Korea are recommended.

• Journal of Ecology and Environment
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• 제43권3호
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• pp.320-331
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• 2019

Background: Dioecious plant species having both male and female plants have been investigated regarding sex-related characteristics such as sex ratio, sex-differential resource requirements, and spatial segregation of the sexes. Habitat loss and fragmentation are major threats to the survival of plant populations, but dioecious species are particularly more prone to such habitat degradation than non-dioecious species because of their dimorphic sexual system. We examined the sex-related demographics of two Ilex cornuta populations being different regarding land use history. Methods: During 2016-2017, we examined I. cornuta trees with a basal diameter ${\geq}1.5cm$ in the Yongsu-ri population (YS population) and the Gotjawal Provincial Park population (GP population). Plant sex (male, female, or unsexed) was identified. The tree size (basal diameter and height of the main stem), clonal production (the ramet numbers per genet), and vitality for each clone were measured. The associations between population, sex, tree size, clonal production, and vitality were examined using ANOVAs and contingency table analyses. Finally, point pattern analyses using O-ring statistics were conducted to assess spatial patterns. Results: Upon excluding unsexed trees, the YS population with 74 trees was significantly male-biased (0.66), while the GP population with only 26 trees had a 1:1 sex ratio. In both populations, males and females did not differ in tree size. Although the mean number of ramets differed significantly between populations, females tended to produce more ramets than males. The proportion of weak trees was significantly higher in the YS than in the GP population. Neither population showed evidence of spatial segregation of the sexes. Conclusions: The two populations of dioecious I. cornuta are characterized by the small number of trees and relatively high frequencies of non-reproductive trees. Both indicate that these populations are quite susceptible to environmental and genetic stochasticity. On the other hand, the differences between populations in sex ratio, clonal production, and vitality suggest that conservation efforts for I. cornuta need to be population-specific. In order to help recover and enable this vulnerable species to persist, it is necessary to find ways to enhance their sexual reproduction and simultaneously reduce habitat disturbances due to anthropogenic activities.

• 식물분류학회지
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• 제51권4호
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• pp.372-377
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• 2021

전남 완도군 섬지역에서 발견된 Stachyurus praecox Siebold & Zucc.를 우리나라 미기록 식물로 보고한다. 이 수종은 일본의 난·온대지역에 넓게 분포하고 있으며, 특산수종으로 알려져 왔다. 꽃은 총상화서에 달리며, 형태적으로는 양성화지만, 기능적으로는 자웅이주로 관찰되었다. 화관은 흰색 또는 연한 보라색 꽃잎과 꽃받침은 각각 4개이다. 국명은 최초 발견지 지역명과 꽃차례 모양이 장식용으로 달리는 여러 가닥의 실을 의미하는 뜻으로 쓰이는 "술"을 고려하여 "완도술꽃나무"로 신칭하였으며, 이에 대한 기재문과 도해, 사진을 제시하였다.