• Journal of Ecology and Environment
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• v.43 no.3
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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.

• Korean Journal of Plant Taxonomy
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• v.47 no.3
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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.

• Plant Biotechnology Reports
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• v.2 no.4
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• pp.239-243
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• 2008

Simmondsia chinensis (Link) Schneider, a multipurpose and monogeneric dioecious shrub from arid zones, has emerged as a cash crop all over the globe. Its seed propagation poses severe problems due to its male-biased population: the male:female ratio is 5:1. Investigations have been carried out to generate a sex-specific Inter-simple sequence repeat (ISSR) marker for the early detection of male and female plants. Of the 42 primers analysed with a bulk sample of pooled male DNA and a bulk sample of pooled female DNA, only one primer, UBC-807, produced a unique ~1,200 base-pair fragment in the male DNA. To validate this observation, this primer was re-tested with individual male and female samples from eight cultivars. A similar unique ~1,200 bp fragment was present in the male individuals of all eight cultivars and completely absent in the female individuals tested. This is the first report of the use of ISSR markers to ascertain sex in physiologically mature S. chinensis plants.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.309-313
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• 1998

RAPD (Random Amplified Polymorphic DNA) analysis was conducted to Schisandra nigra plants in order to select the specific markers for monoecious and dioecious individuals. RAPD results using eighty random 10-mer primers revealed that S. nigra had a different banding pattern from S. chinensis and Kadsura japonica. When DNA isolated from leaves of monoecious and dioecious plants were used as PCR template, only five primers, OPA-17, OPA-19, OPB-03, OPB-09 and OFB-16, showed polymorphic band patterns. No variation in banding profiles within male or female individuals was observed when these five primers were used whereas three monoecious plants (No 1, No 2 and No 3) showed different banding patterns one another, A 750 bp segment was amplified by primer OPB-3 from male individuals. On the other hand, two segments, 950 bp and 1690 bp, with OPA-19 and 700 bp of segment with OPB-3 were amplified in female individuals. These result indicate that the specific buds of male and female S. nigra could be used as genetic markers for the early discrimination of male and female individuals.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.334.2-334
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• 1998

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.272.2-272
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• 1999

No Abstract, See Full Text

• Journal of Plant Biotechnology
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• v.50
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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.

• Korean Journal of Plant Resources
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• v.16 no.1
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• pp.55-60
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• 2003

The genetic variation of random amplified polymorphic DNA (RAPD) patterns of genomic DNAs was investigated in dioecious plant Rumex acetosa L., which carries different sex chromosome complements in female (2n=12A+XX) and male (2n=12A+XY$_1$Y$_2$). One hundred and twenty random primers consisted of 10-mer were used for PCR amplification. Polymorphic bands were found in 24 primers. Specific bands for female and male were 16 and 18, respectively. Especially, a band of 1,440 bp from the OPC-10 primer was male specific. These sex specific RAPD markers are used to understanding the sex determination mechanism in plants.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.188.3-188
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• 2003

No Abstract, See Full Text

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.682-688
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• 2020

Hemp (Cannabis sativa L.) is a dioecious plant, although monoecious plants are bred in some cultivars for fiber or seed production. Recently, hemp has received attention for medicinal use with some cannabinoids, including cannabidiol. Self-fertilization for breeding inbred lines is difficult because of dioeciousness and anemophily in hemp. This experiment was conducted to develop a self-fertilization method by forming female flowers and seeds from male plants of dioecious hemp. To induce the formation of female flowers on male plants, 500 mg L^-1 of ethephon was sprayed on plants at soon, seven and fourteen days after primordia formation. The plant ratio of female flowers formation and the number of harvested seeds were increased by ethephon treatment. Female flowers of male plants have 5 stigmas in contrast to the dual stigma of female 1plants. Male plant seeds were lighter and smaller than those from female plants. Although the germination rate was lower than that of normal seeds from female plants, the seeds from male plants germinated to grow seedlings. Thus, we suggest that hemp plants should be treated with ethephon at soon after primordia formation to induce the formation of more female flowers on the male plants.