• Journal of Forest and Environmental Science
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• v.32 no.3
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• pp.311-322
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• 2016

Since forest trees form the basis of forest ecosystem, their prolong subsistence is crucial for various flora and fauna. The foremost challenges to sustain the forest ecosystem comprise of the declining forest tree population accompanied with structural changes due to afforestation and exploitation of forest area, environment changes, pests, pollution, and introgressive hybridization. For ex situ conservation approach, in vitro techniques encompass basic role for conserving tree genetic resources, predominantly where natural propagules like recalcitrant seed might not be appropriate for long-term conservation. The practice includes restricted growth techniques, conventional micropropagation, production and storage of synthetic seeds, and cryopreservation. Even though these practices have been applied chiefly to herbaceous species, but recently, woody species were also focused upon. Key conceptions, challenges and techniques for forest tree seed conservation are discussed briefly in this review with special emphasis on some successful cryopreservation approaches for long-term storage.

• Journal of Forest and Environmental Science
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• v.34 no.5
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• pp.388-394
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• 2018

An efficient and reproducible protocol for in vitro germination of seeds of Couroupita guianensis has been developed in the present study. Couroupita guianensis is a medicinally important tree and categorized as threatened plant species by the IUCN. The seeds were surface sterilized using 0.1% $HgCl_2$ and inoculated on MS (Murashige and Skoog) and Woody Plants (Llyod and McCown) medium. The seeds with partially removed seed coat responded better (100%) on half strength MS medium as compared to the full (51%), one-fourth strength MS (79%) and the WP medium. Half strength MS medium conjunct with $2.0mg{\cdot}L^{-1}$ indole-3 butyric acid (IBA) was found best among the different types of auxins and cytokinins tested for seed germination, as all the seeds germinated on this medium combination. The seedlings were successfully hardened in the greenhouse and restored in the field with 83% survival rate. The protocol can be used as conservation measure for large scale multiplication of this threatened forest tree species.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.183-191
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• 2022

Ginseng (Panax ginseng C.A. Meyer) is a perennial plant and propagates by seeds, and those need after-ripening for germination. To be ready for climate change and to ensure a stable seed supply, the technique for storing seeds in short-term and long-term in large quantities is required. In this study, dehisced ginseng seeds from two locations, batch #1 and batch #2, were stored at -3.5℃ with different moisture content, and after 3, 15, and 27 months of storage, the percentage of radicle emergence and shoot emergence were measured. After 3 months, radicle emergence and shoot emergence were normal only when the seed moisture content was more than 35%, and overall, germination was higher in batch #2 than in batch #1. After 15 months, the partially dehydrated seeds, with a moisture content between 45 to 54%, showed the highest germination rates, and most of the undried seeds were spoiled and failed to germinate. Seeds with moisture content lower than 25% had poor germination, too. The partially dehydrated seeds also succeeded in germination and growth in the soil after 15 months of storage, but deteriorated after one more 1 year, too. In summary, ginseng seeds look like have temperate recalcitrant seed characteristics, and partial dehydration allows extension of seed longevity.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.442-450
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• 2023

This study sought to determine the desiccation tolerance and storage behavior of Sarcandra glabra seeds to assist in the establishment of an ex-situ conservation strategy for the species. The basic germination characteristics of S. glabra seeds were investigated. Subsequently, the seeds were dried to various desiccation levels to allow for analysis of their germination characteristics and seed integrity. In addition, the seeds were subjected to germination tests after being stored for different durations. The initial seed moisture content following the removal of the fleshy fruit was 32.8%, and the fresh seeds maintained their seed viability even after a decrease in the seed moisture content to 4.8%, while the germination percentage was 81.0%. The germination percentage of the seeds decreased to 55.0% and 30.0% when they were desiccated to moisture contents of 2.3% and 2.2%, respectively. By contrast, when the stored seeds were desiccated, they maintained their seed viability and vigor at a moisture content of 18.6%; however, when the moisture content decreased below 5.0%, both the seed viability and vigor significantly declined and the germination percentage fell below 20.0%. Furthermore, analysis of the seed leachate revealed that the decrease in the seed viability and vigor was associated with both increased electrical conductivity and increased concentrations of inorganic compounds such as potassium and calcium. In conclusion, the findings of this study show S. glabra seeds to possess desiccation tolerance that falls somewhere between the recalcitrant and intermediate seed types, with the observed variations depending on the degree of deterioration.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.164-168
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• 2014

To determine the optimal storage method and longest possible storage period of Zostera marina seeds, we examined post-storage germination rates using different storage methods and periods for Z. marina seeds harvested in southern coast of Korea. Storage methods included in seawater at room temperature with air supply, seawater at $4^{\circ}C$, seawater at $30^{\circ}C$, an aquarium with continuous seawater circulation, seawater at room temperature in an airtight tank, a refrigerator at $-20^{\circ}C$, and a desiccator at room temperature. Germination rates of Z. marina seeds stored in seawater at $4^{\circ}C$ showed highest germination (52.0%), whereas those of seeds stored in seawater at room temperature and an aquarium were 27.4% and 17.7%, respectively. But the seeds stored in seawater at $30^{\circ}C$, a refrigerator, and a desiccator did not germinate. Storage periods were 10, 20, 30, 60, 180 and 240 days of storage. Z. marina seeds maintained germination rates of 46.4~52.4% until 10~60 days of storage, but showed rapidly decreasing germination rates after then and no germination after 240 days.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.438-444
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• 2011

This study was conducted to investigate temperature effect on seed germination behaviors and seed viability changes by drying periods of three Ulmus species (Ulmus davidiana var. japonica (Rehder) Nakai, U. pumila L., and U. parvifolia Jacq.) distributed in Korea. Statistical analysis showed that temperature had a significant effect on mean germination time in three Ulmus species, but its effect on germination percentage was only shown in U. parvifolia (p<0.01). U. davidiana var. japonica and U. pumila germinated relatively consistent in all temperature conditions, especially the latter showed high germination behaviors in low temperatures (10-15$^{\circ}C$). U. parvifolia germinated well in high temperature (25$^{\circ}C$), while this species rarely germinated in low temperature conditions (10-20$^{\circ}C$). The results confirm that seeds of U. pumila and U. parvifolia are orthodox seeds which can be stored under 4-8% moisture condition, and U. davidiana var. japonica seed is recalcitrant seed which is difficult to store for a long time. In conclusion, these differences of the germination behaviors for three Ulmus species seem to be adaptive regimes of their natural habitats, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.4
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• pp.316-320
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• 2015

In order to improve the transformation efficiency of zoysiagrass by increasing the frequency of callus formation from mature seeds and plant regeneration, the effect of pre-treatment with sea sand was examined. Mature zoysiagrass seeds were given 10 min of swelling time before sea sand treatment using a sea sand and seed ratio of 1 : 1 and a vortex shaking speed of 6 (1,000 rpm) for 10 min. The seeds showed increased callus formation that was more than 2 times the rate in the control. In addition, plant regeneration efficiency was also increased when embryogenic callus induced from sea sand-treated mature seeds was cultured in regeneration medium. These results will be very helpful for improving the genetic transformation frequency of zoysiagrass, a recalcitrant monocot grass.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.278-285
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• 2008

An efficient transformation method for soybean [Glycine max (L.) Merr.] using meristematic tissues of germinating seeds has been established. The embryonic axes were excised from germinating seeds of Korean soybean cultivar, Iksannamulkong and 0.5-2 cm long segment containing meristematic tissues were prepared by cutting hypocotyl region. The explants were inoculated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector with the bar gene as a selectable marker gene and a ${\beta}-glucuronidase$ (GUSINT) reporter gene, and then co-cultured for 7 days on co-cultivation medium (CCM). The meristematic tissues were cultured on shoot induction medium (SIMP6) supplemented with 0.4 mg/l $N_6-benzylaminopurine$ (BAP) and 0.1 mg/l indolebutyric acid (IBA) in the presence of 6 mg/l L-phosphinotricin (PPT) for 2 weeks and the surviving explants were transferred to shoot elongation medium (SEMP6). Transformation was confirmed by Southern blot analysis and the transformation efficiencies ranged from 1.48 to 2.07%. The new modified transformation method was successfully implemented for obtaining several transgenic lines with SMV-CP gene. It is expected that this method could efficiently be used for the transformation of recalcitrant soybean cultivars.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.15-15
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• 2019

The walnut (Juglans regia L.), a member of the Juglandaceae, is native to the mountain ranges of central Asia. This species of walnut is valued commercially for its nuts and in some areas for its timber. The seeds of walnut are recalcitrant and it has strong integument dormancy and their germination is irregular, making its natural propagation difficult. Low percentage of seed germination and long propagation cycle are the main problems of propagation. This study was conducted medium composition on in vitro plantlet regeneration from axillary buds of walnut. It has proved to be the most generally applicable and reliable method of in vitro propagation. Micropropagation culture that axillary buds are excised aseptically enables faster multiplication of plants. The axillary buds of walnut new cultivar "Sinlyeong" were cultured on two basal media which contained the different plant growth regulators depending on the respective shooting and rooting stage. After 12 weeks, the shoot generation rate was 85.3%, the shoot number and its length were 1.9/explant and 2.7 cm in the most favorable medium composition. The percentage of rooting was 25.4%. From these results, it was found the optimum basal medium and plant growth regulator for in vitro plant regeneration from axillary buds of walnut new cultivar "Sinlyeong". However, we have continued to search the other medium additives to enhance the rate of walnut root.

• Journal of Forest and Environmental Science
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• v.37 no.4
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• pp.323-330
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• 2021

Zygotic embryo culture was performed to propagate evergreen oak, Quercus myrsinifolia, which has recalcitrant seeds and is difficult to propagate by cuttings. Zygotic embryos appeared in WPM medium after 14 days, and after 56 days, they developed into complete plants with cotyledons and roots. The medium suitable for zygotic embryo culture was 1/4 WPM medium, showing a shoot growth of 2.43 cm and root growth of 8.7 cm after 8 weeks of culture. As a result of investigating the effect of GA₃ on the growth of plants germinated from zygotic embryos through GA₃ treatment, the best growth was shown in 0.5 mg/l GA₃ treatment. The in vitro rooting and growth of IBA-treated zygotic embryo-derived plants were good in the 0.5 mg/l IBA treatment and rooting and shoot growth were not observed at higher concentrations. And the callus induction rate also increased as the concentration of IBA increased. Plants grown in vitro were transferred to a plastic pot containing artificial soil and acclimatized in a greenhouse for about 4 weeks, resulting in more than 90% survival. As a result of this study, the zygotic embryo culture method was confirmed to be effective for mass propagation of Q. myrsinifolia. The results of this study are expected to contribute significantly to the mass propagation of elite Q. myrsinifolia.