• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.128-133
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• 1993

This experiment was carried out to evaluate the germination characteristics of Korean red rice seeds. Ten lines of the long grain and ten lines of the short grain Korean red rices were tested for dormancy, shoot emergence rate at different water and soil depth. Both the long and short grain type seeds of Korean red rice germinated over than 99% immediately after harvest, so that no dormancy was observed in the Korean red rices. Shoot emergence rate of the long grain red rices at 7cm of water depth and that of the short grain red rices at 11cm were 83.3% and 83.5% respectively, while those of the indica check Samgangbyeo and japonica check Seomjinbyeo were 0%. Shoot emergence rates of the long and short grain red rices at 7cm of soil depth were 71.1% and 73.9% respectively, while those of the check varieties Samgangbyeo and Seomjinbyeo were 40.0% and 28.0% respectively. Thus, the Korean red rices were expected to be useful germplasm source for direct seeding.

• Korean journal of applied entomology
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• v.49 no.1
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• pp.17-22
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• 2010

Pachynematus itoi Okutani emerges three times a year, and overwinters as a pre-pupa in cocoon. First emergence of P. itoi was from 7th May to third June. Second and third emergence was from 20th June to 13th July and fourth to 25th August, respectively. Mean oviposited egg number was 59, and egg period was about 9 days. Hatching rate was >90%. Oviposited egg number was the highest in the first needle cluster of short shoot followed by second and third. P. itoi did not oviposit on single needle (long shoot) of Larix leptolepis (Sieb. et Zucc.). Larva had five instars, and larval period was about 20 days. Larva prefer needle cluster of short shoot to single needle of long shoot. Mature larva descended from host tree and pre-pupa in cocoon overwinter at topsoil.

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.256-261
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• 2009

This study was carried out to examine the effects of cutting condition on the rooting and their subsequent growth of cut flower in plug cutting of summer-flowering chrysanthemum 'Iwanohakusen'. The more leaves were attached to the cutting, the higher shoot growth and rooting were. Shoot growth of cuttings was not affected by cutting length, but rooting was better in over 5 cm long cutting. Shoot growth was enhanced by increasing thickness of cutting, and 5.5 mm thick cutting was favored in rooting. When the many leaves were attached on the cutting, the length and weight of cut flower increased. Over 7 cm long cutting showed higher values in growth of cut flower and ray flower number. Cutting of 5.5 mm diameter showed more favorable growth of cut flower than the other treatments. Therefore, it is concluded that rooting of cutting and consecutive growth of cut flower was improved when 7 cm long and 5.5 mm diameter cutting with 4 leaves was used in plug cutting of chrysanthemum 'Iwanohakusen'.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.540-544
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• 2001

The effect of long day treatment on the growth and flower bud differentiation of persimmon tree grown in a heated plastic house was investigated. The rate of leaf sprout was 65% in the long day treatment and 71% in natural day (control). In the long day, the shoot grew 16.7 cm longer, full bloom and harvest days were shorter, fruit weight was 16% lighter, and the sweetness and firmness of fruit were lower. The photosynthesis rate in the long day treatment was higher, showing the tendency of increasing with time. However, the rate of photosynthesis increased after 1600 hours showed higher than the control. Carbohydrate accumulation in the shoot was decreased, with higher nitrogen content and lower C/N ratio in the long day. The number of flower primordia per bud was less, and the days for differentiation was longer in the long day.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.284-288
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• 2004

The response of dissolved oxygen (DO) concentrations caused significant change in root number, root length, coleoptile length, shoot length and leaf age of seedlings. The genotypic difference in the effect of DO also highly significant (P<0.01) for all of the seedling traits. The number and length of root were extremely inhibited at the condition of $0.39\pm0.09$ DO concentration. While the coleoptile elongated markedly in the lowest DO concentrations, the shoot did not develop. The root growth was improved slightly at the $1.39\pm0.27mg L^{-1}$, however, there were no difference among genotypes at these two low DO concentrations. As the DO concentration become higher, the growth of root and shoot was improved remarkably. Root number, root length and shoot length was significantly different between $20\;and\;30^{\circ}C$ in DO rich and normal conditions, the development of those traits were apparently accelerated in high water temperature, however those traits of seedlings in DO deficiency were not different between the two temperatures except for shoot length. On the other hand the coleoptile length was not affected by the stagnant water temperature; it was stimulated by the low DO concentration. The competition of DO was greater as the seedling density was increased in the stagnant water, therefore the seedlings grown under high density have long and white coleoptiles, and the growth of roots and shoots was retarded severely.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.36-36
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• 2021

Cryopreservation has been broadly used as an efficient method for a long-term conservation for many types of plants especially vegetatively propagated plants. Among several cryopreservation methods, a droplet-vitrification was the most widely applicable and efficient method. Studies have developed protocols for strawberry using droplet-vitrification method and suggested the practical use of the protocol for large number of germplasm with a little modification. In this study, the droplet vitrification method of shoot tip has been tested on 31 accessions provided around the world. Shoot tips were precultured on Murashige and Skoog (MS) liquid medium supplemented with 0.3~0.5M sucrose. Precultured explants were osmoprotected with loading solution, 35% of PVS3 (C4, 17.5% glycerol and 17.5% sucrose) for 40 min and exposed to dehydration solution, PVS3 (B1, 50% glycerol and 50% sucrose) for 60 min. Then, the explants were transferred onto droplets containing 2.5 uL PVS3 on sterilized aluminum foils prior to direct immersion in liquid nitrogen (LN) for 1hr. The cryopreserved shoot tips were rapidly warmed in a water bath at 40C and then unloaded in MS with 0.8M sucrose for 40 min. The shoot tips were cultured in NH₄NO₃-free MS post culture medium for 2 weeks. Subsequently, the explants were moved to the MS medium for 6 weeks and evaluated the regrowth rate. By this droplet-vitrification protocol, twenty-four accessions showed at least 40% regrowth rate. Out of 24 accessions, 'Nonsan1ho' had the highest regeneration rate of 85.8% and 'Jumbo pureberry' had the lowest with 42.1%.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.571-579
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• 2023

In this study, cryopreservation by droplet-vitrification was applied to pear (Pyrus spp.) germplasm. We focused on the development and assessment of various strategies for the selection of suitable tissue, osmoprotection, and dehydration. We also evaluated post-thaw recovery of cryopreserved explants by droplet-vitrification. Preferentially, we tested the effects of preculture and loading treatments to determine which tissues were more suitable, either the apical shoot tips or the axillary buds. Apical shoot tips showed the better regrowth rate than in vitro axillary buds. The most effective techniques for cryopreservation were as follows. Shoots from in vitro seedlings which had been cultured for about 5-6 weeks were cold-hardened at 4℃ for one week, excised shoot tips were precultured on liquid MS medium including 0.3 M sucrose for 31 hours and 0.7 M sucrose for 17 hours, osmoprotected in loading solution (LS) for 40 min, and then cryoprotected in dehydration solution (PVS3) for 90 min. In addition, we found that regrowth rates of explants on regrowth medium after exposure to liquid nitrogen (LN) were higher than those on MS medium. Results indicated that the highest regrowth percentage was 95.6% for 'Bartlett' cultivar and 68.9% for 'BaeYun No.3' cultivar. Consequently, apical shoot tips of two pear cultivars, 'Bartlett' (P. communis) and 'BaeYun No.3' (P. pyrifolia), were successfully cryopreserved by droplet-vitrification. Results of this study show that the enhanced droplet-vitrification method described in the present study could be used as an effective means for long-term storage of pear genetic resources.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.4
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• pp.50-58
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• 1999

This study was carried out to investigate the growth characteristics and propagation methods of L. obtusiloba as a woody landscape plant. The results are obtained as follows: L. obtusiloba was dioecious shrub and shaped with bush type. Leaves were ovate, obtuse, cordate, 7.05 cm long, 7.20 cm wide, and petiole 2.0 cm long. Flowers of L. obtusiloba were diclinous. Soil acidity ranged from pH 4.06 to 5.53 with the lowest at the Mt. Soo-Ri. Mt. Soo-Ri located near factory district, which was considered to damaged by environmental deteoration. While soil organic matter was highest at Mt. Soo-Ri, inorganic nutrients were low. L. obtusiloba grows in the area with low soil acidity and low content of inorganic. Therefore it seemed to be tolerant to air pollution. L. Obtusiloba was high seed germination rate in the plug box and its shoots were longer than seeding box and softwood cutting of L. obtusiloba showed the rooting rate of 50% at 5,000ppm on June 23. To develop a mass propagation method of Korean native L. obtusiloba through an axillary bud culture as a woody landscape plant, about 2∼3 cm shoots induced from explant were subcultured to new media contained different growth regulators. Shoots multiplied most effectively on a WPM containing 1.0 mg/l BA, producing 5.5 shoots with a shoot length of 2.5 cm per shoot explant.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.38-43
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• 1994

The effect of thidiazuron on callus growth and shoot regeneration of Solanumspecies was very positive. Increasing concentrations of thidiazuron stimulated callus growth of Solanum ptycanthum and Solanum nigrum. Shoot regeneration of S. ptycanthum and S. nigrum was greater on medium with thidiazuron than that with IAA and BA. Thidiazuron at $0.5{\mu}M$ or above increased the number of shoots regenerated from S. ptycanthum calli compared to the IAA with BA. High concentrations of thidiazuron $( >I{\mu}M)$ increased the number of shoots than BA or low levels of thidiazuron and IAA or BA The addition of IAA to thidiazuron media reduced S. ptycanthum shoot formation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.62-62
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• 2022

Freesia has been an important worldwide cut flower because of its fragrance, long vase life and the wide color range of the flower. The conventional propagation methods by seeds and corms have many disadvantages such as shorter inflorescences with fewer numbers of florets, a reduction in cut flower quality and the accumulation of plant viruses in corms by successive cultivation. Therefore, the conventional propagation systems in Freesia needs to be replaced with tissue cultures to overcome the disadvantages. This study explored an efficient multiplication protocol using the combination of plant growth regulators (PGRs) for developed cultivar 'Sunny Gold'. The combination between 6-benzylaminopurin (BA) and α-naphthalene acetic acid (NAA) did not produce new shoots but developed enlarged roots. BA only treatments and the combination between BA and kinetin treatments were effective on shoot multiplication. The highest average number of shoots was 5.3 in the presence of 3 mg/L BA and 0.5 mg/L kinetin. To produce corms and cormlets, proliferated shoots were subcultured on 1/2 Murashige and Skoog (MS) medium supplemented with 90 g/L sucrose, 1 g/L charcoal and 7 g/L plant agar and placed at 4℃ in the dark for 6 months. The small size of corms and comlets were produced. The average number of regenerated comlets was 2.75 per shoot. The results showed that shoot multiplication is more efficient than cormlet regeneration for in vitro freesia proliferation.