• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.193-207
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• 1993

The seed dormancy of weed species is the important mechanisms to unfavorable conditions but it brings about critical problems in weed control. The factors which induced dormancy were varied with species and their physiological conditions. More than 20 of 50 species of dominant weed species showed the seed dormancy. When several physical treatments were given to seeds to break the dormancy, each species showed the different responses. The germination percentage and germination velocity were increased with alternating temperature. The treatment of more than 4 weeks of stratification had strong effect on dormancy breaking. The ${\alpha}-amylase$ activities of germinating seeds were increased in proportional to the period of stratification treatment of dormant seeds. The contents of soluble protein and soluble sugar were changed slightly with stratification.

• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.317-321
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• 2001

This study was carried out with Lilium oriental hybrid cv. Casa Blanca to observe the effect of in vitro culture conditions on ex vitro sprouting of bulblets. Low temperature (15$^{\circ}C$) inhibited the growth of in vitro bulblets while high temperature ($25^{\circ}C$) enhanced the growth. Bulblets cultured at 15$^{\circ}C$ did not show dormacy while those cultured at 2$0^{\circ}C$ ,$25^{\circ}C$ had a longer dormancy period. High sucrose concentration (9%) induced longer dormancy. Dormancy period was also prolonged in bulblets cultured in vitro at high temperature ($25^{\circ}C$). Dormancy period was more affected by in vitro culture temperature rather than sucrose concentration. Physiological dormancy was released more rapidly when bulblets were cultured at $25^{\circ}C$ for 6 weeks and further transferred at 15$^{\circ}C$ and cultured for another 12 weeks. Treatment of ABA induced the dormancy in Lilium bulblets but when bulblets were subjected to chilling treatment (4$^{\circ}C$ for 8 weeks) nearly 100% sprouting were observed. The medium containing 1.0 mg/L BA or 1.0 mg/L fluridone was also effective to produce non-dormant bulblets.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.85-93
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• 1984

This research was carried out to study the seed dormancy of radishes which were used for summer vegetation. The differences of dormancy of cultivars, maternal effects, the effect of full day length to mother plants, and the effects of chemical treatments for breaking the seed dormancy were considered for this study. These results sere summarized as follows; 1. The germination percentage of 7 cultlvars sown just after harvest were as follows;SP70-:0, PS11-:37.5, GJ75-:75.5, JD127-:77.5, YH85-:81.0, M55-:96.5, and JC73-:98.0%. 2. The dormany of $F_1$ seed of radish was severe when SP70-was used for mother plant. 3. Germination behavior was different by the maturity of plants grown for seed production. The dormancy of seed harvested from immature field-grown plants sown Nov. 10 was deeper than mature plants sown Mar. 22. 4. The germination ratio of tire seed of SP70-radish was increased by treatment of full day length to tire mother plant during full period of growing or since first flowering stage, while that was 0% by treatment since yellow ripening stage. 5. GA 200 ppm+thiourea 0.2% treatment was most effective for breaking of radish seed dormancy.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.564-573
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• 2016

This research was performed to develop mass propagation method of round-leaved sundew (Drosera rotundifolia L.) for improving horticultural usefulness. Seeds were collected around Hwaseong-si, Gyeonggi-do in October of 2011 and experimented upon while being dry-stored at 4 ± 1.0℃ (darkness). Seed length of a major and minor axis were 1.58 ± 0.060 and 0.21 ± 0.016 ㎜, respecrively, and weight of 1,000 seeds was 6.24 ± 0.172 ㎎. Seeds were thus classified as ‘dwarf seeds’. Regarding the dormancy type, since round-leaved sundew seeds were dormancy broken and germinated at 20~30℃ under the light condition after wet-chilling treatment for 12 weeks, seeds were estimated to have physiological dormancy. Germination conditions of dormancy broken seeds were found to be 20℃ and light condition (54.7%), but germination decreased at higher temperature. Percent germination (PG), germination energy (GE), mean germination time (MGT) and T₅₀ were effectively improved by chemical treatment such as GA₃ 200 ㎎/L + kinetin 20 ㎎/L and wet-chilling treatment for 14 weeks. In conclusion these optimal conditions were thought to be a useful method for raising seedling uniformly.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.457-462
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• 2019

This study was conducted to investigate seed dormancy type and germination characteristics of Lonicera chrysantha. In imbibition test, the seeds imbibed water readily. Therefore, the seeds did not have physical dormancy (PY). The seeds have undeveloped embryo at seed dispersal and, then the E:S ratio (embryo/seed ratio) increased more than about 46% just before germination. In temperature experiments (5, 15, 20 and $25^{\circ}C$), the seeds did not germinate during incubation at $5^{\circ}C$. At $20^{\circ}C$, the seeds started to germinate from a week after sowing and the final germination was 86.7% at 2 weeks after sowing. At $15^{\circ}C$, the seeds started to germinate at 2 weeks and the final germination rate was 75.0% at 4 weeks after sowing. At $25^{\circ}C$, the seeds started to germinate at a week and the final germination rate was 48.3% at 19 weeks after sowing. Consequently, Optimum temperature of germination is $20^{\circ}C$ that shown highest final germination rate and shortest mean germination time. The seeds germinated all temperature treatments within 4 weeks except to $5^{\circ}C$. Therefore, it is concluded that seeds of L. chrysantha have only morphological dormancy (MD).

• Korean Journal of Environmental Biology
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• v.19 no.4
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• pp.270-277
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers induced in vitro of two potato (Solanum tuberosum L. cv. Dejima and cv. Superior) cultivars with different storage duration were irradiated with ${\gamma}$ radiation at the dose of $0.5{\sim}30$ Gy. Sprouting rate, growth and tuber yield of ‘Dejima’ microtuber were increased by ${\gamma}$ radiation in the range of $2{\sim}16$ Gy. In the microtuber of ‘Superior’, the sprouting rate was promoted by 2 Gy and 4 Gy irradiation, and the growth and tuber yield by 0.5 Gy and 4 Gy irradiation. There were not that much difference in chlorophyll content of potato plantlet by the low dose ${\gamma}$ irradiation. These results suggested that low dose ${\gamma}$ radiation stimulated the dormancy breaking and potato growth.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.3
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• pp.185-191
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• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.105-112
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• 1979

Effect of gibberllin on the breaking of bud dormancy of root and growth of aerial parts were investigated under laboratory and field condition for the prolongation of shoot growth duration, shortening of fruit bearing age and the increase of root yield. Drop application of GA (0.5ml of 50ppm) on rhizome of one year old root broke bud dormancy better than by low temperature. Soaking for one hour of one year old roots which wintered in the field in GA (50-200ppm) greatly accelerated the emergence of new buds while kinetin was only effective at low level (50ppm). GA substantially increased stem length in early stage and petiole length later on while kinetin increased stem diameter. Under the field condition with polythylene film tunnel (PET) in early spring the soaking in GA (50ppm for 1 hour) of rhizome of 4 year old root with replanting and dropping GA (50ppm, 1ml) on rhizome without replanting brought earlier emergence (29days) in comparison with that in the usual field. PET alone caused 14 day-early emergence. GA increased the length of stem and petiole only in early stage and replanting decreased only petiole length in later stage. Soaking in GA with replanting caused the Pronounced decrease in peduncle length, percentage of (ruin set and dry weight of reproductive organ (fruits and peduncle). Dropping without replanting showed significant decrease only in dry weight of reproductive organ. Fruit maturing was 20 days earlier than in usual held with little difference between GA and PET. It is well expected that GA could be used for early emergence of bud, shortening of root dormancy period, thinning of fruit and higher root yield according to application amount and methods.

• Journal of Ginseng Research
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• v.11 no.2
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• pp.111-117
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• 1987

The phase and times on the development of dormancy bud in seedling, and those of flower organs in 2-year-old ginseng are different to those of over 2-,3-year-old plant, respectively. The growing aspects of dormancy bud in seedling were investigated from rooting stage (April, 8) to Mid-June, and those of flower organs in 2-year-old plant had done once in two days late in April after compound leaves were unfolded. Firstly, the formation of dormancy bud in seedling was begun on Mid-late in March. This is early about one month compare with those of over 2-year-old plant. Fine bud in seedling was formed between cotyledons, at W spot under young shoot. Secondly, development of flower organs in 2-year-old plant was completed from late of April to early of May after compound leaves of transplanted plant were unfolded. In tare, this is very different characteristics because plants of any other ages form the flower organs one year ago. Thirdly, flower organs of ginseng plant, over 3-year-old plant, always develop in the rhizome formed one year ago, but those of 2-year-old plant develop in apical shoot meristem.

• FLOWER RESEARCH JOURNAL
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• v.18 no.2
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• pp.93-97
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• 2010

The objective of this study was to investigate the effect of hot water and dipping times, and hot- PGR's solution on dormancy breaking of Lilium Oriental Hybrid 'Casa Blanca' and 'Siberia' bulblets regenerated in vitro. Hot-water treatments with distilled water were effective not sprouting rate but shortening of days to sprouting. While $100mg{\cdot}L^{-1}\;GA_{4+7}$ was effective in the dormancy breaking process of bulblets. The content of mitochondrial protein and fumarase activity were highest in bulblet of $100mg{\cdot}L^{-1}\;GA_{4+7}$ addition in hot water treatment. Therefore $GA_{4+7}$ addition in hot-water treatment seem to be the alternative dormancy breaking method to low-temperature treatment in Lilium Oriental Hybrid bulblet regenerated in vitro.