• 한국작물학회지
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• 제27권3호
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• pp.193-197
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• 1982

수도의 동일요소에 형성된 각 관근의 신장량은 다음과 같은 관계에 있음을 알았다. 1. 분벽아를 제거하여 각 관근만을 sink로 하였을 경우에는 중륵의 가까운 곳에 형성된 관근이 분벽아쪽에 형성된 관근보다 신장량이 좋았다. 2. 분벽아가 관근과 같이 sink로서 존재할 경우, 전출엽요소에서 출근한 관근이 가장 길었으며 또 분벽경 부근에 형성된 관근이 그 다음이었고 중륵 쪽에 형성된 관근이 가장 짧았다.

• 식물조직배양학회지
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• 제27권2호
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• pp.101-107
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• 2000

야콘의 절편체로부터 탈분화 조건을 규명하고, 잎의 절편체로부터 재분화 및 기내관아 형성조건을 조사하기 위하여 절편체를 배양하였다. 야콘의 잎으로부터 캘러스 형성에 MS배지가 $\frac{1}{2}$MS 및 B$_{5}$ 배지보다 효과적이었다. 잎, 엽병 및 측아 절편체로부터의 캘러스 형성률은 2,4-D 1.0, 2.0 mg/L에 kinetin 또는 BA를 0.2, 0.4 mg/L 혼용처리구가 NAA 1.0, 2.0 mg/L에 kinetin 또는 BA를 각각 0.2, 0.4 mg/L 혼용처리구보다 캘러스 형성률이 높았다. 잎으로부터 형성된 캘러스는 BA 1.0 mg/L처리에서 70%의 캘러스 증식율을 보였다. BA 1.0, 2.0 mg/L 처리 시 계대배양이 약 3~4개월 이상 지속되면서 캘러스 증식과 함께 재분율이 63% 이상 되었으나 kinetin 처리구에서는 관찰할 수 없었다. BA의 첨가에 의해 치상 후 약 3~4개월이 경과하면서 기내 소관아를 형성하기 시작하여 약 5~6개월 후에는 많은 양의 기내관아를 얻을 수 있었는데, BA를 5 mg/L 첨가한 배지에서 82.8%로써 기내소관아 형성률이 가장 높았으며, BA의 함량 증가에 따라 기내소관아 형성률도 증가하는 경향이었다. 그러나 BA의 함량이 5 mg/L이상 증가함에 따라 잎이 두꺼웠으며 줄기는 절간장이 짧고 분화 후에 생육을 지속하지 못하고 고사하였다. 한편, BA를 2 mg/L첨가하고 sucrose 첨가량을 다르게 하였을 경우, 5% sucrose를 첨가한 배지에서 소관아 형성률이 88.0% 로써 일반적으로 사용하는 3% 처리의 60.0%에 비하여 약28%증가하였다. 포장에서 수확한 관아의 액아와 기내관아의 액아의 조직학적 관찰 결과 크기에 차이가 있을 뿐 형태는 같은 것으로 관찰되었다.

• 한국자원식물학회지
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• 제32권1호
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• pp.53-62
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• 2019

본 연구는 우리나라에 자생하고 있는 비비추속 식물 6종(일월비비추, 주걱비비추, 다도해비비추, 좀비비추, 한라비비추, 흑산도비비추)의 정단을 이용하여 대량증식과 품종개발 등을 위한 기내증식체계를 확립하고자 하였다. 정단은 0.5, 1.0, 2.0, 4.0 mg/L BA와 0.1, 0.5, 1.0, 2.0 mg/L TDZ를 0.1 mg/L NAA와 각각 혼용한 조건과 PGRs을 무첨가한 조건(control)의 MS배지에 배양하였다. 배양 8주 후에 embryogenic callus, somatic embryo, crown bud, 그리고 신초와 뿌리의 분화 및 생육, 생체중 등에 대하여 조사하였다. 6종의 비비추 식물 모두에서 control에 비하여 PGRs 처리구의 embryogenic callus와 somatic embryo 형성율, 다신초 분화율이 높았다. 분화된 신초의 개수는 일월비비추는 2.0 mg/L TDZ에서 5.4개, 주걱비비추와 다도해비비추는 1.0 mg/L TDZ에서 각각 3.3개, 5.8개, 좀비비추는 0.5mg/L BA에서 11.1개, 흑산도비비추는 0.5 mg/L TDZ에서 9.8개, 한라비비추는 1.0 mg/L BA, 0.1 mg/L TDZ에서 8.1개로 가장 많았다. Somatic embryo 형성에서는 다도해비비추와 흑산도비비추가 처리한 PGRs에 대해 효과적이었고, 일월비비추, 주걱비비추, 좀비비추, 한라비비추에서는 상대적으로 효과가 적었다. 4종의 자생 비비추(일월비비추, 주걱비비추, 다도해비비추, 흑산도비비추)에서 조사된 crown bud도 control에 비하여 PGRs 처리구에서 더많이 형성되었다. 주걱비비추는 cytokinin의 종류 및 농도와 상관없이 callus와 신초 분화에 큰 효과가 나타나지 않았지만, crown bud의 형성에는 TDZ에서 약간 증가하였다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.27-27
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• 2021

Yacon [Samallanthus sonchifolius (Poepp. & Endl.) H. Robinson], a member of Compositae plants, has sweet taste and crisp texture. Unlike other Andean root crops such as potato and sweet potato, the cultivation area of yacon has increased recently, since it is known to have large content of fructooligosaccharides (FOS). Since there are no yacon varieties bred in Korea, we have been trying to create new genetic resources using gamma-ray. The optimal gamma-ray dosage for mutation breeding in yacon was investigated. Crown bud and green bud of yacon were exposed to doses of gamma rays from 20 Gy to 80 Gy, and subsequently planted in a greenhouse. After 50 days of sowing, the survival rates and growth decreased rapidly at doses above 40 Gy, while all of crown bud individuals died above 60 Gy. The median lethal dose (LD50) of crown bud and green bud was 22.4 and 36.6 Gy, and the median reduction doses (RD50) for plant height, fresh weights, and tuberous root weight were 20-40 Gy, respectively. A dose of 20-40 Gy was found to be optimal for mutation breeding in yacon. Considering the growth factors, the optimum doses were determined to be within the range of 20-40 Gy for the selection of useful mutant lines. M2-M3 mutant lines were obtained from 20-60 Gy gamma-ray-irradiated M1 plants through clonal propagation. These mutant lines will be used for the development of a new variety of yacon plant with high FOS and no crack tuberous root.

• 원예과학기술지
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• 제33권1호
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• pp.31-38
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• 2015

This study was carried out to investigate the relationship between endogenous polyamines (PAs) and floral bud differentiation in chrysanthemum (Chrysanthemum morifolium). In this study, PA content (free, bound, and conjugated) in apical buds, leaves, and roots changed appreciably during floral bud differentiation. PAs accumulated during series of processes such as floral induction, differentiation of floret primordia, and crown formation in apical buds; changes in PAs in apical buds may have a relationship with those in leaves and roots. The levels of free PAs and conjugated PAs [putrescine (Put) and spermine (Spm)] in apical buds rapidly increased during the initiation stage of floral bud differentiation, while free and conjugated spermidine (Spd) reached their highest levels at the stage of floret primordium differentiation. In the free, conjugated, and bound PA fractions, the changes in Spm content were negligible compared to those of Put and Spd throughout the experiment. These findings indicate that PAs participate in regulating the process of flower bud differentiation in chrysanthemum.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1997년도 추계 학술대회지
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• pp.84-85
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• 1997

• Journal of Ecology and Environment
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• 제35권3호
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• pp.177-188
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• 2012

We analyzed crown development in Aucuba japonica Thunb. var. japonica resulting from the responses of phytoelements to habitat light conditions over a long period of time. Over the years, the degree of extension unit (EU) dimorphism and the degree of anisophylly were higher under shaded conditions than in brighter conditions. An overall temporally increasing pattern in the degree of EU dimorphism was found while no clear-cut trend was found in the case of anisophylly. EU length and number of leaves per EU co-varied in a spatio-temporal context. The number of terminal buds and their sizes acted as the key initiators of morphological differences of phytoelements which were further amplified following bud break. Leaf area density was displayed mostly in the apex peripheral layer of the crown and the apex layer received most of the incident light. There was a tradeoff between annual leaf production and mean leaf size. Depending on the heterogeneity of irradiance level within a crown, correlative growth inhibition caused higher EU mortality at brighter sites. Due to high mortality, shorter EUs had a mere role in the construction of structural framework of the crown except for the formation of some gaps. There was a strong convergence of EU dimorphism, anisophylly, EU extension growth and variations in leaf size towards formation of functional crown to reduce potential self-shading. Depending on the irradiance level, Aucuba japonica Thunb. var. japonica showed two different modes of crown expansion. At the brighter sites, individual crown expansion was progressive while at the darker sites, individual crown expanded in a diminishing manner and maintained a stable size. A plant's "growth diminishing phase" appeared earlier at shaded sites than brighter sites.

• Applied Microscopy
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• 제47권4호
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• pp.242-250
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• 2017

The purpose of this study was to characterize the prenatal and postnatal development of the mouse parotid salivary gland and tooth, and to investigate the relationship between the developmental timing of the two organs. Development of parotid salivary gland begins on embryonic day 15 (E15), which is the prebud stage; E17 is the initial bud stage; E21 to postnatal day 3 (PN3) is the pseudoglandular stage; PN5 to PN10 is the canalicular stage; and PN21 is the terminal bud stage. At E15, the developing maxillary molar tissue is at the bud stage; at E17, it is at the cap stage; at E21, it is at the early bell stage; PN3 to PN5 comprises the advanced bell stage; at PN10, it is at the crown stage; at PN21, it is at the functional stage. Therefore, unlike the other major salivary glands, the development of mouse parotid salivary gland is completed through a process of prenatal and postnatal morphogenesis and becomes functional at about the same time as the developing tooth. The developmental completion times of the parotid salivary gland and tooth are closely related to the weaning time of animal.

• 대한소아치과학회지
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• 제25권2호
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• pp.383-399
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• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• 한국작물학회지
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• 제43권4호
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• pp.223-227
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• 1998

The objectives of this study were to find the sprouting condition and to establish the optimum production methods of plug seedlings in yacon (Polymnia sonchifolia Poepp. & Endl.). The sprouting ratio was greatest at $30\pm 1^{\circ}C$ at 20 days after planting. Crowns with single buds were more effective than those with two or more buds for sprouting, which might be due to the apical dominance. Planting the shoots separated from crown after sprouting in the single- and double-layer polyethylene-covered greenhouses reduced seedling period with 25% and 50%, respectively. Planting the shoots after sprouting was more effective than planting the crown buds. Double-layer polyethylene-covered green-house was good for plug seedling production than open field or single-layer polyethylene-covered greenhouse. The bed soils composed of clay loam : compost or sand : compost (1:l=v:v) were more effective to produce plug seedlings than only clay loam, sand or compost. Seedlings could be produced at 30 days after planting in our studies.