• Journal of Plant Biology
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• 제37권2호
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• pp.159-166
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• 1994

Direct current (DC) applied to cotyledons during a 16 h inductive dark period inhibited the flowering in the short-day plant, Pharbitis nil Choisy cv. Violet. The inhibitory effect of DC was more profound when the current flowed from roots to cotyledons, showing its polarity-dependent action. The second half on the inductive dark period was more sensitive to DC stimulus. The flowering was significantly depressed only when DC stimuli were applied to the translocation path of the floral stimulus from the induced cotyledon to the apex, suggesting that the transport of floral stimulus was damaged by the DC treatment. The vegetative apex culture bioassay system showed that a significant level of the floral stimulus activity existed in the phloem exudate from the cotyledons which would fail to form their own floral buds. These results strongly support the hypothesis that DC partially impede, at least temporarily, the transmission path of the floral stimulus from florally-induced cotyledon to the apex, rather than depressing in situ synthesis of the floral stimulus.

• 한국산림과학회지
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• 제94권2호통권159호
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• pp.67-72
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• 2005

The objectives of this study were to identify the period of initiation of floral primordia in black locust (Robinia pseudoacacia L.) and subsequent development of floral buds until following spring. Four mature trees of black locust located in Suwon, Korea were selected. Bud samples were collected from the current-year shoots, starting from mid June to July every week, from August to October and from February to April every month. The buds were fixed in FAA solution, dehydrated, and imbedded in paraffin for microscopic observation. Buds collected on June 16, and 23, 1997, contained primitive primordia that might be interpreted as early floral primordia. By June 30, a bud showed a positive indication of inflorescence primordium with a well-formed shoot apex. All the inflorescence primordia observed throughout the collection periods were always associated with unique hairy appendages around the primordium and enclosed within a sclerenchymatous chamber. By July 7 and 15, a floral apex had early bud scales. By July 22, primitive inflorescence developed into visible arrangement of individual floral primordial By July 29, the inflorescence developed into whirl arrangement of individual floral primordia in a transverse section, but showed little further development until October 15. The inflorescence primordia seemed to over-winter at this stage. Buds collected from February 15 and March 24 the following year also showed no further development of inflorescence primordia. By April 7 the inflorescence started to show further development with elongated axis. At this time individual flowers were easily recognized.

• 식물분류학회지
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• 제48권3호
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• pp.172-184
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• 2018

We examined the floral morphology of 15 taxa of five genera (Cynanchum, Marsdenia, Metaplexis, Tylophora, and Vincetoxicum) in Korean Asclepiadoideae using a stereoscopic and scanning electronic microscope to clarify and describe the floral characteristics. In this study, the corolla and corona types, the types of corona lobes, appendages on the corona lobes, and the apex shape of the style head are considered as diagnostic characteristics at the generic level. The genus Vincetoxicum, which is treated as a synonym of the genus Cynanchum in Korea, is distinguished from Cynanchum by the interstaminal part on the corona, fleshy and mainly triangular or ellipsoid corona lobes, and various corolla colors. In Cynanchum, various corona types have been observed, while Vincetoxicum have similar corona types among the taxa. In addition, the main floral characteristics at the species level were as follows: flowering time, inflorescence, corolla color, trichomes on the corolla surfaces, apex shape of the corona lobe, and trichomes on the ovary. This study presents the taxonomic importance of floral morphology by providing descriptions and diagnostic characteristics among the genera and species investigated.

• 한국약용작물학회지
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• 제11권2호
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• pp.122-126
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• 2003

겨우살이 기생위치는 숙주목(상수리나무 등)의 종류에 관계없이 대부분 지면에서 5-10m높이의 일사량이 많은 상단부에 기생하였다. 줄기의 분화는 주경에서 2개씩 연속분지를 형성하였고, 잎은 정단줄기의 상단부에 2매씩 대생하였으며, 종실은 연황색의 7-8mm 크기의 장과였다. 겨우살이 화아분화는 초기 둥근 돔형의 화아정단이 형성되고 엽원기가 1, 2매 차례로 분화한 다음 심장형으로 발달하며 악편이 발생하였는데, 중앙부에서 먼저 진행되었고 이어 양측 면에 2개를 형성하였다. 잎은 이면의 표피 2-3층 아래에 기공과 공변세포가 관찰되었고, 겨우살이는 기주목의 흡착부에서 기주조직의 코르크층을 통과하여 목질부에 뿌리를 내리고 여러 갈래로 분지하여 생장하는 것을 확인하였다.

• Journal of Photoscience
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• 제7권3호
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• pp.103-108
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• 2000

We have evaluated a new mutagenesis strategy called random insertional mutagenesis with subtracted cDNA fragments. The cDNAs from long day Arabidopsis plants were subtracted by cDNAs from short day plants using PCR based cDNA subtraction. The subtracted cDNAs were inserted between 35S promoter and 3'-NOS terminator regardless of orientation. When the cDNA library was used for the random insertion into Arabidopsis genome by Agrobacterium-mediated transformation, approximately 15% of transformants showed abnormal development in leaf, floral organ, shoot apex. When 20 mutants were analyzed, 12 mutants showed single cDNA fragment insertion and 8 mutants showed more than 2 transgene insertions. Only two mutants among 12 mutants that have single cDNA insert showed consistent phenotype at T2 generation, suggesting the genetic instability of the mutants.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1996년도 제10회 식물생명공학심포지움 고등식물 발생생물학의 최근 진보
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• pp.4-9
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• 1996

The majority of plants sense environmental signals, such as day length or temperature, to select their transition timing from vegetative growth t flowering. Here, we report the identification of a regulatory gene, OsMADS1, that controls the photoperiod sensitivity of flowering time. Constitutive expression of OsMADS1 in a long-day flowering plant, Nicotiana sylvestris, resulted in flowering in both short-day long-day conditions. Similarly, ectopic expression of the gene in a short-day flowering plant, N. tabacum cv. Maryland Mammoth, also induced flowering regardless of the day length. The transition time was dependent on the level of the OsMADS1 transcript in transgenic plants. These suggest that OsMADS1 is a key regulatory factor that determines the transition from shoot apex to floral meristem and that it can be used for controlling flowering time in a variety of plant species.

• 식물분류학회지
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• 제52권3호
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• pp.144-155
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• 2022

Daphne kiusiana is an evergreen shrub with dense head-like umbels of white flowers distributed in southern Korea, Japan, China, and Taiwan. Plants in China and Taiwan are recognized as var. atrocaulis by having a dark purple stem, elliptic leaves, and persistent bracts. Recently, plants on Jejudo Island were segregated as a separate species, D. jejudoensis, given their elliptic leaves with an acuminate apex, a long hypanthium and sepals, and a glabrous hypanthium. Morphological variations of three closely related taxa, the D. kiusiana complex, were investigated across the distributional range to clarify the taxonomic delimitation of members of the complex. Twelve characters of the leaf and flower were measured from digitized herbarium specimens using the image analysis program ImageJ and were included in a morphometric analysis, the results of which indicate that the level of variation in the characters is very high. The results of a principal component analysis weakly separated D. jejudoensis from D. kiusiana according to their floral characteristics, such as a longer, glabrous hypanthium, and larger sepals. However, some individuals of D. kiusiana, particularly those from Bigeumdo Island, were included in D. jejudoensis. Recognition of D. kiusiana var. atrocaulis based on the leaf shape was not supported in the analysis, and D. jejudoensis may be recognized as a variety of D. kiusiana. Our morphometric analysis shows that digitized images of herbarium specimens could be useful and an additional method by which to investigate more diverse specimens.

• 생명과학회지
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• 제16권3호
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• pp.540-545
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• 2006

T-DNA 매개 형질전환은 삽입 돌연변이를 가지는 형질전환 식물체를 만들기 위한 유용한 방법이다. 애기장대의 shoot 발달 과정에서 중요한 역할을 하는 유전자를 확인하기 위해, 프로모터 trap 식물체 라인을 제작하고 분석하였다. 이를 위해 효율적인 프로모터 trap 백터인 pFGL561을 제작하였다. pFGL561은 basta 저항성 유전자, multiple splicing donor acceptor 서열들, 그리고 프로모터가 없는 GFP 리포터 유전자를 포함하고 있다. Agrobacterium 균주인 GV3101에 pFGL561을 도입하고, 이를 매개로 하여 300개의 $T_1$ 프로모터 trap 식물체를 제작하였고, 이들 식물체에서 GFP 발현을 조사하였다. $T_1$ 식물체에서 GFP 발현 비율은 26.7%로 매우 높았고, 이러한 발현은 $T_2$ 식물체에서도 재확인되었다. 한편, 식물의 shoot 발달에 관여하는 주요 유전자를 동정하기 위해서, shoot에서 GFP발현을 보인 19개 $T_1$ 식물체에서 유래한 $T_2$ 식물체를 대상으로 표현형을 조사한 결과, 비정상적인 shoot발달을 보이는 6개 $T_1$ 라인을 확인하였다. 이들 식물체는 shoot발달의 조절 기작 분석에 매우 유용하게 사용될 수 있을 것이다.