• Genes and Genomics
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• v.40 no.12
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• pp.1259-1267
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• 2018

Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop with high commercial value due to its high nutritional values and favorable tastes. However, irregular bearing attributed to unstable flowering is a major ongoing problem for litchi producers. Previous studies indicate that low-temperature is a key factor in litchi floral induction. In order to reveal the genetic and molecular mechanisms underlying the reproductive process in litchi, we had analyzed the transcriptome of buds before and after low-temperature induction using RNA-seq technology. A key flower bud differentiation associated gene, a homologue of FLORICAULA/LEAFY, was identified and named LcLFY (GenBank Accession No. KF008435). The cDNA sequence of LcLFY encodes a putative protein of 388 amino acids. To gain insight into the role of LcLFY, the temporal expression level of this gene was measured by real-time RT-PCR. LcLFY was highly expressed in flower buds and its expression correlated with the floral developmental stage. Heterologous expression of LcLFY in transgenic tobacco plants induced precocious flowering. Meantime, we investigated the sub-cellular localization of LcLFY. The LcLFY-Green fluorescent protein (GFP) fusion protein was found in the nucleus. The results suggest that LcLFY plays a pivotal role as a transcription factor in controlling the transition to flowering and in the development of floral organs in litchi.

• Molecules and Cells
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• v.42 no.5
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• pp.406-417
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• 2019

RICE FLOWERING LOCUS T 1 (RFT1) is a major florigen that functions to induce reproductive development in the shoot apical meristem (SAM). To further our study of RFT1, we overexpressed the gene and examined the expression patterns of major regulatory genes during floral transition and inflorescence development. Overexpression induced extremely early flowering in the transgenics, and a majority of those calli directly formed spikelets with a few spikelets, thus bypassing normal vegetative development. FRUITFULL (FUL)-clade genes OsMADS14, OsMADS15, and OsMADS18 were highly induced in the RFT1-expressing meristems. OsMADS34 was also induced in the meristems. This indicated that RFT1 promotes the expression of major regulatory genes that are important for inflorescence development. RFT1 overexpression also induced SEPALLATA (SEP)-clade genes OsMADS1, OsMADS5, and OsMADS7 in the greening calli before floral transition occurred. This suggested their possible roles at the early reproductive stages. We found it interesting that expression of OsFD1 as well as OsFD2 and OsFD3 was strongly increased in the RFT1-expressing calli and spikelets. At a low frequency, those calli produced plants with a few leaves that generated a panicle with a small number of spikelets. In the transgenic leaves, the FUL-clade genes and OsMADS34 were induced, but SEP-clade gene expression was not increased. This indicated that OsMADS14, OsMADS15, OsMADS18, and OsMADS34 act immediately downstream of RFT1.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.66-71
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• 1980

Sesame cultivar Suweon 9 was sown at two planting time, June 19 and July 3, to study flowering and seed maturation process. Flowering began at 37-40 days after sowing at the 2-4th node and proceeded to upper node with the speed of 1.78 days (June 19 planting) and 1.56 days (July 3 planting) per node until Sept. 1. Sesame capsule reached its full size about 10 days after flowering. Number of sesame seed increased until 15 days, but seed weight gain occurred from 10 days to 35 days after flowering, that meant 25 days the actual seed filling period. The capsule flowered later than Aug. 14 remained immature. There was no more seed weight gain when average. temperature dropped below $20^{\circ}C$ (around Sept.15) and 50% of leaves had senesced. Discussion includes that sesame as an 8determinate plant may have independent source-sink relationship at each node.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.51-51
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• 2022

Water dropwort (Oenanthe stolonifera DC.) is a perennial herbaceous plant that grows wild throughout Korea. As of 2020, 24,819 tons (51.7% of open field, 48.3% of facility) are produced in 1,278 ha (59.9% of open field, 40.1% of facility) nationwide. Water dropwort, which is rich in nutrients such as vitamins and iron, is mainly cultivated by vegetative propagation method using local traditional species, however, seed propagation and breeding of cultivars are insufficient so far. Since securing, propagating and continuous characterization of various genetic resources are required to breed new cultivars, this study was conducted to compare the main characteristics of domestic genetic resources and to improve their utilization. Growth characteristics such as plant height, fresh weight, plant type, and flowering date were investigated for the 89 varieties of genetic resources owned by Jeollabuk-do Agricultural Research and Extension Services after vegetative propagation in the individual pots. Also, the morphological image information of leaves and flowers was constructed. Genetic resources were collected nationwide and originated in 30 regions including Hwaseong, Siheung and Jeju. Their plant types could be classified into straight, intermediate and creeping types according to their morphological characteristics, and at this time, the number of intermediate types accounted for the largest proportion. Flowering was carried out under high-temperature and long-day conditions in summer. According to the flowering date, they could be classified into early, middle and late flowering varieties, and at this time, the middle flowering varieties occupied the largest proportion. As a result of the investigation of vegetative growth characteristics, varieties with long plant height, heavy fresh weight and thick stem thickness were identified. Along with this result, it is thought that classification and selection of genetic resources for various purposes will be possible through additional investigations such as analysis of components and antioxidant activity. Moreover, it is judged that such results can be used as basic data for breeding new water dropwort cultivars in the future.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.61-69
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• 2015

This study was carried out to investigate the effects of shipping temperature and harvesting stage on the quality and vase life of cut flower in standard chrysanthemum 'Baekma' for export. Cut flowers harvested at flowering stage 4 were stored for 24 hours at $5^{\circ}C$, and then quality and vase life were evaluated after simulated shipping for 48 hours at 5, 20, and $35^{\circ}C$. In addition, cut flowers harvested in flowering stage 1 to stage 6 were evaluated after simulated shipping for 72 hours at $5^{\circ}C$. As shipping temperature increased, $CO_2$ concentration inside the box rapidly increased, and $O_2$ concentration greatly decreased. The vase life of cut flowers was extended by 3 days and chlorophyll content of leaves, fresh weight, solution uptake, and flower diameter were better maintained in $5^{\circ}C$ shipping than in 20 or $35^{\circ}C$ shipping. The vase life of cut flowers harvested at flowering stage 1 or 2 was extended by 5.2 or 5.5 days compared to those harvested at flowering stage 6, more 6. The fresh weight was lower and flower diameter was smaller by 1.3 or 2.5 cm in cut flowers of flowering stages 1 through 3 than flowering stages 4 through 6. In addition, the cut flowers of flowering stages 4 through 6 showed higher solution uptake than those of flowering stages 1 through 3. These results suggest that shipping at $5^{\circ}C$ of cut flowers harvested at flowering stage 4 is preferential for promoting vase life and quality of cut flower in standard chrysanthemum 'Baekma' for export to Japan.

• FLOWER RESEARCH JOURNAL
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• v.16 no.4
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• pp.260-265
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• 2008

Studies were carried out to elucidate the effect of temperature, glasshouse forcing date and $GA_3$ on the growth and flowering of pot Hydrangea macrophylla Ser. The plant height was elongated in the $5^{\circ}C$ treatments as 38 cm compared with $20^{\circ}C$ treatment as 6.7 cm, and stem length showed the similar results. The leaf length and width was broadened in the lower temperature, and stem diameter showed the same tendency. The first flowering date in the $15^{\circ}C$ and $20^{\circ}C$ treatment shortened markedly than $5^{\circ}C$ treatment. Days to flowering date of $5^{\circ}C$ was 161 day, while it shortened as 88 day in the $15^{\circ}C$ treatment. The flowering rate was 75.8~90.7% in the temperature. The plant height was elongated in the late glasshouse forcing date, and the leaf length and width showed the similar tendency. The plant height increased in the higher concentration of $GA_3$ compared to the control, and leaf length and width showed the similar results. The first flowering day was advanced by 7 days in the $GA_3$ $50mg{\cdot}L^{-1}$ treatment which had been transferred to greenhouse on Dec. 30 compared with the control of which first flowering day was March 17, and the days to first flowering was conspicuously shortened in the late glasshouse forcing treatment. The width of flower cluster was increased in the $GA_3$ at Dec. 30 glasshouse forcing treatment. The flowering rate was markedly decreased as 62.3% in the control of Nov. 15 treatment, but was increased as 97.9% of $GA_3$ $50mg{\cdot}L^{-1}$ of Jan. 15 treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.76-83
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• 1984

This experiment was performed to investigate the flowering habit of sesame (Sesamum indicum L.). Sesame varieties tested could be classified into 8 different plant types by their morphological traits such as capsule shape, capsule setting habit and branching types among sesame gene pool of Crop Experiment Station, ORD. The first flower was appeared at the lowest node on main stem. Flowers were appeared progressively toward the tip of the main stem and also toward the tips of branches. The interval of flowering for a node was about one day, but 3 to 8 days for the flowers on the tips. Side flowers started at 4 to 5 nodes lower than those of center flower at the same day. Flowers were beared 2 by 1 node on the middle part of flower setting node (7-9) in mono capsule setting habit in spite of its normal is 1 by 1 node on the other nodes. Flowers were beared opposite direction on each node of stem and flowering toward the tip of main stem composed of cross shape between nodes and spiral, reverse of clockwise direction. We called this habit as cross spiral flowering order and cross spiral phyllotaxis. The first flower on branches was appeared when center flower on the 5th node of main stem began to flower. The branches produced at higher nodes on main stem showed larger flowering periods and more number of flowers than that at lower parts. BTB (Branch, Tricapsule, Bicarpels, 4 Loculi) type showed three capsule setting habits and same flowering period both on main stem and branches while BTQ (Branch, Tricapsule, Quadricarpels, 8 Loculi) type showed three capsule setting habit on main stem and mono-capsule setting habit on branches. In BTQ type, the period of flowering was much shorter on branches than on main stem. Branching type was considered more promising than non branching type for the breeding of early maturing high yielding variety because branching type has the advantage of bearing a lot of flowers in comparatively short flowering period.

• The Korean Journal of Ecology
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• v.8 no.1
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• pp.53-59
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• 1985

Phenological development, flowering and leafin times of Rhododendron muronulatum and R. schlippenbachii along elevagtion were studied at Mt. Kwanak, 629m high above the sea level, in Seoul. Flowering and leafing time of the former were delayed at the rate of 2.3~3.3 days and those of the latter were of 2.0~3.0 days per 100m ascent. Phenological changes of both plant species were closely correlated with minimum air temperature first, and then soil water content and minimum soil temperature among the climatic factors. Phenological difference caused by altitude and slope direction(southeast-northwest) among the topographic factors was admitted at the high significance level, but the difference by ridgevalley was little.

• Journal of Plant Biotechnology
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• v.4 no.4
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• pp.179-181
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• 2002

Nodal explants of Ocimum basilicum L. (Sweet basil, Lamiaceae), showed shoot proliferation after 7-10 days on MS media containing 1.5 mg/L kinetin. In vitro flowering was achieved from 90% of the shootlets which were sub cultured on a half strength MS media fortified with 5 mg/L BAP and 1 mg/L IAA. Cytokinin alone or in combination with $CA_3$and NAA resulted in shoot proliferation only. For rooting the plantlets were subcultured on MS basal medium supplemented with 3 mg/L NAA and rootlets emerged after 10 days of incubation. The survival percentage of transplanted plantlets was 70%.

• Journal of Plant Biology
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• v.37 no.2
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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.