• 한국자원식물학회지
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• 제19권2호
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• pp.340-343
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• 2006

개화후 강우 시기가 홍화의 생육과 종실의 품질에 미치는 영향을 구명하기 위해 시험을 수행한 결과는 다음과 같다. 개화후 강우 시기에 따른 지상부 및 꽃 봉오리 병해 발생 정도는 각각 3.3, 1로서 영향을 미치지 않았다. 등숙 비율은 주경은 개화후 $1{\sim}5$일 강우시 37.4%, 1차 분지는 개화후 $6{\sim}10$일 강우시 63.0%로서 가장 낮았다. 10a당 수량은 무강우의 327kg/10a에 비해 개화후 $6{\sim}10$일과 개화후 $11{\sim}15$일 강우시 $282{\sim}281kg/10a$으로서 각각 14% 감소되었다. 종실의 색도(명도=L)는 개화후 $21{\sim}25$일 강우시 73.5, $26{\sim}30$일 강우시 69.9로서 무강우 79.3에 비해 크게 낮아졌다. 이상의 결과에서 볼때 수확기 강우에 의한 종실의 품질 손실 방지를 위해서는 개화후 25일까지는 수확을 해야 할 것으로 사료된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.100-100
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• 2017

FT is one of the major floral activator in plant flowering. FT determines the changing point of time from vegetative stage to reproductive stage. To understand the role of FT homologs in short-day plant soybean, we identified 10 soybean FT homologous genes and named GmFTs. We figured out that 10 GmFT genes were further categorized into three subclades through phylogenetic analysis. Expression analysis of GmFT genes indicated that they might have different functions in photoperiod-dependent soybean flowering. Most of GmFTs, for example, GmFT2a, GmFT2b, GmFT5a and GmFT6 mainly expressed in soybean leaves at short-day condition. However, interestingly GmFT1a and GmFT4 represented opposite expression pattern to other GmFTs. Arabidopsis transgenic plants overexpressing GmFT2a and GmFT5a exhibited extremely early flowering. In contrast, overexpression of GmFT4 delayed flowering of Arabidopsis transgenic plants. The results suggest that GmFT4 has antagonistic role to other GmFTs in soybean flowering. Interestingly, mRNA level of GmFT2a is higher in early flowering soybean accessions than in late flowering ones. Moreover, the highest point of mRNA level of GmFT2a showed the positive correlation with the timing of flowering of soybean accessions. But that of GmFT4 showed opposite pattern. Here, we report that soybean FT homologs might acquire different functions in photoperiod-dependent flowering through the functional diversification during evolution.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.308-316
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• 2018

Background: Genus Sasa, dwarf bamboos, are considered to be species that lower biodiversity in the temperate forests of East Asia. Although they have a long interval, they, the monocarpic species, have a unique characteristic of large-scale synchronized flowering. Therefore, once they have flowered and then declined, it may be an opportunity for suppressed surrounding species. A previous study reported that Sasa borealis showed specialized flowering nationwide with a peak in 2015. However, this was based on data from a social network service and field survey at Mt. Jeombong. Therefore, we investigated S. borealis in the forests of five national parks in order to determine whether this rare synchronized flowering occurred nationwide, as well as its spatial distribution. Results: We found a total of 436 patches under the closed canopy of Quercus mongolica-dominated deciduous forests in the surveyed transects from the five national parks. Of these patches, 75% occupied a whole slope area, resulting in an enormous area. The patch area tended to be larger in the southern parks. Half (219 patches) of the patches flowered massively. Among them, 76% bloomed in 2015, which was consistent with the results of the previous report. The flowering rate varied from park to park with that of Mt. Seorak being the highest. The culms of the flowering patches were significantly taller (F = 93.640, p < 0.000) and thicker (F = 61.172, p < 0.000). Following the event, the culms of the flowering patches declined, providing a good opportunity for the suppressed plant species. The concurrent massive flowering of the mature patches was believed to be triggered by some stress such as a spring drought. Conclusion: We confirmed that the rare synchronized flowering of S. borealis occurred with a peak in 2015 nationwide. In addition, we explored that S. borealis not only monopolized an enormous area, but also dominated the floors of the late-successional Q. mongolica-dominated deciduous forests. This presents a major problem for Korean forests. As it declined simultaneously after flowering, there are both possibilities of forest regeneration or resettlement of S. borealis by massively produced seeds.

• 한국환경농학회지
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• 제35권4호
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• pp.256-262
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• 2016

BACKGROUND: 'Shiranuhi' mandarin is one of the popular citrus cultivars in Jeju Island, Korea. However, the emergence of scion roots since the past few years has altered its flowering, fruiting, and quality. Girdling of branches is one of the methods of increasing flowering in citrus trees. METHODS AND RESULTS: This experiment was conducted to determine the effect of girdling on the flowering and yields of scion rooted 'Shiranuhi' mandarin hybrid. We selected normal trees without scion roots as controls. The trees with scion roots were divided into two groups: trees without girdling and with girdling on main branches. Each group contained five replications and the experiment was conducted in Gosan and Harye of Jeju Island. The scion rooted trees revealed severely decreased flowering and low flowering/leaf ratios; however, the leaf/fruit ratio significantly increased. But, girdling on main branches significantly increased flowering and the flowering/leaf ratio. In the scion rooted trees, yields dropped due to poor flowering; however, girdling of branches efficiently improved the yields of the trees. Fruit quality, fruit size, and fruit weight of scion rooted trees were low in comparison with the control, whereas girdling of the branches improved flowering and the fruit weight to some extent. No significant difference in soluble solid contents was observed. CONCLUSION: Girdling is an effective method to induce flowering of the scion rooted 'Shiranuhi' mandarin trees. In addition, yields of scion rooted trees were improved.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.265-271
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• 2018

Background: Temperature-driven variation in pollinator assemblage and activity are important information, especially at high altitudes, where rising temperature trends exceed global levels. Temporal patterns of pollinators in a flowering season can be used as a proxy to predict the changes of high-altitude plants' mutualistic relationships. We observed a spring temperature change in one population of a high-altitude endemic species, Megaleranthis saniculifolia on Mt. Sobaeksan, and related it to pollinator assemblage and activity changes. Methods: This study was conducted at two sites, each facing different slopes (NE and NW), for two times in the spring of 2013 (early-flowering, April 27-28, vs. mid-flowering, May 7-8, 2013). We confirmed that the two sites were comparable in snowmelt regime, composition of flowering plants, and flower density, which could affect pollinator assemblage and activity. Pollinator assemblage and activity were investigated at three quadrats ($1m^2$ with 5-m distance) for each site, covering a total of 840 min observation for each site. We analyzed correlations between the temperature and visitation frequency. Results: Twelve pollinator species belonging to four orders were observed for M. saniculifolia at both sites during early- and mid-flowering times. Diptera (five species) and hymenopteran species (four species) were the most abundant pollinators. Pollinator richness increased at both sites toward the mid-flowering time [early vs. mid = 7 (NE) and 3 (NW) vs. 9 (NE) and 5 (NW)]. Compared to the early-flowering time, visitation frequency showed a fourfold increase in the mid-flowering time. With the progression of spring, major pollinators changed from flies to bees. Upon using data pooled over both sites and flowering times, hourly visitation frequency was strongly positively correlated with hourly mean air temperature. Conclusions: The spring temperature change over a relatively brief flowering period of M. saniculifolia at high altitudes can alter pollinator assemblages through pollinator dominance and visitation frequency changes. Thus, this study emphasizes information on intra- and inter-annual variations in the mutualistic relationship between pollinators and M. saniculifolia to further assess the warming impacts on M. saniculifolia's reproductive fitness.

• Journal of Plant Biotechnology
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• 제50권
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• pp.190-199
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• 2023

Date palm (Phoenix dactylifera L.: Arecaceae) is a dioecious species where only female trees bear fruits. In their natural state, date palms produce dates once a year. However, in Thailand, some trees were observed to produce dates during the off-season, despite no variations in morphology. The availability of such off-season fruits can significantly increase their market value. Interestingly, most female off-season date palms investigated in this study were obtained through micropropagation. Hence, there is an urgent need for genetic markers to distinguish female offseason flowering plantlets within tissue culture systems. In this study, we aimed to develop random amplification of polymorphic DNA-sequence characterized amplified region (RAPD-SCAR) markers for the identification of female off-season flowering date palms cultivated in Thailand. A total of 160 random decamer primers were employed to screen for specific RAPD markers in off-season flowering male and female populations. Out of these, only one primer, OPN-02, generated distinct genomic DNA patterns in female off-season flowering (FOFdp) individuals compared to female seasonal flowering genotypes. Based on the RAPD-specific sequence, specific SCAR primers denoted as FOFdpF and FOFdpR were developed. These SCAR primers amplified a single 517-bp DNA fragment, predominantly found in off-season flowering populations, with an accuracy rate of 60%. These findings underscore the potential of SCAR marker technology for tracking offseason flowering in date palms. Notably, a BLAST analysis revealed a substantial similarity between the SCAR marker sequence and the transcript variant mRNA from Phoenix dactylifera encoding the SET DOMAIN GROUP 40 protein. In Arabidopsis, this protein is involved in the epigenetic regulation of flowering time. The genetic potential of the off-season flowering traits warrants further elucidation.

• Molecules and Cells
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• 제39권10호
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• pp.715-721
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• 2016

Plants have become physiologically adapted to a seasonally shifting environment by evolving many sensory mechanisms. Seasonal flowering is a good example of adaptation to local environmental demands and is crucial for maximizing reproductive fitness. Photoperiod and temperature are major environmental stimuli that control flowering through expression of a floral inducer, FLOWERING LOCUS T (FT) protein. Recent discoveries made using the model plant Arabidopsis thaliana have shown that the functions of photoreceptors are essential for the timing of FT gene induction, via modulation of the transcriptional activator CONSTANS (CO) at transcriptional and post-translational levels in response to seasonal variations. The activation of FT transcription by the fine-tuned CO protein enables plants to switch from vegetative growth to flowering under inductive environmental conditions. The present review briefly summarizes our current understanding of the molecular mechanisms by which the information of environmental stimuli is sensed and transduced to trigger FT induction in leaves.

• 한국작물학회지
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• 제25권4호
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• pp.81-85
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• 1980

Field experiment was conducted to determine the optimum harvesting time in winter rape (Brassica napus L.) by investigating the percent oil, 1, 000 seed weight, seed yield, dehiscent pod ratio and oil yield at 46, 50, 54, 58, 62, 66 and 70 days after flowering. Variation of all characters with days after flowering could be explained significantly by second degree polynomial equations. Percent oil and 1, 000 seed weight increased until 62 days after flowering and thereafter these traits decreased, while seed yield increased to 58 days after flowering and thereafter this trait decreased. This controversy was due to the drastic increase in dehiscent pods beyond 58 days after flowering which brought loss in seed yield. These results suggest that optimum harvesting time is 58 days after flowering and it should not be later than 60 days after flowering.

• The Korean Journal of Ecology
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• 제6권1호
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• pp.18-21
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• 1983

Patterns of flowering periods of Ben Lawers, Eastern suburbs of Melbourne, and Tasmanian floras are compared. The total sum of each flowering period of the following floras are gradually increased from Ben Lawers to Tasmania and Eastern subarbs of Melbourne. These patterns seem to be related with the factors of temperature. A peak of the flowering periods of Ben Lawers flora occur' in July, while Eastern suburbs of Melbourne in October, and Tasmania in November to Decomber. The patterns of these flowering periods are characteristic of and divided into two categories, northern arctic and southern temperaturate hemispheric types.

• 한국작물학회지
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• 제47권6호
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• pp.437-442
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• 2002

선발된 단기개화성 유전자원의 개화 특성 및 농업적 형질을 구명하여 협실의 균일도 향상에 의한 상품가치가 높은 땅콩을 육성하고자 수행한 결과를 요약하면 다음과 같다. 1. 단기개화성 계통들의 출현기는 대광땅콩에 비하여 1-3일 빨랐으며, 개화기는 비슷하였으나, 개화기간은 대광땅콩이 52일인데 비하여 단기개화 계통들은 36-47일로써 5-16일이 짧았으며, 초형별로는 valencia type이 가장 짧았다. 2. 초형별 개화수는 virginia ＞ spanish ＞ valencia 순으로 적었으며, 40일 이하의 극단기개화 계통은 valencia type이 23%로 가장 많았다. 3. 초형별 차광에 따른 개화억제율은 대광땅콩의 63%에 비하여 valencia 43% ＞ virginia 35% ＞ spanish 10%순 이었으며, 농업적 형질별로 감소율은 valencia type이 가장 적었다. 4. 개화와 기상요인 상관정도는 온도와는 각 초형 공히 고도의 정의상관의 유의성이 있었으나, 일조시수와는 유의성이 인정되지 않았다. 5. 초형에 따른 절위별 자방병 분포비율은 저위절(제1절과 2절)에서 virginia 97%, spanish 88%, ㅍ미두챰 93%로 대광땅콩의 85%에 비하여 3-l2% 높았으며, 절위별 착협 분포비율은 저위절(제1절과 2절)에서 virginia 100%, spanish 95%, valencia 96%로 대광땅콩의 74%에 비하여 21-26%높았다. 6. 개화 후 일수에 따른 성숙협 비율은 대광땅콩에 비하여 단기개화 계통들이 평균 12-17% 높았으며, 단기개화 계통들의 각 형질과의 상관은 개화시와 개화일수, 개화일수와 성숙협 비율과는 고도의 부 상관이었다.