• 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.

• BMB Reports
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• 제51권4호
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• pp.163-164
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• 2018

CONSTANS (CO) induces the expression of FLOWERING LOCUS T (FT) in the photoperiodic pathway, and thereby regulates the seasonal timing of flowering. CO expression is induced and CO protein is stabilized by FLAVIN-BINDING KELCH REPEAT F-BOX PROTEIN 1 (FKF1) in the late afternoon, while CO is degraded by CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) during the night. These regulatory cascades were thought to act independently. In our study, we investigated the relationship between FKF1 and COP1 in the regulation of CO stability in response to ambient light conditions. A genetic analysis revealed that FKF1 acts as a direct upstream negative regulator of COP1, in which cop1 mutation is epistatic to fkf1 mutation in the photoperiodic regulation of flowering. COP1 activity requires the formation of a hetero-tetramer with SUPPRESSOR OF PHYA-105 (SPA1), [$(COP1)_2(SPA1)_2$]. Light-activated FKF1 has an increased binding capacity for COP1, forming a FKF1-COP1 hetero-dimer, and inhibiting COP1 homo-dimerization at its coiled-coil (CC) domain. Mutations in the CC domain result in poor COP1 dimerization and misregulation of photoperiodic floral induction. We propose that FKF1 represses COP1 activity by inhibiting COP1 dimerization in the late afternoon under long-day conditions, resulting in early flowering.

• 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.

• Journal of Ecology and Environment
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• 제31권2호
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• pp.153-159
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• 2008

The timing of the canopy phenology onset (CPO hereafter) indicates the initiation of the growing season, with rapid increases in exchange rates of carbon dioxide and water vapor between vegetation and atmosphere. The CPO is regarded as a potential indicator of ecosystem responses to global warming, but the CPO shows considerable spatial variation depending on the species composition and local temperature regime. at a given geographic location. In this study, we evaluated the utility of satellite observation data for detection of the timing of the CPO. Leaf area indices (LAI) obtained from the Moderate Resolution Imaging Spectrora-diometer (MODIS) were utilized to detect and map the onset dates from 2001 to 2006. The reliability of MODIS-based onset dates was evaluated with ground measured cherry blossom flowering data from national weather stations. The MODIS onset dates preceded the observed flowering dates by 8 days and were linearly related with a correlation coefficient of 0.58 (p < 0.05). In spite of the coarse spatial (1 km) and temporal (8 days) resolutions of MODIS LAI, the MODIS-based onset dates showed reasonable ability to predict flowering dates.

• Journal of Ecology and Environment
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• 제31권2호
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• pp.139-146
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• 2008

To clarify the relationship between the timing and the duration of flowering among populations, plants, and individual flowers, the dates of flower budding, flowering and deflowering were monitored for ten woody species from March 1 to June 30, in 2005, 2006 and 2007, in temperate deciduous forests at three sites of Namsan, and individual plants from seven woody species were monitored from March 1 to May 31, in 2006. Total durations of flower budding, flowering, and deflowering varied among the plant species. Three durations of these phenological stages of Stephanandra incisa were the longest (74 days, 109 days, and 101 days, respectively), and those of Prunus serrulata var. spontanea were the shortest (7 days, 7 days, and 4 days, respectively). For each species, phenological durations varied among years but were similar among the study sites in the same year. There was no relationship between flowering time and flowering duration on the population level. On the plant level, the duration of flower budding was over 11 days in all specie; S. incisa had the longest duration (73.3 days), and that of Styrax japonica was long as well (29.0 days), while that of Prunus leveilleana was the shortest (11.3 days). The longer the mean flower budding duration, the greater the difference among the plants within a species. The flowering duration of for S. incisa was 92.2 days, while that of Forsythia koreana was 27.2 days. The flowering durations of all other species were $10{\sim}20$ days. The deflowering duration was 92.0 days in S. incisa and <15 days in all other species. Differences among the plants in deflowering duration were smaller than those of the other phenological stages. In the species that flowered in April, the correlation coefficient between the flowering duration and the first flowering date was negative and significant. However, in the species that flowered in May, the correlation between flowering duration and the first flowering date was not significant. For individual plants of all species except for S. alnifolia, the earlier the flowering time, the longer the flowering duration. Differences between flowering time and flowering duration across years were significant in six species.

• 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.

• 한국농림기상학회지
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• 제25권4호
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• pp.427-435
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• 2023

이상기상으로 인한 봄꽃 개화 시기의 변화는 식물의 생장기간 뿐 아니라 생물계절을 포함한 생태계의 모든 측면에 영향을 미친다. 따라서 봄꽃 개화 시기를 예측하는 것은 산림 생태계의 효과적인 관리에 필수적이다. 본 연구에서는 464곳의 산림에서 수집된 날씨정보를 기반으로 대한민국 산림의 대표적인 5가지 수종(미선나무, 아까시나무, 철쭉, 산철쭉, 마가목)의 2023년 개화 시기를 예측하기 위해 과정 기반 모형을 사용하였다. 이를 위해 28개 지역의 9년간(2009-2017) 개화 시기 자료를 활용하여 모형을 개발하였다. 개화 시기는 식물의 세 개 이상의 위치에서 처음으로 꽃이 피는 것을 기준으로 측정되었다. 본 연구에서는 STDD와 GDD 과정 기반 모형을 사용하여 개화 시기를 예측하였으며, 두 모형 모두 일반적으로 우수한 성능을 보였다. 과정 기반 모형의 주요 입력변수인 날씨 자료는 산악기상관측시스템과 기상청에서 제공하는 기온 정보를 융합하여 1km의 공간 해상도로 일 단위 기온 자료를 생성하였다. 지역별 보정 계수를 생산하고 적용하기 위해 랜덤포레스트 기계 학습을 활용하여 STDD와 GDD 모형을 기반으로 예측 정확도를 개선하였다. 결과적으로 보정 계수가 적용될 때 대부분의 수종에서 개화 시기의 예측 오차가 작았으며, 특히, 미선나무, 아까시나무, 철쭉에서 평균제곱근오차가 각각 1.2, 0.6, 1.2일로 매우 낮았다. 모형 성능을 평가하기 위해 10회의 무작위 샘플링 테스트를 실시하고, 최적의 결정계수 값을 가진 모형을 선택하여 모형의 성능을 평가하였다. 그 결과, 마가목을 제외한 모든 수종에서 보정 계수가 적용된 모형에서 결정계수가 최소 0.07에서 최대 0.7 증가하였으며 최종적으로 75%에서 90%의 설명력을 가졌다. 이를 기반으로 수종별 보정 계수를 산출하였으며, 1km 해상도의 전국 단위 개화시기예측 지도를 제작하였다. 본 연구는 식물의 계절 변화에 대한 자료로 활용될 것으로 예상되며, 수종 및 지역별로 개화 시기를 상세히 설명하여 기후 변화로 인한 계절 변화를 연구하는 데에 유용할 것으로 기대된다. 또한 우리나라 산림의 주요 수종에 대한 정확도 높은 개화 시기 예측 서비스는 산림 방문객들의 산림 경험 만족도를 크게 높일 수 있으며, 양봉업 등 임업 종사자들의 경제적 향상에 기여할 것으로 기대된다.

• 한국작물학회지
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• 제45권5호
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• pp.282-287
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• 2000

Soybean [Glycine max (L.) Merrill] crops, grown in a rice soybean rotation, can suffer when grown in soil with excessive moisture. The objective of this work were to determine the reduction in growth and yield, responses of vegetative and reproductive growth of soybean to excessive soil moisture achieved by prolonged irrigation. Responses of different cultivars were determined at growth stages from V6 to R8 to clarify the sensitive growth stages or characteristics to excessive soil moisture. Cultivar differences in response to excessive soil moisture condition were conspicuous in seed dry weight and harvest index (HI) but not in the response of seed number or pod number per plant. The timing of irrigation causing the condition of excessive soil moisture influenced the vegetative or reproductive traits. Soybean plants were more affected by irrigation commencing at the pre-flowering than at the post-flowering stage. Post-flowering irrigation did not reduce growth of vegetative organs significantly; in fact the growth of stems and leaves was facilitated by the prolonged irrigation commencing at flowering. Differences between cultivar response to prolonged irrigation were assumed to relate to the reduced amount of assimilates translocated to the reproductive organ.

• 화훼연구
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• 제26권4호
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• pp.179-186
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• 2018

Ranunculus asiaticus characterizes colorful and attractive flower shapes that are related with the ornamental value of bulbous plants. Improving ornamental value of bulbous flowers has been the general goal of floricultural market. Gibberellic acid ($GA_3$) and benzyladenine (BA) play an important role in growth and developmental processes in floriculture. Combinational treatments of these two hormones have been used in floriculture to improve flower quality. We assessed the effects of combined $GA_3$ and BA, as well as the individual effects of each hormone, on growth characteristics using soil drench application to eight R. asiaticus cultivars, 'Giallo Millepetali', 'Bianco Millepetali', 'Arancio Millepetali', 'Rosa SC', 'Arancio Pratolino', 'Giallo Pratolino', 'Bianco Pratolino', and 'Rosa Ch Pratolino'. $GA_3$ treatments increased plant height and first flower size of R. asiaticus cultivars. Moreover, about 5 to 9 days to flowering were averagely shortened by $GA_3$ treatments compared to controls. On the other hand, the opposites, including first flower size and days to flowering, were observed for cultivars treated with BA, compared with controls. Treatments of $GA_3$ + BA generally affected growth traits, such as plant height, flower size, and the timing of flowering on some R. asiaticus cultivars. In particular, about 5 to 6 days to flowering were reduced on average by Treatments of $GA_3$ + BA. Our results showed positive growth effects, including plant height, days to flowering, first flower height, number of flowers from the application of individual and combined hormones to R. asiaticus cultivars and demonstrate a role for these hormones in future bulbous floriculture.

• 한국습지학회지
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• 제22권2호
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• pp.113-120
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• 2020

본 연구에서는 국가적색목록 취약종(VU)인 꼬리명주나비와 그것의 유일한 먹이 식물인 쥐방울덩굴의 보전을 위하여, 수변 지역에 서식하는 쥐방울덩굴의 서식지 환경과 이들 중 생육과 생식에 영향을 미치는 주요 환경 요인을 파악하고자 하였다. 이를 위하여 네 개의 국내 쥐방울덩굴 서식지(가평, 평택, 청주, 여주)에서 2018년 7월과 10월에 방형구 조사를 수행하였으며, 주요 동반종, 초식 곤충의 출현 여부, 지지대의 유형, 토양의 이화학적 특성을 조사하였다. 조사결과 쥐방울덩굴 개체군의 서식지 환경과 생육 및 생식 양상은 지역에 따라 다르게 나타났다. 특히, 평택 개체군에서 가장 빠른 생육 속도와 개화 및 결실 시기를 나타냈으며, 청주와 여주 개체군에서는 인간의 교란으로 인한 지상부 손상이 원활한 생육을 방해한 것으로 드러났다. 본 연구에서 쥐방울덩굴의 생육 속도는 쥐방울덩굴의 초기 생육 시기부터 제공된 지지대의 유형에 영향을 받은 것으로 판단된다. 쥐방울덩굴의 개화 및 결실 시기에는 경쟁과 섭식 스트레스의 생물적 요인과 높은 토양 양이온 함량의 비생물적 요인이 복합적으로 작용한 것으로 여겨진다. 따라서 쥐방울덩굴 개체군의 빠른 생육과 적절한 시기의 개화와 결실을 위해서 안정적인 지지대의 제공과 경쟁과 섭식 스트레스의 완화를 위한 노력이 필요할 것으로 보인다.