• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.50-57
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• 1997

Using a bioassay for tuber enlargement activity, which was carried out with culture of microtuber of nodal stem segments in vitro, the endogenous substances was detected from leaves of yam(Diosorea alata L., cv. Solo Yam) treated under the short and the long day length condition. Tuber enlargement activity was found in both the aqueous and ethyl acetate phase of extract obtained from leaves of yams. Those activity was found in both the aqueous and ethyl acetate phase of extract obtained from leaves of yams. Those activities increased under the short day length, whereas not increased under the long day length. Guided by bioassay, the active substances in the ethyl acetate phase were purified by charcoal adsorption chromatography. The result obtained indicated that the 40% ethanol fraction contained the most prominent tuber enlargement activity. In seasonal changes of the leaves, tuber enlargement activity remained almost constant during summer(June-August), but after. the middle of September, the activity increased gradually and then reached a maximum in early October. Jasmonic acid (JA) was isolated with the guidance of microtuber test and identified by gas chromatography. The level of endogenous JA in the leaves of plants was more than $290{\mu}g/kg$ at the 10 hr day length. These results seem evidences for the occurrence of the tuber enlargement activity which is formed in leaves under the short days and transmitted to under ground part to induce growth and enlargement of tuber.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.205-216
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• 2002

This study was conducted to examine the effect of long-day (LD) period before short-day (SD) treatment on the vegetative growth of greenhouse-grown cut chrysanthemum cv. Reagan Improved at Wageningen Agricultural University, The Netherlands. Rooted cuttings of cut chrysanthemum cv, Reagan Improved were transplanted on 6th, 13th, 20th of September and all of them were treated with LD before SD treatment on 27th of September, The periods from transplanting until final harvest were 70, 77, and 84 days for 1, 2, and 3 week-LD treatment, respectively. The final plant height increased in the plot of 3 week-LD period and decreased in the plot of 1 week-LD period before the SD treatment. Total fresh weight and the leaf area were increased more in the plot of 3 week-LD period than that of 1 week-LD period, but the absolute growth rate after SD treatment was the same on plant growth rate and increase of the number of leaves in all treatments. The final dry matter production (g.m$^{-2}$ ) was increased more in the plot of 3 week-LD period than that of 1, 2week-LD period before SD treatment. Plant height and fresh weight were followed by the condition of LD period. In addition, dry mass production was highest in 3 week-LD period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.31-36
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• 1972

These studies were carried out to find out the proper plant spacing and the optimum amount of nitrogen for maximum yield, on the occasion of early planting with creen vegetable (soybean for cook with rice) at the low temperature in early spring. The plant spacing were applied in 5 levels (50cm$\times$5cm, 50cm$\times$10cm, 40cm$\times$10cm, 30cm$\times$10cm and 30cm$\times$20cm) and the amount of nitrogen were applied in 4 levels (non, standard, twice and triple-amount), The triple super phosphate and potassium chloride were applied only in standard amount. The promotion of flowering was practised by the short-day treatment for 10 days (11 hr. a day). The variety examined was the early maturing one, HOKKAI # 1. and the results are as follow. 1. The plant spacing for maximum yield by the promotion of branch, pod and garin per a plant recognized the fact that there were 2 levels (50cm$\times$10cm and 30cm$\times$20cm planting method) and the maximum yield by the promotion of pod and grain per area showed the fact that there were 2 levels (50cm$\times$5cm and 30cm$\times$10cm planting method) in narrow planting method. 2. The optimum amount of nitrogen applied for maximum yield of pod and grain per area recognized w hat was sufficient as standard amount.

• Molecules and Cells
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• v.26 no.4
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• pp.368-372
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• 2008

Recent molecular and genetic studies in rice, a short-day plant, have elucidated both conservation and divergence of photoperiod pathway genes and their regulators. However, the biological roles of rice genes that act within the autonomous pathway are still largely unknown. In order to better understand the function of the autonomous pathway genes in rice, we conducted molecular genetic analyses of OsFVE, a rice gene homologous to Arabidopsis FVE. OsFVE was found to be ubiquitously expressed in vegetative and reproductive organs. Overexpression of OsFVE could rescue the flowering time phenotype of the Arabidopsis fve mutants by up-regulating expression of the SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) and down-regulating FLOWERING LOCUS C (FLC) expression. These results suggest that there may be a conserved function between OsFVE and FVE in the control of flowering time. However, OsFVE overexpression in the fve mutants did not rescue the flowering time phenotype in in relation to the response to intermittent cold treatment.

• Molecules and Cells
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• v.25 no.4
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• pp.559-565
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• 2008

Members of the TGA family of basic domain/leucine zipper transcription factors regulate defense genes through physical interaction with NON-EXPRESSOR OF PR1 (NPR1). Of the seven TGA family members, TGA4/octopine synthase (ocs)-element-binding factor 4 (OBF4) is the least understood. Here we present evidence for a novel function of OBF4 as a regulator of flowering. We identified CONSTANS (CO), a positive regulator of floral induction, as an OBF4-interacting protein, in a yeast two-hybrid library screen. OBF4 interacts with the B-box region of CO. The abundance of OBF4 mRNA cycles with a 24 h rhythm under both long-day (LD) and short-day (SD) conditions, with significantly higher levels during the night than during the day. Electrophoretic mobility shift assays revealed that OBF4 binds to the promoter of the FLOWERING LOCUS T (FT) gene, a direct target of CO. We also found that, like CO and FT, an OBF4:GUS construct was prominently expressed in the vascular tissues of leaf, indicating that OBF4 can regulate FT expression through the formation of a protein complex with CO. Taken together, our results suggest that OBF4 may act as a link between defense responses and flowering.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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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.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.3
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• pp.4483-4491
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• 1977

The results obtained are as follows; 1. The variation of the temperature in a vinyl house without heating system is similar to that of air temperature in a day. The difference of maximum temperature and minimum one in a day is 27$^{\circ}C$ which is two times greater than the daily difference of air temperature. 2. When the length of the duct is increased, the high temperature zone is built up in the direction of warm air discharge from the duct, and the low temperature zone is built up in the opposite direction of warm air discharge. But, in case of the duct length is short (0.05 L), the temperature distrubution in a vinyl house become uniform. It is concluded that the shorter length of the duct, the better the distribution of the temperature in a vinyl house is. 3. When the duct is installed at high position, the high temperature zone is built up in the upper zone of the vinyl house and the low temperature zone is built up in the lower zone. And when the position of the duct is low, the rate of temperature variation along the vertical direction become high, and the direct contact of warm air with the plant in the house is occured. It is concluded that the duct should be installed at the position of slightly higher than the plant height. 4. When the fuel consumption rate is fixed at the 101/hr, the lowest temperature warming rate in the vinyl house is 5$^{\circ}C$ without regard to the air temperature.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.71-75
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• 1997

For the establishment of early selection of heat-tolerant clones through in vitro tuberization of true potato seeds, different temperature treatments for in vitro tuberization were investigated. The ratios of tuberization at 2$0^{\circ}C$ on var. Superior and DTO-33 treated with 5 mg/L of BAP and 500 mg/L of CCC, were 85% and 92%, respectively. At 3$0^{\circ}C$, the ratio of tuberization on DTO-33 was 37%, which revealed strongly heat-tolerant clone. In culture system of in vitro tuberization, the number of tubers per flask at 2$0^{\circ}C$ on non-subculture incubation was more than that on subculture incubation. The condition of non-subculture and short-day treatment for 4 weeks was good for production as 10.6 tubers per flask, which was very similar to that of long-day treatment. On the other hand, tuber diameter on long-day treatment was greater as 11.2 mm than on short-day treatment. Therefore, in vitro tuberization from true potato seeds could be induced under the condition of long-day treatment at darkness.

• Journal of Photoscience
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• v.7 no.3
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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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.548-558
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• 1990

Physiology and genetics of early maturity in cereals are the subject of practical as well as scientific interest for agronomist and plant breeders, Thorough understanding of the true nature of such a complex character requires physiological and genetical knowledge about the internal factors, which are closely bound up with and react to some particular external or environmental factors. From the practical point of view. experiments should be conducted under controlled conditions. especially the day length and temperature, so that the genotypic differences pertaining to these factors may be discerned. Takahashi and Yasuda (1958, 1970) maintained that at least three physiological factors were responsible for determining earliness in barley. namely. (1) spring and winter habit of growth or vernalization requirement, (2) ogitioeruiduc response or sensitivity to short-day, and (3) earliness factor in a narrow sense or minimal vegetative growth. The same situations were true in common wheat also (Yasuda and Shimoyama, 1965), In this report. physiology and genetics of internal factors and their relations to the time of heading in the field will be presented with some problems concerning differences in mechanism of early maturity between barley and wheat.