• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.382-389
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• 2005

This study was conducted to establish the system of effective in vitro propagation by various explant sources culture of Bippeastrum hybridum Hort, 'Dazzler'. We tested the effects of optimal explant source, plant growth regulators on bulblet formation and plant regeneration. Callus was readily produced on the different tissues excised from floral buds whereas, bulbs and shoots were formed only on pedicel explants as compared with anthers, styles and ovaries. Pedicel is the best optimal explant for in vitro propagation. Two distinct pathways, organogenesis through callus and direct bulblet formation, could be recognized in pedicel culture. Up to the $80-100\%$ of bulblet formation and shoot organogenesis from the pedicel in fifteen days before anthesis were effectively induced by MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L BA. Plantlet regeneration was successfully achieved from pedicel-derived callus, via shoot bud induction or direct bulblet formation. The bulblets with blooming flower were produced within 2 years.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.336-342
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• 1988

An experiment was carried out to know the effects of paclobutrazol application time on the lodging related traits and yield of a rice variety. Seomjinbyeo, at two nitrogen leveles. Paclobutrazol (3kg 10a of 0.6% G) was applied 43, 33, 23, and 13 days before heading (DBH) and lodging related traits were observed 10, 20, 30, and 40 days after heading (DAH). Earlier applications of paclobutrazol reduced the length of lower internodes and later applications reduced the upper internodes. Culm length tended to decrease as time of paclobutrazol application delayed. Although lodging was not occurred in all plots. lodging index of paclobutrazol treated plots was lower than that of control and increased with maturity, Fresh weight of shoot increased up to 30 DAH and then decreased. Both fresh weight and breaking strength did not show consistent tendency with time of paclobutrazol application and observation. Direct effect of shoot fresh weight contributing to lodging index decreased with maturity. but that of breaking strength and culm length was similar during the ripening stages. Direct effect contributing to lodging index was greater in the order of breaking strength culm length. and fresh weight 40 DAH. Starch content of culm base decreased up to 20 DAH and then increased up to 40 DAH. Cellulose content increased up to 20 DAH, but hemicellulose and lignin did not change significantly during the ripening stages. Starch, cellulose, hemicellulose, and lignin contents of culm base did not correlated with breaking strength and time of paclobutrazol application did not show consistent results. Paclobutrazol applied 13 DBH did not reduce yield of rice. but the earlier applications reduced yield due to a reduced number of spikelets per panicle.

• Journal of Sericultural and Entomological Science
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• no.12
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• pp.13-16
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• 1970

The studies were intended to clarify the correlations between the characters and the influences upon yield of mulberry trees. The analysis of covariance was used to obtain the genotypic correlations and phenotypic correlations among the eight characters namely branch length, node number, branch diameter, branch number per stock, total branch weight, old branch weight, new shoot and leaf weight, etc., and path-coefficients were calculated by Dewey's method (5). The results obtained are summarized as follows： 1. Genotypic correlations were slightly higher than the corresponding phenotypic correlations between tile characters as shown in Table 1. It could be indicated that hight leaf yield was genetically correlated with almost all characters studied except branch diameter. 2. Leaf yield of mulberry trees was mainly associated with the characters such as node number per branch, total branch weight and old branch weight, etc. 3. Branch length, branch diameter, branch number per stock and new shoot weight had little direct influence upon yield but it had rather considerable indirect in fluence upon yield by increasing the node number and total branch weight per stock. As a result, it can be concluded that total branch weight is primarily determined by branch number per stock and old branch weight, and in turn the leaf yield of mulberry trees is secondary determined by the node number by increasing the branch diameter and length which are positively correlated with branch number per stock and new shoot weight of mulberry trees.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.111-111
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• 2022

According to data from the Ministry of Environment, food waste accounted for 27% of the nation5 s household waste in 2020, and 4.67 million tons of food waste is being discharged per year. According to the Food Waste Direct Landfill Prohibition Act, food waste must be incinerated, composted, fodder, and decomposed before landfilling. The cost of incineration and landfilling of food waste is considerable. Therefore, through the process of turning food waste into fertilizer, we are going to investigate the limit of crop application and the change in the growth of crops during continuous use of food waste fertilizer. This study investigated the growth of lettuce such as shoot length, root length, leaf number, fresh weight, and dry weight after treating lettuce with food waste dry powder mixed fertilizer. The experiment was carried out continuously in 2021 (1st year) and 2022 (2nd year), and the treatment groups were set to No Treatment (NT), Chemical Fertilizer (CF), Mixed Fertilizer (MF×1), and Mixed Fertilizer×2 (MF×2), was repeated 3 times. As a result of the 1st year growth survey, there was no significant difference between NT and CF in the case of shoot length, but MF×1 and MF×2 were significantly decreased compared to NT. Root length was not significantly different in all treatment groups. As for the leaf number, there was no significant difference between NT and MF×1, but CF and MF×2 were significantly decreased compared to NT. In fresh weight, MF×1 and MF×2 were significantly decreased compared to NT, and in the case of dry weight, there was no significant difference between NT, MF×1, and MF×2. As a result of the 2nd year growth survey, there was a significant difference in CF and MF×2 in leaf number, but there was no significant difference in all treatment groups with respect to shoot length, root length, fresh weight, and dry weight. Through continuous additional research, it is necessary to confirm the change in soil composition and the growth of crops due to food waste fertilizer treatment.

• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.229-235
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• 1999

To identify the differences on plant growth and yield of two rice cultivars among direct water-seeding methods broadcasting on flooded paddy surface(BF), drilling on flooded paddy surface(DF), and puddled-soil drill seeding(PD) under markedly different weather condition between 1995 and 1996. The mean air temperature for duration from May to June, early growth stage of rice in 1995 was lower $1{\sim}3^{\circ}C$ than that in normal or 1996. In 1995 the respiratory consumption index during panicle formation stage and early ripening stage was higher than those of in 1996 or normal year. Number of seedling stand among the methods of direct seeding rice appeared slightly higher in order of BF>DF>PD. Properly in Nonganbyeo, the number of seedling stand was much low in 1995 compared with in 1996. The leaf area index and shoot dry weight at early growth stage of rice plant and culm length at mature in 1995 were larger in direct water seeding rice than those of machanical transplanting rice, but in 1996. Faster ripening speed and shorter ripening period of rice crop appeared in 1996 compared to in 1995. It was due to higher growing degree-days, sunshine hours and solar radiation during rice growing season in 1996. Dongjinbyeo rice showed higher yield than Nonganbyeo which had lower ripened grains especially in 1995.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.212-222
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• 1994

Thiobencarb retarded the growth of new leaves in only barnyardgrass under dry condition while under water condition the shoot growth of broadcast rice, and both shoot and root growth of barnyardgrass was considerably inhibited. Root elongation of rice and barnyardgrass was severely inhibited only under water condition, while that of transplanted rice was slightly inhibited. Inhibition of shoot and root growth in broadcast, drilled rice and barnyardgrass under water condition was much higher than that under dry condition, whereas the inhibition was less in transplanted rice than direct seeded rice. Microscopically, thiobencarb severely inhibited shoot growth and development of barnyardgrass by inducing tubular-like leaves. The cells of the shoot apices of treated barnyardgrass seedling under dry condition was vacuolated and irregularly arranged. Under water condition, leaf primordia of broadcast rice was constricted, barnyardgrass showed tubular-like leaves, inhibited apices elongation and vacuolated cells(visually lack cytoplasm).

• Journal of Power Electronics
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• v.15 no.6
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• pp.1609-1618
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• 2015

DC microgrids are considered as prospective systems because of their easy connection of distributed energy resources (DERs) and electric vehicles (EVs), reduction of conversion loss between dc output sources and loads, lack of reactive power issues, etc. These features make them very suitable for future industrial and commercial buildings' power systems. In addition, the bipolar-type dc system structure is more popular, because it provides two voltage levels for different power converters and loads. To keep voltage balanced in such a dc system, a bidirectional dual buck-boost voltage balancer with direct coupling is introduced based on P-cell and N-cell concepts. This results in greatly enhanced system reliability thanks to no shoot-through problems and lower switching losses with the help of power MOSFETs. In order to increase system efficiency and reliability, a novel burst-mode control strategy is proposed for the dual buck-boost voltage balancer. The basic operating principle, the current relations, and a small-signal model of the voltage balancer are analyzed under the burst-mode control scheme in detail. Finally, simulation experiments are performed and a laboratory unit with a 5kW unbalanced ability is constructed to verify the viability of the bidirectional dual buck-boost voltage balancer under the proposed burst-mode control scheme in low-voltage bipolar-type dc microgrids.

• Journal of Plant Biotechnology
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• v.7 no.3
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• pp.161-167
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• 2005

Brassinosteroids are steroidal plant hormones and are known to modulate physiological and cellular response in a wide range of plant species. Considerable insights has been achieved of the physiological role of brassinosteroid in Brassica species in the past few years, but their effect on direct organogenesis has not been extensively studied. In this sense, under optimal basal media and growth conditions we tested the cellular and organogenic response of 24-epibrassinolide (EBL) in a variable concentration (0.1 to $5.0\;{\mu}M$) and Zeatin (Z) (1.0 to $100\;{\mu}M$) and their synergic effect on hypocotyl explants of cauliflower and broccoli. The isolated EBL accelerated cell elongation and promotes direct organogenesis. One micromolar EBL + $10\;{\mu}M$ of Z was the most efficient combination for cell elongation, cell differentiation as well as for organogenesis. A suppressing effect on root induction was confirmed for all the tested hormone levels. The general results indicate a synergic effect of EBL-Z and EBL potentates Zeatin activity, at least in certain tissues. Besides de genetic factors, we can speculate that the natural hormone concentration in the explants might affect the responses by application of exogenous growth regulators. Experiments with new plant growth regulators, like brassinolide, are important aiming to maximize or accelerate plant regeneration for in vitro multiplication or for genetic transformation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.289-294
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• 1990

This study was carried out to investigate the lodging patterns and the direct and indirect effects of several agronomic characters upon lodging of soybean plants. Most of the lodged plants had bent main stem above first stem node at higher plant density. Lodging was significantly correlated with plant height, internode length and shoot fresh weight in two soybean cultivars, Paldalkong and Jangyeobkong. Root fresh weight was also significantly correlated with lodging in Paldalkong, Jangyeobkong and Kwangkyo. Length of internode showed the greatest direct effect on lodging in Paldalkong and Jangyeobkong.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.151-155
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• 2020

This study was conducted to determine the effects of the selection of an appropriate sowing method in on ginseng growth, and the results are as follows. SAS (semi-automatic sower), commonly used by direct seeding farms, provides fast operation speed but results in high labor cost, while (Hooper Seeder Sowing) offers fast operation speed and high germination rate, but leads to increased laborer's fatigue. Daily working area per sower was 6,611 ㎡ for a motor type, and the operation time to sow 3,305 ㎡ was 15 hours for broadcast planting, and 8 hours for SAS. The germination rate of 1-year-old ginseng according to direct seeding was 69.1% for the treatment plot under broadcast planting, followed by 66.4% and 67.3% for manual sower and hoop sower, respectively, and the germination rate of SAS was the lowest at 64.2%. In addition, there were no differences in shoot and root growth of 1-year-old ginseng among the sowing methods. Therefore, the sowing method can be chosen depending on the economic size of ginseng farmers. That broadcast sowing (BS) is appropriate for small scale farmers, while motor-driven seeder sowing (MDS) for direct seeding is more suitable for large scale farmers.