• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.104-109
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• 2019

The crops recommended for the plant factory system are diverse. The importance of planting density in the plant factory is being recognized. The objective of this study was to determine the optimal planting density for growth and quality of kohlrabi in a closed-type plant factory system. The kohlrabi was grown under fluorescent lamps and nutrient film technique system. The growth and quality of kohlrabi were investigated under four different planting densities ($22plants/m^2(15{\times}30cm)$, $27plants/m^2(15{\times}25cm)$, and $33plants/m^2(15{\times}20cm)$). There were no significant interactions between Shoot fresh and dry weights per plant or bulb stem fresh and dry weights per plant and planting density. Shoot fresh and dry weight per area or bulb stem fresh and dry weight per area were the highest at $33plants/m^2$. There were no significant interactions between plant height, leaf area, photosynthetic rate, hardness, and chlorophyll content and planting density. Significant differences in Bulb stem height and diameter, and brix were observed. Bulb stem height and diameter and brix of kohlrabi were the highest at $22plants/m^2$. Based on our results, we conclude that the optimal planting density is $33plants/m^2$ for growth of kohlrabi, however, the optimal planting density is $22plants/m^2$ for quality of kohlrabi in a closed-type plant factory system.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.493-498
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• 2014

The objective of this study was to make growth and yield models for common ice plant (Mesembryanthemum crystallinum L.) using expolinear functional equations in a closed-type plant production system. Three-band radiation type fluorescent lamps with a 12-hours photoperiod were used, and the light intensity was $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Nutrient film systems with three layers were used for plant growth. Environmental conditions, such as air temperature, relative humidity and $CO_2$ concentration were controlled by an ON/OFF operation. Leaf area, shoot fresh and dry weights, light use efficiency of common ice plant as function of days after transplanting, accumulative temperature and accumulative radiation were analyzed. Leaf area, shoot fresh and dry weights per area were described using an expolinear equation. A linear relationship between shoot dry and fresh weights was observed. Light use efficiency of common ice plant was $3.3g{\cdot}MJ^{-1}$ at 30 days after transplanting. It is concluded that the expolinear growth model can be a useful tool for quantifying the growth and yield of common ice plant in a closed plant production system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.115-120
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• 1981

Effect of soil water on the growth of Panax ginseng(2 years old) was investigated through pot experiment. the results were as follows. 1. Optimum soil moisture content for root yield appeared to be 65.5% of field capacity(22.1% fresh weight basis) and at 31.5%(10.7% fresh weight basis) relative growth rate was nil. 2. Under suboptimum condition of soil moisture, emergence of shoot and leaf unfolding was delayed. The rate of emergence of shoot and leaf area was also decreased while missing shoot rate was increased. 3. Root yield was positively correlated with leaf area per plant(r=0.91 **), stem diameter (r=0.73**), stem length(r=0.71 **) fresh top yield(r=0.93**) and negatively with missing shoot rate(r=-0.77**). 4. Fresh root weight showed negative correlation(r=-0.80**) with water content of root indicating that tissue is more compact when grown at sufficient water.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.106-110
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• 2016

In this study, a planting density-growth-harvest (PGH) chart was developed to easily read the growth and harvest factors such as crop growth rate, relative growth rate, shoot fresh weight, shoot dry weight, harvesting time, marketable rate, and marketable yield of common ice plant (Mesembryanthemum crystallinum L.). The plants were grown in a nutrient film technique (NFT) system in a closed-type plant factory using fluorescent lamps with three-band radiation under a light intensity of $140{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 12 h. Growth and yield were analyzed under four planting densities ($15{\times}10cm$, $15{\times}15cm$, $15{\times}20cm$, and $15{\times}25cm$). Shoot fresh and dry weights per plant increased at a higher planting density until reached an upper limit and yield per area was also same tendency. Crop growth rate, relative growth rate and lost time were described using quadratic equation. A linear relationship between shoot dry weight and fresh weights was observed. PGH chart was constructed based on the growth data and making equations. For instance, with within row spacing (= 20 cm) and fresh weight per plant at harvest (= 100 g), we can estimate all the growth and harvest factors of common ice plant. The planting density, crop growth rate, relative growth rate, lost time, shoot dry weight per plant, harvesting time, and yield were $33plants/m^2$, $20g{\cdot}m^{-2}{\cdot}d^{-1}$, $0.27g{\cdot}g^{-1}{\cdot}d^{-1}$, 22 days, 2.5 g/plant, 26 days after transplanting, and $3.2kg{\cdot}m^{-2}$, respectively. With this chart, we could easily obtain the growth factors such as planting density, crop growth rate, relative growth rate, lost time and the harvest factors such as shoot fresh and dry weights, harvesting time, marketable rate, and marketable yield with at least two parameters, for instance, planting distance and one of harvest factors of plant. PGH charts will be useful tools to estimate the growth and yield of crops and to practical design of a closed-type plant production system.

• Korean Journal of Medicinal Crop Science
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• v.22 no.5
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• pp.384-390
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• 2014

This study was carried out in order to investigate the early growth and root development characteristics of Peucedanum japonicum container seedlings. The experiment was performed by containers (128 and 200 cavities containers) and shading levels (0%, 35%, 50% and 75% shading). Germination rate of P. japonicum seeds was getting higher in the lower shading level and the highest in the full sunlight (71.9%). Plant height was the highest under 50% shading of all containers. Fresh weight and dry weight of the shoot (leaves + stem) were the highest under 50% shading of all containers, too. Meanwhile, fresh weight and dry weight of the root per plant were the highest under the full sunlight of 128 cavities container such as 0.34 g and 0.03 g, respectively. Total root length, root project area and root surface area were higher under the full sunlight of 128 cavities container such as 234.5 cm, $6.6cm^2$ and $20.8cm^2$, respectively and the next higher was under 35% shading such as 201.7 cm, $5.9cm^2$ and $18.4cm^2$, respectively. A case of root volume was the highest with $0.15cm^3$ under the full sunlight. As a result of the surveying the whole experiment, it is concluded that the shoot and root of P. japonicum seedling grow nicely by maintaining 35% shading.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.165-170
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• 2014

The objective of this study was to make growth and yield models of sowthistle (Ixeris dentata Nakai) by using an expolinear functional equation in a closed-type plant production system. The growth and yield of hydroponically-grown sowthistle were investigated under four different planting distances ($15{\times}10$, $15{\times}15$, $15{\times}20$, and $15{\times}25$ cm). Shoot dry weights per plant was the highest at $15{\times}25$ cm, but was the lowest at $15{\times}10$ cm. Shoot dry weights per area was the highest at $15{\times}15$ cm, but was the lowest at $15{\times}25$ cm. The optimum planting density and planting distance for yield of sowthistle were 44 plants/$m^2$ and $15{\times}15$ cm, respectively. Shoot dry weights per plant and per area were showed as an expolinear type functional equation. A linear relationship between shoot dry and fresh weights was observed to be linear regardless of the planting distance. Crop growth rate, relative growth rate and lost time in an expolinear functional equation showed quadratic function form. Radiation use efficiency of sowthistle was $4.3-6.1g{\cdot}MJ^{-1}$. The measured and estimated shoot dry weights showed a good agreement using days after transplanting as input data. It is concluded that the expolinear growth model can be a useful tool for quantifying the growth and yield of sowthistle in a closed-type plant production system.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.66-70
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• 2005

The experiment was carried out to investigate the effects of gamma radiation on the early growth performance and physiological traits of BT2 clone tea, the most promising cultivar released by Bangladesh Tea Research Institute. The fresh shoot cuttings were irradiated with seven different levels of gamma radiation such as 0, 10, 20, 30, 40, 50 and 60 Gy from Cobalt 60Co source (Dept. of PlantBreeding, Bangladesh Institute of Nuclear Agriculture). Thereafter, the irradiated shoot cuttings were planted in polythene bags and kept under natural conditions. It was observed that callusing was initiated from 8th weeks after placement of tea shoot cuttings in the polythene bags and completed by 12th weeks. The morphological growth of tea shoot cuttings were recorded under varying levels of gamma radiation and growth stages. It was observed that the number of leaves, number of primary branches, base diameter, root length and total leaf area per plant significantly increased with the progress of time and increasing levels of gamma radiation, however, the plant height showed decreasing trend with the increasing levels of gamma radiation, which could be due to the change in chromosomal structure and genetic makeup. After 56 weeks of planting, the plant height, the number of leaves and primary branches per plant, base diameter, root length and total leaf area per plant recorded were 65.70 cm, 30.67, 7.33, 1.48 cm, 23.50 cm, and 1250.67 cm2 per plant respectively under the radiation level 60 Gy, whereas the corresponding figures of the above parameters at the control treatment were 76.21 cm, 18.33, 3.67, 0.92 cm, 17.75 cm and 778.33 cm2 per plant, respectively. A significant relationship was observed among the physiological growth parameters with the increasing levels of gamma radiation. The total dry matter gain, leaf area index, absolute growth rate and relative growth rate were significantly influenced with the rising levels of gamma radiation (up to 60 Gy), whereas the net assimilation rate of individual tea plant non-significantly responded as compared to those of control treatment. Finally after 56 weeks of planting, the maximum total dry weight gain, leaf area index, absolute growth rate, relative growth rate and net assimilation rate recorded under 60 Gay radiation level were 40.25 g/plant/week, 4.25, 1.18 g/week, 0.0621g/g/week and 17.07 g/m2/week respectively.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.241-241
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• 2017

Sweet potatoes (Ipomoea batatas (L.) LAMK.,) have been cultivated in Central and South America for about 2000 years and are now grown mainly in Asia and South America. Sweet potatoes are annual in the temperate region, but are classified as perennial in the tropical region. In 2000, the cultivation area of sweet potatoes decreased to about 16,000 ha in 2000, but the cultivation area increased slightly in recent 20,000 ha in Korea. Sweet potatoes do not show higher maximum dry matter production of 120 ~ 150g per plant, and the leaf area index (LAI), which maximizes dry matter production, is known as 3.0 ~ 4.0. As the leaf area increase, the penetration of light into the canopy becomes poor, and sufficient photosynthesis cannot be achieved in the lower leaves, on the other hand the respiration increase, which results in poor dry matter production. This study was conducted to know the responses of sweet potatoes to intensive shading treatment of 80% shading. This experiment was conducted for about 42 days from September 6, 2016 to October 18, 2016 at Gyeongsang National University Experimental Farm, Jinju, Korea. The plant canopy was shaded with black nylon 80% shade cloth suspended 1.2 m above the ground. The photosynthetic rate, stomatal conductance, chlorophyll fluorescence, SPAD and NDVI were measured in 3 replicates every 7 days after shading initiation. After the fresh weight was measured, the samples were dried at $80^{\circ}C$ in a dry oven and measured. By the 80% shading treatment, chlorophyll fluorescence of the treated plants was slightly higher than that of the control, the SPAD value was higher by 3.4 and NDVI value was higher by 0.01. However, photosynthetic rate and stomatal conductance were lower than those of the control. The stomatal conductance of the control were two times higher than those of the control and the photosynthetic rate of the control was four times higher than that of the control. In control, plant showed a tendency to steadily increase in fresh weight and dry weight. However, in the case of shading treatment, the tendency to increase in the fresh and dry weight of tuberous roots was not clear. The fresh weight of shoot showed a tendency to increase steadily while the difference between treatment and control was not large, but tended to decrease after frost.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.226-230
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• 2004

Plant growth should be affected by mulching method. The study was done to examine the effect of different mulching methods on growth and yield of Atractylodes japonica Koidz. The experiment was done by six different mulching methods; no mulching, rice straw, transparent polyethylene (PE), black PE, two combined treatments of rice hull and transparent PE or black PE. Green shoot and related characters, growth and yield of early and late stages were measured on May 8, June 8 and October 26, respectively. Green shoot fresh weight was the highest in transparent PE mulching, while number of leaves, shoot and stem lengths were the greatest in rice straw mulching of the methods. In its early stage, rice straw mulching had the fewest number of leaves, roots, stems, the smallest width of leaves, and the least fresh weights of shoots and rhizomes. Combined mulching of black PE and rice hull showed the highest values in root-related characters; number of roots, fresh weights of rhizomes and roots. In its late stage, the treatment effects shown in the early stage disappeared owing to high temperature of mid-summer so that there was no significant difference between the mulching treatments. Yield per unit area and marketable yield were the highest in rice straw mulching, and combined mulching of black PE and rice hull.