• Journal of Life Science
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• v.20 no.7
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• pp.1127-1133
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• 2010

The total photosynthetic rate in leaf mustard lines, which was calculated as the sum of the photosynthetic rate and the respiration rate, was not significantly different from their photosynthetic rate. Plant height, standing of rosetteness, showed a similar change to its specific leaf area (SLA). With increasing the plant height, leaf density increased and leaf color was lighter. It was found that shoot dry weight of leaf mustard was more affected by respiration. Also, it was hypothesized that respiration occurred not only in the leaf but also the stem. It was found that mustard lines whose leaf density was low showed a higher shoot growth. From this result, it was concluded that selection of a leaf mustard line with a larger SLA and lower leaf thickness could be effective in increasing photosynthetic rate.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.2
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• pp.122-129
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• 2016

It is important to know the sensitivity of shrubs to de-icing salt in order to set guidelines for ecological tolerance of evergreen shrubs along roads. Therefore, the aim of this study was to investigate the influence of de-icing salt, calcium chloride($CaCl_2$), on the growth and physiological characteristics of three evergreen shrubs, Euonymus japonica, Rhododendron indicum, and Buxus koreana. Plants were exposed to calcium chloride at different concentrations(weight percentage, 0% as control, 1.0%, 3.0%, and 5.0%) through amended soil maintained from the start of the experiment in October of 2014 until termination in March of 2015. The survival rate, plant height, leaf length, leaf width, leaf shape index, number of leaves, fresh weight, dry weight, dry matter, root/top ratio, chlorophyll contents, fluorescence, photosynthesis, stomatal conduct, and transpiration rate were recorded. Elevated calcium chloride concentrations decreased plant height, leaf length, leaf width, leaf shape index, fresh weight, dry weight, dry matter, and R/T ratio of the three shrubs. Root growth responded more sensitively than the top growth to salinity. However Euonymus japonica was more tolerant to salt stress than Rhododendron indicum and Buxus koreana. Their growths were totally inhibited by $CaCl_2$ above 3.0% and 1.0% concentrations, respectively. Chlorophyll content, fluorescence, photosynthesis, stomatal conduct, and transpiration rate of both Rhododendron indicum and Buxus koreana were reduced sharply, while Euonymus japonica exhibited mild reductions compared to plants grown in control when increasing calcium chloride was used. Especially, the transpiration rates of Rhododendron indicum, and the photosynthesis and stomatal conduct of Buxus koreana were suppressed as the concentrations of calcium chloride increased. Therefore, Euonymus japonica should be considered as an ecologically tolerant species with proven tolerance to de-icing salt.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.392-399
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• 2013

This study aimed to investigate responses of photosynthesis, plant growth, and phytochemical contents to different artificial light sources for 'Seneca RZ' and 'Gaugin RZ' two butterhead lettuce (Lactuca sativa L.). In this study, fluorescent lamps (FL), three colors LEDs (red, blue and white, 5 : 4 : 1; RBW) and metalhalide lamps (MH) were used as artificial lighting sources. Photoperiod, air temperature, relative humidity, EC, and pH in a cultivation system were maintained at 16/8 h, $25/15^{\circ}C$, 60~70%, $1.4{\pm}0.2dS{\cdot}m^{-1}$, and $6.0{\pm}0.5$, respectively. The photosynthetic rate of both two butterhead lettuce were the highest under RBW in middle growth stage. However, in late growth stage, the photosynthetic rate of both two butterhead lettuce were higher under RBW and MH than FL. The light sources showed significant results for plant growth but those effects were different to variety. Fresh and dry weight of 'Gaugin RZ' butterhead lettuce under MH were heavier than other lights in all growth stages. Growth of 'Seneca RZ' butterhead lettuce was maximized highest under MH in middle growth stage and FL in late growth stage. In the leaf tissue of 'Seneca RZ' butterhead lettuce, tipburn symptom occurred under all light sources and in the leaf tissue of 'Gaugin RZ' butterhead lettuce, it occurred under two light sources except for fluorescent lamps in late growth stage. kinds of lamp affect plant growth more than plant quality. Relative growth rate of both two butterhead lettuce was faster in middle growth stage than late stage. Growth of 'Gaugin RZ' was shown by kinds of lamp in middle growth stage and but it was not significantly affected by light sources and variety in late stage. Most of the phytochemical contents of two butterhead lettuce were significantly affected by different light sources. Contents of all vitamins showed higher than other light sources on RBW for both two lettuce, especially ${\beta}$-Carotene content of 'Gaugin RZ' was the highest. Plant growth, photosynthesis, and phytochemical contents were observed significant effects by different light sources for two butterhead lettuce but those effects were highly different between variety and kinds of phytochemicals. Therefore, the selection of optimum light source should be considered by variety and kinds of phytochemicals in the plant factory.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.199-212
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• 2014

The physiological responses of three common temperate species, Pinus densiflora, Fraxinus rhynchophylla, Sorbus alnifolia to elevated $CO_2$ was investigated using open top chambers with different $CO_2$ concentrations. Morphological (stomatal size, density and area) and physiological characteristics (maximum rates of photosynthesis, carboxylation and electron transport) were compared among trees grown under ambient, ambient ${\times}1.4$ (~550 ppm) and ambient ${\times}1.8$ (~700 ppm) $CO_2$ concentrations for last four years. Morphological responses were different among species. F. rhynchophyllar increased their stomatal size and S. alnifolia had higher stomatal density under elevated $CO_2$ than ambient. Stomatal area decreased in P. densiflora, whereas it increased in S. alnifolia. However, the maximum photosynthesis rate increased in all species up to 43.5% by S. alnifolia under elevated $CO_2$ and the enhancement increased with time. Even with four years of exposure to elevated $CO_2$, there was no sign of acclimation in the maximum carboxylation rate and the maximum electron transport rates in all species. Especially, S. alnifolia even showed the temporary increase of photosynthetic capacities in spring, when leaf nitrogen concentration was high with new leaf development. There was no significant differences in diameter growth rate in any species due to high variation in their tree sizes, however accumulated diameter and biomass for four years showed significantly increment in all species under elevated $CO_2$. For example, S. alnifolia showed 59% increase in diameter at the ambient ${\times}1.8$ (~700 ppm) compared to ambient.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.148-156
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• 2023

This study was conducted in an indoor cultivation room and chamber where environmental control is possible to investigate the effect of temperature and irrigation interval on photosynthesis, growth and growth analysis of potted seedling cucumber. The light intensity (70 W·m^-2) and humidity (65%) were set to be the same. The experimental treatments were six combinations of three different temperatures, 15/10℃, 25/20℃, and 35/25℃, and two irrigation intervals, 100 mL per day (S) and 200 mL every 2 days (L). The treatments were named 15S, 15L, 25S, 25L, 35S, and 35L. Seedlings at 0.5 cm in height were planted in pots (volume:1 L) filled with sandy loam and treated for 21 days. Photosynthesis, transpiration rate and stomatal conductance at 14 days after treatment were highest in 25S. These were higher in S treatments with a shorter irrigation interval than L treatments. Total amount of irrigation water was supplied evenly at 2 L, but the soil moisture content was highest at 15S and lowest at 25S > 15L > 25L, 35S and 35L in that order. Humidity showed a similar trend at 15/10℃ (61.1%) and 25/20℃ (67.2%), but it was as high at 35/25℃ (80.5%). Cucumber growth (plant height, leaf length, leaf width, chlorophyll content, leaf area, fresh weight and dry weight) on day 21 was the highest in 25S. Growth parameters were higher in S with shorter irrigation intervals. Yellow symptom of leaf was occurred in 89.9% at 35S and 35L, where the temperature was high. Relative growth rate (RGR) and specific leaf weight (SLA) were high at 25/20℃ (25S, 25L), RGR tended to be high in the S treatment, and SLA in the L treatment. Water use efficiency (WUE) was high in the order of 25S, 25L > 15S > 15L, 35S, and 35L. As a result of the above, the growth and WUE were high at the temperature of 25/20℃.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.371-381
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• 1988

The purpose of this study was to investigate the physiological response to salt treatments in the leaves of several tree species. The results obtained were as follows : 1. The water potential of tree leaves damaged with various salt concentrations did not change nearly for 10 hours after treatment. As time elapsed after treatment, however, the higher salt concentration in soils, the higher leaf water potential was observed. 2. Leaf water potential of species intolerant to salt was higher than tolerant species due to the severe dehydration from cells. 3. According to the water relation parameters obtained from P-V curves, the values of ${\pi}_{\sigma}$ and ${\pi}_{\rho}$ in the damaged leaves were higher, but those of $V_{\rho}/V_{\sigma}$ and Emax were lower than those of the intact leaves. 4. The photosynthesis rate of tree leaves decreased remarkably with increasing the salt concentrations in soils, and it decreased faster for species intolerant cintolerant to salt.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.142-145
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• 2007

Growth characteristics according to mixture ratio of used-rockwool in pot nursery, in Pinus densiflora, Torreya nucifera, Quercus acutissina and Fraxinus mandshurica nursery, was investigated. The used-rockwool on mixture ratio between used-rockwool and control (peatmoss: pearlite=1:1, v/v) were 0%, 30%, 50% and 70%. Flesh weight, dry weight and height of tree, in Pinus densiflora nursery, increased much more in 50% and 70% media but trunk diameter of tree had no difference according to mixture ratio. In Torreya nucifera nursery, flesh weight and height of tree in 70% medium and trunk diameter and numbers of shoot of tree in 50% and 70% media increased. Flesh weight, height and trunk diameter of tree, and chlorophyll (SPAD) and photosynthesis rate, in Quercus acutissina nursery, increased much more in 50% and 70% media, but dry weight of tree had only difference between non-mixed and mixed with rockwool. In Fraxinus mandshurica nursery, flesh weight and photosynthesis rate of tree increased much more in 70% medium, height, trunk diameter and total chlorophyll of tree had difference according to non-mixed and mixed with rockwool or had no only difference according to mixture ratio, respectively.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.267-272
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• 2012

Overcoming harsh light environment, as well as increased growth of crops even in high-quality production can play an important role when using the LED light system of photosynthetic products will be able to effectively reduce consumption. In this study, low efficiency of farm greenhouses, growing annual reduction in income due to rising operating costs and increase crop growth by inducing the proper planting environment Factory-type raise farmers' income and at the same time will contribute to the increase of Light device using LED Supplemental through photosynthesis, promote and improve product quality, plant growth regulators are considered possible for them to develop more efficient LED devices and LED Optical processing devices of Light leaf lettuce grown using normal fluorescent or incandescent bulbs grown in the results than the growth can see that the speed improvements. Usually shipped from seedling to harvest leaf lettuce from 25 to 30, whereas optical processing device be required red light (wavelength: 645nm) using a leaf of lettuce grown enough to be harvested after seven days increased the rate of growth. In addition, red light (wavelength: 645nm) and blue light (wavelength: 470nm) emitting at the same time, room, and grown for 5 days to harvest the growth rate was fast enough.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.187-193
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• 2007

Higher plants can be categorized as C3, C4 or CAM according to their photosynthetic pathways, and some succulent plants are known to shift their patterns of photosynthesis from C3 to CAM in response to environmental stresses such as salt treatment or water deficiency. To investigate fundamental photosynthetic patterns and the induction of pattern shifts (C3, CAM, C3-CAM etc.) as a result of environmental stresses, we measured the water content, diurnal changes in pH, net $CO_2$ exchange, transpiration rate, total ionic contents, and osmolality of Kalancoe daigremontiana, Sedum kamschaticum and Sedum sarmentosum which belong to Crassulaceae known as representative CAM plant, after 10 days of drought treatment. S. kamschaticum and S. sarmentosum did not show a significant difference in diurnal pH variation in the treatment and control conditions. However, the pH of drought-treated Kalancoe was low at night and high in the daytime, with a pH value between 4 and 5. Typical CAM plants display a net $CO_2$ exchange that increases at night and decreases in the daytime. Kalancoe displayed the predicted pattern. However, S. kamschaticum and S. sarmentosum showed a photosynthetic pattern more typical of C3 plants, and did not show changes in photosynthetic pattern under drought stress. Kalancoe also showed a transpiration rate typical for CAM pho-tosynthesis, whereas the transpiration rates of S. kamschaticum and S. sarmentosum were in the typical range for C3 photosynthesis. Kalancoe had high total ionic contents during the night, which decreased somewhat during the daytime, whereas S. kamschaticum and S. sarmentosum displayed the opposite pattern. This result is similar to the diurnal patterns of changes in pH in the three plant species, which suggests a relationship between pH and ionic contents. S. sarmentosum showed lower osmolality under drought stress than in the control condition, whereas the osmolality of Kalancoe and S. kamschaticum did not differ between conditions. S. sarmentosum may have maintained internal water content by lowering its osmolality and raising its total ionic contents. In conclusion, Kalancoe displayed the characteristic responses of a typical CAM plant, whereas S. kamschaticum and S. sarmentosum displayed aspects of the C3 photosynthetic pattern under drought conditions. These results suggest that S. kamschaticum and S. sarmentosum (Crassulacea) in Korea overcome drought stress by increasing solute and ionic contents internally rather than changing their photosynthetic pattern from C3 to CAM under drought stress.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.46-50
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• 2009

This study was carried to investigate effects of optimum supply strengths of 'Sonneveld' nutrient solution on growth characteristics in container seedling of trees (Pinus densiflora, Torreya nucifera, Quercus acutissina and Fraxinus mandshurica) using developed media with used-rockwool. Flesh weight, height and trunk diameter in container seedling of Torreya nucifera were better in high strengths. In container seed ling of Torreya nucifera, flesh weight more increased in 1.5 and 3.0 strengths and hight and trunk diameter more increased in 1.5 strength than the rest. Flesh weight in container seedling of Quercus acutissina was heaviest in 2.0 strength and was lightest in 1.0 strength. Height and dry weight in 2.0 and 3.0 strengths and trunk diameter and total chlorophyll in 2.0 strength were better than in the rest. Besides photosynthesis rate was more high in 1.5 and 2.0 strengths than in the rest. In container seedling of Fraxinus mandshurica, flesh weight, height and trunk diameter more increased in 0.5 strength and total chlorophyll and photosynthesis rate were good in 0.5 and 2.0 strengths. Most growth characteristics were poor in 3.0 strength.