• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.271-274
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• 2015

The objective of this study was to investigate the effects of composition of nutrient solution on the growth and quality of baby leaf vegetables (tat soi, romaine lettuce, beet, and red radish) hydroponically cultivated in plant factory. The seeds of four vegetable crops were sown in urethane sponges and cultivated for 14 days in a plant factory. Light intensity and photoperiod were $110{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and 16 h, respectively; and air temperature in photo/darkperiod was maintained at $25/20^{\circ}C$. Tap water was used for irrigation for 7 days after sowing, and then plants were irrigated for 7 days using tap water and the nutrient solutions of Korea Wonshi, Japan Enshi, and Yamazaki for lettuce. At 14 days after sowing, the fresh weight of tah soi was highest in the nutrient solution of Yamazaki for lettuce, and there were no significant differences among nutrient solutions in beet and red radish. When we compared leaf color using Hunter's a value, the nutrient solution of Korea Wonshi and Japan Enshi increased green color in baby leaf vegetables, while the nutrient solution of Yamazaki for lettuce increased red color. Total phenolic content of romaine lettuce was highest in the nutrient solution of Korea Wonshi, but tat soi, beet, and red radish showed no significant differences among nutrient solutions in total phenolic contents. From these results, we suggest that using the nutrient solution of Korea Wonshi can enhance the growth and quality of romaine lettuce and the nutrient solution of Yamazaki for lettuce is appropriate for enhancing the growth and red color of beet and red radish in plant factory.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.242-248
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• 1986

To study the effect of cold water irrigation at the reproductive growth stage of rice plants on several growth characters related to source and sink and nutrient uptake, the present experiment was carried out under the different conditions of water temperature and water depth. Deep irrigation with normal temperature water increased culm length, panicle length and panicle exsertion but with cold water resulted adversely. Most sensi-tive response in 5 cm water-depth appeared at reduction division stage and in 20 cm depth at panicle formation stage. Secondary branches and spikelets were increased in number by deep irrigation with normal temperature water, but decreased and degenerated by deep irrigation with cold water at panicle formation stage resulting in high spikelet sterility and low grain filling. Deep irrigation with normal temperature water increased the contents of total nitrogen, phosphate, potassium and silicate in leaf blades, branches and chaff. However, cold water irrigation reduced the uptake of phosphate, potassium and silicate except nitrogen particularly in deep irrigation. Ratios of phosphate, potassium and silicate to total nitrogen content were decreased by cold water irrigation. Branches seemed to have higher requirements for phosphate, potassium and silicate than leaf blades and chaff. Silicate-to-total nitrogen ratio in leaf blades, branches and chaff had significant correlations with yield showing closer relationship between yield and the ratio of silicate to total nitrogen in branches in particu-lar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.195-202
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• 1995

This experiment was performed to characterize the optimum water table level for the growth and yield of barley(var. Olbori) and wheat(var, Grumil), Olbori and Grumil were grown in the 550 liter plastic pot filled with silt loam or sandy loam, During the whole growth period, the water table adjusted to be 20, 30, 40, 50, and 70cm, Higher water table was resulted in the decrease in plant height and top dry weight, but in the increase of the ratio of top to root dry weight, especially in barley, This suggested that high water table level affected more the growth of top than that of root, The number and area of green leaves were decreased as the water table was higher than 30 to 40cm at the late growth period(May 18, 1993), The largest number and area of green leaves were shown at 50cm of water table in sandy loam and at 70cm in silt loam, As the water table was high, the leaf chlorophyll content was low, And barley was affected more significantly than wheat by soil texture, The photosynthetic activity was decreased remarkably at 20cm water table, Heading period was 2 to 3 and 4 days earlier at the 20cm water table of sandy loam in barley and wheat, respectively, However this earlier heading was not shown in silt loam, Grain filling was accelerated 5 to 7 days earlier in barley and 10 days in wheat grown at 20cm water table, The highest yield was present at 50 and 70cm water table, The yield was decreased remarkably at 20cm water table, resulting that yield reduction ratio of barley was 71.1% and 72, 2%, and that of wheat was 41.0% and 60, 0% in sandy loam and silt loam, respectively, High water table decreased the number of spike per unit area, but increased the seed weight per spike in barley, However, High water table reduced the seed weight per spike in wheat. There was significant correlation between yield and leaf chlorophyll content in wheat and barley, Yield was correlated significantly with green leaf area in barley, and with top dry weight, ratio of top to root dry weight chlorophyll content and photosynthetic activity in wheat. The optimum water table was 50 to 70cm in wheat and barley, They grew fairly well at 30cm water table of sandy loam, and at 40cm of silt loam.

• Journal of the korean society of oceanography
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• v.38 no.2
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• pp.68-79
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• 2003

Although seagrasses are relatively abundant, few studies have been conducted on seagrass physiology and ecology in Korea. Zostera marina is the most abundant seagrass species, widely distributed throughout all coastal areas of the Korean peninsula. To examine seasonal dynamics and spatial variations of eelgrass, Zostera marina distributed on the coast of Korea, morphological characteristics, biomass, tissue nutrient constituents, leaf productivity and environmental factors were monitored monthly from the eelgrass beds in Kabae Bay and Kosung Bay on the south coast of the Korean peninsula from June 2001 to June 2002. Eelgrass density, biomass, morphological characteristics, leaf productivities, and tissue nutrient constituents exhibited clear seasonal variations, and these seasonal trends reflected seasonal changes in water temperature. Eelgrass shoot density and biomass at Kabae Bay site showed more obvious seasonal trends than Kosung Bay. No strong seasonality in Kosung Bay site appeared to be caused by high water temperature ($>30{\circ}C$) during summer months at this site. Despite differences in nutrient availabilities between two study sites, eelgrass biomass and leaf productivities were not significantly different between study sites, and this lack of spatial variations implies that the ambient nutrient availabilities at the present study sites are in excess of seagrass nutrient demand. Eelgrass tissue N content and sediment pore water DIN concentrations exhibited reverse relationship at the present study. This reverse relationship suggests in situ nutrient concentrations are not good indicator of nutrient availabilities, and regeneration and turnover rates of sediment nutrients are also important factors to determine nutrient availabilities at the site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.129-135
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• 2017

This study examined the antioxidant activity of the water extract from graviola leaves to develop a harmless and highly stable natural antioxidant. The total polyphenol content, total flavonoid content, DPPH radical scavenging activity, and MTT assay activity were measured. As a result, 62.3 g of the water extract from graviola leaves was obtained at $98^{\circ}C$ using 300 g of graviola leaf powder. The total polyphenol content was $291.97+2.39{\mu}g/mL$ and the total flavnoid content was $161{\pm}7.85{\mu}g/mL$ in a 1 mg/mL water extract from graviola leaves. The DPPH radical scavenging activity showed 51.6%, 67.8%, 79%, 82.4% and 83.9% at concentrations of 1, 2.5, 5, 10 and 15 mg/mL. This shows concentration-dependent scavenging activity and significant antioxidant activity. As a result of measuring the toxicity about HDF cells, a HDF cell survival rate of 100% was observed at a 150 mg /mL concentration, which was the same as that of the control group and a higher cell survival rate at a lower concentration. In conclusion, the graviola leaf extract can be developed as a material of food or cosmetics containing natural antioxidants.

• Journal of Forest and Environmental Science
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• v.22 no.1
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• pp.71-75
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• 2006

Water relations of Kalopanax pictus leaves obtained from the P-V curve. In the upper leaves of Kalopanax pictus seedlings, the original osmotic pressure at maximum turgor was -1.44 MPa, and the osmotic pressure at incipient plasmolysis point was -1.84 MPa, and the relative water content at incipient plasmolysis point was 78.2%.

• Journal of the Korean Society of Food Culture
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• v.17 no.1
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• pp.70-77
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• 2002

Jangachi(salted and fermented vegetable) has been made by Korean traditionally using several kinds of vegetables, which is a good source of variety of nutrients and vitamins. There are many methods for making Jangachi. Generally soy sauce Jangachi is made through two steps. First, as a pretreatment, vegetables are soaked in salt water. Second, soaked vegetables are fermented in various ingredients like soy sauce, sugar, garlic, ginger and so on. This study was performed to observe changes in contents of chemical components and sensory evaluation of pretreated perilla leaf. Perilla leaf was soaked in water with different levels of salt concentration(2, 5 and 8 %) and soaking time(1, 3 and 5 days). The optimal level of salt and soaking time was determined with the results of sensory evaluation by response surface methodology and analysis of composition. The moisture contents decreased as the levels of salt and soaking time increased. The moisture content of untreated sample was 87.5 % and when soaked for 5 days in the water of 8 % salt concentration, it became 78.27 %. pH of Perilla leaf was high in high levels of salt concentration and short soaking time. Total acidity was so opposite to pH that was low in high levels of salt concentration and short soaking time. In the water of 8 % salt concentration, total acidity was 0.14 % when soaked for 1 day, 0.20 % for 3 days and 0.30 % for 5 days. Salt contents became greater as the soaking time increased. As the results of puncture test, soaked Perilla leaf's toughness increased as the levels of salt increased and soaking time decreased. Among the sensory attributes, greenness increased as the levels of salt concentration increased when soaked for more than 3 days. Saltiness and bitterness became greater as the levels of salt concentration increased. Perilla flavor decreased with the short soaking time. Off-flavor increased with the increased levels of soaking time and decreased salt concentration when soaked for more than 3 days. Toughness decreased as the levels of soaking time increased. Crispness increased with the increased levels of salt concentration. The condition of pretreated Perilla was optimum when it soaked for 42 hours in 4 % salt concentration.

• Journal of Life Science
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• v.18 no.2
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• pp.154-161
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• 2008

The physiological and photochemical responses of rice seedling to NaCl stress were investigated through measuring leaf relative water content (RWC), root water uptake and chlorophyll fluorescence. When plants were exposed to increased salinity stress, the visual symptoms of injury were significant at ${\geq}$500 mM NaCl concentration for 4 and 5 day stress periods. The differences in Fv/Fm between control treatment and plants treated with 500 mM and 1,000 mM NaCl were evident after 5 day and 4 day, respectively, whereas in root water uptake its effect was observed at 500 mM and 1,000 mM NaCl at 2 day of salt-stressed periods. Leaf RWC in salt-stressed plants decreased gradually with increasing salinity in exogenous solution and duration of salt stress, and these decrease showed leaf RWC of 58-68% atduration over 2 day stress of 1,000 mM NaCl treatment and 88% at 1 day stress. NaCl stress led to a significant inhibition of the light-induced greening in etiolated rice plants, especially in 4 and 5 day salt-stressed plants, which linearly decreased with NaCl concentration ($R^2$=0.812 and 0.918, respectively). The effects of NaCl stress in rice seedlings indicate that water uptake in root is more sensitive to increasing NaCl concentration and stress duration than Fv /Fm in leaves compared with the same NaCl concentration.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.264-273
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• 2016

This study was conducted to find out the influence of water stress from May to June on photosynthesis, shoot growth and fruit quality of apple trees. Fuji'/M.9 apple trees were root pruned at full bloom (30th April), parallel to the row of 30 cm or 60 cm from the trunk, to one side or both sides of trunk. The average value of afternoon leaf water potential from May to June of the no root pruning was maintained over -1.80 MPa, but that of root-pruning treatments was maintained under -1.80 MPa. In the comparison of average value of leaf water potential from May to June by root-pruning degree, the root pruning both sides at 30 cm from trunk was lowest (-2.06 MPa), followed by the root pruning both sides at 60 cm (-2.02 MPa) and the root pruning one side at 30 cm (-1.91 MPa). Root pruning one side at 30 cm or both sides at 60 cm reduced photosynthetic rate from May to June by 80% or 65%, respectively, compared with no root pruning. So, the degree of decreasing total shoot length or average fruit weight compare to the no root pruning of the root pruning one side at 30 cm was 25% or 11%, respectively, and those of the root pruning both sides at 30 cm was 45% or 15%, respectively. However, the soluble solid content and fruit color of the root pruning was higher than those of the no root pruning, and those of the root pruning both sides was higher than root pruning one side. These results indicate that the fruit enlargement was decreased when the average value of average leaf water potential from May to June was under -1.80 MPa, and the shoot growth was decreased when that was under -2.00 MPa.

• Journal of Plant Biology
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• v.5 no.3
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• pp.6-10
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• 1962

Leaf samples, raised on the N-deficient and N-abundant sand and sprayed with varying concentration of urea, were analized for their total chlorophyll concentration. It was observed that the depression periods of the chlorophyll content appeared at first by spraying with urea; it appeared on the 3rd day in the N-deficient plots and on the 6th day in the N-abundant plots. Causes of the depression of chlorophyll may be assumed to be in an excessive urea, an accumulation of ammonia from urea absorbed, and depression of water content owing to urea application. The maximum content of the chlorophyll was shown on the 6th day in N-deficient and on the 12th day in the N-abundant plots. The young leaves activity formed the chlorophyll by urea foliar spray, compared with the mature ones. This result was consistent with previous paper.