• 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℃.

• Korean Journal of Environment and Ecology
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• v.37 no.3
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• pp.182-191
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• 2023

This study was carried out to identify the distribution and growth characteristics and evaluate the conservation status of the Michelia compressa Maxim., a rare and endangered wild plant II, in the habitats in Korea. A total of 314 individuals were found in the natural habitats of Heuksan Island and Jeju Island and were divided into four populations. About 45.9% (144 individuals) were distributed in the range of 401m~500m above sea level. The average height of trees was 2.7(±4.8)m, the diameter at breast height was 12.6(±13.9)cm, and the number of branches was 1.0(±0.5) on average. 54.3% of the sapling individuals of M. compressa were distributed within a radius of 30 m from the mother tree, 25.8% were distributed between 31 m through 40 m, and most (90.1%) were distributed within a radius of 60 m. The fact that sapling individuals of M. compressa are not identified even around some mature individuals and appear only in extremely limited areas is estimated to be closely related to the growth conditions as well as the environment of the natural habitats. The dispersal of M. compressa is presumed to be related to the birds and natural seedlings because water puddles, a resting place for birds beyond the range of natural seedlings, characterize its habitats. The IUCN Red List evaluation criteria at the regional and national level of M. compressa corresponds to the Critically Endangered category, and the domestic population under the category of "CR B2ab(v); C2a(i); D."

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.537-545
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• 2011

This study was conducted to obtain basic information on physiological and proteomic responses of barley seedlings to salt stress. Shoot dry weight decreased significantly as the level of soil salinity increased. Salt stress-induced decrease of relative shoot dry weight was lower in cv. "Sanglok" than in cv. "Sunwoo". Under the salt stress, SPAD value decreased, and the value was higher in cv. "Sanglok" than in cv. "Sunwoo". Sodium ion content in the leaves increased as NaCl concentration increased, and the content was higher in cv. "Sunwoo" than in cv. "Sanglok". The K⁺/Na⁺ ratio was higher in cv. "Sanglok" than in cv. "Sunwoo". Salt stress-induced alterations in protein expression of the leaves were detected by two dimensional electrophoresis, and 47 protein spots showing altered expression were selected. Among the selected protein spots, 17 protein spots were up-regulated and 28 spots down-regulated in cv. "Sanglok". In cv. "Sunwoo", 14 protein spots were up-regulated and 27 spots down-regulated. Out of 47 deferentially expressed protein spots, 18 protein spots were identified using mass spectrometry and NCBI protein database. Among the identified proteins, ten proteins are known to be involved in various stress responses, but the others are not directly involved in stress responses.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.520-530
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• 2011

This study was carried out to evaluate the possibility of rice double cropping in Korea by assessing the growth and yield performance of rice cultivars transplanted at the extremely-early date. When the transplanted rice seedling was exposed to low temperature below 0℃, the survival rate decreased drastically. However, short exposure to below 0℃ one or two times did not damage transplanted rice seedling so severely. Thus, the earliest transplanting in spring would be possible when minimum temperature rises above 0℃. Compared with the conventional seedling nursery tray (CSNT), seedling rearing with the potted nursery tray was more effective for increasing leaf age and seedling dry weight during nursery period. In the first rice cropping, rice cultivation with seedlings reared in PSNT showed shorter growth duration and cumulative temperature from transplanting to heading than that with seedlings reared in CSNT. The earliest heading date on July 4 in Jinbuolbyeo was earlier by two to three days than that of Dunaebyeo. If rice has not exposed to cold damage, the earliest heading date of Jinbujolbyeo can advance to June 30 or July 1. In this case, rice harvest would be possible on August 5, enabling the rice transplanting of the second rice cropping before August 10. At transplanting time with low temperature damage rice yield were less than 400 kg/10a while rice yield exceeded 400 kg/10a at transplanting time without low temperature damage.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.502-514
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• 2023

This study was conducted to understand the long-term changes in soil physiochemical properties and seedling growth in Larix kaempferi (larch) stands planted in clear-cut larch and Pinus rigida (pine) forest soils over an 11-year period after reforestation. Two-year-old bare-root larch seedlings were planted in 2009-2010 at a density of 3,000 seedlings ha^-1 in clear-cut areas that harvested larch (Chuncheon and Gimcheon) and pine (Wonju and Gapyeong) stands. We analyzed the physiochemical properties of the mineral soils sampled at 0-20 cm soil depths in the planting year, and the 3^rd, 7^thand 11^th years after planting, and we measured seedling height and root collar diameter in those years. We found significant differences in soil silt and clay content, total carbon and nitrogen concentration, available phosphorus, and cation exchangeable capacity between the two stands; however, seedling growth did not differ. The mineral soil was more fertile in Gimcheon than in the other plantations, while early seedling growth was greatest in Gapyeong. The seedling height and diameter at 11 years after planting were largest in Wonju (1,028 tree ha^-1) and Chuncheon (1,359 tree ha^-1) due to decreases in stand density after tending the young trees. The soil properties in all plantations were similar 11 years after larch planting. In particular, the high sand content and high available phosphorus levels (caused by soil disturbance during clear-cutting and planting) showed marked decreases, potentially due to soil organic matter input and nutrient uptake, respectively. Thus, early reforestation after clear-cutting could limit nutrient leaching and contribute to soil stabilization. These results provide useful information for nutrient management of larch plantations.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.180-185
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• 2012

The objective of this study was carried out to elucidate the effect of LEDs (light emitting diodes) irradiation in relation to early growth and inorganic elements in leaf lettuce (Lactuca sativa L. 'Rollo Rosa'). In morphological changes of leaves, shoot elongation and hypocotyl length showed poor growth in red light irradiation, while the red + blue light irradiation induced shorter plant height and much greater leaf numbers resulting in increased fresh weight. In change of the Hunter's color and SPAD values, lettuce seedlings grown under in red + blue and fluorescent light irradiation had a higher $a^*$ value, otherwise SPAD values were not changed in these light irradiations. Interestingly, relative chlorophyll contents showed 1.8 times increased redness in the treatment of red + blue light irradiation. Inorganic element (N, Ca, Mg, Mn, and Fe) and ascorbic acid contents were increased in lettuce plants grown under LEDs light irradiation compared to those of lettuce grown under the fluorescent light which showed higher P and Mn contents. In conclusion, it is considered that red + blue light irradiation which stimulates growth and higher nutrient uptake in leaf lettuce could be employed in containers equipped with LEDs.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.495-500
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• 2001

Seed germination, seedling growth, plant establishment after transplanting, set of female flowers, and subsequent fruit growth were examined in cucumbers grown in soils having varying electrical conductivities (EC) of $1.0-5.0dS{\cdot}m^{-1}$ adjusted by adding different amount of a commercial compound fertilizer (N : $P_2O_5$ : $K_2O$ = 21 : 17 : 17). Slower seed germination was recorded in soils having EC value of $3.0dS{\cdot}m^{-1}$ or higher and little or no germination took place in soils with EC $4.0dS{\cdot}m^{-1}$ until 8 days after sowing. Suppression of seedling growth was apparent in soils having EC level of $2.5dS{\cdot}m^{-1}$. All seedlings died eventually at EC level of $3.5dS{\cdot}m^{-1}$. Leaf color became progressively dark green with the increase in EC from 1.0 to $3.0dS{\cdot}m^{-1}$. The first female flower was formed at higher node and the number of days required for the first flowering of female flower increased with the increase in EC values up to $3.0dS{\cdot}m^{-1}$. Occasionally, leaf yellowing and self-topping symptoms appeared in plants grown in soils having EC level of $3.0dS{\cdot}m^{-1}$.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.318-322
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• 2014

The effects of cover crops on weed suppression were evaluated in this study. Weed suppressing effects of hairy vetch cover crops were evaluated in summer grain fields. Cover crops were sown at the sowing rate of $60kg\;ha^{-1}$ on Oct. 2012 and Feb. 2013 without basal fertilization. Three weeks old sorghum seedlings were transplanted after minimum tillage on June 2013. Hairy vetch cover crop treatment significantly reduced weed biomass in the transplanted sorghum. By smothering, the cover crops reduced weed biomass to economic level in sorghum. Besides the weed suppression, hairy vetch cover crop resulted in green manure effect on crop growth. Hairy vetch treatment showed beneficial effects on sorghum growth. Reduction of weeds caused by use of strip-tillage machine and polyethylene film mulching was 71% and 88%, respectively. At harvest, yield of sorghum was greater in order of polyethylene film mulching > hairy vetch cover crop > control in transplanted fields.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.659-668
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• 2013

The objective of this study was carried out to elucidate the effect of LEDs (light emitting diodes) irradiation in relation to early growth and inorganic elements in leaf lettuce (Lactuca sativa L. 'Chung Chi Ma'). In morphological changes of leaves, shoot elongation and hypocotyl length showed poor growth in red light irradiation, while the red+blue light irradiation induced shorter plant height and much greater leaf numbers resulting in increased fresh weight. In change of the Hunter's color and SPAD values, lettuce seedlings grown under in red+blue and fluorescent light irradiation had a higher $a^*$ value, otherwise SPAD values were not changed in these light irradiations. Interestingly, relative chlorophyll contents showed 1.8 times increased redness in the treatment of red+blue light irradiation. Inorganic element (N, Ca, Mg, Mn, and Fe) and ascorbic acid contents were increased in lettuce plants grown under LEDs light irradiation compared to those of lettuce grown under the fluorescent light which showed higher P and Mn contents. In conclusion, it is considered that red+blue light irradiation which stimulates growth and higher nutrient uptake in leaf lettuce could be employed in containers equipped with LEDs.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.41-45
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• 2014

This study was conducted to investigate the effects of crown numbers on growth and yield of ever-bearing strawberry (Fragaria ${\times}$ ananassa Duch.) 'Goha' cultivar. Strawberry seedlings were planted with $55{\times}30cm$ distance on April 29, and the randomized block experimental was designed by putting the crown numbers by 1, 3, 5 and crown-unremoved as the control. At the early growth stage, as the numbers of crown decreased, the size of leaf became larger and inflorescence diameter became thicker. Plant height became higher as the number of crown increased at the final harvesting time. Fresh weight of crown-unremoved plants was 118 g, showing 77.2 g higher than that of plants with one crown. Numbers of the developed inflorescence of plants with five crowns and crown-unremoved was 20.1, whereas 6.8 of plants with one crown, resulted in 13.3 more crowns. However, crown number did not significantly affect the fruit quality. As the crown number increased, the average fruit weight was lighter and the marketable fruit rate was shown to decrease significantly. The marketable yield of crown-unremoved plants was $17,372kg{\cdot}ha^{-1}$, showing 68% higher than plants with one crown. Therefore, crown management without thinning crowns was recommended and inflorescence thickness less than 3 mm should be removed for successful production of ever-bearing strawberry 'Goha' cultivar during summer season.