• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.178-184
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• 2019

Strawberry ($Fragaria{\times}ananassa$) is one of the most important and popular fruit crops in the world, and 'Sulhyang' is one of the principal cultivars cultivated in the Republic of Korea for the domestic market. The growth and flower induction in strawberry is the process which influences directly on fruit bearing and yield of this crop. In this study, effect of benzyladenine (BA), gibberellic acid ($GA_3$), and salicylic acid (SA) on growth and flower bud induction in strawberry 'Sulhyang' was investigated. The 3-week-old runner plants, grown in 21-cell propagation trays, were potted and cultivated in growth chambers with $25^{\circ}C/15^{\circ}C$ (day/night) temperatures, 70% relative humidity (RH), and light intensity of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density (PPFD) provided by white light emitting diodes (LEDs). The runner plants were treated with one of three concentrations, 0 (control), 100, and $200mg{\cdot}L^{-1}$ of BA, $GA_3$, or SA solution. The chemicals were sprayed two times on leaves of runner plants at an interval of two weeks. After 9 weeks the results showed that the application of all chemicals caused reduction of root length and chlorophyll (SPAD) content as compared to the control. The lowest chlorophyll (SPAD) content was recorded in plants treated with $GA_3$. However, the treatment of $200mg{\cdot}L^{-1}$ $GA_3$ promoted leaf area, leaf fresh weight, and plant fresh weight. The greatest flower induction (85%) and number of inflorescences (4.3 inflorescences per plant) were observed in the treatment of $200mg{\cdot}L^{-1}\;SA$, followed by $100mg{\cdot}L^{-1}\;SA$. Overall, results suggest that foliar application of $GA_3$ solution could accelerate plant growth, while foliar application of SA solution could induce hastened flowering. Further studies may be needed to find out the relationship between $GA_3$ and SA solutions treated in a combination, and the molecular mechanism involved in those responses observed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.127-136
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• 2019

Sweet sorghum (Sorghum bicolor L. Moench), compared to traditional crops, has been evaluated as a useful crop with high adaptability to the environment and various uses, but cultivation has not expanded owing to a lack of related research and information in Korea. This study was conducted to estimate heading date in 'Chorong' sweet sorghum based on climate data of the last 30 years (1989 - 2018) from six regions (Jeonju, Buan, Jeongup, Imsil, Namwon, and Jangsu) in Jellabuk Province. In addition, we compared the growth and quality factors by sowing date (April 10, April 25, May 10, May 25, June 10, June 25, and July 10) in 2018. Days from sowing to heading (DSH) increased to 107, 96, 83, 70, 59, 64, and 65 days in order of the sowing dates, respectively, and the average was 77.7 days. The effective accumulated temperature for heading date was $1,120.3^{\circ}C$. The mean annual temperature was the highest in Jeonju, followed in descending order by Jeongup, Buan, Namwon, Imsil, and Jangsu. The DSH based on effective accumulated temperature gradually decreased in all sowing date treatments in the six regions during the last 30 years. DSH of the six regions showed a negative relationship with mean temperature (sowing date to heading date) and predicted DSH ($R^2=0.9987**$) calculated by mean temperature was explained with a probability of 89% of observed DSH in 2017 and 2018. At harvest, fresh stem weight and soluble solids content were higher in the April and July sowings, but sugar content was higher in the May 10 ($3.4Mg{\cdot}ha^{-1}$) and May 25 ($3.1Mg{\cdot}ha^{-1}$) sowings. Overall, the April and July sowings were of low quality and yield, and there is a risk of frost damage; thus, we found May sowings to be the most effective. Additionally, sowing dates must be considered in terms of proper harvest stage, harvesting target (juice or grain), cultivation altitude, and microclimate.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.3
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• pp.208-220
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• 2019

The seasonality of leaf fall has important implications for understanding the response of trees' phenology to climate change. In this study, we quantified the leaf fall pattern with a model to estimate the timing and speed of leaf litter according to species and considered the nutrient use strategy of canopy species. In the autumns of 2015 and 2016, leaf litter was collected periodically using 36 litter-traps from the deciduous forests in Gwangneung and sorted by species. The seasonal leaf fall pattern was estimated using the non-linear regression model of Dixon. Additionally, the resorption rate was calculated by analyzing the nitrogen concentration of the leaf litter at each collection time. The leaf litter generally began in early October and ended in mid-November depending on the species. At the peak time (T50) of leaf fall, on average, Carpinus laxiflora was first, and Quercus serrata was last. The rate of leaf fall was fastest (18.6 days) for Sorbus alnifolia in 2016 and slowest (40.8 days) for C. cordata in 2015. The nitrogen resorption rates at T50 were 0.45% for Q. serrata and 0.48% for C. laxiflora, and the resorption rate in 2015 with less precipitation was higher than in 2016. Since falling of leaf litter is affected by environmental factors such as temperature, precipitation, photoperiod, and $CO_2$ during the period attached foliage, the leaf fall pattern and nitrogen resorption differed year by year depending on the species. If we quantify the fall phenomena of deciduous trees and analyze them according to various conditions, we can predict whether the changes in leaf fall timing and speed due to climate change will prolong or shorten the growth period of trees. In addition, it may be possible to consider how this affects their nutrient use strategy.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.534-539
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• 2018

'Hwawang' is an early maturing and short statured rice cultivar adaptable to the rice-cash crop rotation system that was developed by the rice breeding team of the Department of Southern Crop, National Institute of Crop Science (NICS), Rural Development Administration (RDA), Korea, in 2012. This cultivar was derived from the cross of YR25867 (Hitomebore//YR21247-B-B-B-49-1/Sasanishiki BL4) and YR25866 (Akidagomachi//YR21247-B-B-B-49-1/Sasanishiki BL4) during the 2005/2006 winter season and was fixed as a homozygous line by a doubled haploid breeding system. In the replicated yield trial in 2009, a promising line (YR26253Acp26-1) showed a good phenotype and high yield potential, and so it was selected and designated as 'Milyang256'. The local adaptability test of 'Milyang256' was carried out at three locations from 2010 to 2012. It was named 'Hwawang' and had a high head rice ratio and good eating quality. The culm length of 'Hwawang' averaged 62 cm during the yield trials and was 10 cm shorter than that of 'Keumo'. The number of spikelets per panicle of 'Hwawang' was significantly lower than that of 'Keumo', but the number of tillers per hill was higher. This variety showed resistance to bacterial blight disease but was moderately susceptible to both leaf and neck blast. The milled rice yield of 'Hwawang' was 452 kg/10 a at the late transplanting stage of the local adaptability test. Thus, 'Hwawang' is well adapted to the rice-cash crop rotation system in the southern plain area. (Registration No. 5106)

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.609-615
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• 2011

Forsythia saxatilis is a Korean endemic plant designated as rare and endangered by the Korea Forest Service (KFS). Growth and physiological characteristics of F. saxatilis were investigated under two different light intensities in order to figure out an appropriate growth environment for conservation and restoration of the species in its natural habitat. Shoot length, leaf size and weight, photosynthetic pigment content and photosynthetic parameters were measured for F. saxatilis grown at two experimental plots under relative light intensities (RLI) of 20% and 60% of the full sun, respectively. Fresh leaf weight of plants grown under high relative light intensities (RLI-60) exceeded that of plants grown at 20% RLI. The ratio of fresh leaf weight to leaf size at RLI-60 was 1.47 times superior comparing to that recorded at RLI-20. The content of photosynthetic pigments such as chlorophyll a, b and carotenoid were higher in plants grown at RLI-60, whereas the ratio of total chlorophyll to carotenoid content was higher in the leaves at RLI-20. Photosynthetic rate, stomatal conductance and transpiration rate at RLI-60 were, respectively, 2.5, 2.65 and 1.79 times higher comparing to those recorded at RLI-20. Water use efficiency, however, was higher at RLI-20. The chlorophyll/nitrogen ratio was 1.83 times higher at RLI-20 than at RLI-60. In contrast, the ratio of net photosynthesis to chlorophyll content at RLI-60 was 2.58 times higher than that of RLI-20. In conclusion, light intensity might be the major factor affecting growth and physiological characteristics of F. saxatilis grown under canopy of tall tree species.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.733-743
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• 2020

We estimated the carbon storage of coal mines reclaimed using Betula platyphylla (BP), Pinus koraiensis (PK), and Pinus spp. (PS, Pinus densiflora, Pinus rigida, and Pinus thunbergii). The carbon storage of tree biomass (TB), forest floor(FF), mineral soil (MS), and the total forest were quantified. Reclaimed sites were located in Gangwon-do, Gyeongsangbuk-do, and Jeollanam-do; reclamation was conducted at various times in each region. The carbon storage (ton C ha^-1) in FF (BP: 3.31±0.59, PK: 3.60±0.93, PS: 4.65±0.92), MS (BP: 28.62±2.86, PK: 22.26±5.72, PS: 19.95±3.90), and the total forest(BP: 54.81±7.22, PK: 47.29±8.97, PS: 45.50±6.31) were lower than that of natural forests (NF). The carbon storage in TB was lower in BP (22.57±6.18) compared to NF, while those in PK(21.17±8.76) and PS (20.80±6.40) were higher than in NF. While there were no significant differences in the carbon storage of TB, FF, and the total forest among tree species, results from MS showed a significant difference among species. TB and the total forest carbon storages in all sites increased after reclamation. Soil pH and cation exchange capacity values in BP and PS were lower than in NF. Amounts of labile carbon, available phosphate, and microbial biomass carbon in reclaimed sites were less than half of NF. There are a number of methods that could increase the reclamation efficiency. Applications of lime or organic fertilizers, as well as tillage operations, may improve soil properties in reclaimed coal mines. Additionally, pruning and thinning would increase tree growth thereby increasing carbon storage.

• Korean Journal of Environment and Ecology
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• v.36 no.3
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• pp.327-337
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• 2022

Ecological restoration is considered a good means to prevent biodiversity loss in terms of the ecosystem's health and sustainability. However, there are difficulties in putting it into practice as there is no comprehensive and objective standard for the selection of plant species, such as environmental, ecological factors, and restoration goal setting. Therefore, this study developed an evaluation index necessary for selecting plant species for restoration using the Delphi method that synthesizes the opinions of the expert group. A survey with 38 questionnaires was conducted twice for experts in ecological restoration, etc., and the importance and priority of evaluation indicators were analyzed by dividing the restoration targets into inland and island regions. The result of the importance analysis showed that "native plants" had the highest average of 4.9 among the evaluation indices in both inland and island regions, followed by "seed security", "propagation", and "root growth rate". In the inland region, the index priority was analyzed in the order of "native plants", "appearance frequency", "root growth rate", "distribution range", and "seed security" in the island region, it was analyzed in the order of "native plants", "root growth rate", "appearance frequency", "distribution range", and "tolerance", showing slight differences between the two indicators. As a result of the importance and priority indicator analysis, we set the mean importance and priority of 4.1 and 2.9, respectively, in the inland region and 4.2 and 2.9, respectively, in the island region. As for the criteria of selecting plant species for ecological restoration, the "native plants" had the highest importance and priority. "Seed securing", 'viability", "topography", "proliferation", "tolerance", "soil conditions", "growth characteristics", "early succession", "distribution range", "appearance frequency", and "germination rate" were classified into subgroups of low importance and priority. The lowest indicators were "final stage of succession", "transition period", 'transition stage", "root", "reproduction", "soil", "appearance", "technology", "landscape", "climate", and "germination rate". We expected that the findings through objective verification in this study would be used as evaluation indicators for selecting native plant species for ecological restoration.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.65-77
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• 2020

In order to industrialize of Dendranthema indicum (L.) DesMoul., which is a lot of commercially available and is synonymous with chrysanthemum tea, in the autumn of 2018, Dendranthema indicum (L.) DesMoul. seeds were collected from its own native region, and the seeds were germinated after refrigerated storage. Young seedlings were subjected to experiments in February, March, and April in the open field to examine the effects on the harvesting of leaves by distance and the growth of leaves and stems. The results of analyzing the components by collecting the leaves+stem after collecting the flower of Dendranthema indicum (L.) DesMoul. are as follows. 1. When D. indicum (L.) DesMoul. seedlings were planted according to the transplanting date, the number of flowers was 17.1 in the transplanting date in April. The diameter of the flower was 2.9cm, 16ea, 6.5~6.6g in the fresh weight, and the dry weight of the case was 1.1~1.2g. The leaves were 46~47ea in March and April in the planted area, 5.2~5.3cm in leaf length and 3.5~3.6cm in leaf width. 2. When planted D. indicum (L.) DesMoul. seedlings according to transplanting distance, the number of flowers was 16.2 when planted at 20×20cm intervals and, 16.8~17.1 at 30×30~50×50cm intervals. The diameter of the flower was 2.7~2.8cm, the number of petals was 8, the length of the petal was 0.8 cm, and fresh weight was 6.5~6.6g per flower. Leaves had the largest number of 47 of 30×30cm and 40×40cm, and leaf length appeared at the longest 6.2cm in the 50×50cm treatment area, but 5.2cm in the other treatment areas. 3. The extraction yield of D. indicum (L.) DesMoul. leaves+stems was 7.93%, and the extraction solvent colors were light green at 50, 60% and green at 70, 80, 90, 100%. The extraction yield of D. indicum (L.) DesMoul. flowers was 7.58%, the color of the extraction solvent was light yellow at 50, 60 and 70%, yellow at 80 and 90%, and dark yellow at 100%. 4. We confirmed 11 kinds of ingredients such as in D. indicum (L.) DesMoul. flowers are gallic acid, 4-hydroxy benzoic acid, methyl gallate, 4-hydroxy-3-methoxy benzoic, caffeic acid, salicylic acid, p-coumaric acid, sinapic acid, naringin, 4-melthoxyben, flavone. The content was 29.200-36.900ppm. 5. The components contained in the D. indicum (L.) DesMoul. leaf+stem, salicylic acid appeared at 6,129.526ppm, and the next 4-methoxyben was 1,966.714ppm. It was methyl gallate 8.197ppm, 4-hydroxy-3-methoxy benzoic 6.994ppm, caffeic acid 5.566ppm, flavone 4.522ppm, p-coumaric acid 3.787ppm, gallic acid 1.893ppm that appeared in the content below 10ppm.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.1
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• pp.13-34
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• 2022

Soil moisture data have been collected at 11 agrometeorological stations operated by The Korea Meteorological Administration (KMA). This study aimed to verify the accuracy of soil moisture data of KMA and develop a correction formula to be applied to improve their quality. The soil of the observation field was sampled to analyze its physical properties that affect soil water content. Soil texture was classified to be sandy loam and loamy sand at most sites. The bulk density of the soil samples was about 1.5 g/cm³ on average. The content of silt and clay was also closely related to bulk density and water holding capacity. The EnviroSCAN model, which was used as a reference sensor, was calibrated using the self-manufactured "reference soil moisture observation system". Comparison between the calibrated reference sensor and the field sensor of KMA was conducted at least three times at each of the 11 sites. Overall, the trend of fluctuations over time in the measured values of the two sensors appeared similar. Still, there were sites where the latter had relatively lower soil moisture values than the former. A linear correction formula was derived for each site and depth using the range and average of the observed data for the given period. This correction formula resulted in an improvement in agreement between sensor values at the Suwon site. In addition, the detailed approach was developed to estimate the correction value for the period in which a correction formula was not calculated. In summary, the correction of soil moisture data at a regular time interval, e.g., twice a year, would be recommended for all observation sites to improve the quality of soil moisture observation data.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.74-80
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• 2022

The vegetation of historical sites has been a form of vegetation that has remained since some years ago, but in modern times, vegetation and terrain have been deformed or damaged due to urban development, which was followed by an industrialization. As a solution to this, it is necessary to establish a plan for restoration and management by referring to the vegetation and landscape remaining in the historic site as indicators. This study was conducted to provide basic data for vegetation and landscape management of Baekje Historic Sites in Seoul by comparing and analyzing location characteristics, existing vegetation, and remaining vegetation of past substitutional vegetation for Pungnaptoseong and Mongchontoseong, Baekje Historic Sites in Seoul. As a result of the study, Pungnaptoseong and Mongchontoseong are located near the main stream of the Han River, Pungnaptoseong is located on a flat land consisting of natural embankments and floodplains, and Mongchontoseong is located on a hilly area. In the case of existing vegetation, it has been confirmed that Pungnaptoseong mainly has ornamental trees planting sites, while Mongchontoseong has a distribution of residual species from the past that grow in villages and hilly lowlands. The Substitutional vegetation of Pungnaptoseong and Mongchontoseong was synthesized based on the location characteristics and actual vegetation, it is estimated that the hilly areas may have been divided into "Quercus aliena Blume.", "Quercus mongolica Fisch. ex Ledeb." and so on, "Pinus densiflora Siebold & Zucc." on dry land,"Salix koreensis Andersson.", "Juglans mandshurica Maxim.", "Alnus japonica (Thunb.) Steud." in rivers and tributaries, "Quercus acutissima Carruth." in the main part of the forest, "Pinus densiflora Siebold & Zucc.", "Salix koreensis Andersson.", "Zelkova serrata (Thunb.) Makino." as a divine tree in the beginning of the village. Since the 1960s, all substitutional vegetation in the past has disappeared due to the introduction of foreign species and the creation of urban areas in Pungnaptoseong and Mongchontoseong, and the landscape has also been damaged. Fortunately, the substitutional vegetation was estimated in consideration of the species of residual trees distributed along the walls, climate, location characteristics, and times, but this study was conducted based on literature and existing vegetation surveys. Therefore, it is necessary to supplement the past target vegetation in Baekje historical sites in Seoul through quantitative experiments such as plant relic analysis in the future.