• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.189-195
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• 2007

Helicteres isora is medicinally important plant effective against asthma, diabetes, hypolipidemia, HIV, besides a good source of diosgenin. Seed dormancy and low rate of natural fruit production make this plant a perfect candidate for developing an in vitro method useful for its clonal propagation and further biotechnological developments. This is the first report on in vitro production of this plant. Nodal explants obtained from aseptically germinated seedlings were cultured on MS medium (Murashige and Skoog 1962) fortified with indole-3-acetic acid (IAA) ($0.57-22.83\;{\mu}M$), indole-3-butyric acid (IBA) ($0.41-16.58\;{\mu}M$), 6-benzylaminopurine (BA) ($0.44-17.75\;{\mu}M$) and kinetin (Kin) ($0.46-13.94\;{\mu}M$) either singly or in combinations of IAA + BA, IAA + Kin and BA + Kin. Combinations of cytokinins (BA and Kin) were most suitable for multiple shoot induction and $13.94\;{\mu}M\;Kin\;+\;13.31\;{\mu}M\;BA$ was optimum (79% frequency) associated with high number of microshoots (7.1 shoots per explant) after 20 days of culture. Maximum shoot elongation and proliferation (10 shoots per explant with 4.8 cm average height) was achieved on MS media containing $2.32\;{\mu}M\;Kin\;+\;2.22\;{\mu}M\;BA\;+\;2.85\;{\mu}M\;IAA$. High rooting frequency (70%) was achieved on MS medium (1/2 basal strength) fortified with $4.14\;{\mu}M$ IBA, while activated charcoal showed inhibitory effects on rooting. Hardening was done with 76% survival rate and these plants were growing without any visual defects and morphologically mimicking the naturally growing plants.

• Korean Journal of Medicinal Crop Science
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• v.22 no.6
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• pp.469-474
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• 2014

This study was performed to investigate the effects of sowing density and number of seeds sown on the emergence rate and growth characters of Panax ginseng C. A. Meyer under direct sowing cultivation in a blue plastic greenhouse. Ginseng seedlings, derived from seeds sown directly at different densities (90, 108, 135, and 162 seeds per $162m^2$), were cultivated in sandy loam soil within a blue plastic greenhouse. In contrast to the emergence rate, which decreased with an increase of sowing density, number of survival plant showed an increasing trend. Interestingly, the emergence and number of survival plant were significantly enhanced when 2 or 3 seeds were sown per hole compared with when one seed was sown per hole. Growth of the aerial parts of ginseng were not markedly influenced by sowing density or the number of seeds sown. However, chlorophyll content (SPAD values) increased with an increase in sowing density. Root parameters, such as root length, diameter, and weight, and the number of lateral roots decreased with an increase in sowing density, but were not noticeably influenced by the number of seeds sown. Total saponin content was the highest in the treatment plot containing 135 seeds. Similarly, the content of each ginsenoside was also tended to be higher in this treatment than in other treatment plots. On the basis of the results obtained in this study, it was possible to determine the optimal sowing density and seed number for the direct sowing cultivation of ginseng in blue plastic greenhouse.

• Journal of Ginseng Culture
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• v.4
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• pp.128-141
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• 2022

Baengnyeongdo Island, which belongs to Ongjin-gun, Incheon, is an island in the northernmost part of the West Sea in South Korea. Baengnyeong Island is the 15th largest island in Korea and covers an area of 51 km². The Korea Ginseng Corporation (KGC) investigated the possibility of growing ginseng on Baengnyeong Island in 1996. In 1997, thanks to the support of cultivation costs from Ongjin-gun, the first ginseng seedbed was built on Baengnyeong Island. In 1999, the seedlings were transplanted to a permanent field under a contract with KGC. In 2003, the first six-year-old ginseng harvest was performed, and KGC purchased all production according to the contract. Since then, KGC has signed on to grow ginseng until 2012 and purchased six-year-old ginseng until the fall of 2016. Since 2014, the GimpoPaju Ginseng Agricultural Cooperative Association has signed a ginseng production contract. According to a survey of nine 6-year-old ginseng fields (total 5,961 units) on Baengnyeong Island, the top five with good growth had a survival rate of 42.6 to 68%, and the bottom four with poor growth had an extremely low survival rate of 11.1 to 21.3%. The four fields with low survival rates were where hot peppers were planted before ginseng cultivation. It is believed that the excess nitrogen remaining in the soil due to the treatment of compost or manure during pepper cultivation causes ginseng roots to rot. The average incidence of Alternaria blight was 8.6%. Six six-year-old ginseng gardens were low at 1.1 to 4.7%, while the other three were high at 16.7 to 20.9%. It is assumed that the reason for the low survival rate and high incidence of Alternaria blight is a rain-leaking shield. Farmers used rain-leaking shields because the precipitation on Baengnyeong Island was smaller than on land. One field showed 3% of leaves with yellowish brown spots, a symptom of physiological disturbance of the leaf, which is presumed to be due to the excessive presence of iron in the soil. To increase the production of ginseng on Baengnyeong Island, it is necessary to develop a suitable ginseng cultivation method for the island, such as strengthening the field management based on the results of a scientific study of soil, using rain-resistant shading, and installing drip irrigation facilities. I hope that ginseng will become a new driving force for the development of Baengnyeong Island, allowing ginseng products and food to thrive in the beautiful natural environment of the island.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.210-216
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• 2023

Conventionally, the seeds of Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. have been directly sown at the field without using the plug seedling method. Plug seedlings have the advantage of promoting germination and convenient transplanting. However, there is little information about propagation of R. glutinosa using the plug seedling method. This study was conducted to investigate the optimal seed rhizome length, diameter, and sowing direction of R. glutinosa for establishing the plug seedling method. Seed rhizome length and diameter were separated by 1, 2, 3 cm and 0.3-0.5, 0.6-1.0, 1.1-1.5 cm, respectively. And seed rhizomes were sown in vertical and horizontal directions. The survival rate in 1 cm length of seed rhizomes was lower than in other treatments. The leaf length, leaf width, number of leaves, SPAD, leaf area, and fresh and dry weights of shoot and roots were the greatest in 3 cm length of seed rhizomes. As the seed rhizome diameter decreased, the growth characteristics of R. glutinosa tended to increase. When R. glutinosa was sown horizontal direction, the leaf length, leaf width, number of leaves, and leaf area were significantly higher than in the vertical direction. In conclusion, when sowing seed rhizome in a plug tray, using a length of 3 cm, a diameter of less than 1 cm, and sowing in a horizontal direction is considered an appropriate sowing method for R. glutinosa.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.22-27
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• 1984

The effects of solarization on the suppression of soilborne plant pathogen and the growth promotion of cucumber plants were examined in artificially infested soil by vinyl mulching and not mulching from July 25 to August 25, 1983. During the solarization period, the highest temperatures were $58^{\circ}C,\;45^{\circ}C,\;and\;42^{\circ}C$, at 5cm, 15cm, and 25cm of soil depth respectively. The inoculum of cucumber wilt pathogen, Fusarium oxysporum f. sp. cucumerinum, was mixed with soil 30cm deep and saturated with water. The pathogen was completely killed after 30dys of solarization in 5cm soil depth and 98 percent of inoculum was eliminated in 15cm soil depth. But the survival rate of the fungi in 25cm soil depth of solarized plot did not show significant differences compared with those in nontreated plot in 5cm and 15cm depth. Although some of the pathogenic fungi might survive from solarized soil in 15cm and 25cm depth, the ability of microconidia production was reduced significantly The number of microconidia grown on Komada's medium in isolates the primary colonies from solarized soil was less than that in isolates from nontreated soil approximately by one fourth. The first subcultured solates from the solarized soil grown on potato dextrose agar also produced a small amount of microc. onidia compare with that of subcultured isolates from nontreated soil. Cucumber seedlings planted in the soil collected from solarized plot grew much better than that in the soil from nontreated plot at any of soil loved, especially in 5cm of soil depth. And the fruits harvested from cucumber plants grown in the solarized plot were more in number and leavier in weight than that from nontreated plot. Besides the typical symptom development, significant growth suppression wvas recognized with increase of inoculum density of F. oxysporum f. sp. cucumerinum at early stage of cucumber seedlings in steam sterilized soil.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.29-39
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• 2019

The objective of this study was to suggest a suitable amount of fertilizer using the changes in growth performances and soil properties for improving survival and quality of Zelkova serrata trees in a harvested Pinus rigida plantation. One-year-old containerized seedlings of Z. serrata were planted with the density of 3000 seedlings $ha^{-1}$ in end of March 2011 at Gwangneung experimental forest, Pocheon. Solid compound fertilizer (N:P:K=3:4:1) were applied yearly in three amounts (control: no fertilization, F1: $180kg\;ha^{-1}$, and F2: $360kg\;ha^{-1}$) every May from 2011 to 2013. We analyzed soil properties before (2011) and after (2012 and 2017) fertilization. And we measured the root collar diameter and height of Z. serrata trees from 2011 to 2016, and then calculated H/D ratio and stem volume. Soil properties at Z. serrata plantation did not show difference according to fertilization level in every investigation year. As time passed after planting, however, concentrations of total nitrogen and available phosphorus were increased from decreased. The growth of root collar diameter, height and stem volume of Z. serrata trees at F2 plot were significantly higher those at the other plots after only 2 years of fertilization. Because Z. serrata tree demand to more nutrient during the early growing period. The survival rate of Z. serrata trees at control plot was significantly lower than that at the other plots. This might be due to Z. serrata trees at control plot had not the upper hand from competition with vegetation at the early in planting. However, the growth of height and stem volume of Z. serrata trees between F1 and F2 plots did not show difference over 6 years after planting. Consequently, we could suggest that Z. serrata trees need to F1 fertilization level for considering improving survival and quality of Z. serrata trees and economical efficiency of plantation managements after harvesting P. rigida plantation.

• Journal of Biosystems Engineering
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• v.42 no.3
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• pp.227-233
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• 2017

Purpose: Morphological properties of soybean roots are important indicators of the vigor of the seed, which determines the survival rate of the seedlings grown. The current vigor test for soybean seeds is manual measurement with the human eye. This study describes an application of a machine vision technique for rapid measurement of soybean seed vigor to replace the time-consuming and labor-intensive conventional method. Methods: A CCD camera was used to obtain color images of seeds during germination. Image processing techniques were used to obtain root segmentation. The various morphological parameters, such as primary root length, total root length, total surface area, average diameter, and branching points of roots were calculated from a root skeleton image using a customized pixel-based image processing algorithm. Results: The measurement accuracy of the machine vision system ranged from 92.6% to 98.8%, with accuracies of 96.2% for primary root length and 96.4% for total root length, compared to manual measurement. The correlation coefficient for each measurement was 0.999 with a standard error of prediction of 1.16 mm for primary root length and 0.97 mm for total root length. Conclusions: The developed machine vision system showed good performance for the morphological measurement of soybean roots. This image analysis algorithm, combined with a simple color camera, can be used as an alternative to the conventional seed vigor test method.

• Molecules and Cells
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• v.37 no.11
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• pp.795-803
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• 2014

To withstand ever-changing environmental stresses, plants are equipped with phytohormone-mediated stress resistance mechanisms. Salt stress triggers abscisic acid (ABA) signaling, which enhances stress tolerance at the expense of growth. ABA is thought to inhibit the action of growth-promoting hormones, including brassinosteroids (BRs). However, the regulatory mechanisms that coordinate ABA and BR activity remain to be discovered. We noticed that ABA-treated seedlings exhibited small, round leaves and short roots, a phenotype that is characteristic of the BR signaling mutant, brassinosteroid insensitive1-9 (bri1-9). To identify genes that are antagonistically regulated by ABA and BRs, we examined published Arabidopsis microarray data sets. Of the list of genes identified, those upregulated by ABA but downregulated by BRs were enriched with a BRRE motif in their promoter sequences. After validating the microarray data using quantitative RT-PCR, we focused on RD26, which is induced by salt stress. Histochemical analysis of transgenic Arabidopsis plants expressing RD26pro:GUS revealed that the induction of GUS expression after NaCl treatment was suppressed by co-treatment with BRs, but enhanced by co-treatment with propiconazole, a BR biosynthetic inhibitor. Similarly, treatment with bikinin, an inhibitor of BIN2 kinase, not only inhibited RD26 expression, but also reduced the survival rate of the plant following exposure to salt stress. Our results suggest that ABA and BRs act antagonistically on their target genes at or after the BIN2 step in BR signaling pathways, and suggest a mechanism by which plants fine-tune their growth, particularly when stress responses and growth compete for resources.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.143-153
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• 2018

Soil characteristics along with various container lengths have an important role in the early survival rate and growth of seedlings by influencing the seedling quality. This experiment was conducted to investigate the effect of container length and different soil mixtures on the growth of poplar in a greenhouse. Two types of soil, homogeneous vs. heterogeneous, were used along with two container lengths (30 vs. 60 cm). The heterogeneous soil was made by dividing 50% vermiculite from a mixture of 25% vermicompost and 25% nursery soil in volume. For the homogeneous soil, the above three soil types were mixed together. Populus euramericana clone cuttings were planted in late April, and then, the growth height, root collar diameter (RCD) and biomass were measured in August. The height of the poplar was not significantly affected by container length and soil type, but the RCD was significantly affected by soil type. Leaf and root biomass was higher at the long container than at the short container for both soil treatments, but stem biomass was lower at the heterogeneous soil than at the homogeneous soil treatment. Root to shoot biomass ratio was higher at the heterogeneous soil treatment than at the homogeneous soil treatment by 12%. In conclusion, heterogeneous soil along with a long container is suitable to increase the carbon allocation into the root.