• Korean Journal of Medicinal Crop Science
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• v.27 no.5
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• pp.315-321
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• 2019

Background: There have been no studies to date on rhizome development and optimal harvest timing for Rehmannia glutinosa. We therefore, undertook this investigation. Methods and Results: R. glutinosa 'Jihwang 1' was sown in early May and harvested in early November. Growth investigations were carried out at intervals of 10 days between 90 and 180 days after sowing (DAS). Leaf length, leaf width, and number of leaves increased until 150 DAS but decreased after 160 DAS. Rhizome length increased until 120 DAS subsequently, rhizome diameter increased rapidly between 130 and 150 DAS. Thus, the key period for rhizome enlargement in R. glutinosa is thought to be 130 to 150 DAS. Fresh root yield increased sharply from 916 kg/10a to 1,914 kg/10a between 4 and 5 months after sowing (MAS). Dry matter ratio increased gradually from 19.2% at 4 MAS to 24.4% at 6 MAS. Finally, the level of catalpol, a key active ingredient, increased sharply from 0.41% to 4.21% between 5 and 6 MAS. Given the dry matter ratio, catalpol content and yield measured, we suggest that optimal R. glutinosa harvest time is 6 MAS. Conclusions: Based on our results, the key period for rhizome enlargement is 130 to 150 DAS and optimal harvest timing is 6 MAS. We anticipate that these and other results of this study can be used to inform cultivation of R. glutinosa.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.31-38
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• 2018

This study was conducted to investigate the possibility of biochar as an alternative medium to peatmoss using for Aster spathulifolius. We cultivated A. spathulifolius in four potting media with different mixing rates (v/v) of peatmoss (P) and biochar (B) as follows: B0+P3, B1+P2, B2+P1, and B3+P0 with vermiculite 3 + perlite 3. Also, we analyzed the chemical properties of media and the plant growth characteristics. The results were as follows: In case of media's chemical condition, B0+P3 and B1+P2 treatments showed higher tendency (p < 0.05). Plant height on B0+P3 and B1+P2 treatments was much higher than that on other treatments (p < 0.05). Root length on B1+P2 treatment was higher than on B0+P3 treatment (p < 0.05). B0+P3 and B1+P2 treatments showed higher number of leaves and dry biomass than other treatments. Therefore, our results support that Biochar : Peatmoss : Vermiculite : Perlite (1/3 : 2/3 : 1 : 1, v/v) could be a more economical potting medium for A. spathulifolius than peatmoss : vermiculite : perlite (1 : 1 : 1, v/v).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.37-37
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• 2021

Calystegia soldanella L. is a perennial herbaceous halophyte belonging to the convolvulaceae family, which mainly grows in coastal sand dunes in Korea. Shoots and rhizomes are edible, and roots called 'Hyoseon Chogeun' are known to have medicinal effects such as antipyretic, sterilization, and diuretic. In addition, physiological activities of antioxidant, anti-inflammatory, antiviral, antifungal and PTP-1B (protein tyrosine phosphate-1B) inhibition have been reported. In this study, in vitro induction cell lines of C. soldanella L. collected from the coastal sand dunes in Jeju island was redifferentiated into adventitious roots that can be used as medicinal resources. Also the biomass of mass-proliferated adventitious roots using a bioreactor were evaluated. Plants of C. soldanella L. were collected from the crevice of the seashore in the coastal area of Taeheung 2-ri, Namwon-eup, Seogwipo-si. Then, it was separated into leaves, stems, rhizomes, and roots, and surface sterilized with 70% ethyl alcohol and 2% NaOCl (sodium hypochlorite). After washing with sterilized water, each organ section was cultured in Hormone-free MS medium (Murashige & Skoog Medium). As a result, the induction response rates were evaluated at 85% and 55%, respectively, in terms of callus formation and shoot generation in the rhizome segment. In the case of the adventitious roots morphological characteristics induced by single-use treatment of auxin-based plant growth regulators IBA and NAA from redifferentiated shoots were compared. Most efficient adventitious root culture method as a rooting rate, number, length, and biomass proliferation in the bioreactor system was confirmed when treated by culturing in MS salts, Sucrose 30 g·L^-1, and IBA 1mg·L^-1 for 4 weeks. In this study, the medium composition and culture period were confirmed using a bioreactor system to mass-proliferate adventitious roots derived from C. soldanella L. in Jeju island. Also this adventitious root line developed a new medicinal material could increase value of the bio-industry ingredient through quantitative and qualitative screening of phyto-bioactive compounds.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.161-170
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• 2013

We analyzed the effect of changing water level and turbidity on plants that serve to maintain slope stability on levees. In this experiment, soil collected from upstream of Imha Dam was placed in a water tank and planted with river plants of the Salix species: Salix gracilistyla, S. koreensis, and S. glanduosa. Plant regrowth was analyzed stage-by-stage during a recovery period. In addition, we assessed the tolerance of the plants to concentrated torrential rainfall and examined their recovery rates. The results indicate that in the case of these three Salix species, which are the most prevalent river plants in Korea, stem growth is arrested following serious damage and high turbidity. The possibility of regrowth was very low during the 20-day non-submerged recovery period. Although the number of leaves initially decreased during this period, subsequent regrowth was reasonably high: recovery in S. gracilistyla, S. koreensis, and S. glanduosa was up to 59.3%, 251.3%, and 148.4% respectively, compared with the initial condition.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.251-255
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• 2007

Floret flowering of a monocarpic plant Orostachys japonicus should be controlled to change its harvest time. The study was done to clarify the effect of pinching time of inflorescence with many florets (Aug. 25, Sept. 8 and 22, Oct. 4) on its growth, morphological characters, and flowering. Night-break treatment of 2 hours at midnight were done since Aug. 25 when afterward samples were taken every 2 weeks to Nov. 4. Growth, morphological and flowering related characters were measured from each sample. Plant height, inflorescence length and number of leaves including bracts showed significant difference between the treatments because they were sharply increased until each pinching time. Stem diameter did nearly same. Leaf and bract, floret, shoot and total dry weights had similar response to the plant height, but stem and root dry ones did similar response to the stem diameter. Most florets were removed by the pinching treatments after formed ones were increased until each pinching time. Few florets were left after the treatment, meaning that night-break treatment after that could be skipped.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.456-464
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• 2017

We examined the effect of nutrient solution concentration in the second half of growing period on the pre- and postharvest characteristics of two leaf lettuce cultivars, 'Geokchima' and 'Cheongchima'. Plants were grown hydroponically in a deep flow technique (DFT) system at different concentrations of National Horticulture Research Institute hydroponic nutrient solution: 1/2 strength (S), 1S, 2S, and 4S. Lettuce leaf growth, number of leaves, and shoot fresh weight of both cultivars were greatest in plants grown in the 1S treatment. Compared to other treatments, pigment and nutrient ion contents were greater in the 4S treatment. Growth of lettuce was greatest in the 1S treatment, and decreased at higher or lower concentrations of nutrient solution. However, postharvest characteristics such as fresh weight loss, leaf chlorophyll level, and external appearance were better in both cultivars when grown in 2S solution. Variations in weight loss and SPAD values were smallest in the 2S treatment. These results show that the optimal nutrient concentration for growth does not necessarily provide the optimal postharvest storability.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.43-47
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• 2013

This study was conducted to develop the most effective method in promoting onion set in cultivars 'Josaengsseondebol' and 'Daeji' for all year-round production. This was done by extending the day length for 41 days. For both cultivars, the period to reach the maximum number of leaves developed was shortened as the exposure to day length increased. Between the two cultivars, 'Josaengsseondebol' reaches its maximum leaf formation for a shorter duration compared with 'Daeji'. In effect to bulb size, cultivar 'Josaengsseondebol' having a night break of 1, 2, and 16 hours light condition had better bulb enlargement compared with the non-treated bulbs. In the case of cultivar 'Daeji', only bulbs exposed to a night break of 2 and 16 hours light condition had better bulb enlargement. The percentage of marketable set yield in cultivar 'Josaengsseondebol' having a night break of 1 hr, 2 hrs, 16 hrs light condition, and control or untreated bulbs were 84%, 92%, 90%, and 6% respectively. In the case of cultivar 'Daeji', treated with a night break of 1 hr, 2 hrs, 16 hrs light condition, and untreated bulbs had a percentage marketable set yield of 7%, 55%, 64%, and 0% respectively. Based on these results, it is therefore concluded that night break treatment is considered to be effective method in promoting off-season onion set cultivation in cultivar 'Josaengsseondebol'.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.17-21
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• 2011

Korean bennudagrass collections showed diverse genetic variations in their morphology, growth habit, and cytological aspects. Chromosome number and nuclear DNA content of the bennudagrasses indicated a ploidy level ranging from triploid (2n=3x) to hexaploid (2n=6x). In this study, we investigated the different responses of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase) and cell membrane stability of those bennudagrass cytotypes to lower temperature and shorter day length, which meets a dormant induction in Korea. All the antioxidant enzymes were found to be higher during dormant stage, while the heme-containing catalase which converts hydrogen peroxide ($H_2O_2$) to water and oxygen molecules was activated before dormant initiation in the three cytotypes except for hexaploid bennudagrass. The triploid and tetraploid which exhibited relatively finer leaves and a rapid establishment speed were found to show increased activities of superoxide dismutase and peroxidase enzyme. The malondialdehyde(MDA) which is a product of lipid peroxidation in the cell membrane damaged by the hydroxyl radical was increased in all cytotypes as temperature declined, and tri- and tetraploids which had more protective antioxidant enzymes demonstrated a significantly lower MDA production. Similarly electrolyte leakage was higher in penta- and hexaploidy, seemingly more damage to cell membrane when low temperature was implemented. Results indicated that antioxidant responses of different cytotypes were genetically specific, which needs to be investigated the relevance with the low temperature tolerance in the bermudagrass further at the molecular level.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.1-6
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• 1986

The growth, development, and morphological characteristics of Echinochtoa colons (L.) Link were determined through one life cycle. E. colons emerged 2 to 3 days after seeding (DAS) and reached the two leaf stage by 8 DAS. During the early growth stages, root length was greater than plant height, but the relationship was reversed from 4 weeks after seeding (WAS). Tillering started from the third leaf of the main culm as the sixth leaf on the main calm emerged. The unfolding of the leaves and tillering followed a regular pattern during the vegetative growth period. This resulted in the production of 19 tillers (5 primary, 12 secondary, 1 tertiary, and I nodal) at the 14-leaf stage. Shoot-root weight ratio was highest just before panicle initiation. The second spike from the top of the panicle was the shortest and produced the fewest seeds. Thereafter, spike length and the number of seeds per spike generally increased, the lower the position of the spike on the panicle. Seeds on the lower spikes weighed less and had lower germination ability than those from the upper spikes. Adventitious roots arose from the leaf sheath bases of a flowering stalk. The ability to produce adventitious roots was greater in a younger stalls than in an older stalk.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.794-802
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• 2014

The aim of this study was to determine the effect of day-length extension treatment using LED lighting (blue, green, red, or 3 mixed) on vegetative growth and flowering of freesia 'Yvonne', in comparison to that using glow lamps and metal halide lamps. Lighting treatments were imposed from 5 PM to 8 PM for 150 days from after flower bud differentiation to flowering end. For the period from leaf emergence to floral bud formation, no light source affected plant height but the number of leaves was decreased by the metal halide lamp. The highest SPAD value in the flower bud developing period occurred in the metal halide lamp treatment. The time of flowering was advanced by blue or green LED treatment compared to the no lighting control. The green LED lighting advanced flowering by 6 and 8 days compared to no lighting and metal halide lamp treatment, respectively. The blooming period tended to be shortened by the red LED treatment. As for the flower characteristics of 'Yvonne', floret length and width, and the weight of cut flowers were highest in the metal halide lamp treatment. Red LED decreased corm width and weight of 'Yvonne' while glow lamp decreased height and weight. Starch contents in corm were not influenced by the lighting source. Our results indicate that the green LED lighting advanced the time of flowering and the metal halide lamp was good for cut-flower quality.