• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.51-55
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• 2005

Chinese leymus (Leymus chinensis Trin.) is a perennial grass that is widely distributed at high pH sodic and arid soil in the northeastern Asia. An efficient regeneration system was established through somatic embryogenesis of mature seeds to understand its high adaptability to harsh environmental conditions on the basis of molecular biology. The calli were efficiently induced (about $70\%$) from mature seeds on MS medium supplemented with $1.5\;\cal{mg/L}$ 2,4-D. Somatic embryos were formed from the surface of embryogenic callus on MS medium supplemented with $2.0\;\cal{mg/L}\;kinetin\;and\;0.5\;\cal{mg/L}$ NAA after 3 weeks of culture. Roots were induced from the shoot when transferred to MS medium without plant growth regulator for 1 week. Plant regeneration rate was $36\%$ and regenerated plantlets were grown to normal mature plants in pot. An efficient plant regeneration system in this study will be useful for molecular breeding of L. chinensis.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.377-383
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• 1997

Studies were conducted on the nature of allelopathic effect of the substances in the waste of ginkgo leaves from pharmaceutic factory. In the first step, to find out whether there was any allelophatic effect, young seedlings of radish and rice were grown in the water (crude) extract of ginkgo leaf waste and in different liquid/lquid partitioned fractions of EtOAc at pH 9, EtOAc at pH 3, and BuOH. As second step, attempts were made to isolate and identify the allelophatic substance in different liquid/liquid partitioned fractions using GC/MS and NMR techniques. The water (crude) extract of ginkgo leaf waste retarded the growth of radish seedlings under 10% concentration. In case of rice seedlings, the water extract of ginkgo leaf extract showed adverse effect on the growth when combined with $3.3{\times}10^{-6}M$ gibberellin A3. All of the liquid/liquid fractions of crude extract showed strong retardation of seedling growth of radish and rice at the concentration of 1%. Allelophatic substance was isolated from the crude extract using liquid/liquid partition, column chromatography and HPLC techniques. The analytical results of isolated componet using GC/MS and NMR proved that the allelophatic substance in the ginkgo leaf wastes is catechol; one of phenol compounds. Based on the experiences current study, a practical method for the testing of allelophatic effect of crude extract of some materials was proposed. In this method, rice seeds were allowed to sprout until the length of coleoptile to reach 0.5 mm. Such seedlings were submerged in the solution containing supposedly allelophatic substance and the length of shoot and root was measured 3 days after treatment.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.686-693
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• 2012

To develop a technique for mass-propagation of virus-free sweet potato [Ipomoea batatas (L.) Lam.] plant using nutrient film technique (NFT), the growth characteristics of 4 cultivars as affected by nutrient solution composition and cutting size were investigated. 72 cells (35 mL/cell) plug trays filled with vermiculite and perlite (1:1, v/v) were used. Vine length, fresh and dry weights of virus-free plants were the greatest in the nutrient solution recommended by National Horticultural Research Station in Japan, followed by that recommended by National Institute of Horticultural & Herbal Science in Korea, and Yamazaki's nutrient solution for lettuce. The growth of uppershoot cuttings was the best among 4 subsections of cutting. Vine length, and fresh and dry weights increased in the longer cutting treatments, and were better in 'Shinzami' and 'Yeonhwangmi' than those in 'Mannami' and 'Shincheonmi'. Vine diameter and length of the longest root were not significantly affected by the cutting size and cutting source. The growth characteristics of the single node cutting were not significantly different from those in 2-node cutting. The efficiency of rapid mass-propagation could be promoted with single node cuttings and uppershoot cuttings grown in NFT system.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.918-924
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• 2008

This research investigates the influences of the presence of aquatic macrophytes on the changes of biogeochemistry in the sediments through the comparative analysis of porewater and sediments. From the in situ measurements, elevated SO$_4{^{2-}}$ concentrations were observed in the rhizosphere during the growing season, which was resulted from the oxidation of reduced sulfide in the sediments by the oxygen release from the plant roots. There was sufficient AVS in the sediments to induce observed SO$_4{^{2-}}$ concentrations. The amount of oxygen in the oxidation of AVS to produce observed SO$_4{^{2-}}$ concentrations is 0.85 g/m$^2$ day which is relevant to the results of other researches. The AVS concentrations in the vegetated sediments increased with the depth whereas there is higher mass of AVS in the surface of the non-vegetated sediments. This shows that evapotranspiration induces the transportation of SO$_4{^{2-}}$ in the surface water into the anaerobic sediments. In addition, the elevated organic content caused by the presence of plants increased $\beta$-glucosidase activities which play an important role in the carbon cycle of the sediments.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.247-251
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• 2008

During a 35-day growth cycle, N, P, and K uptake was determined by measuring changes in their contents in culture solutions. At harvest, plants were separated into the roots, base organs and shoot, and dried for tissue analysis for N, P, and K. The uptake rates of N, P, and K followed cyclical patterns that was related to shoot development and harvest, but were independent of the transpiration rate. Uptake of N declined from 5.6 mmol $plant^{-1}$ $day^{-1}$ just prior to the cycle initiation to 4.0 mmol $plant^{-1}$ $day^{-1}$ at day 15. Uptake rate steadily increased as flower stems reached maturity up to 10.3 mmol $plant^{-1}$ $day^{-1}$ day 35. Uptakes rates of P and K followed similar patterns of N uptake. Tissue concentrations of N and P steadily decreased since day 15. Content of K was the lowest at day 20 and steadily increased thereafter. In the root tissue, N and K contents were the lowest at day 15, increased to day 30, and then decreased at day 35. Tissue P content was just a reverse of those of N and K.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.129-134
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• 2012

Research was focused on the improvement of poor drainage problems on golf course fairway which had not been performed soil test or properly amended during the course construction. The analysis of the drainage problem basically was caused by a deterioration of soil physical properties by the top layer compaction. The soil hardness reached about 3,000 Kpa around 5~6 cm of soil profile. The slow infiltration speed to subsoil by the compaction was caused directly a poor drainage capacity. However, the properly amended sand soil showed an apparent value of 1,500 Kpa through the subsoil. The water content test showed a similar result that higher rate of 20~30% and ideal rate of 8~12% at poor drainage area and successfully amended area, respectively. However, an imported topsoil media which had higher content of silt and clay from a trans-planted sod had made a heterogeneous soil profile and that caused a poor drain capacity by a low infiltration rate. Those drainage problems triggered to buildup a reduced soil layer by poor soil gas exchange. The soil environment of deoxidation enhanced anaerobic microbial population and induced methane gas build-up to 55 ppm, and that resulted an adverse effect on turf growth by root growth retardation, consequently.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.196-208
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• 1994

Some additional fungi were collected during two field trips to Ullung Island in July and September of 1992. Through the observation of agaric fungi, 36 mushrooms were identified to the species or subspecies and are listed below. Among them, three species and one subspecies, Mycena luteopallens, Mycena macrocystidiata, Amanita hemibapha ssp. similis, and Pluteus petasatus, were confirmed new to Korea and are registered here with descriptions.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.314-325
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• 2002

The effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) on plant growth and N metabolic responses were examined in perennial ryegrass plants exposed to drought-stressed or well-watered condition. Mycorrhizal inoculation improved significantly leaf water potential, dry mass and P content. Drought stress increased significantly nitrate concentration in roots where the increase was much less in AM than non-AM. Drought stress decreased the concentration of soluble proteins in non-AM shoots, whereas non-significant decline occurred in AM shoots even under drought condition. The concentrations of ammonia and proline in drought stressed non-AM plants significantly increased, while mycorrhizal inoculation lowered significantly ammonia and proline accumulation. The decrease in leaf dry weight in drought stressed-plants was significantly correlated to the increase in ammonia (p<0.01) and proline concentration (p<0.01). These results suggested that the increased P content and N assimilation by mycorrhizal inoculation may be associated with drought stress tolerance, showing the moderating effects on shoot growth inhibition and ammonia accumulation in drought stressed-plants.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.779-786
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• 2012

Many farmers have been seeking alternatives to chemical fertilizer for successful organic fruit production. This experiment was carried out to investigate the replaceability of chemical fertilizer by cover crop and slurry composting biofiltration (SCB) liquid manure (LM) application in pear orchard. Three treatments were contained in this experiment; cover crop only and cover crop + LM treatment, and control (chemical fertilizer application). Dry weight and mineral contents of gramineous cover crops were significantly increased in LM-combined treatments than that of leguminous species. Bulk density of soil was decreased in rye + LM and hairy vetch + LM treatments, compared with each cover crop treatment. Soil pH was lowest in fertilizer treatment and soil nitrate content became similar between treatments after rainy season. Available soil phosphate was lower in cover crop and cover crop + LM treatmemts than control, but exchangeable Mg was higher. The mineral content and net assimilation rate of leaves showed no difference between the treatments. As a result, it is suggested that the application of SCB liquid manure in pear orchard managed by cover crops is desirable to maintain the productivity by improving soil physical properties and potential nutrient recovery.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.498-505
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• 2010

To evaluate the effectiveness of AMF on the growth of horticultural crops, we compared mycorrhizal and non-mycorrhizal plants, lettuce (Lactuca sativa L.), that were inoculated with AMF propagules. As compared to the AMF- seedlings, in AMF+ seedlings at 3 weeks after sowing, the number of leaves increased 9%, leaf fresh weight increased 59%, leaf area increased 58%, and leaf length and width increased 21-22%, and chlorophyll content increased 2%. Furthermore, at 9 weeks after sowing, compared to the AMF- plants, in lettuce plants inoculated with AMF at the sowing and transplanting stages, the number of leaves increased 21% and 18%, leaf fresh weight increased 51% and 41%, root fresh weight increased 56% and 47%, and chlorophyll content increased 18% and 19%, respectively. Further this experiment indicated that the growth responses of lettuce plants inoculated with AMF during transplanting were similar to those inoculated with AMF during sowing. The results imply that the AMF infection timepoint is not important. The P content in the leaves of lettuce plants inoculated with AMF during transplanting was significantly higher (217%) than that of leaves from lettuce plants not inoculated with AMF. In contrast, the P content of the leaves of lettuce plants inoculated with AMF during the sowing stage was similar to that of leaves of control lettuce plants. In this experiment, P and chlorophyll content in AMF+ lettuce plants were higher than in AMF- plants, indicating that the photosynthetic rate was improved with AMF inoculation.