• Korean journal of applied entomology
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• v.10 no.1
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• pp.31-38
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• 1971

Tolerance test in plastic vat, pot and fold tests were carried out to investigate the selective herbicides for soybean culture in sandy loam. The soybean plants showed great tolerance against herbicides such as Tri-allate (Avadex-BW), Alachlor (Lasso), Butachlor (Machete), Propachlor (Ramrod), Nitrofen (TOK), MO, HE-314, Nitrofen/Dinoseb(TOK/DNBP), and Chlo.oxu.on (Tenoran), and the growth was normal even when each was treated with the herbicides up to 2ft3 times of the recommended concentrations. Soybean plants showed a slight tolerance against Prometryne (Gesagard), Propazine (Gegamil), Diuron (Karmex), Metabromuron (Patoran), Linuron (Lorox) and Swep when each was treated with herbicides up to 1-2 times of the recommended concentrations. Great injury or withering was noticed due to the high sensitivity of soybean to Simazine (CAT) and to Floumetron (Cotoran). In pot and field experiments with herbicides such as Butachlor (Machete), Alachlor (Lasso), Nitrofen (TOK), Kerb, Nitrofen/Dinoseb (TOK/DNBP), Swep, Linuron (Lorox), Simazine (CAT) and PCP, the following results were obtained: Great injuries were noticed with Simazine (CAT). Also, Linuron (Lorox) and Kerb showed a slight injury at early growth stage of soybean, Nitrofen (TOK) , Nitrofen/Dinoseb (TOK/DNEP), Alachlo. (Lasso), Butachlo. (Machete) and Swep had high selectivities for soybean and no injury was noticed. With respect to herbicidal effects there was a greatly significant difference between treated plots and non-treated plots with the exception of Simaaine (CAT) plot in field test. E. crusgalli and C. sanguinalis were tolerant against Simazine(CAT) and Linuron(Lorox). Cyperus and E. annuus were tolerant against Kerb. Great herbicidal effects on grasses were observed in Alachlor (Lasso) and Butachlor (Machete) plots. Among broad-leaf weeds, P. hydropiper and C. album were tolerant against Butachlor (Machete) and Alachlor (Lasso). When soybean was treated with the herbicides such as Alachlor (Lasso) (ai. 150g/10a), Butachlor (Machete) (ai. 300g/10a), Nitrofen (TOK) (ai. 250g/10a), Linuron (Lorox) (ai. 75g/10a) once after seeding, no additional wording was required till harvest.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.321-321
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• 2017

Water availability in rainfed lowlands (RFL) is strongly affected by climate change. In RFL, rice plants are exposed to soil moisture fluctuations (SMF) but rarely to simple progressive drought as widely believed. Typical RFL field is characterized by a about 5-cm thick high bulk density hardpan layer underneath the cultivated layer at about 20 cm depth that impedes deep root development. Root system has the ability to develop in response to changes in SMF, known as phenotypic plasticity. We hypothesized that genotypes that can adapt to RFL have root plasticity. The roots can sharply respond to re-wetting after drought period and thus penetrate the hardpan layer when the hardpan is wet and so becomes relatively soft, and thus access water under the hardpan. This study aimed to identify CSSLs derived from a cross between Sasanishiki and Habataki which adapted to such RFL conditions. We used 39 CSSLs together with the parent Sasanishiki, which were grown in hydroponics and pot under transient soil moisture stresses (drought and then rewatering), and compared with continuously well-watered (WW) (control) up to 14 days after sowing (DAS), and 20 DAS, respectively. Based on the results of hydroponics and pot experiments, we selected a few lines, which were grown in the soil-filled rootbox with artificial hardpan layer and without artificial hardpan. For the rootbox without artificial hardpan, plants were grown under WW and transient soil moisture stresses for 49 DAS. While the rootbox with artificial hardpan, the plants were grown under WW (control) and SMF (WW up to 21 DAS, 1st drought (22-36 DAS), rewatering (37-44 DAS), and followed by 2nd drought (45-58 DAS)). Among the 39 CSSLs, only CSSL439 (SL39) consistently showed significantly higher shoot dry weight (SDW) than Sasanishiki under transient soil moisture stress conditions as well as SMF conditions in all the experiments. Furthermore, under WW, SL39 consistently showed no significant differences from Sasanishiki in shoot and root growth in most of traits examined. SL39 showed significantly greater total root length (TRL) than Sasanishiki under transient soil moisture stress, which is considered as phenotypic plasticity in response to rewatering after drought period. Such plastic root development was the key trait that effectively contributed to root elongation and branching during the rewatering period and consequently enhanced the root to penetrate hardpan layer when the soil penetration resistance at hardpan layer reduced. In addition, using the rootbox with artificial hardpan layer ($1.7g\;cm^{-3}$, heavily compacted), SL39 showed greater root system development than Sasanishiki under SMF, which was expressed in its significantly higher TRL, total nodal RL, and total lateral RL at hardpan layer as well as at below the hardpan layer. These results prove that SL39 has plasticity that enables its root systems to penetrate hardpan layer in response to rewatering. Under SMF, such root plasticity contributed to its higher gs and Pn.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.184-188
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• 1997

To investigate the absorption and transfer factor(TF) of Sr-85 by rice(Oryza sativa L.), experiments were carried out through pot cultivations on a sandy-loam soil treated 74 and 222Bq per gram of soil in a plastic film house. Sr-85 absorption rates of Ilpoombyeo, late maturing variety and Odaebyeo, early maturing variety, at harvesting stage, were 0.39-0.43% and 0.66-0.73%, respectively. Sr-85 absorption rates of Odaebyeo were about 1.5 times higher than those of Ilpoombyeo. Ratios of Sr-85 radiation and Sr-85 concentration in brown rice were much lower compared with those in straw and husk. Sr-85 concentrations in each part of Odaebyeo were remarkably higher than those of Ilpoombyeo. Transfer factor of Sr-85 from soil to plant ranged from 0.037 of brown rice to 4.13 of rice straw at harvesting stage. The order of the Sr-85 transfer factor in plant parts was straw>husk>brown rice. Sr-85 concentrations treated in soil had no effect on the growth and yield of rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.245-255
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• 1994

Weak persistence of white clover (Trifolium repens L.) under continuous grazing management has been limited its availability in the mixture with grasses. The experiment was carried out to determine the effect of defoliation interval on the regrowth and morphological characters of the clover cultivars. Individual plants of Regal (large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 15cm plastic pot containing a 1: 2: 1 soil:sand:Promix mixture for 55 days, and then clipped to remove all fully expanded leaves every 7, 14 or 28 days. For the analysis of the cultivar response, plants were sampled on the final harvest date(0), and 1, 3, 7, 14 and 28 days after the final harvest date. Harvested dry weight of all cultivars declined as defoliation interval was increased, and that of Regal was the highest compared to the other cultivars. During the regrowing period, increase of total plant dry weight was due to that of leaf and petiole dry weight, and that of Osceola was greater than the others. Although total leaf area and mean single leaf area were increased during the regrowing period, they were reduced with increased defoliation interval and those of Osceola were the greatest until 14-days regrowth. S184 possessed the most number of leaves and Osceola did the longest petiole since 14-days regrowth although the more defoliation, the less nunber of leaves per plant and the shorter petiole. Stolon length and growing tips of all cultivars increased steeply during regrowth, while they were decreased with increased defoliation interval and those of S184 were the highest. More frequent defoliation had detrimental effects on regrowth of white clover, although larger leaf type was productive but less persistent in a mixture with grasses than smaller leaf type.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.964-972
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• 2010

Objective of this research was to determine the influence of physico.chemical properties of root substrates on growth of daughter plants that were developed through plastic bag cultivation of mother plants in 'Seolhyang' strawberry propagation. Six different formulations of root substrates for daughter plant cultivation were peatmoss + vermiculite (5:5, A), peatmoss + perlite (7:3, B), coir dust + perlite (7:3, C), coir dust + peatmoss + perlite (3.5:3.5:3.0, D), rice-hull + coir dust + perlite (2:7:1, E), and rice hull + coir dust (3:7, F). The 10 cm plastic pots filled with formulated substrates were located near the plastic bag where mother plants were growing. Then the runners and daughter plants originated from mother plants were fixed on each root substrate filled into 10 cm plastic pot and daughter plants were grown in the plastic pots. The container capacity and air space showed big differences among substrates tested. The substrates E and F had the less container capacity and the higher air space than other substrates tested. This indicates that the two substrates would have difficulties in water managements during the raising of daughter plants. The substrates of A, B, and D which contained peatmoss in formulation had higher nitrogen concentrations than those containing coir dust or rice hull. The substrates of E and F which contained rice hull had lower nitrogen, phosphorus and potassium concentrations than those that contained coir. The crown diameters of daughter plants grown in substrate A were around 13 mm which is thicker than those grown in other substrates. The fresh weights of daughter plants grown in A substrate were the heaviest followed by C, F, D, E, and B. The dry weight of daughter plants showed similar tendency to those of fresh weight. The daughter plants which had heavy fresh and dry weights and thick crown diameter are considered good seedlings. Based on this justification, the substrates of A, C and F are acceptable for daughter plant growth of 'Seolhyang' strawberry.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.73-81
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• 1996

The expriment was carried out to clarify the fertilizer efficiency of a garbage-based compost in cultivation of leaf vegitables. 1. Only application of 8 tons per 10 of the compost did not have any growth injury to "Osaka-shirona" (a cultivar of Brassica pekinensis L.) in a pot experiment 2. In four continuous cropping with application of 3 tons per 10 a of the compost before every seeding, "Osaka-shirona" grew satisfactorily. 3. Osaka-shirona, spinich and garland chrysanthemum were cultivated under a plastic house applied with 2 tons per a of each of the garbage-based compost and cattle manure, delayed release fertilizer and bark compost on the market. There was no difference of the vegetable yields among the applied field, as well as of the contents of ${\beta}$-carotene, vitamin C, Ca and Fe.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.1
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• pp.30-36
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• 1995

Pasture composed of about 30% botanical composition of white clover (Trijolium repem L.) is desirable in its productivity and quality. To get information on maintaining its productivity in the pasture, the experiment was canied out to determine the effect of infrequent, frequent defoliation or their alternation on change of its harvest yield and growth. Individual plants of Regal, Louisiana S-1, Grasslands Huia and Aberystwyth S184 were grown in 22cm plastic pot containing a 2 : 1 : 1 soil : sand : Peat moss mixture for 27 days after transplanting 50day seedlings raised on 3cm pots, and then all their fully expanded leaves are removed. Defoliation treatments were forced every 1 (CC, frequent), 4 week (RR, infrequent) or their alternations (CR, RC) after 8 weeks from the removal. To analyze the treatment effects, plants were sampled on 0 (the removal day), 4, 8, 12 and 16 weeks after the removal and seperated to leaves, petioles, stolons and roots. Each harvest yield of infrequent defoliation (RR) was higher than that of frequent defoliation (CC). Their alternations (RC, CR), however, forced fluctuation of the yield according to defoliation interval. Fraction weights from their altemations showed intermediate ones of infrequent and Frequent defoliation whose weights did the similar result to their harvest yields. Fraction and total dry weights per plant, shoot/root ratio were changed by relative span of defoliation interval, which resulted from the weights of leaves and petioles, removed parts. Root and total dry weight per plant of Regal were greater than the other cultivm in infrequent defoliation interval regardless of continuous or alternations. Productivity of white clover in pasture, therefore, can be controlled by alternation of infrequent and frequent defoliation or reverse.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.293-296
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• 1990

The effect of wallastonite, potassium chloride and potassium sulphate on the ammonification and nitrification of urea was studied in a non-planted green house experiment, filling with 500g soil in plastic pot and incubating for 17 days. Potassium sulphate gave superior effect on the neutralizing soil acidity of wallastonite than potassium chloride and raised soil pH which promoted ammonification and subsequent nitrification of urea. Less than 20% $NO_3-N$ against the sum of $NH_4-N$ and $NO_3-N$ was accumulated in soils incubated bellow pH 6.0. It seemed that pH 5.2 to 6.0 was the critical range for the nitrification of ammonium, or raising the concentration of ammonia in soils to the toxic level to the nitrification. It appeared that the nitrification could be occuring in low moisture, air dried, conditions of soil.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.223-225
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• 2007

Many plant growth-promoting rhizobacteria (PGPRs) have been known for beneficial effects on plants including biological control of soilborne pathogens, induced systemic resistance to plant pathogens, phytohormone production, and improvement of nutrient and water uptake of plants. We developed a simple and rapid method for screening potential PGPR, especially phytohormone producing rhizobacteria, or for analyzing their functions in plant growth using cucumber seedling cuttings. Surface-sterilized cucumber seeds were grown in a plastic pot containing steamed vermiculite. After 7 days of cultivation, the upper part 2 cm in length of cucumber seedling, was cut and used as cucumber cuttings. The base of cutting stem was then dipped in a microcentrifuge tube containing 1.5ml of a bacterial suspension and incubated at $25^{\circ}C$ with a fluorescent light for 10 days. Number and length of developed adventitious roots from cucumber cuttings were examined. The seedling cuttings showed various responses to the isolates tested. Some isolates resulted in withering at the day of examination or in reduced number of roots developed. Several isolates stimulated initial development of adventitious roots showing more adventitious root hair number than that of untreated cuttings, while some isolate had more adventitious root hair number and longer adventitious roots than that of untreated control. Similar results were obtained from the trial with rose cuttings. Our results suggest that this bioassay method may provide a useful way for differentiating PGPR's functions involved in the development of root system.