• Korean Journal of Weed Science
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• v.30 no.3
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• pp.199-205
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• 2010

This study was conducted to investigate the phytotoxic effects of 19 essential oils on seed germination and initial growth of rapeseed (Brassica napus L.). We found that anise, cinnamon, citronella, clove, geranium, lemongrass, mustard and pine oils completely inhibited germination of rapeseed at $100{\times}$ dilute solution. Based on the inhibition rates of rapeseed emergence and initial growth, three essential oils (cinnamon, clove, and geranium) were selected as potential bio-herbicides. Under pre-emergence applications of cinnamon, clove, and geranium oils at 90 kg ai $ha^{-1}$, rates of rapeseed emergence were 7.1, 25.0, and 3.6% and its initial growth were 22.0, 9.9 and 11.0%, respectively.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.42-48
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• 1994

The toxic compounds of sorghum stem extracts were isolated by different organic solvents and pH, and characterized and quantified in terms of their inhibition of seed germination and seedling growth in Echinochloa colona(L.) Link and radish(Raphanus sativus L.). Sequential partitioning of stem extract with various organic solvents with increasing polarity showed that all fractions of hexane, ethyl ether, methylene chloride, ethyl acetate, and the aqueous remainder inhibited germination and seedling growth in E. colona. Of the five fractions, the ethyl ether fraction had the greatest inhibitory effect on E. colona. Further separation of the ethyl ether fraction at different pH(pH 2-11) showed that phytotoxic compounds were acidic. The result indicates that the phytotoxin present in the stem extract may be nonpolar and acidic.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.407-412
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• 1997

Allelopathic activity of methanol extract from medicinal plants was determined based on the inhibition of germination, shoot and root length of Echinochloa crus-galli. The response was depended on the source of extracts and concentrations. Of the 20 test plants tested, Cnidium officinale showed most inhibition according to germination, shoot and root length of E. crus-galli. Based on the plant parts, the root extract of C. officinale had more inhibitory effect on E. crus-galli than the stem+leaf extract. Phytotoxic effects of the root extract on E. crus-galli showed 75% inhibition of seed germination, 95% inhibition of shoot growth, and 100% inhibition of root growth at the concentration of 1g/petridish. Sequential partitioning of root extract with organic solvents with increasing polarity showed that the ethylacetate fraction had the greatest inhibitory effect on E. crus-galli. Germination was not inhibited at any rate of ethylacetate fraction but shoot and root growth, were significantly inhibited even at 2mg/petridish. This indicates that the most toxic phytotoxin present in the root extract may be moderate polar compound.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.9-14
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• 1988

Three varieties of Echinochloa crus-galli (L.) Beauv. and five collections different in gross morphology from the E. crus-galli species were obtained in a lowland rice field located in Jukjeol-Ri, Soyang-Myeon, Wanju-Kun, Jeonbug to compare the ecological and physiological characteristics. There were great variations in seed dormancy, relative growth rates, days required to panicle emergence and panicle morphology among the collections. On the basis of the cluster analysis using the different characteristics, the collections were divided into three groups; E. crus-galli var. frumentaceae and its two ecotypcs, E. crus-galli var. echinata and its two ecotypes, and E crus-galli var. crus-galli and its one ecotype. There were differential responses in percent germination and post-germination growth of the collections to butachlor (2-chloro-2', 6'-diethyl-N-butoxymethyl acetanilide).

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.305-311
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• 2014

The cultivation area and use of genetically modified (GM) crops have been increased continuously over the world. Seed distribution and transgenes to environmental ecosystem is one of the most important factors in risk assessment and risk management of GM crop. Safe management for the development and commercialization of GM crops is required according to The Act on Transboundary Movements of Living Modified Organisms,etc (LMO Act) in Korea. This study was conducted to setup the environmental monitoring system of GM zoysiagrass (event JG21 and JG21-MS). The monitoring was performed in 4 GMO confined fields, Sungwhan, Ochang, Jeju University and Jeju Namwon. In the result of monitoring, we could not found any gene flow and distribution of GM zoysiagrass in the 3 fields, but one spill of JG21 was found in the Namwon field in 2012. These results suggest that continuous monitoring is necessary to detect the occurrence of GM zoysiagrass for preventing genetic contamination in natural environment.

• Korean Journal of Weed Science
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• v.30 no.1
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• pp.25-33
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• 2010

Several experiments were conducted in growth chambers and a greenhouse to determine the influence of various environmental factors on seed germination and seedling emergence of Indian jointvetch. Fully matured seeds of Indian jointvetch germinated only 42%. The germination percent increased as the storage temperature increased with time. More than 90% seeds germinated when the seeds were kept at $40^{\circ}C$ for seven months, but germination was 58.9 and 55.1% when kept at 25 and $4^{\circ}C$, respectively. Non-dormant seeds of Indian jointvetch germinated 91.1 and 92.4% at 30 and $30/25^{\circ}C$, respectively. Germination percent increased with increasing both prethermal temperature and time. The prethermal temperature of $90^{\circ}C$ for 40 minutes was the best for maximum germination (94.5%). Germination and growth of Indian jointvetch tended to decrease slightly until -0.3 MPa osmotic potential (water stress induction) and then declined drastically and the seeds did not germinate at below -0.5 MPa osmotic potential. Indian jointvetch seems to grow well in moist and flooding conditions since emergence and growth of seedling increased with increasing soil moisture content and the water level.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.13-17
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• 1986

This experiment was carried out to study the germination behavior and the density effect of Capsella bursa-pastoris Medicus on barley yields. Seed dormancy of C. bursa-pastoris was broken on middle of July. No light was required for germination of C. bursa-pastoris seeds. Higher germination showed at $15^{\circ}C$ than at $0^{\circ}C$ or $6^{\circ}C$. Effective temperature for dormancy breakdown of seed was at $5^{\circ}C$ for 30 days rather than at $40^{\circ}C$. Reduction in barley yield showed with increasing the plant density of C. bursa-pastoris.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.250-261
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• 1989

This study was conducted to evaluate the effect of retardent Paclobutrazol on the seed quality factors such as oil content, protein content and fatty acid composition in peanut cv. Saeddle(early variety) and Napung(medium variety). The results are summarized as follows : Oil content of seed was appeared to increase when Paclobutrazol was applied and especially it was remarkably increased at 120 ppm-90 DAS both in varieties. Even though protein content showed a little increase at 120 ppm-70 DAS in early variety and 120 ppm -90 DAS in medium variety, however, it was decreased in most case. Saturated fatty acids such as palmitic and stearic acid was reduced by Paclobutrazol treatment but unsaturated fatty acids such as oleic, linoleic, eicosenoic and eicosadienoic acid was tended to increase in early variety while palmitic acid was increased in medium variety but linoleic acid reduced and no change was observed in oleic acid content.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.141-148
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• 1989

Echinochloa species collected from 13 places of Korea appeared to be morphologically very different. They were classified by Yabuno's seed morphology method into two species such as Echinochloa oryzicola and Echinochloa crus-galli which have two varieties such E. crus-galli var, cuss-galli and var, praticola. Among them, E. oryzicola was morphologically similar to Oryza sativa, but it had small leaf length with straight from, no awn, late heading and little interspecific variance. As compared with E. oryzicola, E. eras-galli var. crus-galli, and var, praticola showed a great variance exerting so difficulty in classifing them morphologically, particularly a great variance in leaf length, tiller number and grain size. E. oryzicola species showed the more sensitive response to butachor and thiobencarb herbicides than E. eras-galli var. praticola and var. eras-galli. However, E. eras-galli var. praticola was themore sensitive one to pretilachloa herbicide than such as E. oryzicola and E. eras-galli var. eras-galli, indicating that Echinochloa species might have a selective response to the annual herbicides tested.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.49-57
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• 2015

This research was initiated to analyze the periods of spring green-up and winter leaf discoloration of three ornamental grasses which have potential to be widely used with seed propagation. Two native grasses of Arundinella (Arundinella hirta var. ciliata Koidz), fountaingrass (Pennisetum alopecuroides (L.) Spreng), and switchgrass (Panicum virgatum L.) was tested. Spring green-up were evaluated after one year growth from seed propagation on April 1, 2009. Arundinella started with quick pick of spring green-up during $13^{th}$ to $20^{th}$ of May. Fountaingrass and switchgrass showed relatively slow picks of green-up during $20^{th}$ to $27^{th}$ of May. However, winter leaf discoloration started on swtichgrass and fountaingrass but Arundinella terminated relatively slowly. Swtichgrass showed the pick discoloration during $8^{th}$ to $15^{th}$ of October from the bottom to top parts of the plant. Fountaingrass showed the pick winter discoloration started from bottom to top parts during the $22^{nd}$ to $29^{th}$ of October. However, Arundinella showed relatively slow discoloration from upper to bottom parts during October $29^{th}$ to November $5^{th}$. Arundinella showed a relatively higher ornamental value with 125 days of the complete green period compared than fountaingrass and swtichgrass which maintained approximately 105 days of green period.