• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.16-16
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• 2019

The Cassava (Manihot esculenta Crantz) is a perennial woody shrub cultivated mainly in the tropics for its starchy tuberous roots. It belongs to the family Euphorbiaceae which also includes rubber (Hevea brasiliensis) and castor bean (Ricinus communis). Among tropical crops, rice, sugarcane, maize and cassava are the most important sources of calories for human consumption. Problems in the propagation of cassava are virus diseases and low rates of seed germination. Thus, a study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with single node after sterilization, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, single-node stem segments, approximately 1 cm in length, were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate was 55.6%, the shoot number and its length were 1.0/explant and 2.3 cm in the most favorable medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.393-400
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• 1989

The amounts of $^{14}CO_2$ evolved during the $^{14}C-bentazon$ aging in soil for 3 and 6 months were 6.1 and 14.8% of the original radioactivity, respectively. The presence of earthworms in soil tended to increase the uptake of $^{14}C-bentazon$ by the roots of rice plants, even if it was not statistically significant. The evolution of $^{14}CO_2$ from $^{14}C-bentazon$ in soil increased in the presence of rice plants and earthworms compared with in the absence of them. The uptake of $^{14}C-bentazon$ residues by rice plants decreased remarkably with increasing the aging period within the limit of 3 months both in the absence and presence of earthworms, but there is not much difference between 3-month-aging and 6-month-aging. Much larger amounts of $^{14}C-labelled$ compounds were translocated to the shoots, compared with the data from a previous investigation using maize plants. The amount of non-extractable bound residue increased remarkably with the aging period up to 3 months. The polarity of the compounds extracted from soil increased with the aging and the growing of rice plants, indicating the formation of some polar metabolites.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.421-428
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• 2010

A foliage contact herbicidal substance was separated from ethyl ether fraction in n-hexane extract of Saussurea lappa roots and identified as dehydrocostus lactone [(3aS,6aR,9aR,9bS)-3,6,9-trimethylidene-3a,4,5,6a,7,8,9a,9b-octahydroazuleno[5,4-d]furan-2-one](DHCL). When DHCL at 4,000 ppm was foliage-applied to two grasses and two broadleaf plants, greater than 85% necrotic injury was obtained from large crabgrass, maize and soybean, whereas only about 40% necrotic injury appeared in black nightshade, indicating that DHCL has no gross morphological selectivity, but shows difference in contact response among the plant species tested. Conductivity in incubation medium of the leaf disks treated with DHCL increased as the incubation time continued. Relatively low contact injury in black nightshade as compared with the other three plant species tested was attributed to decrease in absorption of DHCL due to relatively high amount of cuticle. DHCL did not require light in the herbicidal action and there were no inhibitory effects on seed germination and cell elongation. Acetyl-CoA carboxylase activity was inhibited by 30% and 58% at $100\;{\mu}M$ and $1000\;{\mu}M$ DHCL, respectively. These results suggested that the herbicidal action of DHCL was related with inhibition of fatty acid synthesis which in turn caused to weaken cell membrane integrity.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.34-41
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• 1994

To better understand the allelopathic effect of sorghum(Sorghum vulgare L.), the inhibitory activities of water extracts of the stem, leaf and root, and of residues of the stem to major crops and weeds associated with them were evaluated. The allelopathic activity of sorghum plants was species specific, and depended on source and concentration. Germination, and shoot and root length of all test species were inhibited by the different concentrations of the stem extract. Among the crop species, radish showed the most inhibition, followed by wheat and rice. Maize was the least sensitive species. Of the weed species, Ipomoea triloba was most inhibited, followed by Echinochloa colona and Rottboellia cochinchinensis. The water extracts of leaves, stems, and roots significantly inhibited germination and seedling growth in E. colona and radish. The stem extract gave the greatest inhibitory effect on E. colona while all three extracts produced similar response in radish. In the greenhouse trial, sorghum stem residue placed on the soil surface as mulch significantly inhibited seedling growth in E. colona and radish, but not that in rice.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.426-433
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• 1988

A pot experiment was conducted to find out the effects of application of slacked lime and fused super-phosphate on the lead uptake of upland crops in a lead added soil. Lead concentration of the soils were adjusted to 0, 150, 300mg/kg respectively. The slacked lime was applied at the equivalent amount of lime requirement with extra 150kg/10a, and 2 times for the fused superphosphate. The results obtained were as follows: 1. Lead contents in crops increased in the order: sesame > maize > potato > sweet potato > soybean > green perilla > peanut > red bean. 2. Lead contents in parts of crops were increased in the order; root > stem > leaf > grain. 3. Increasing lead concentration in soils, lead content in the plant was increased and crops yield were decreased. 4. Lead contents in soybean and green perlilla were decreased in slacked lime application treatment. 5. The lead contents in leaf and grain of soybean and green perllila decreased with decreasing in the ratio of Pb/Ca+Mg equivalent in soil. 6. Grain yield were increased in slacked lime, but were decreased in fused superphosphate application treatment. 7. With increasing the soil Pb contents, calcium and phosphate contents were increased in leaf and stem, but calcium was decreased in roots. 8. $1N-NH_4$ OAC soluble Pb contents in soil were 26-50 ppm and 42-70 ppm, respectively, for 150mg/kg and 300mg/kg lead treatments. 9. The soil pH was increased in the order of slacked lime, fused superphosphate and nontreatment.