• Korean Journal of Weed Science
• /
• v.15 no.2
• /
• pp.141-147
• /
• 1995

Glyphosate(N-[phosphonomethyl]glycine) applied to the assimilate-exporting leaves or sprayed to the whole plants of tomato(Lycopersicon esculentum Mil var. Moneymaker). Glyphosate induced the rapid accumulation of shikimic acid within 24 h. The accumulation of shikimic acid companied with chlorophyll loss in meristematic leaves, i.e. apical leaves. The chlorosis was acropetal in apical region of young growing leaf. The degradation of chlorophyll seems to be a secondary or tertiary effect of glyphosate. However, the level of shikimic acid accumulated was reduced except for roots and apical leaves from 5 days after treatment. The accumulating levels are considerably differed through the applicated regions. The level of shikimic acid is highest at the apical meristem 4 days after the application to 3rd old leaf.

• Korean Journal of Weed Science
• /
• v.31 no.4
• /
• pp.394-400
• /
• 2011

Ancient mix seeding that started in China and generated in Korea is one of the methods of securing foods against natural calamities. The history of this technology was excerpted and presented from Chinese agricultural books as "Jeminyosul"(closely one upon the other 5C), "Wangjungnongseo"(from 1313) and Korean agricultural books as "Nongsajikseol"(from 1429), "Hanjeongrok"(from 1610), "Saekyeong" (from 1676), "Jeungbosanrimkyeongje"(from 1766), "Kwanongsocho"(from 1799), "Rimwonkyeongje" (from 1843). In this study, we suggested new environment-friendly agricultural technique to save labors using ancient mix seeding principle, which is seeding different varieties rice without fertilizer and agricultural pesticides. It is essential prerequisite to have the process such as injecting Azolla, no-tillage direct and broadcast seeding with multiple varieties of rice. Based on the results of previous studies, we evaluated the practical validity.

• Research in Plant Disease
• /
• v.19 no.4
• /
• pp.281-287
• /
• 2013

In surveys of weed occurrence undertaken from 2006 to 2007, near to the Daegu experimental fields of the National Institute of Crop Science, plants belonging to 31 families, 74 genera and 96 species were found. For the investigation of the natural or alternative hosts of Soybean yellow mottle mosaic virus (SYMMV), 495 plant samples belonging to 26 families 84 species were subjected to RT-PCR. SYMMV was detected only from legume plants such as Glycine soja, Vigna angularis var. nipponensis, Trifolium repens, and Lespedeza cuneata. Among legume plants tested, more than a third of G. soja (wild soybean) contained SYMMV, indicating that the wild soybean played an important role as a reservoir of SYMMV. Wild soybeans may be infected with SYMMV as early as mid-July. Considering the results of early infection and the high infection rate of seed and seed transmission of SYMMV in G. soja, wild soybeans may have played an important role in the completion of disease cycle of the virus.

• The Plant Pathology Journal
• /
• v.36 no.5
• /
• pp.476-490
• /
• 2020

The parasitic weed, Orobanche crenata, is one of the most devastating constraint for faba bean production in Mediterranean regions. Plant host defense induction was reported as one of the most appropriate control methods in many crops. The aim of this study was to elucidate the effect of salicylic acid (SA) and indole acetic acid (IAA) on the induction of faba bean resistance to O. crenata under the field and controlled experimental conditions. Both hormones were tested on two contrasting faba bean genotypes: Giza 843 (partially resistant to O. crenata) and Lobab (susceptible) at three different application methods (seed soaking, foliar spray, and the combination of both seed soaking and foliar spray). Soaking seeds in SA or IAA provided the highest protection levels reaching ~75% compared to the untreated control plants. Both elicitors limited the chlorophyll content decrease caused by O. crenata infestation and increased phenolic compound production in host plants. Phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase activities were stimulated in the host plant roots especially in the susceptible genotype Lobab. The magnitude of induction was more obvious in infested than in non-infested plants. Histological study revealed that both SA and IAA decreased the number of attached O. crenata spikes which could be related to specific defense responses in the host plant roots.

• Hwankyungkyoyuk
• /
• v.13 no.2
• /
• pp.63-73
• /
• 2000

The purpose of this study are two-fold; 1) to identify the differences in the view of environmental value between 6-years-olds and 12-years-old, 2) to identify the differences in the attitude towards animals and plants between male-and female students. To accomplish the purposes of this study, two researchers deeply interviewed ten 6-years-old and 12-years-old boys and girls, respectively. First, the interviewees are asked to rank six constituents in nature, human-being, tiger, ant, gingko tree, weed, and stone, from their views of environmental value. Then, the interviewees were asked to talk about their various interaction with animals and plants. The results of this study are as follows; 1) In evaluating the value of nature constituents, 12-years-olds tended to be affected by scientific knowledge. On the other hand, 6-years-olds tended to evaluate the value of nature constituents by their emotional feeling; 2) From the perspectives of environmental ethics, 12-years-olds showed attitudes in anthropocentric or holistic ethics. On the other hand, 6-years-olds showed attitudes in nonanthropocentric ethics; 3) In evaluating the value of nature constituents, 12-year-olds tended to consider the constituent′s instrumental values and 6-years-olds tended to consider their intrinsic values; 4) From the perspectives of "ethics of care", females, especially 12-years females tended to take care of plants. The results propose more emphasis of environmental "sensuous" in school environmental education. And male- and female students should be expected fairly in their environmental attitudes, especially in taking care of natural creatures.

• Korean Journal of Plant Taxonomy
• /
• v.53 no.1
• /
• pp.54-59
• /
• 2023

Naturalized populations of two alien plants were newly found, and we describe their morphological characteristics and habitats with photographs. One is a member of Juncaceae, Juncus torreyi Coville, and was newly found at a pool of a beach in Gangwon-do. This rush is native to North America and belongs to the sect. Ozophyllum (subgen. Juncus) according to certain morphological characteristics, such as its racemose inflorescence, the absence of floral bracteole, and unitubular leaves with perfect septa. J. torreyi is easily distinguishable from Korean rushes by its long rhizomes with swollen nodes and globular head with 25-100 flowers. Its introduction into Japan and Europe was reported, but the ecological risk associated with its over-dispersal is not known. The other alien plant is a submerged plant, Egeria densa Planch. (Hydrocharitaceae), which was found in streams in Gyeongsangbuk-do and ditches in the Busan-si area, both of which being in the watershed of the Nakdong River. Egeria densa is similar to Hydrilla verticillata (L.f.) Royle, which is native to Korea. However, it is distinguished from H. verticillata by its larger flowers and lack of overwintering organs. This alien plant is native to South America and was introduced for aquarium gardening and naturalized around the world. Egeria densa is treated as a malignant weed due to its asexual reproduction and rapid growth. Size changes and the number of populations of E. densa must be investigated.

• Korean Journal of Weed Science
• /
• v.3 no.1
• /
• pp.29-38
• /
• 1983

Growth habit, intraspecific competition of Digitaria sanguinalis, and interspecific competition between soybean and D. sanguinalis were evaluated to obtain the basic informations on establishing an effective control measure in upland corps. The earlier planting on April 1 produced approximately 3.5 times higher dry matter than that of the latest planting on July 22 and resulted in the earliest heading on July 8 and the latest heading was observed on September 4 planted on July. 22, but the interval between planting and heading dates was shortened progressively as the planting dates were delayed, showing irregularity of heading within a hill. Tiller numbers per plant were inhibited as densities increased from one to forty. One plant planted per pot produced significantly higher tiller numbers than density of 5 to 40 plants per pot. However, total tiller numbers was the highest in density of 40 plants planted per pot. Regardless of planting densities used, D. sanguinalis at all densities produced the similar dry matter per pot, showing severe intraspecific competition as density increased, but on each plant basis dry weight production was the highest in the lowest density such as one plant planted per pot. Competition between soybean and D. sanguinalis for the entire growing season decreased the total dry weight of soybean by 59.6%. Soybean required the maintenance of a weed free condition, about 3 to 4 weeks immediately after seeding, for obtaining the maximum yield, beyond which soybean crops effectively suppressed the growth of D. sanguinalis.

• Korean Journal of Weed Science
• /
• v.12 no.4
• /
• pp.374-379
• /
• 1992

Response of medicinal plants(58 species in 28 families) cultivated or naturally grown in Korea on paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) was determined. All the plants, except for Jiwhang(Rehmannia glutinosa Liboch.) were killed by paraquat at 0. 8kg $ha^{-1}$. Jiwhang showed a great resistance to paraquat. The phytotoxic effect did not occur in Jiwhang with paraquat applied at 3.2kg $ha^{-1}$. Only 10% growth inhibition of Jiwhang was obtained at 4.8kg $ha^{-1}$. Normal growth of Jiwhang also occurred when at 0.8kg $ha^{-1}$ of paraquat different application dates from 2 leaf stage(LS) to 8 LS and/or five-repeated applications at 20-day intervals starting from 3 LS were employed. However, Jiwhang was completely killed by glyphosate[N-(phosphonomethyl) glycine], 2,4-D[2,4-dichlorophenoxy) acetic acid], and dicamba[3,6-dichloro-2-methoxy benzoic acid]+2, 4-D at the respective recommended rates.

• Korean Journal of Weed Science
• /
• v.16 no.2
• /
• pp.160-170
• /
• 1996

Several physiological responses were investigated in plants treated with TOPE as a preliminary step to know its action site. Unlike photo-dependent diphenylethers, herbicidal activity of TOPE appeared slowly and its typical symptoms were both burning of leaf blades and abnormal division of meristem in grasses, Similarly, both leakage of cell electrolytes and the curling of cotyledon margin were also shown in cucumber(Cucumis sativus L.). Biosynthesis of chlorophyll in etiolated cucumber cotyledon was not inhibited directly by treatment of TOPE at low light intensity(5.5${\mu}$ mol $m^{-2}s^{-1}$ PAR) and protoporphyrin IX was not also accumulated. The contents of phytoene, phytofluene and ${\beta}$-carotene were abnormaly increased. Photosynthesis was inhibited only at high concentration. Mitochondrial respiration was inhibited at high concentration but rather increased significantly at 10${\mu}$M of TOPE. However, respiration inhibitors did not alleviate the two symptoms of TOPE in cucumber cotyledon. In the same experiments, using inhibitors of protein or nucleic acid biosynthesis, only one of the two symptoms was alleviated by chloramphenicol and cycloheximide. In contrast, both symptoms were alleviated by actinomycin-D and hydroxyurea, suggesting that nucleic acid metabolism might be preferentially related to the mode of action of TOPE. DNA, RNA and protein contents were accumulated in both cucumber cotyledon and rice (Oryza sativa L.) routs treated with TOPE, and the DNA of them was increased at first. Thus, it is conjectured that TOPE increase nucleic acid metabolism directly or indirectly, and then disturb various metabolic pathways causing abnormal physiological and morphological effects followed by final death.

• Weed & Turfgrass Science
• /
• v.7 no.2
• /
• pp.166-169
• /
• 2018

Repeated use of ACCase inhibiting herbicides for a long time has resulted in increases of resistant Echinochloa oryzicola populations in paddy fields in middle west area of Korea. This study aims to investigate current status of herbicide resistant E. oryzicola in Gyeongsangnam-do, in which there is less information about herbicide resistance. For resistance frequency and dose-response study, seeds from 100 individual plants of E. oryzicola in Gyeongsangnam-do were collected and tested with cyhalofop-butyl. Seven percent of plants from Gyeongsangnam-do was resistant at a recommended rate of cyhalofop-butyl. $GR_{50}$ values (herbicide rates required to reduce plant growth 50%) for one representative resistant populations and five susceptible populations were $738g\;a.i.\;ha^{-1}$ and 66-234 (average 147)$g\;a.i.\;ha^{-1}$, respectively, indicating average 5 times difference in resistance. Although lower rate of frequency of herbicide resistance in Gyeongsangnam-do than in Jeollabuk-do, increases of herbicide resistance are expected in this area because of increases of direct seeded rice fields and increases of dependence on a specific herbicide. Therefore, it is necessary to monitor herbicide resistance regularly and conduct integrated herbicide resistance management in this area.