• Journal of Plant Biotechnology
• /
• v.30 no.4
• /
• pp.405-410
• /
• 2003

Environmental stress is the major limiting factor in plant productivity. In order to evaluate the stress tolerance of potato plants, leaf discs of two potato cultivars, Atlantic and Superior, were subjected to various stress conditions of high temperature, methyl viologen, H2O2, or $H_2O$$_2$. When potato leaf discs were exposed to high temperature at 37$^{\circ}C$ for 84 hr, Atlantic plants, a cultivar with high sensitivity to heat stress, showed about 20％ higher membrane damage than Superior plants. When exposed to 2$\mu$M methyl violgen (MV), a superoxide generating non-selective herbicide, for 36 hr, Atlantic plants also showed about 38％ higher membrane damage than Superior plants, and were more susceptible up to 10$\mu$M MV concentration tested. On treatment with 0.75M NaCl, Atlantic plants also had about 45％ less chlorophyll contents in leaf discs than Superior plants. There was, however, no difference in chlorophyll content of two cultivars at higher NaCl concentrations. The effect of $H_2O$$_2$ on the two cultivars was mixed. At low $H_2O$$_2$ concentration (25 mM) , Superior plants were more susceptible to $H_2O$$_2$stress after 36 hr. However, at high $H_2O$$_2$ concentration (100 mM), Atlantic plants exhibited higher susceptibility after 36 hr. The results indicate that in vitro leaf discs reflecting the whole plants in this study will be useful for selection and characterization of elite transgenic potato plants with enhanced tolerance to environmental stress.

• Korean Journal of Weed Science
• /
• v.3 no.2
• /
• pp.208-222
• /
• 1983

To control ideally the weeds in orchards and systematize the utility of herbicides, the mixing effect of oxyfluorfen and paraquat was evaluated. Combinations of oxyfluorfen with paraquat were increased the control efficacies at any treatment without giving damage to fruit trees and appeared a synergism. The control effects were reduced from 80-90% to 40-60% as the time advanced. However, the relative synergistic index was higher at 60 days after treatment in preemergence treatment and at 90 days after treatment in early and late postemergence treatment, respectively. Also the index was relatively higher at lower dosage of both herbicides.

• Korean Journal of Weed Science
• /
• v.15 no.1
• /
• pp.30-38
• /
• 1995

Soil-applied pre-emergence herbicide, pyrazolate(4-(2, 4-dichlorobenzoyl)-1, 3-dimethyl pyrazol-5-yl-p-toluene sulphonate) induced, twist effect of shoots of barnyardgrass under dry conditions, and etiolated leaf and stem of that under water condition. Plant height and root length of rice broadcast on soil surface were similar to the untreated control, but plant height of rice drilled in soil was more inhibited than root length as compared with the untreated control, while development of barnyardgrass seedling was severely inhibited at 20 days after application. The inhibition rate was much higher under water condition than under dry condition, but difference in rice and barnyardgrass did not abserve. However, growth of transplanted rice shown to increase to the untreated control. Shoot and root fresh weight of rice broadcast on soil surface was increase as compared with the untreated control, and that of rice drilled in soil was not affected whereas that of barnyardgrass was severely inhibited by 42% and 41%, respectively. Under dry condition at 20 days after pyrazolate application while root growth of rice broadcast on soil surface under water condition was deadly inhibited and development of barnyardgrass was almost completely inhibited. On the other hand, microscopic studies showed that constriction of mesophyll cell by destruction of chloroplast of barnyardgrass were occurred only under dry condition, whereas damage of rice and barnyardgrass under water and transplanting condition were not observed. Anatomical change in the meristernatic region of rice and barnyardgrass was not occurred, and similar to intact plant regardless of cropping patterns.

• Korean Journal of Organic Agriculture
• /
• v.19 no.1
• /
• pp.65-82
• /
• 2011

In order to evaluate the weed suppressing effect of Solanum viarum Dunal. In this study species diversity in patch of S. viarum and allelopathic effects of the aqueous extracts on S. viarum were investigated. Number of species and species diversity in site close to patch of S. viarum were decreased gradually 1site ($7.7{\pm}2.0,\;1.5{\pm}0.2$), 2site ($5.3{\pm}1.2,\;1.2{\pm}0.2$) and 3site ($4.0{\pm}1.7,\;0.9{\pm}0.1$). And total phenolic compounds of soil in survey area were increased gradually site1 ($0.16{\pm}0.01mg\;g^{-1}$), site2 ($0.17{\pm}0.01mg\;g^{-1}$) and site3 ($0.22{\pm}0.02mg\;g^{-1}$). So the number of species and species diversity (r=-0.692, P<0.05) were negatively correlated with increased total phenolic compounds of soil in the survey area. The relative germination ratio, the mean germination time, the relative elongation ratio, the fresh weight and the dry weight of receptor plants are generally getting decreased while the concentration of the aqueous extracts from S. viarum escalate. But every ratio was various depending on the growing regions, the kind of receptor plants and the treatment of the aqueous extracts. Especially, the radicle by injection of the aqueous extracts concentration of S. viarum was influenced more than the shoot on the same condition. The total phenolic compounds on region of S. viarum was gradually increased in stems (fresh $0.56{\pm}0.02mg\;g^{-1}$, dry $1.58{\pm}0.08mg\;g^{-1}$), roots (fresh $1.77{\pm}0.07mg\;g^{-1}$, dry $2.64{\pm}0.06mg\;g^{-1}$), leaves (fresh $6.01{\pm}0.14mg\;g^{-1}$, dry $7.04{\pm}0.29mg\;g^{-1}$), seeds (fresh $6.21{\pm}0.17mg\;g^{-1}$, dry $9.08{\pm}0.73mg\;g^{-1}$) in order. On the contrary, the negative correlation on germination and growth of receptor plants was shown by total phenolic compounds on the each parts of S. viarum. We think that the aqueous extracts of S. viarum showed allelopathic effects on other plants. Therefore, S. viarum holds the higher competitiveness in plant community in Jeju Island and makes possibility of application as natural herbicide.

• Korean Journal of Weed Science
• /
• v.6 no.2
• /
• pp.168-173
• /
• 1986

The effects of varying concentrations and duration of fluazifop-butyl [(${\pm}$)-butyl [2- [4- [(5-(trifluoro methyl)-2-pyridinyl] oxy] phenoxy] propanate] treatment on cell division, cell enlargement, and protein synthesis were studied. Oat (Avena staiva L.) were treated from 0 to 48 hr with concentration ranging from $1{\times}10^{-6}M$ to $1{\times}10^{-3}M$ of fluazifop-butyl in the cell division study. There was a significant reduction in the mitotic indices of oat roots treated with $1{\times}10^{-4}M$ after 6 hr. After 18 hr treatment, All herbicide treatment inhibited cell division significantly. After 24 hr treatment almost 100% inhibition of cell division occurred at $1{\times}10^{-4}M$ to $1{\times}10^{-3}M$ while 20% inhibition of cell division occurred at $1{\times}10^{-6}M$ concentration at same exposure period. The greatest inhibition of cell division occurred between 0 to 18 hr. The avena coleoptile straight- growth test were used to determine the influence of fluazifop-butyl on eoleoptile growth. Significant inhibition of elongation of oat coleoptiles were observed at $1{\times}10^{-7}M$ to $1{\times}10^{-3}M$ after 24 hr incubation. Protein incorporation study showed that the $1{\times}10^{-4}M$ of fluazifop-butyl caused 60% inhibition of protein synthesis. It was concluded that the growth of inhibition of plants caused by fluazifop-butyl results from inhibition of cell division, cell enlargement, and protein synthesis.

• Korean Journal of Weed Science
• /
• v.17 no.4
• /
• pp.439-444
• /
• 1997

The causes of late establishment of barnyardgrass and their density effect on rice yield loss were examined in 1996 and 1977. Herbicide application on 5 to 15DAT(Days after transplanting) increased from 6% to 52.5%, 1988 to 1992, and their ingredient amount for barnyardgrass control decreased to 41.7-87.5% in Korea. Most late establishment of barnyardgrass in machine transplanted rice field were not late germinated but revived ones. The number of late established barnyardgrass were 0.5, 2.0 and 13.3/$m^2$, on direct seeded at May 10, and machine transplanted May 23 and June 9, individually. Relation on rice yield and the number of barnyardgrass at machine transplanted field showed highly significant equation, as y=543.3 4.7x, r=0.9039 in 1996 and y=515.8 10.4x+0.066$x^2$, $R^2$=0.9532 in 1997. Theoritical yield loss by regress equation showed 2% per one plant of barnyardgrass per $m^2$ and 5, 10, 20, 50, and 80 plants of barnyardgrass decreased rice to 10, 19, 35, 69 and 79%, individually.

• The Korean Journal of Pesticide Science
• /
• v.9 no.1
• /
• pp.70-80
• /
• 2005

To evaluate the exposure of molinate in agricultural environment and its effect against the non-target crop in air, this experiment was conducted to elucidate volatilization characteristics of molinate in aquatic condition and to determine critical concentration of molinate in the air causing phytotoxicity to Chili pepper. Cumulative volatilized rate of molinate from water was 22.7% at $35^{\circ}C$ for water temperature and 20 L/min for air velocity while 3.2% at $25^{\circ}C$ and 10 L/min within 47 hour after applied under closed system, respectively. The molinate concentrations in air above 60 cm height from soil surface of valley and open paddy rice field were reached the highest value of 18.17 and $11.59{\mu}g/m^3$, respectively within 24 hours after applying granular formulation at dose rate of molinate 150 g/1,000 $m^2$. However, their concentrations were drastically diminished to around 0.18 and $0.51{\mu}g/m^3$ level in 20 days after application, which volatilization pattern were similar to both regions. Also, the concentration of molinate in air above 60 cm height from soil surface was distributed higher 2 times than that above 180 cm height. Meanwhile, a phytotoxic symptom against the nearby chili pepper was revealed within three days after applied and molinate was detected $0.004{\sim}0.006$ mg/kg level from severe damaged leaves. The dose and exposure relations of molinate in the air against the non-target crop was also investigated in lab trial. The phytotoxic symptom, shriveled leaves, of the chili pepper was encountered by exposing two days with concentration of $13.6{\mu}g/m^3$, three days with $6.8{\mu}g/m^3$ or four days with $3.4{\mu}g/m^3$. The symptom was still recovered within four weeks after the plants had received fresh air. On the other hand, the phytotoxic response through root uptake of the herbicide in water culture was relatively insensitive, in which the symptom is observed ten days with the concentration of 300 ${\mu}g/L$.

• Korean Journal of Weed Science
• /
• v.14 no.2
• /
• pp.94-100
• /
• 1994

This experiment was conducted to determine selective mechanism of cyhalofop-butyl ester ((((R-butyl 2-(4-(4-cyano-2-fluorophenoxy) phenoxy) propionate)) between rice and Echinochloa crus-galli. 100ppm of cyhalofop-butyl ester inhibited over 90% of seedling growth of E. crus-galli when applied at 3 leaf stage and complete inhibition was observed at 180ppm applied at the 4 leaf stage, but rice(Chucheongbyeo) was not inhibited by cyhalofop-butyl ester even at 230ppm, regardless of its growth stages(3, 4, 5 and 6 leaf stages). Cyhalofop-butyl ester applied through stem at 10 and 50ppm moved most rapidly to the meristem and resulted in the highest injury on plant height, root length and fresh weight of E. crus-galli. compared with root or leaf application. Seedlings of rice and E. crus-galli at 3 or 4 leaf stage were dipped in 180ppm of cyhalofop-butyl ester solution for 1 minute and aboveground parts of E. crus-galli and rice were removed immediataly after dipping treatment. Regrowth of E. crus-galli was inhibited by the herbicide by 41.7%, but no inhibition was observed in rice. Further, content of chlorophyll reduced to 18.7% of the untreated control, showing appearence of almost being killed, but no effect on chlorophyll content of rice was observed.

• Korean Journal of Weed Science
• /
• v.4 no.1
• /
• pp.79-87
• /
• 1984

Herbicidal effects of alachlor to peanuts were observed under different formulations (granule containing 5.0% a.i. and emulsifiable concentrate containing 43.7% a.i.) and levels (granule with 3 and 6kg/l0a and emulsion with 300㏄/l0a) with the transparent polyethylene (P.E.) film mulching. Formulations and levels of alachlor did not affect emergence ratio, time of emergence and flowering, and early growth of peanuts such as the number of leaves and branches, length of branches; and shoot dry weight at 20 and 40 days after planting, but early growth was enhanced by P.E. film mulching. At harvest, weed dry weight was positively correlated with length of branches, but negatively correlated with the number of branches and shoot dry weight. Acalyphu australis and Chenopodium album were not effectively controlled by the application of alachlor and growth of C. album was retarded under P.E. film mulching. Portulaca oleracea and Digitaria sanguinalis were effectively controlled by alachlor, but they were not affected by P.E. film mulching. At harvest, D. sanguinalis, A. australis, and Echinochloa crus galli were predominant weeds in all treatments; persistence of alachlor may not be long enough to control even sensitive weeds to alachlor such as D, sanguinalis in the field of peanuts of which canopy development was relatively slow. Weed dry weight at harvest was negatively correlated with the number of pods and grain yield of peanuts. Among the yield components only the number of nods per plant was positively correlated with grain yield. Hana weeding after July 1 increased grain yield of Peanuts even in alchlor applied plots.

• Korean Journal of Weed Science
• /
• v.5 no.2
• /
• pp.202-210
• /
• 1985

Requirements in weed control in a mulberry field are much similar to those in orchards, but also feature a longer period of weed control of various kinds of persistent weeds, i.e., spring, summer, and winter annuals as well as perennials. In addition the mulberry tree is relatively more sensitive to herbicide injury. Hence, very few herbicides have been used in mulberry field. The present study was conducted to evaluate the usefulness of oxyfluorfen in comparison with alachlor and simazine, which are registered for ordinary mulberry field in Korea, for weed control efficacy in the new, rapidly increasing practice of transparent polyethylene-film mulched and densely planted younger mulberry culture. Dominant spring weeds were Galium spp., Erigeron spp., Polygonum senticosum, and Chenopodium spp. in the non-mulched interbed area in contrast to the Digitaria spp. and Potulaca spp, under mulch. Dominant summer weeds were Digitaria spp., Portulaca spp., Erigeron spp., Artemisia spp. and Calystegia japonica in the non-mulched interbed area while weeds did not occur significantly during summer under mulch which were shaded by vigorously growing mulberry trees. The weeds occurred under mulch in spring reduced shoot growth of young mulberry tree resulting in the reduced yield of mulberry leaves for silkworms. The weeds occurred in the interbed area did not affect until May, but interfered later summer- and fall-growth of mulberry tree. Early single spring application of alachlor(EC), simazine(WP) or oxyfluorfen(EC) at a rate of 650 g, 750 g or 350 g ai per ha, respectively, controlled most annuals satisfactorily to fall in the mulched bed area. In the nonmulched interbed area, however, thrice does of alchlor or simazine was necessary for satisfactory control of spring weeds, followed by summer application of alachlor or simazine at twice dose level as tank mixture with paraquat at 490 g ai per ha for satisfactory control of summer to fall weeds. Single spring application of oxyfluorfen at a rate of 1400 g ai per ha was persistently effective to control satisfactorily even summer and fall weeds. However, heavy rainfall splashed soil borne oxyfluorfen to the lower branch leaves causing some leaf burns. Spring application of oxyfluorfen at a rate of 350 g ai per ha followed by summer application of oxyfluorfen and paraquat tank mixture (350 g ai + 490 g ai) was the best choice for the non-mulched interbed area weed control among the treatments.