• Animal cells and systems
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• v.10 no.1
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• pp.21-25
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• 2006

In the present study, Dravya-an organic compound used for seed treatment along with the common fungicides to test its compatibility in the management of Alternaria padwickii in paddy. Dravya (a sea weed extract) was found highly compatible with fungicides like Bavistin and Dithane M-45. Incidence of Alternaria padwickii and Bipolaris oryzae was also reduced to a greater extent in the paddy seed samples of Dravya treatment. On the other hand, it also enhanced the seed germination and seedling vigour. Seedlings of treated samples also showed enhanced activity of peroxidase upon challenge inoculation with Alternaria padwickii. The enzyme activity in the seedlings challenged with the pathogen was two fold more over control. The suppression in disease incidence in growing plants indicated the promising effect of Dravya and Dithane M-45 under green- house conditions.

• Plant Resources
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• v.8 no.2
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• pp.116-121
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• 2005

Compositae plants are known to contain biologically active substances that are allelopathic to agricultural crops as well as weed species. Aqueous or methanol extracts and plant residues from leaves of Xanthium occidentale were assayed against alfalfa (Medicago sativa) to determine its allelopathic effects, and the results showed that the extracts applied onto filter paper significantly inhibited seed germination as well as root growth of alfalfa. Aqueous leaf extracts of $40g\;L^{-1}$ were completely inhibitory on root growth of alfalfa, while root growths of barley (Hordeum vulgare L.) and soybean (Glycine max L.) were less sensitive. Leaf residue incorporation at $100g\;kg^{-1}$ into soil on seedling growth of barnyard grass (Echinochloa crus-galli Beauv. var. oryzicola Ohwi) inhibited both shoot and root fresh weights of barnyard grass by 94 and $96\%$, respectively. Methanol extracts from BuOn and EtOAc fractions of X. occidentale reduced alfalfa root growth more than did those from hexane and water fractions. The results based on bioassay of extracts and residues show that X. occidentale had potent an allelopathic activity against other plant species.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.211-218
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• 1991

The allelopathic potentials of several Korean weeds were inverstigated in the greenhouse and laboratory. Aqueouse extracts and plant litters of several weeds were tested at different dilutions for allelopathic effect on germination and Barley growth of crop species. Among the several species of weeds. Portulaca oleracea and Chenopodium album had the highest allelopathic effect to the four species to 30%, while the extract of Portulaca oleracea increased those to 4.7% on an average when compare with control plant. In greenhouse experiment Portulaca oleracea highly reduced the emergence rate indices of barley, soybean. radish and corn to 30, 49, 36 and 68% that of control plant, respectively. Plant height and dry weight of indicate plants were reduced by the residues of Portulaca oleracea and Chenopodium album.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.207-213
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• 1997

This study was conducted to correlate changes in plant growth and flowering behavior with inhibition of gibberellin synthesis following application of GA biosynthesis inhibitor. Two sorghum genotypes, wild-type and phyB-1(phytochrome B mutant) which grow fast and flowers early relative to the wild-type, were used. Both growth and floral initiation of these two genotypes were greatly affected by ancymidol concentration increased. However, these growth inhibition and delayed flowering are almost completely overcome by simultaneous applications of 31.6ppm $GA_3$. The ability of $GA_3$ to reverse the effect of the inhibition on both growth and floral initiation in sorghum suggests a role for native GAs in sorghum flowering. This result was contrast to the fact that in some long day plants GA biosynthesis inhibitors will inhibit shoot elongation but not floral initiation. In sorghum, inhibition of vegetative growth by GA biosynthesis inhibitor is accompanied by a delay in flowering. Ten ppm of ancymidol treatments drastically reduced all early-13-hydroxylation pathway GAs($GA_{12}$, $GA_{53}$, $GA_{19}$, $GA_{20}$, $GA_3$, and $GA_8$) levels.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.67-71
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• 1997

This experiment was conducted to test the allelopatic activity on germination and early seedling growth of weed species by barley and sorghum plants residues. The fresh barley extraction inhibited the germination and early seedling growth of weeds, Echinochloa crus-galli, Sataria viridis, and P. oleracea. As the extract concentration increased, the germination and early seedling growth of weeds was significantly inhibited. The water extraction of dried barley and sorghum residues also ehibited the strong inhibition effect on germination and Barley seedling growth of weeds. Digitaria sanguinalis, Siegesbechia pubescens, Sectaria viridis, P. oleracea, E. crus-galli. In the dried barley and sorghum residues mixture into the vermiculite, as the dried residue concentration ncreased, emergence percentage, length of shoot and root of weeds, D. saguinalis, S. viridis, S. pubescens, Ammaranthus lividus, and Solanum nigrum, was significantly inhibited. More than 10% concentration of dired residue caused 80% emergence percentage and growth inhibition. From this study, we conclude that barley and sorghym weeds. These results suggest that barley and sorghum has some possibility to control some weed species like natural herbicide.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.109-113
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• 1985

Experiments were conducted to know the ecology of injurious paddy field weeds, Scirpus hotarui and aneilema japonica in 1982-1983. Almost all emergences of the both species were on the soil surface in emergence depth. The vigorous growth stage was before Aug. 18, and the plant height and branch numbers were decreased and the days to flower were diminished by the shortday length treatment. A. japonica was not renewed by once cutting, but cutting S. hotarui on vigourous tillering stage was the most effective renew the growth and all of overwintered plants were renewed in emergence. The more these weeds emergence, the less rice yields.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.44-51
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• 1997

Glyphosate had no effect on 5-enolpyruvylshikimate-3-phosphate synthase(EPSP-synthase) biosynthesis per se. But it inhibited clealy the activity of EPSP-synthase. EPSP-synthase seemed to be synthesized as a higher molecular weight(54 kDa) presusor protein and to be transported into plastid. The apparent molecular weight of mature EPSP-synthase in plastid is 45 kDa. Thus, the molecular size of transit peptide appeared to be about 9 kDa. The etiolation for 48 h after glyphosate application did not exhibit the inhibition of translocating level of EPSP-synthase across chloroplast envelope in actively growing meristematic leaves. But even when the plants were etiolated 2 hr after glyphosate treatment, a complete inhibition did not occur at least within 12 hr, i.e. 2 hr after beginning light period, suggesting that EPSP-synthase biosynthesis appeared to be not completely light dependent and the level of EPSP-synthase translocation to chloroplast could be controlled by an unknown regulatory mechanism of light dependent herbicidal effect of glyphosate.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.60-66
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• 2012

Crabgrass (Digitaria sanguinalis L.), Dandelion (Taraxacum platycarpum H. DAHLST.), Annual bluegrass (Poa annua L.), Gree kyllinga (Kyllinga brevifolia var.), Red clover (Trifolium pratense L.), Annual lespedeza (Kummerowia striata (Thunb.)Schindl.), Mugwort (Artemisia capillaris Thunb.), Horseweed (Erigeron canadensis L.), Field horsetail (Equisetum arvense L.) are major weeds in turf. In this study, 23 medicinal plant extracts were tested for herbicidal activities against crabgrass and dandelion in the course of major weed in turf. In pot experiment, we implemented pre-emergence application used medicinal plant extracts showed herbicidal activity in petridish experiment. In effect, inhibition rates of germination were 61.0% at Curcuma longa extract and 62.5% at Cnidium officinale extract in crabgrass pot experiment, and 77.8% at Ailanthus altissima extract in dandelion pot experiment.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.103-108
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• 1990

Germination test, nutrient culture test and pot experiment were conducted to determine selectivity of naproanilide between rice plants and paddy weeds. Naproanilide more severely inhibited growth of Scirpus juncoides, Sagittaria pygmaea and Cyerus serotinus than that of rice plant and Echinochloa crus-galli at germination stage. Root growth was severely inhibited than that of shoot growth by naproanilide treatment. Naproanilide severely inhibited rice plant and Echinochloa crus-galli at 30 uM, Sagittaria pygmaea at 1 uM and Cyperus serotinus at 10 uM in nutrient culture test, Rice plant and Echinochloa crus-galli did not show the difference of tillers and dry weight, but Scirpus juncoides, Morzochoria vaginalis and Aneilema keisak were severely inhibited at 15g/a and Sagittaria pygmaea and Cyperus serotinus at 30g/a in pot trial.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.23-27
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• 1994

Nutrient culture study was initiated to examine the selectivity of dithiopyr(S, S-dimethyl 2-difluoromethyl)-4-(2-methylpropyl)-6-(trifluoro methyl)-3, 5-pyridine dicarbothiate) in rice(Oryza sativa L.) and barnyardgrass(Echinochloa crusgalli Beauv.). Absorption and translocation of $^{14}C$-dithiopyr in rice and barnyardgrass were also investigated to determine their selective mechanism. Rice was very tolerant, but barnyardgrass was susceptible to dithiopyr. The absorption of dithiopyr was greater in barnyardgrass than in rice and most of them remained in the roots of both species. Dithiopyr was absorbed by roots and basal shoots of both species. Translocation of dithiopyr was very low but was higher in barnyardgrass than in rice. Therefore, this study suggest that the selectivity of dithiopyr between rice and barnyardgrass may be mainly attributed to the absorption and translocation of dithiopyr in plants.