• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.30-35
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• 2004

Compositae plants are known to contain biologically active substances that are allelopathic to agricultural crops as well as weed species. Aqueous extracts from leaves of Xanthium occidentale were assayed against alfalfa (Medicago sativa) to determine their allelopathic effects, and the result showed that the extracts applied onto filter paper significantly inhibited seed germination as well as root growth of alfalfa. Untreated seeds germinated in 60h, but extract concentrations greater than 30g $\textrm{L}^{-1}$ delayed seed germination. The extracts significantly inhibited seed germination of alfalfa, and $\beta$-amylase activity of alfalfa and barley seeds during 24-36 hours after treatment. Aqueous extracts of 40 g $\textrm{L}^{-1}$ from X. occidentale were completely inhibited the hypocotyl and root growth of alfalfa. Aqueous leaf extracts showed the highest inhibitory effect and followed by root and stem extracts. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol extracts. By means of high-performance liquid chromatography, chlorogenic acid and trans-cinnamic acid were quantified as the highest amounts from water and EtOAc fractions, respectively. BuOH and EtOAc fractions of X. occidentale reduced alfalfa root growth more than did hexane and water fractions. The findings of the bioassays for aqueous or methanol extracts reflected that the inhibitory effect of extract was closely related to the level of responsible allelochemicals found in plant extracts.

• Plant Resources
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• v.7 no.1
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• pp.69-76
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• 2004

Lettuce (Lactuca sativa L.) is known to contain water-soluble substances that are biologically active. Aqueous or methanol extracts and residues from leaves of lettuce plants were assayed to determine their allelopathic effects, and the causative allelochemicals from fractions were quantified by means of HPLC analysis and bioassayed. Extracts from oven-dried leaf samples were more phytotoxic than those from freeze-dried samples. Leaf extracts of 40 g L$^{-1}$ were completely inhibitory on root growth of alfalfa (Medicago sativa L.), while root growths of barley (Hordeum vulgare L.) and soybean (Glycine max L.) were less sensitive. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol leaf extracts. The major allelopathic substances analyzed by HPLC were coumarin, trans-cinnamic acid, o-coumaric acid, p-coumaric acid and chlorogenic acid. Of them p-coumaric acid was found as the greatest amount (8.9 mg 100 g$^{-1}$ ) in the EtOAc fraction; only coumarin was found in all the fractions. Hexane and EtOAc fractions of L. sativa reduced alfalfa root growth more than did BuOH and water fractions. These results suggest that lettuce had potent herbicidal activity, and that its activity differed depending on type and amount of causative compounds by fraction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.348-353
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• 1996

Mutation tachniques inducing more useful mutations and reducing somatic effects need to be improved for crop breeding. Seeds of barley varieties ; Dema, Grosso were treated with two types of mutagens ; 1) chemical treatment: single treatment or double treatment of two mutagens (N-nitroso-N-methylurea ; MNH, Sodium Azide; NaN$_3$) 2) gamma ray irradiation treatment. After treatment, half of seeds were used for germination test and half of seeds were sown to the field. With the higher dose of mutagen both chemical and gamma ray were plants treated, the higher rate of growth reduction rate was in M$_1$ seedling. In chemical treatment, germination rate of seeds, growth rate of coleoptile and root in double treatment of chemical mutagens were better than single treatments, especially in same dose. Growth inhibition rate of plant in double treatment of 1.0mM MNH(0.5mM MNH + 0.5mM MNH), for example, were less than one of plants of single treatment of 1.0mM MNH in pot and petri dish test. Growth reduction rate of culm and fertility rate in M$_1$ plants double treated in same dose of single treatment were also less than single one. With the higher dose of mutagen both chemical and gamma ray were plants treated, the higher frequency of chlorophyll mutants was in M$_2$ seedling. The rate of chlorophyll mutants in double treatment of chemical mutagens were higher than single treatment. Double treatment methods can be a improved method for induction of new good mutants, which were induced more useful mutations and reduced harmful somatic effects.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.652-665
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• 1997

Allelopathic effects on some crops(rice, barley, wheat, Chinese cabbage, leaf mustard, onion, welsh onion, tobacco, red pepper) for extracts of Phytolacca americana and Armoracia rusticana were investigated in MS solid medium. Germination percentage, radicle length, hypocotyl length, plant height, fresh weight, dry weight, and seedling vigor were rapidly inhibited by methanol extract from Phytolacca americana according to increase of the concentration in test plants. Autotoxicity of Phytolacca americana began to appear at concentrations greater than 50$\mu$l methanol extracts per 20ml medium. The fresh weight and dry weight of Phytolacca americana were also decreased by its own methanol extract according to increase of the concentration. Initial amounts of growth of all crops were also inhibited by methanol extracts from Armoracia rusticana, but the inhibitory effects were lowered than those of methanol extracts of Phytolacca americana. Of four fractions, ethyl acetate, petroleum ether, $1^{st}H_2O, 2^{nd}H_2O$, reextracted from methanol extracts of Phytolacca americana, the ethyl acetate fraction showed the highest allelopathic effects on germination percentage and initial amounts of growth. Chlorophyll contents of rice, barley and Chinese cabbage were more inhibited in the ethyl acetate fraction than in the other fractions. Free proline content of Chinese cabbage was increased 31.2 times in the 100$\mu l$ ethyl acetate fraction, and the contents of rice and barley were also increased according to concentration levels in the ethyl acetate fraction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.136-141
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• 2013

This study was conducted to investigate upland crop at reclaimed sand land 'Saemangeum' for early desalination purpose and to investigate the growth and yield of whole crop barley, which was acceded after summer crop of corn and rice. Seedling establishment of whole crop barley were 216 seedlings/$m^2$(25%) for non-flooding, 43% for 1 month and 58% for 2, 3 month flooding. And it was 60% in rice cultivation. Soil salt concentration was 0.5% in non-flooding treatment, however flooding treatments decreased to 0.2% or less. In general soil salt concentration increased until the middle stage of growing, then became to similar level as the seeding time. Plant height, stem length and number of tiller were increased with flooding treatment. Whole crop barley yield was significantly reduced in non-flooding treatment but rapidly increased by flooding treatment. Yielding at 3 months increased by 504% compared to non-flooding, and rice cultivation was also increased by 536%. Protein and fiber content was low in 1 month flooding treatment, 3 months flooding and rice cultivation showed the similar results in terms of feed value. For desalination purpose in reclaimed land, 3 months flooding treatments of rice cultivation could result in higher yielding for upland crop, such as whole crop barley.

• Current Research on Agriculture and Life Sciences
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• v.10
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• pp.99-108
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• 1992

This experiment was conducted to investigate biological activity of ABA and its analogues on barley shoot growth and peroxidase activity in barley seedlings. The treatments of 3.2 ppm (+)-ABA, 1.2 ppm (S)-(+)-ABA, 0.6 ppm ABA-methyl cinnamate ester compound (AC), and 0.08 ppm ABA-umbelliferone ester compound (AU) inhibited the growth of barley seedlings by more than 80% as compared with untreated control. The increase in barley shoot-inhibit activity of (S)-(+)-ABA became 3-fold than the activity of racemic ABA, and those of AC and AU higher than that of (S)-(+)-ABA by about 2.5 and 16 times, respectively. Peroxidase activities of barley shoots during the early growth stage were kept at a constant levels without ABA treatment, but in the treatment of racemic ABA, (S)-(+)-ABA, AC and AU increased the activities. Furthermore, the peroxidase activities increased as the higher concentration of ABA and its analogues were applied.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.23-28
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• 1984

From November 5th to December 5th in 1984. this study was carried out to find the effects of the prechilling and predrying treatment on the germination rate, the plant rate, the plant height, and the seedling growth rate in some varieties of barley and malting barley. The result obtained were as follows: In germination rate, barley varieties were the highest at the prechilling treatments for five and eight days and malting barley varieties were the highest at the prechilling treatment for eight days. In predrying, the seven days' treatment revealed higher germination rate than other in all varieties except Sacheon-6, Sacheon-6 showed the highest rate at the five days treatment. The growth rate in all varieties was the greatest at the prechilling treatments for five and eight days. In predrying treatments, the growth rate in Oweolbori and Hyangmaek was more effective at the predrying for three days, in Sacheon-6 for five days, and in Albori for seven days, respectively. The highest plant height was revealed at the prechilling treatment for five days in barley varieties and for eight days in malting barley varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.12-22
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• 1988

The effects of pH and Aluminum treatment on the seedling growth were examined with 11 cultivar under three levels of pH in nutri-culture.. Growth and yield responses of soil pH and nitrogen fertilization were also studied with five cultivars under 3 levels of soil pH and 3 levels of nitrogen application in the field experiment. The effect of pH on the seedling growth was not significant, but Aluminum treatment significantly decreased the seedling growth in nutri-culture except Dusan ＃12. Chlorophyll contents of leaves, dry weight of plants, culm length, spike numbers per unit area, grain numbers per spike, grain weight, and yield were decreased as the decrease of soil pH, and thus highly significant correlation between soil pH during barley growth and yield was observed in all cultivars examined. The stable cultivars to different soil pH with high yield was not found although the decreases of yield were different with cultivars. The increase of nitrogen fertilization significantly increased the nitrogen and chlorophyll contents of leaves, and dry weight of plants, while showed a little effects on the culm length, spike number per unit area, grain number per spike, grain weight and yield. The yield was significantly correlated with culm length, dry weight of plants, grain numbers per spike and 1000 grain weight at each pH levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.14-19
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• 2000

In order to develop an appropriate cultural practice for a newly bred 2-rowed, waxy, naked barley cultivar 'Duwonchapssalbori' in the southern region, 2 varieties, 3 seeding dates, 4 seeding rates were designed with 2 replications. The heading and maturity dates of 'Duwonchapssalbori' were' earlier than 'Saessalbori by 2-5 and 4 days, respectively. Culm length of 'Duwonchapssalbori' was 60 to 66cm with lodging resistance. Grain yields of both varieties were 4.28-4.33 ton/ha in the plot of Oct. 20 seeding, 4.11-4.18 ton in the plot of Oct. 28 seeding, and 3.7-13.89 ton/ha in the Nov. 5 seeding. Grain yield with different seeding rates highly significantly fitted with secondary polynomial equations in the plots of Oct. 20 and Oct. 28 seedings ($R^2$=0.84-0.85), showing the greatest yield with seeding rate of 140kg per ha. However, the grain yield with various seeding rates in the plot of Nov. 5 seeding showed simple linear regression ($R^2$=0.71), showing the seeding rate over 160kg in the case of later seeding to be optimal. Number of spikes per $m^2$ significantly contributed to grain yield, and fitted to simple linear regression ($R^2$=0.881-0.891), suggesting that plenty of early stands should be established at early seedling stage for high grain yield. Young spikes of 'Duwonchapssalbori' in the plot of Oct. 20 seeding elongated with linear increments since Feb. 10 (6.7mm), and showed rapid increment since March 7 (15.1mm). However, elongation of young spikes of 'Saessalbori' began from March 15 with slow increments. From these studies, the optimum seeding date and seeding rate in 'Duwonchapssalbori' were Oct. 20-28 and 140kg per ha for high grain yield in the southern regions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.693-698
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• 1997

Drought resistance and salt resistance of seedlings were compared with the polyethylene glycol(P.E.G) and NaCl solutions of the same osmotic potential($\Psi_\pi$=-10 bar). Plant height, seedling dry weight, chlorophyll content and leaf water potential decreased while the free proline content increased more in the P.E.G. than in the NaCl solution. Free amino acids increased 2.6 times in the P.E.G. solution and 3.6 times in the NaCl solution more than in the untreated(Hoagland's solution). Free proline occupied 66% and 61% of the content of total amino acids under water stress and salt stress, respectively. Besides free proline, phenylalanine in the P.E.G. solution and phenylalanine, alanine and asparagine in the NaCl solution increased distinctly. In short, it was shown that water and salt stress responses in seedling stage were relatively similar.