• Title/Summary/Keyword: SEEDLING GROWTH

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A Study on Light Condition between Pinus densiflora and Quercus variabilis Natural Mixed Forest Stands by Using the Hemispherical Photo Method (수관사진법을 이용한 소나무-굴참나무 천연림에 있어서의 광 조건 연구)

  • Chung Dong-Jun;Kim Young-Chai
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.1 no.2
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    • pp.127-134
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    • 1999
  • This study was performed to obtain the basic data to present rational silvicultural tending plan. It makes these widely distributed pine-oak mixed stand and each of pure stand in middle province on object of this study and do comparative analysis of light condition about stand parameter and natural regeneration according to each slope(north, west and south) conditions of location in central part of South Korea. Sample plots for pine-oak mixed stand and pine and oak pure stand were established on each of southern, northern and western slopes based upon site and growth conditions of the slope. Sample plot was a circle of 0.05ha with a diameter of 25.24 m. A sample plot has between 30 and 40 tree in it. Total 23 sample plots were established; 9 pure pine stands, 8 pine-oak mixed stands. and 6 pure oak stands across lower, middle, upper parts of slopes. Relative light intensity within a stand was' measured by crown- photo(fish-eye lens; 180$^{\circ}$) system through fish-eye lens and by comparing each plot with the denuded through PAR-sensor. The crown closure ratio of pure pine stand (75%) shows much lower than that of mixed stand (90.9%) and pure oak stand (93%). The relative light intensity within a stand showed an opposite result. The crown closure of mixed stands tended to become gradually low as the slope moves from the north to the south, but the relative light Intensity within the stand tended to rise. By analyzing the relationship between the relative light intensity within a stand and stand parameter, light intensity within a stand tended to decrease as the diameter and N/ha increase. Number of oak seedlings and light intensity within a stand is in a straight-line regression relation. In particular, the number of oak seedlings was the highest in mixed stands on the southern slope. But no single pine seedling was found. The unfavorable conditions of l0cm thick litter layer and low relative light intensity in a stand (ranging between 4% and 8%) is considered to prevent pine seeds from germinating.

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Disinfection of Fusarium-infected Rice Seeds by Prochloraz and Gaseous Chlorine Dioxide

  • Jeon, Young-ah;Lee, Young-yi;Lee, Ho-sun;Sung, Jung-sook;Lee, Seokyoung
    • 한국균학회소식:학술대회논문집
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    • 2014.10a
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    • pp.25-25
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    • 2014
  • Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide ($ClO_2$), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous $ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of $ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm $ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using $ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of $ClO_2$. Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at $30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous $ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of $ClO_2$. Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds.

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Effects of Elevated Atmospheric CO2 and Nitrogen Fertilization on Growth and Carbon Uptake of Yellow Poplar Seedlings (대기 이산화탄소 증가와 질소 시비가 백합나무 유묘의 생장과 탄소 흡수에 미치는 영향)

  • Chung, Mi-Sook;Han, Sim-Hee;Kim, Du-Hyun;Lee, Jae-Cheon;Kim, Pan-Gi
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.14 no.3
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    • pp.108-118
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    • 2012
  • To investigate the responses of yellow poplar (Liriodendron tulipifera L.) seedlings to the interactive effects of the elevated atmospheric $CO_2$ level and nitrogen addition, we measured biomass, photosynthetic pigments, photosynthesis, and the contents of nitrogen (N) and carbon (C) from the seedlings after 16 weeks of the treatments. Yellow poplar seedlings were grown under the ambient ($400{\mu}mol\;mol^{-1}$) and the elevated (560 and $720{\mu}mol\;mol^{-1}$) CO2 concentratoins with three different N addition levels (1.2, 2.4, and $3.6g\;kg^{-1}$) in the Open Top Chambers (OTC). The dry weight of the seedlings enhanced with the increased N levels under the elevated $CO_2$ concentrations and the increment of the dry weight differed among the different N levels. Photosynthetic pigment content of the yellow poplar leaves also increased with the increase of the $CO_2$ concentration levels. The effects of the N levels on the photosynthetic pigment content, however, were significantly different among the $CO_2$ levels. Photosynthetic rates were affected by the levels of $CO_2$ and N concentrations. Stomatal conductance and transpiration rates increased with increasing $CO_2$ concentration. The carboxylation efficiency of the seedlings without N addition increased under the higher $CO_2$ concentrations whereas that with N addition decreased under the elevated $CO_2$ concentrations. Nitrogen and carbon uptake in leaf, stem, and root increased with the elevated $CO_2$ concentration level and N addition. In conclusion, under the elevated $CO_2$ concentrations, physiological characteristics and carbon uptake of the yellow poplar seedling were improved and increased with N addition.

Effect of Seeding Dates of Italian Ryegrass Interseeded into Bermudagrass Sod on the Forage Productivity and Botanical Composition of Italian Ryegrass and Bermudagrass (버뮤다그라스 초지에 보파한 이탈리안 라이그라스의 파종시기가 목초생산성과 식생에 미치는 영향)

  • Park, Nam-Geon;Hwang, Kyung-Jun;Lee, Chong-Eon;Kim, Nam-Young;Park, Hyung-Soo;Ko, Moon-Suk;Lim, Young-Cheol
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.31 no.4
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    • pp.383-388
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    • 2011
  • This study was carried out to determine the effect of seeding dates of Italian ryegrass interseeded into bermudagrass sod on the forage productivity and botanical composition of Italian ryegrass and bermudagrass. Experimental plot was located at 200 m altitude within Subtropical Animal Experiment Station, National Institute of Animal Science in Jeju from 2009 to 2010. Seeding date treatments of Italian ryegrass into bermudagrass sod were arranged in a randomized complete block design replicated three times. Italian ryegrass was drilled in row 20 cm apart after clipping the bermudagrass at a cutting height of 2~3 cm. Seeding time was on 15 September, 30 September and 15 October. The dry matter yield of Italian ryegrass was higher in 15 September seeding treatment, the dry matter yields of 30 September and 15 October seeding treatment were not different. The Italian ryegrass interseeded into bermudagrass sod didn't affect the dry matter yield in the summer harvests of bermudagrass, and the dry matter yield of bermudagrass showed the highest in August. In botanical composition, Italian ryegrass showed to reduced growth in early seedling stage after seeding by competition with bermudagrass, but Italian ryegrass was dominant to June increasing of temperature in spring next year and bermudagrass after Italian ryegrass harvests was dominant during summer season.

Studies on the Effects of Silicate and Phosphate Application on the Growth of Rice Seedling (수도묘(水稻苗)에 시용(施用)한 규산(珪酸)과 인산(燐酸)의 영향(影響)에 관(關)한 연구(硏究))

  • Kim, M.K.
    • Korean Journal of Soil Science and Fertilizer
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    • v.3 no.1
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    • pp.17-21
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    • 1970
  • To determine the effects of the silicate and the phosphate on the rice seedlings, 200 grams dry soil of the paddy field taken in the petri dish of 15cm diameter were treated with three levels of silicate(wollastonite) and phosphate. And the same amounts of nitrogen and potash were added constantly to each treated petridish. 100 grains of rice of which variety is Nongrim 25 were sown on each treated petridish simultaneously. After five times continuous culture, the rice plants and the soil were analyzed chemically and the results obtained are summarized as follows: 1. Dry matter weight of the rice seedlings was significantly increased to the increased phosphate absorption, on the other hand that was decreased when the silica absorption was increased. 2. The higher the available phosphate content in the soil after the experiments, the lower the silica content as well as absorption by the plant, and the $SiO_2/P_2O_5$ ratio in the plant was significantly decreased. 3. By the wollastonite application, the available silica, the exchangeable calcium in the soil after the experiment, and the silica content as well as silica absorption and $SiO_2/P_2O_5$ ratio in the rice plant was significantly increased. 4. Higher correlation coefficient was obtained between the exchangeable calcium amount and the silica content or silica/phosphate ratio in the rice plant than the available silica content in soil itself. 5. It is possible to control the silica/phosphate ratio in plant by the control of the silica/phosphate ratio in soil. 6. The relation between the silica/phosphate ratio in plant (y) and the available silica/phosphate ratio in soil (x) was $y=0.665+1.420x-0.0825x^2$ and the goodness of fit(r) was 82%.

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Factors Affecting Herbicidal Phytotoxicity and Efficacy of Antidote, CGA 123' 407, in Rice Nursery (못자리용(用) 제초제(除草劑)의 약해발생(藥害發生) 요인(要因)과 해독제(解毒劑) "CGA 123' 407" 효과(效果))

  • Kim, Soon-Chul;Lee, Soo-Kwan
    • Korean Journal of Weed Science
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    • v.5 no.1
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    • pp.63-72
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    • 1985
  • To establish the method of integrated weed management in rice nurserybed, phytotoxic factors of herbicide and antidote efficacy were evaluated at the Yeongnam Crop Experiment Station in 1982 and 1984. Seven hundred eighty four research items were carried out as weed control research since 1961. While 65% of these were belonged to rice research, only 6% was attributed to nurserybed among rice research. More herbicidal phytotoxicity exhibited when seedbed was pressed just after seeding than sand covered or uncovered seedbed and also this phytotoxic symptom enhanced by using intact seed compared to pregerminated seed. Rinsing practice of seedbed reduced the phytotoxic effect of butachlor and this effect was more pronounced with the number of rinsing operation increase and at the pressed plot. However, herbicidal efficacy was not significantly decreased by rinsing operation. Growth of rice seedling hardly affected where the herbicide was absorbed through root only compared to absorption from both of root and shoot for pyrazolate, butachlor and thiobencarb. Herbicide antidote `CGA 123'407' completely protected from the phytotoxic effect of pretilachlor without arising any adversal effect in weed control. However, without antidote, pretilachlor showed the most severe phytotoxic symptom among used herbicides.

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A New Rice Cultivar "Jogwang" with RSV Resistance and Short Growth Duration (벼줄무늬잎마름병 저항성 단기성 벼 신품종 "조광")

  • Lee, Jong-Hee;Kang, Jong-Rae;Park, Dong-Soo;Yeo, Un-Sang;Kwak, Do-Yeon;Shin, Mun-Sik;Song, You-Chun;Ha, Woon-Goo;Cho, Jun-Hyeon;Kim, Chun-Song;Jeon, Myeong-Gi;Lee, Gi-Yun;Yi, Gi-Hwan;Nam, Min-Hee;Ku, Yeon-Chung;Oh, Byeong-Geun;Kim, Myeong-Ki;Yang, Sae-Jun;Kim, Jae-Kyu
    • Korean Journal of Breeding Science
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    • v.41 no.2
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    • pp.163-167
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    • 2009
  • Jogwang is a new early maturing japonica rice developed in 2007 from a cross between Milyang187 and YR21113-B-B at the Department of Functional Crop Science, NICS, RDA. This cultivar is very suitable to the rice-cash crop double cropping system. Heading date of Jogwang is 2 days earlier than Keumobyeo under the late transplanting cultivation on July 10 at the Yeongnam plain. The tolerance level of this variety to leaf discoloration at seedling stage is very similar to Keumobyeo. It showed slightly lower viviparous germination and premature heading. This cultivar showed resistant reactions to leaf blast and rice stripe virus disease but susceptible to bacterial blight disease and major insect pests. The ratio of milling and head rice recovery of Jogwang is 76.5% and 64.5%, respectively. The milled kernels are translucent with non glutinous endosperm. This cultivar has 7.3% protein and 18.5% amylose content. In local adaptability test, showed that the milled rice yield of Jogwang is $4.90\;MT\;ha^{-1}$. This cultivar is suitable for planting in the plain paddy fields of Honam and Yeonnam regions in Korea.

Effects of Specific Gravity on Germination and Emergence of Foxtail Millet (Setaria italica Beauvois) (염수선 종자 정선법에 따른 조의 발아 및 출현율)

  • Jung, Ki-Youl;Choi, Young-Dae;Chun, Hyen-Chung;Lee, Sang-Hun;Jeon, Seung-Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.2
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    • pp.144-151
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    • 2019
  • The establishment rate of foxtail millet seeds is greatly affected by soil environment conditions. To enhance germination viability and stable production of foxtail millet seeds, it is important to select seeds with a high density. Therefore, this study tested the selection of high-quality seeds using salt solution (specific gravity: 1.000, 1.005, 1.010, 1.015, 1.020, 1.025, 1.030, 1.035, and $1.040g\;L^{-1}$) and investigated their germination rates, percentages of emergence, and seeding quality. In this study, three varieties were tested: 'Hwanggeum', 'Samdachal', and 'Kyeongkwan1'. The thousand seed weight of all three varieties increased proportionally with specific gravity. The highest thousand seed weight was observed at the selection with $1.040g\;L^{-1}$ specific gravity, which also had the highest germination rate of 88.3%, 86.7%, and 90.6%, for 'Hwanggeum'; 'Samdachal'; and 'Kyeongkwan1', respectively. The results of seeding quality indicated that higher the specific gravity during selection, the higher were the values of plant growth (plant height, leaf length, stem diameter, root length, root weight, and stem weight). All the three varieties were found to be longer or heavier for seeds selected at the specific gravity of $1.040g\;L^{-1}$. The packing germination viability investigation found that higher the specific gravity for selection of seeds, the higher was the percentage of emergence (PE) and the emergence rate index (ERI). The PE was the highest for seeds selected at $1.040g\;L^{-1}$ specific gravity (85.3, 83.0, and 87.0%), and ERI was also as high as $2.82d^{-1}\;m^{-1}$ or more at $1.040g\;L^{-1}$. Selection of seeds with salt solution resulted in high germination viability of foxtail millet. Therefore, sowing seeds selected at $1.040g\;L^{-1}$ specific gravity is expected to help substantially in increased productivity.

Effect of methyl jasmonate on the glucosinolate contents and whole genome expression in Brassica oleracea (유묘기 양배추류에서 메틸자스모네이트에 의한 글루코시놀레이트 함량 변화 및 전사체 발현 분석)

  • Lee, Jeongyeo;Min, Sung Ran;Jung, Jaeeun;Kim, HyeRan
    • Journal of Plant Biotechnology
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    • v.46 no.3
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    • pp.189-204
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    • 2019
  • In this study, we analyzed the changes in glucosinolate content and gene expression in TO1000DH3 and Early big seedling upon methyl jasmonate (MeJA) treatment. Analysis of glucosinolate contents after MeJA treatment at $200{\mu}M$ concentration showed that the total glucosinolate content increased by 1.3-1.5 fold in TO1000DH3 and 1.3-3.8 fold in Early big compared to those before treatment. Aliphatic glucosinolates, progoitrin and gluconapin, were detected only in TO1000DH3, and the changes in the content of neoglucobrassicin were the greatest at 48 hours after MeJA treatment in TO1000DH3 and Early big. The transcriptomic analysis showed that transcripts involved in stress or defense reactions, or those related to growth were specifically expressed in TO1000DH3, while transcripts related to nucleosides or ATP biosynthesis were specifically expressed in Early big. GO analysis on transcripts with more than two-fold change in expression upon MeJA treatment, corresponding to 12,020 transcripts in TO1000DH3 and 13,510 transcripts in Early big, showed that the expression of transcripts that react to stimulus and chemical increased in TO1000DH3 and Early big, while those related to single-organism and ribosome synthesis decreased. In particular, the expression increased for all transcripts related to indole glucosinolate biosynthesis, which is associated with increase in glucobrassicin and neoglucobrassicin contents. Upon MeJA treatment, the expression of AOP3 (Bo9g006220, Bo9g006240), TGG1 (Bo14804s010) increased only in TO1000DH3, while the expression of Dof1.1 (Bo5g008360), UGT74C1 (Bo4g177540), and GSL-OH (Bo4g173560, Bo4g173550, Bo4g173530) increased specifically in Early big.

Distribution Characteristics, Population Structure and Dynamics of the Endangered Plant, Viola websteri Hemsl. (멸종위기야생식물인 왕제비꽃(Viola websteri Hemsl.)의 분포특성과 개체군 구조 및 동태)

  • Chae, Hyun-Hee;Kim, Young-Chul;Kwak, Myoung-Hai;Nam, Gi-Heum
    • Korean Journal of Environment and Ecology
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    • v.35 no.1
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    • pp.48-67
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    • 2021
  • Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.