• 한국작물학회지
• /
• 제51권4호
• /
• pp.295-297
• /
• 2006

Potassium (K) distribution in rice (Oryza sativa L.) root was studied by confocal laser microscopy, using potassium sensitive fluorescent dye potassium-binding benzofuran isophthalate (PBFI). Significantly high intensity of K-specific fluorescence was detected at the root cap region followed by meristematic and basal regions. A negligible or fainted fluorescence was observed at the root hairs area. These results suggest that K is heavily distributed in the apical area of rice root, which may be required in higher concentration for division and extension of cells, as it is the rapidly growing region of the root, moreover, may also be involved in water uptake by creating osmotic gradient across membranes.

• 한국유기농업학회지
• /
• 제5권1호
• /
• pp.137-147
• /
• 1996

For the purpose of acquiring microbial agents that can be utilized to biologically control the major airborne diseases to apple trees, such as canker(Botryosphaeria dothidea), bitter rot(Glomerella cingulata), alternaria leaf spot(Alternaria mali), root rot(rosellinia necatrix), canker(Valsa ceratosperma) and gray mold rot(Botrytis cinerea), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogens causing major diseases to apple trees and identifed. Screening of more than 5,000 species of microorganisms collected in nature for them antagonistic action to the pathogens causing 5 major diseases to apple trees resulted in selection of effective species. Out of the 11 species, one species designated as CAP134 demonstrated outstanding activity. The bacterial strain, CAP134 exerted antagonistic efficiency of 57% on an isolated strain and 40% on a donated strain of Botryosphaeria dothidea., 52% on an isolated strain and 46% on a purchased strain of Alternaria mali, 60% on Valsa ceratosperma 25% on Glomerella cingulata, and 64% Rosellinia necatrix. The CAP134 was identified as a bacterial strain to Bacillus subtilis ATCC 6633 based on morephology, culture conditions, and physio-biochemical characteristics.

• Applied Microscopy
• /
• 제30권2호
• /
• pp.233-240
• /
• 2000

미분화된 엽상체 및 연결사와 뿌리로만 구성되어 있는 개구리밥(Spiroela polyrhiza)식물체의 구조분화 양상이 연구되었다. 엽상체는 엽육세포 내에 발달하여 있는 다수의 엽록체와 않은 막으로 구획화된 기실이 잘 발달되어 있어 광합성 및 부유에 중요한 역할을 하고, 측부로 발달하는 연결사에는 기실이 형성되어 있지 많으며 탈리층을 형성하여 모엽상체와 자엽상체를 분리시킨다. 뿌리는 흡수 및 식물체의 중심을 잡는데 중요한 역할을 하며, 근단부위에는 액포화된 근관세포층이 뚜렷히 발달하여 있다. 뿌리의 피층에는 원주형 기실이 형성되어 있으며 피층세포 내에는 잘 발달된 골지체, 미토콘드리아, rER등의 세포소기관들이 치밀하게 분포하였다. 엽상체, 연결사, 뿌리세포에는 엽록체가 발달하며 다수의 원형질 연락사가 분포하였다. 개구리밥은 10mm내외의 매우 축소된 식물체를 구성하나 효율적으로 잘 발달된 구조 분화체계를 이룬다. 이러한 구조는 수표면에 부유하여 빠르게 생장 및 증식하는 작은 식물체 크기와 이들의 괌은 생활환과 밀접한 관계가 있는 것으로 추정된다.

• International Journal of Oral Biology
• /
• 제37권2호
• /
• pp.51-56
• /
• 2012

Tooth development involves bud, cap, bell and hard tissue formation stages, each of which is tightly controlled by regulatory molecules. The aim of this study was to identify genes that are differentially expressed during dental hard tissue differentiation. Sprague-Dawley rats at postnatal days 3, 6 and 9 were used in the analysis. Differential display RT-PCR (DD-PCR) was used to screen differentially expressed genes between the 2nd (root formation stage, during mineralization) and 3rd (cap stage, before mineralization) molar germs at postnatal day 9. The DNA detected in the 2nd molar germs showed homology to osteonectin only (GenBank accession no. NM_012656.1). The level of osteonectin mRNA expression was much higher in the 2nd molar germs than in the 3rd molar germs and was found to increase in a time-dependent manner from the early bell stage to the root formation stage in the 2nd molar germs. The pattern of osteonectin protein expression was consistent with these RT-PCR results. Osteonectin protein was found by immunofluorescent analysis to localize in odontoblasts and preodontoblasts rather than the dentin matrix itself. Further studies are needed to validate the involvement of osteonectin in mineralization and root formation.

• 한국환경과학회지
• /
• 제1권2호
• /
• pp.145-155
• /
• 1992

The effect of various supplies of lead singly and in combination with aluminium on growth and chlorophyll biosynthesis was investigated in 7-day-old Vigna anguluris seedlings. Expose to 50 $\mu$N Pb or more drastically reduced root elongation rate. Significant depressions in root growth was observed within 1 day and no recovery of growth was seen over the duration of treatment period. Root elongation decreased depending on the Pb concentrations. Root growth inhibition was stronger than shoot growth inhibition. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of main roots. Inhibition of root and shoot elongation by Pb was lessened by combined exposure of Pb and Al, suggesting that the presence of AA reverse the inhibitory effect of Pb alone. With the histochemical sodium rhodizonate method the rate of Pb uptake was dependent on the Pb concentration and exposure time of the roots to Pb salts. Pb was first deposited on the root surface and then translocated radially in the root cap cells. During a longer Pb administration (up to 72 h) Pb penetration was nonuniform, with accumulation within the cortex or endodermis. There was drastic reduction in chlorophyll content by Pb. The Pb inhibition of chlorophyll synthesis was concentration dependent. 5-Aminolevulinic acid dehydratase (ALAD) activity exhibited distinct inhibition from control. Reduction in chlorophyll content was accompanied by proportional changes in ALAD activity. Chlorophyll content and ALAD activity were less affected by combined exposure of Pb and Al, suggesting that Al has a protective effect against the inhibiting action of Pb on photosynthetic activity.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제1권2호
• /
• pp.145-155
• /
• 1997

The effect of various supplies of lead singly and in combination with aluminium on growth and chlorophyll biosynthesis was investigated in 7-day-old Vigna angularis seedlings. Expose to 50 uM Pb or more drastically reduced root elongation rate. Significant depressions in root growth was observed within 1 day and no recovery of growth was seen over the duration of treatment period. Root elongation decreased depending on the Pb concentrations. Root growth inhibition was stronger than shoot growth inhibition. The initiation of lateral roots appeared to be more sensitive to Pb than the growth of main roots. Inhibition of root and shoot elongation by Pb was lessened by combined exposure of Pb and Al, suggesting that the presence of Al reverse the inhibitory effect of Pb alone. With the histochemical sodium rhodizonate method the rate of Pb uptake was dependent on the Pb concentration and exposure time of the roots to Pb salts. Pb was first deposited on the root surface and then translocated radially in the root cap cells. During a longer Pb administration (up to 72 h) Pb penetration was nonuniform, with accumulation within the cortex or endodermis. There was drastic reduction in chlorophyll content by Pb. The Pb inhibition of chlorophyll synthesis was concentration dependent. $\delta-Aminolevulinic$ acid dehydratase (ALAD) activity exhibited distinct inhibition from control. Reduction in chlorophyll content was accompanied by proportional changes in ALAD activity. Chlorophyll content and ALAD activity were less affected by combined exposure of Pb and Al, suggesting that Al has a protective effect against the inhibiting action of Pb on photosynthetic activity.

• International Journal of Korean Welding Society
• /
• 제3권1호
• /
• pp.34-38
• /
• 2003

It has been used many kinds of horizontal butt-welding methods at block-to-block erection stage in shipbuilding companies. For examples, some companies use conventional FCAW process with one side or both sides groove joint welding, others use carriage with torch holder type mechanized welding method. Although lots of efforts were done until now, some problems in quality and productivity still remain in ship's hull welding. In this study, we have attempted to raise productivity and quality on horizontal position of welding with following 3 items. 1) Prepare groove condition with no root gap for making easy fit-up work. 2) Develop improved MAG (100% $CO_2$ gas shielding) welding process with solid wire for making sound root bead from one side. 3) Develop and apply quite new automatic welding carriage. The stability of new welding process was confirmed by conducting mechanical tests of weldments to verify the soundness of weldments.

• 대한수학회논문집
• /
• 제20권4호
• /
• pp.641-644
• /
• 2005

Let L/F be a Galois quadratic extension such that F contains a primitive n-th root of 1. Let N = L(${\alpha}^{{\frac{1}{n}}$) where ${\alpha}{\in}L{\ast}$. We show that if $N_{L/F}({\alpha})\;{\in}L^n{\cap}F$, and [N : L] = m, then $G(N/ F) {\simeq}D_m$ or generalized quaternion group whether $N_{L/F}({\alpha})\;{\in}\;F^n\;or\;{\notin}F^n$, respectively.

• 한국작물학회지
• /
• 제40권3호
• /
• pp.285-296
• /
• 1995

본 시험은 톨페스큐의 잎과 뿌리신장 및 동화산물의 생장점부위의 종적인 해부학적 고찰을 통해 세포분열, 신장, 그리고 성숙속도등 세포역학 및 세포의 생리적 반응에 대한 질소의 효과를 연구하고자 수행하였다. 공시품종은 경당 수량성이 높은 HYT 품종과 경당 수량성이 낮은 LYT 품종이었으며, 이들은 엽신장 및 분얼성 등 생리적 특성이 다른 품종이다. 1. 근관, 표피세포, 피층세포, 도관세포로 크게 구분되는 뿌리생장부위는 약 3.2mm로 잎생장부위(약 25~30 mm)보다 훨씬 짧았으며, 근관부위는 약 0.4~0.5 mm였다. 2. 근관세포의 경우 분열시 크기는 약 5 $\mu{m}$, 최종크기는 약 40 $\mu{m}$였으며 피층세포와 도관세포의 분열시 크기는 각가 8.5 $\mu{m}$와 13.0 $\mu{m}$, 최종 크기는 각각 120$\mu{m}$와 650$\mu{m}$로 큰 차이가 있었다. 3. 뿌리생장부위의 피층세포와 도관세포의 분열 직후 또는 최종크기는 질소시용수준에 영향을 받지 않았으나, 세포신장속도는 질소시용수준에 영향을 받아 높은 질소수준(200ppm)에서 보다 낮은 질소수준(50ppm)에서 약 2배 정도 빨랐다. 4. 뿌리세포의 분열속도는 질소의 영향을 받아 피층세포의 경우 50ppm N 수준에서 시간당 약 4.5 세포, 200ppm N 수준에서는 시간당 약 2.3 세포였으며, 도관세포의 경우는 각각 시간당 0.9 세포와 0.6 세포였다. 5. 뿌리세포가 분열 후 최대로 신장하기까지는 시간은 피층세포의 경우 50ppm N에서 약 21 시간, 200ppm N에서 약 43시간이 소요되었으며, 도관세포의 경우는 각각 약 37 시간과 73 시간이 소요되었다. 6. 뿌리생장부위의 피층세포와 도관세포의 비율을 조사한 결과, 세포 분열부위에서는 1:1이었으나, 세포신장부위에서는 그 비율이 증가해 생장점으로부터 1.0 mm 위치에서 5:1로 증가해 계속 유지되었다. 7. 뿌리생장에 대한 질소의 효과를 분석해 볼 때, 질소는 뿌리세포의 크기보다는 세포분열과 세포신장속도에 크게 영향함을 알 수 있었다.

• 한국작물학회지
• /
• 제27권1호
• /
• pp.72-77
• /
• 1982

고려인삼의 삽목에 의한 영양번식방법을 개발하고저 완전히 전엽된 3매 소엽을 부착한 묘삼경을 삽수로 취하여 NAA의 처리농도가 이들 삽수의 발근에 미치는 영향을 조사하는 한편 삽목용토 및 삽목방법이 발근 및 발근후의 근생장에 미치는 영향을 조사하였다. NAA는 삽목후 관수시 NAA용액으로 관수하였던 바 1.0ppm 용액의 관수가 발근율 및 발근후의 근생장에 가장 효과적이었으며 또한 삽목용토로는 부엽토와 모래의 혼합토가 가장 이상적이었다. 삽목후 삽수에 부착된 엽에서의 증산을 억제하고 삽수의 고사를 방지하기 위해서는 Acril film으로 만든 덮개로 삽수의 지상부를 씌워 주는 것이 삽수의 발근에는 물론 특히 발근후의 근생육에 효과적이었다. 한편 5매의 소엽이 부착되어 있는 2년생 인삼의 엽병을 삽수로 하여 부엽토와 모래의 혼합토에 삽목하고 1.0ppm의 NAA 용액을 관수하였던 바 역시 양호한 발근율과 근생장을 보였는데 근의 생장량은 묘삼에서 취한 경삽보다는 약간 부진하였다.