• Title/Summary/Keyword: IT Technique

Search Result 22,985, Processing Time 0.054 seconds

Epidemiological Studios on Clonorchis sinensis Infection along the Nam-river in Gyeongnam Province, Korea (남강유역 간흡충감염의 역학적 조사연구)

  • 배경훈;안영겸
    • Parasites, Hosts and Diseases
    • /
    • v.21 no.2
    • /
    • pp.116-186
    • /
    • 1983
  • An epidemiological study on Clonorchis sinensis infection along the Nam-river (total length ; 186km) flowing in Gyeongsang-nam-do, southern part of Korea, was carried out. Formalin-ether concentration technique and Stoll's egg counting method were employed to figure out the prevalence of C. sinensis infection. For the detection of cercariae from Parafossarulus sp., the snail host of C. sinensis, each snail was placed in aerated tap water, and examined for expelled cercariae. For observing the metacercariae the fresh water fish favorably eaten in raw conditions wore prepared by means of pressing the muscles between two slide glasses and/or by digesting them with artificial gastric juice. The fresh water fish were fed to the rabbits to get the worms and to identify the morphology of adult C. sinensis. The results are summarized as follows: 1. Overall Prevalence of C. sinensis infection was 38.75 from 5,291 examinees; 44.15 (1,408 out of 3,196) in male and 30.4% (637 out of 2,095) in female. 2. The prevalence rates were 42.0% at the upper stream, 41.2% around the vicinity of Jinyanglake, 34.2% at Jinju city, 34.2% at middle stream and 40.3% at down stream regions, respectively. 3. By age, the highest positive rate (53.4∼54.3%) was observed in 30 to 59 years of age. In this age group, the rate in males was 59.7∼62.2%, and in females 42.2∼44.4%, In the age group of less than 19 years it was 7.5∼20.9%. 4. By social strata, the positive rate was 16.5% in the primary school children, 22.6% in school students, 46.2% in teachers and local officers and 49.6% in the general inhabitants. 5. The quantitative examinations with the stool collected from clonorchiasis cases revealed that the light infection (less than 4,000/EPG) was 53.6%, moderate infection (4,001∼10,000 /EPG) 30.3% and heavy infection (more than 10,001/EPG) 16.1%, respectively. More than half of total cases examined were light infection, and 73.2% of female examinees were lightly infected with this cuke. 6. The average value of EPG was 4,963 (male, 6,057; female, 2,557 and the highest value was obtained from the age group of 30 to 59 years (5,240∼6,454). 7. The prevalence of Metagonimus yokogawai infection in humans was 5.5%, and 89.8% of metagonimiasis cases wore double-infected arith C. sinensis. The highest prevalence rate was observed in Jinju city (11.2%). 8. Total of 5,005 Parafossarulus sp., the snail intermediate host of C. sinensis, were examined for the detection of cercariae. The cercarial expulsion rate was 0.34%, and the snails collected in Jin-yang-lake side and in the down stream expelled mainly the cercariae of C, sinensis. 9. About 788 cercariaejday (range: 127∼1,503) were expelled daily from a snail naturally infected with C. sinensis. The snails which released more than 1,000 cercariae/day were 30.8% out of total collected. A snail uniquely released 5,840 cercariae/day in this study. 10. The other trematode cercariae besides C. sinensis were also detected, and the rates out of total snails were the cercariae of Losogenes liberum 6.71%, Cyathocotyle orientalis 0.26%, Notocotylus attenuatus 2.52% and Mucobucaris 0.54%, 11. Ten out of 18 species of fresh water fish caught along the river harbored the metacercariae of C, sinensis. The highest rate of metacercarial infection in fish was detected in Pseudorasbora larva (85.9%). The fish mainly eaten by the inhabitants along the Nam-river, and the metacercarial infection rates were: Zacco platypus 8.0%, Hemibarbus sp. 18.2∼26.7%, Gnathepcgcn sp. 37.5%, Ischikauia steenackeri 42.9% and Pseudogobio esocinus 16.7%. 12. Out of 36 P. larva, the number of metacercariae were about 109 (ranEe; 18∼446) per fish and 27 per gram of flesh. The fish caught in spring harbored the highest number of metacercariae. As indicated above, the prevalence of C. sinensis infection in the inhabitants residing around the Nam-river was relatively high. The farther toward the upper stream areas, the higher was the positive rate of C. sinensis infection, and most of clonorchiasis cases were lightly infected. The snail hosts of C. sinensis distributed all around the Nam-river. Several species of freshwater fish were infected with the metacercariae of C. sinensis and the infection rates were relatively high. To prevent C. sinensis infection in the endemic areas, the effective health education system is suggested as a control measure, although mass treatment is also expected to be useful, using chemotherapeutic agents such as "praziquantel", a recently developed anthelminthic for C. sinensis inftraction.

  • PDF

Current status of Brassica A genome analysis (Brassica A genome의 최근 연구 동향)

  • Choi, Su-Ryun;Kwon, Soo-Jin
    • Journal of Plant Biotechnology
    • /
    • v.39 no.1
    • /
    • pp.33-48
    • /
    • 2012
  • As a scientific curiosity to understand the structure and the function of crops and experimental efforts to apply it to plant breeding, genetic maps have been constructed in various crops. Especially, in the case of Brassica crop, genetic mapping has been accelerated since genetic information of model plant $Arabidopsis$ was available. As a result, the whole $B.$ $rapa$ genome (A genome) sequencing has recently been done. The genome sequences offer opportunities to develop molecular markers for genetic analysis in $Brassica$ crops. RFLP markers are widely used as the basis for genetic map construction, but detection system is inefficiency. The technical efficiency and analysis speed of the PCR-based markers become more preferable for many form of $Brassica$ genome study. The massive sequence informative markers such as SSR, SNP and InDels are also available to increase the density of markers for high-resolution genetic analysis. The high density maps are invaluable resources for QTLs analysis, marker assisted selection (MAS), map-based cloning and comparative analysis within $Brassica$ as well as related crop species. Additionally, the advents of new technology, next-generation technique, have served as a momentum for molecular breeding. Here we summarize genetic and genomic resources and suggest their applications for the molecular breeding in $Brassica$ crop.

A Kinematics Analysis of Uchi-mata(inner thigh reaping throw) by Kumi-kata types and Two different Opponent's Height in Judo[II] (유도 맞잡기 타입과 받기의 신장에 따른 허벅다리걸기의 Kinematic 분석[2])

  • Kwon, Moon-Seok;Kim, Eui-Hwan;Cho, Dong-Hee
    • Korean Journal of Applied Biomechanics
    • /
    • v.12 no.2
    • /
    • pp.143-157
    • /
    • 2002
  • This study was to analyze the kinematic variables when the subjects performing Uchi-mata(inner thigh reaping throw) by Kumi-kata types((How to grasp A or B?) and two different opponent's height in Judo. Kinematic variables were temporal, posture. Data analysis was collective comparison of two-way ANOVA, t-test by type A&B and two different opponent's height. There were significant difference of Kumi-kata types(p<.05) in the time elapsed on Kake phase(KP : throwing phase) and hip, knee, ankle-angle of the attacking foot in the 1st stage of KP and knee, ankle-angle of the attacking foot and hip, knee ankle-angle of the supporting foot in the 2nd stage of KP. There were significant difference of two opponent's(p<.05) in the time elapsed on KP and hip-angle of the supporting foot in 1st stage of KP. Therefore, the interaction effect(p<.05) were in the time elapsed on KP and hip-angle of the supporting foot in the 2nd stage of KP. So, It could be suggested that Judoka hold on the part-behind neck lapel(type A) at the sleeve with the other of Judogi jacked when opponent's height was short. Because the time elapsed on KP of type B was not so fast as type A(p<.05) during performed Uchi-mata, and also the bigger hip-angle of the supporting foot in the 2nd stage of KP grew, the faster the time elapsed on KP became.

Ionic currents elicited by the hypotonic solution in hamster eggs (저장성 용액에 노출된 햄스터 난자에 관찰되는 이온전류의 변화)

  • Choi, Won-yeong;Kim, Yang-mi;Haan, Jae-hee;Huh, Il-oh;Park, Choon-ok;Hong, Seong-geun;Pyu, Pan-dong;Kim, Jong-shu
    • Korean Journal of Veterinary Research
    • /
    • v.36 no.2
    • /
    • pp.305-312
    • /
    • 1996
  • Cell volume regulatory mechanisms are usually disclosed by exposure of cell to anisotonic media. If a cell is suddenly exposed to hypotonic media, it swells initially like an osmometer but within minutes regains its original cell volume. This behavior has been labelled as regulatory cell volume decrease(RVD). RVD is believed to result from the loss of permeable ions through the membrane. In this study, we examined hypotonically induced changes in the membrance currents involved in RVD by using whole cell voltage clamp technique in the unfertilized hamster egg. At -40mV of the holding potential, the stationary current was maintained in the hamster egg exposed to isotonic solution composed of, mainly, 115mM NaCl and 40mM mannitol. Hypotonic solution was prepared by removing mannitol. Therefore, the concentrations of $Na^+$ and $Cl^-$ in this hypotonic media were the same as those in the isotonic solution. Following 30 to 60 sec after applying the hypotonic media to the egg, the inward current was evoked. This inward current was eliminated by $100{\mu}M$ 4-acetamido-4'-isothiocyanostil-bene-2,2'-disulfonic acid(SITS), an anion channel blocker, leaving the small outward current component. Further addition of 2mM $Ba^{2+}$, a broad $K^+$ channel blocker, completely abolished the small outward current left even in the presence of SITS during hypotonic stress. These results suggest that $K^+$ and $Cl^-$ move out of cells, resulting in RVD. To test the involvement of $Na^+$ in RVD, 20mM Na-isethionate was substituted for mannitol in isotonic media(135mM $Na^+$) and Na-isethionate (20mM) was freed the hypotonic solution. Only $Cl^-$ concentration in both isotonic and hypotonic media was kept constant at 115mM, whereas concentration of $Na^+$ was lowered in hypotonic solution to 115mM from 135mM in isotonic solution. Hypotonic medium induced the outward current in the egg equilibrated isotonically. This current was reduced by $100{\mu}M$ SITS but was augmented by 2 mM $Ba^{2+}$. In terms of RVD, these results imply that $Cl^-$ efflux is coupled with $K^+$, maybe for electroneutrality during hypotonic stress and/or with $Na^+$ via unknown transport mechanism(s). From the overall results, the hypotonic stress facilitates the movement of $Cl^-$ and $K^+$ out of the hamster egg to regain cellular volume with electroneutrality. If there exist a difference in $[Na^+]_0$ between isotonic and hypotonic solution, another transport mechanism concerned with $Na^+$ may, at least partly, participate in regulatory volume decrease.

  • PDF

Scapular Free Flap (유리 견갑 피판 이식술)

  • Chung, Duke-Whan;Han, Chung-Soo;Yim, Chang-Moo
    • Archives of Reconstructive Microsurgery
    • /
    • v.5 no.1
    • /
    • pp.24-34
    • /
    • 1996
  • There are many kinds of free flaps for management of extensive soft tissue defect of extremities in orthopaedic field. Free vascularized scapular flap is one of the most useful and relatively easy to application. This flap has been utilize clinically from early eighties by many microsurgical pioneers. Authors performed 102 cases of this flap from 1984 to 1995. We have to consider about the surgical anatomy of the flap, technique of the donor harvesting procedures, vascular varieties and anatomical abnormalities and success rate and the weak points of the procedure. This flap nourished by cutaneous branches from circumflex scapular vessels emerges from the lateral aspect of the subscapular artery 2.5-5cm from its lateral origin passing through the triangular space(bounded by subscapularis, teres minor, teres major, long head of triceps). The terminal cutaneous branch runs posteriorly around the lateral border of the scapular and divided into two major branches, those transeverse horizontally and obliquely to the fascial plane of overlying skin of the scapular body. We can utilize these arteries for scapular and parascapular flap. The vascular pedicle ranged from 5 to 10 cm long depends on the dissection, usually two venae comitantes accompanied circumflex scapular artery and its major branches. The diameter of the circumflex scapular artery is more than 1mm in adult, rare vascular variation. Surgical techniques : The scapular flap can be dissected conveniently with prone or lateral decubitus position, prone position is more easier in my experience. There are two kinds of surgical approaches, most of the surgeon prefer elevation of the flap from its outer border towards its base which known easier and quicker, but I prefer elevation of the flap from its outer border because of the lowering the possibilities of damage to vasculature in the flap itself which runs just underneath the subcutaneous tissue of the flap and provide more quicker elevation of the flap with blunt finger dissection after secure pedicle dissection and confirmed the course from the base of the pedicle. There are minimal donor site morbidity with direct skin closure if the flap size is not so larger than 10cm width. This flap has versatility in the design of the flap shape and size, if we need more longer and larger one, we can use parascapular flap or both. Even more, the flap can be used with latissimus dorsi musculocutaneous flap and serratus anterior flap which have common vascular pedicle from subscapular artery, some instance can combined with osteocutaneous flap if we include the lateral border of the scapular bone or parts of the ribs with serratus anterior. The most important shortcoming of the scapular free flap is non sensating, there are no reasonable sensory nerves to the flap to anastomose with recipient site nerve. Results : Among our 102 cases, overall success rate was 89%, most of the causes of the failure was recipient site vascular problems such as damaged recipient arterial conditions, and there were two cases of vascular anomalies in our series. Patients ages from 3 years old to 62 years old. Six cases of combined flap with latissimus dorsi, 4 cases of osteocutaneous flap for bone reconstruction, 62 parascapular flap was performed - we prefer parascapular flap to scapular. Statistical analysis of the size of the flap has less meaningful because of the flap has great versatility in size. In the length of the pedicle depends on the recipient site condition, we can adjust the pedicle length. The longest vascular pedicle was 14 cm in length from the axillary artery to the enter point cutaneous tissue. In conclusion, scapular free flap is one of the most useful modalities to manage the large intractable soft tissue defect. It has almost constant vascular pedicle with rare anatomical variation, easy to dissect great versatility in size and shape, low donor morbidity, thin and hairless skin.

  • PDF

Percutaneous Autologous Marrow and Heterograft Bone Grafting in a Treatment for Simple Bone Cyst (경피적 자가 골수 및 이종골 이식을 이용한 고립성 골낭종의 치료)

  • Lee, Keun-Bae;Rowe, Sung-Man;Yoon, Taek-Rim;Son, Il-Jin;Jung, Sung-Taek
    • The Journal of the Korean bone and joint tumor society
    • /
    • v.9 no.1
    • /
    • pp.24-30
    • /
    • 2003
  • Purpose: To clarify the results of simple bone cyst (SBC) treatment in children by percutaneous autologous bone marrow grafting and xenografting. Materials and Methods: We studied seven cases (4 males, 3 females) of SBC, which were treated by percutaneous autologous marrow and heterograft bone grafting from January 1996 to February 1999. Their mean age at surgery was 10 years (6 to 15), and the mean follow-up period was 35.6 months (20 to 52). Three cases were located in the proximal and middle humerus; three cases were in the proximal femur; and one case occurred in the ilium. Mean volume was 14.7 $cm^2$ (10 to 23). Six cases were active, and one was inactive. Five patients had a history of receiving a mean of 3.2 steroid injections. The mean quantity of bone marrow used in treatment was 14.3 ml (10 to 20), and the mean amount of $Lubboc^{(R)}$ heterograft bone (Transphyto S.A. Clermont Ferrand, France) used was 6.4 blocks (5 to 10). Results were analyzed using the modified Neer classification. Results: Five cases completely healed with obliteration of the cyst cavity (Grade IV). Two cases demonstrated sclerosis around a partially visible cyst (Grade III). All treatment results were satisfactory and without intraoperative or postoperative complications. Conclusione: Percutaneous autologous marrow and heterograft bone grafting is recommended as an effective treatment method for simple bone cyst. It offers ease of operative technique, a high rate of healing, a low recurrence rate, low morbidity, a low incidence of postoperative complications, and free from bone graft donor site problems.

  • PDF

Development and Evaluation of a Stage Matched Exercise Intervention Program for Elders - Application of the Tran Theoretical Model - (노인 운동행위 변화단계별 중재프로그램의 개발 및 평가 - 범이론적 모형의 적용 -)

  • Kwon, Yeun-Jung
    • Research in Community and Public Health Nursing
    • /
    • v.13 no.2
    • /
    • pp.205-215
    • /
    • 2002
  • Objectives: This study was designed to develop and evaluate a stage matched exercise intervention program to effectively increase exercise behaviors in urban elders. Methods: The study included three phases: preliminary descriptive data collection, program development, and program evaluation. The data for the preliminary descriptive phase were collected between May and June 2001. The study participants were 89 urban elders who responded a questionnaire that included general characteristics, exercise related experiences, stage, and process of change in exercise behaviors. Data were analyzed using descriptive statistics, $x^2$-test, and content analysis. Development of the program was based on the preliminary data. and a literature review, and was guided by the tran theoretical model. It consisted of strategies to facilitate the process of changes used in each stage. Evaluation of the program was achieved from October to December 2001, using a case study method, in which eight urban female elders participated. Interviews were conducted on a weekly basis in the form of either an individual interview, or group discussion. Each elder subject received education in accordance with the program strategies and education materials. In the case that a subject's stage of change moved into another one, the scores for the process of change were re-measured. The data were analyzed using the content analysis technique. Results: The results were as follows: 1. Elders who participated in the preliminary data collection phase were over 75 years of age, and the majority of them were women. They had a higher educational level, and fewer number of illnesses than the subjects in other studies. Their stage of change was divided into pre-contemplation and maintenance. The social liberation scores were the highest across all stages of change. There was no difference between men and women on scores for processes of change in each stage. 2. The stage matched exercise intervention program that was developed in this study consisted of one counseling type program and three distinguished educational booklet materials. 3. The results of the case studies are as follows: 1) The study participants were 8 women between 75 and 87 years of age. At the first interviews, all of them were in the pre-contemplation stage. All of them reached the action stage before the 7th week. The scores for processes of change that were the focus in each stage increased more than the scores for other processes of change. During the early stages of change, experimental processes increased more than behavioral processes. However. this pattern was reversed during later stages of change. 2) Characteristics of the subjects in each stage were identical as presented at the tran theoretical model. The intervention strategies were effective in the transition occurred in any stage. 3) Barriers for exercise included unwillingness to exercise, fatigue, shortness of breath, and pain. Ways to overcome these barriers were 'learning an alternative exercise method that can be done at home', 'self-promising/ exercise-promising', and 'use of cues to exercise'. 4) The factors that affected the application of the program were consideration of age and personal preference in selecting an exercise pattern, individualized intervention, and use of education materials appropriate to elders. Women over 80 years of age preferred muscle strengthening and stretching exercise, because they can be easily done at home. They also preferred individualized interventions, materials that were easy to read, and education contents appropriate for elders. Conclusion: In conclusion, the stage matched exercise intervention program that considered the characteristics of the elders was effective to facilitate exercise behaviors of the elders.

  • PDF

Geochemistry of Total Gaseous Mercury in Nan-Ji-Do, Seoul, Korea (난지도 지역의 대기수은 지화학)

  • Kim, Min-Young;Lee, Gang-Woong;Shin, Jae-Young;Kim, Ki-Hyun
    • Journal of the Korean earth science society
    • /
    • v.21 no.5
    • /
    • pp.611-622
    • /
    • 2000
  • To investigate the exchange rates of mercury(Hg) across soil-air boundary, we undertook the measurements of Hg flux using gradient technique from a major waste reclamation site, Nan-Ji-Do. Based on these measurement data, we attempted to provide insights into various aspects of Hg exchange in a strongly polluted soil environment. According to our analysis, the study site turned out to be not only a major emission source area but also a major sink area. When these data were compared on hourly basis over a full day scale, large fluxes of emission and deposition centered on daytime periods relative to nighttime periods. However, when comparison of frequency with which emission or deposition occurs was made, there emerged a very contrasting pattern. While emission was dominant during nighttime periods, deposition was most favored during daytime periods. When similar comparison was made as a function of wind direction, it was noticed that there may be a major Hg source at easterly direction to bring out significant deposition of Hg in the study area. To account for the environmental conditions controlling the vertical direction of Hg exchange, we compared environmental conditions for both the whole data group and those observed from the wind direction of strong deposition events. Results of this analysis indicated that the concentrations of pollutant species varied sensitively enough to reflect the environmental conditions for each direction of exchange. When correlation analysis was applied to our data, results indicated that windspeed and ozone concentrations best reflected changes in the magnitudes of emission/deposition fluxes. The results of factor analysis also indicated the possibility that Hg emission of study area is temperature-driven process, while that of deposition is affected by a mixed effects of various factors including temperature, ozone, and non-methane HCs. If the computed emission rate is extrapolated to the whole study area we estimate that annual emission of Hg from the study area can amount to approximately 6kg.

  • PDF

Early and mid-term results of pulmonary valve reconstruction in surgical repair of tetralogy of Fallot; comparison with other techniques of right ventricular outflow reconstruction (활로사징 완전교정술에서 폐동맥 판막 재건술의 조기 및 중기 결과; 우심실 유출로 재건 방법에 따른 비교)

  • Wang, Sheng Wen;Lee, Young Seok;Kim, Si Ho;Kim, Tae Hong;Ban, Ji Eun;Lee, Hyoung Doo;Chang, Yun Hee;Sung, Si Chan
    • Clinical and Experimental Pediatrics
    • /
    • v.49 no.6
    • /
    • pp.635-642
    • /
    • 2006
  • Purpose : The purpose of this study is to determine whether the new pulmonary valve reconstruction technique prevents short-term postoperative pulmonary regurgitation and improves early and mid-term clinical outcome. Methods : We reviewed postoperative echocardiographic variables and chest X-ray films from 31 patients who had undergone valve reconstruction(pulmonary valve reconstruction group : PVR) for the repair of TOF between April 2000 and August 2004. We compared the clinical data of these patients with those from 47 patients who had right ventricular outflow tract reconstruction with a monocusp valve(monocusp ventricular outflow patch group : MVOP) and 22 patients who had a transannular patch repair without a monocusp valve(transannular patch group : TAP). Results : In the PVR group, 25 patients(81 percent) had trivial or mild pulmonary regurgitation in their early post operative echocardiogram. Only 12 patients(26 percent) in the MVOP group had mild pulmonary regurgitation; and no patient in the TAP group had it. Pulmonary valve function was good in 96 percent of the PVR group, 36 percent of the MVOP group, and none in the TAP group in early post-operative echocardiogram. Follow-up echocardiogram(1, 2, 3, 4 years later) of the MVOP and TAP groups showed moderate pulmonary regurgitation and severely decreased valve function in almost all cases. However, in the PVR group 54 percent(16/28), 50 percent(14/28), 37 percent(9/24), and 31 percent(5/16) of the patients had trivial or mild pulmonary regurgitation 1, 2, 3 and 4 years after operation, respectively. The valve function remained good in 80 percent(24/30), 64 percent(18/28), 57 percent(12/21), and 31 percent(5/16) of the patients 1, 2, 3 and 4 years after operation respectively. Conclusion : Pulmonary valve reconstruction is effective in reducing pulmonary regurgitation and right ventricular dilatation in the repair of TOF, even though regurgitation increases with time. Further study is needed to determine long-term results.

Effects of $\textrm{NO}_3$-N:$\textrm{NH}_4$-N Ratio and Elevated $\textrm{CO}_2$ on Growth and Quality of Lactuca sativa L. in Nutrient Film Technique (NFT재배에서 $\textrm{CO}_2$ 시용과 배양액의 $\textrm{NO}_3$:$\textrm{NH}_4$비율이 결구상추의 생육 및 품질에 미치는 영향)

  • 원선이;조영렬;이용범
    • Journal of Bio-Environment Control
    • /
    • v.5 no.2
    • /
    • pp.120-130
    • /
    • 1996
  • Crisphead lettuce(Lactuca sativa L.) was grown in NFT to investigate the effects of NO$_3$-N and NH$_4$-N ratio in nutrient solution and elevated $CO_2$ treatment in the crisphead lettuce growth. This experiment has been conducted under three different ratios of NO$_3$-N:NH$_4$-N(100:0, 75:25, 50:50) with two $CO_2$ concentration (control, 1500ppm ). The results are as follows; 1. In the case of not controlling pH and EC in nutrient solution, pH was gradually increased in NO$_3$-N:NH$_4$-N=100:0 treatment but rapidly decreased in the nutrient solution 2. Daily changes of NO$_3$-N and NH$_4$-N were observed without controlling the nutrient solution. In the treatments of NO$_3$-N:NH$_4$-N ratios were 75:25 and 50:50, NO$_3$-N absorption rates were 27.7% and 26.1%, while NH$_4$-N absorption rates were 87.9% and 71.2%, respectively. 3. There was little differences in total nitrogen of leaves. However phosphorus, potassium, calcium and magnesium contents were highly shown in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. 4. Higher $CO_2$ assimilation rate was shown in plants grown under $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. It dropped significantly with the increase of NH$_4$- N rates in nutrient solution. 5. Fresh weight, leaf number, root length and root weight of crisphead lettuce were far better in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. Growth differences by $CO_2$ elevation were not shown in other NO$_3$-N:NH$_4$-N treatments. 6. The highest nitrate contents of leaves were shown in NO$_3$-N single treatment but shown the lowest vitamin C contents. Nitrate contents of leaves were decreased by $CO_2$ but the effect was slight treatment.

  • PDF