공기중에 존재하는 여러 산화성 물질들은 호흡기의 손상과 관련이 있는 것으로 알려지고 있으며 이와같은 산화성 물질에 의한 손상은 폐에 존재하는 항산화 물질이나 항산화 효소들에 의해 감소 또는 예방될 수 있다. 저자들은 폐의 항산화방어 기전에 대한 흡연의 영향을 흰쥐에서 관찰하였다. 횐쥐를 6개피의 담배연기에 일일 20분씩 90일간 전신 폭로했을때 조직내의 catalase와 superoxlde dismutase(SOD)의 활성이 유의하게 증가되었다(p<0.05) 그러나 glutathione peroxidase의 활성도는 변화되지 않았고 thiol 화합물의 함량은 흡연 시작후 15일에 44%까지 감소되었으나 그후 정상으로 회복되었다. 한편, 횐쥐를 1, 3, 5, 10 및 20개피의 담배연기에 같은 방법으로 15일간 노출시켰을때, catalase는 개피수에 따라서 증가되었고 총 SOD의 활성도는 5개피 이하에서만 특이하게 증가되었으며 대부분 Zn-SOD이었다. 폐에는 한 종의 Cu, Zn-SOD (pI 4.9)와 CN에 내성이 있는 두종의 Mn-SOD(pI 4.7, pI 7.9)가 존재하였고, 등전점이 4.7인 Zn-SOD가 주된 동위효소로써 흡연에 의해 유도되는 형태였다. 이 결과들은 흡연으로부터 폐의 보호는 초기에는 항산화 물질들의 소모로, 그리고 만성 흡연의 경우는 항산화 효소들의 유도로 이루어지며. 특히 Zn-SOD (pI 4.7)와 catalase가 중요한 역할을 하는 것으로 사료된다.

The severities of major tobacco diseases had been surveyed throughout northern Kyeongbuk, a major flue-cured tobacco growing district in Korea, in relation to the actual control method used by the farmers in 1992. At seedling stage, anthracnose caused by Colletotrichum nicotianae was major disease of the plant due to poor damage of the temporary transplanting pots. Mosaic caused by tobacco mosaic virus(TMV) was very severe in certain of greenhouses. Although viral disease caused by TMV, cucumber mosaic virus(CMV) and by potato virus Y(PVY) were severe in fields, but mosaic by TMV was major of the diseases. Potato virus Y was found later than that in Honam district. The late occurrence of the disease might be caused the difference between cultivating method of potato plants in northern Kyeongbuk and that in Honam district. In fields suffered from hail disaster, the damage of tobacco plants by angular leaf spot was severe. Most of tobacco growers had wrong information about the practical methods not only of milk treatment for the protection of the plants from TMV, but also of fungicide applications for the control of other major diseases. It suggested that education on the methods to the farmers must be very important for control of the diseases.

Effect of an avirulent bacteriocin-producing strain(ABPS) of Pseudomonas solanacearum adapted to low temperature on the control of tobacco bacterial wilt was examined under the natural field conditions. The ABPS of p. solanacearum were succeeding-cultured at gradually low temperature, 3$0^{\circ}C$ to 13$^{\circ}C$. The isolates adapted to low temperature grew faster than the wild type either in artificial media or on the tobacco rhizoplane. The control effect of one of the isolates on bacterial wilt was higher than that of the wild type when the bacterial suspension had been poured onto the tobacco rhizosphere soil on 1 day before and 15 days after transplanting to the field. It was suggested that ABPS of p. solanaceamm adapted to the low temperature, might be more effective biological control agent than the wild type.

This experiment were conducted to investigate heterosis and combining ability for several mutant characters by analyzing dialled crosses of flue-cured tobacco. In a dialled cross of 3 flue-cured varieties and the mutant line 83H -5, the heterosis was somewhat higher in Fl than in F2. For growth character, the heterosis was 0.28-6.03% in plant height, leaf number, leaf shape index and yield, and was 43.2% for bacterial wilt disease index. The mutant line 83H-5 showed significantly negative GCA effect for plant height, leaf width and bacterial wilt disease index in Fl and F2, leaf length in F2, and positive GCA effect for total alkaloids, total nitrogen in Fl and days to flower in F2, respectively. Specific combining ability(SCA) in 83H-5 x Hicks was significant in negative effect for leaf length(F2), number of leaves(F2), leaf shape(F1, F2), bacterial wilt(F2) and alkaloids(F1), and in 83H-5 x NC 2326 in positive effect for leaf length(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in positive effect for plant height(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in Positive effect for Plant height(F1, F2), leaf length(F2) and yield(F1, F2).

Nitric oxide of gas phase in cigarette smoke was conveniently determined by Chemiluminescence NO analyzer with 20 ports rotary type smoking machine Data are presented to support this observation. On the basis of this method the amount of NO in the smoke from nonblended and commercial cigarettes were estimated. Gas phase NO concentration in main stream smoke was correlated well with the nitrate levels in tobacco leaves, but there was no correlation with the tar yields. In consequence, it would be considered that the methodology in this study provided simple and rapid quantification for NO in cigarette smoke.

Ridger and vinyl mulcher for 8-10 PS power tiller which were distributed at the rate of one out of 2.3 farm households in Korea, was developed to ease the labor shortage of tobacco production. Devices wheel shaft extension by 30cm at both sides improved the stability of straight drive and enabled to save required labor hours by 50% for ridging at sloping field. Screw type blades were attached on center drive rotavator shaft, gear set was deviled to reverse the rotavator, and it was good at need to adjust the width and height for ridge. As the results, required labor hours for ridging and vinyl mulching could be saved by 90% as compared to conventional manual method after cattle plowing, and by 50% as compared to conventional power tiller method.

Changes in the amount of ribulose 1, 5-bisphosphate carboxylase/oygenase(=RuBisCO) protein, namely fraction I protein, and the protease activity were determined in the 10th leaf of tobacco(Nicotiana tabacum, var. Ky-57) from 10 days after emergence through senescence at 5 days interval. The amount of RuBisCO per deveined leaf rapidly increased during the early growing season, reached a maximal quantity at the around 20 days after leaf emergence, when the leaf has gone through its most rapid expansion, and began gradually to decrease till 30 days after leaf emergence, thereafter significantly declined to 45 days that the leaf has been dried up partly. The pattern of the ratio of RuBisCO protein to soluble protein in quantity changed similar to that of RuBisCO contents in a leaf, that was 43%, 60%, and 21% at the around 10 days, 20 days, and 45 days, respectively. And RuBisCO contents was linearly correlated with the concentration of chlorophyll(r=0.98) throughout the life span of the leaf. So, it was assumed that the leaf color can be a useful indicator for judging whether RuBisCO contents higher or not in tobacco leaves without homogenization. On the other hand, the protease activities for degradation of casein were assayed at pH 5.5. 7.0. and 8.5 with crude extracts desalted on Sephadex G-25. The highest caseolytic activity was found at pH 5.5 throughout the life sawn of the leaf. Also, the activity at 5.5 became gradually to increase from 30 days after leaf emergence, when RuBisCO protein had became to disappear and remarkably increased in the last stage of senescence, although nitrogen contents of the leaf had reached low levels. The caseolytic activity at pH 5.5 was in negative correlation with RuBisCO contents throughout the life span of the leaf, but not in lineality between them. In other words, the caseolytic activity increased in a rapid exponential manner when RuBisCO contents had reached some low levels. These results showed that the leaf age, namely harvesting time, is a very important factor for the production of the tobacco leaf containing higher RuBisCO protein. It was concluded that the practical harvesting time is between 20 days and 30 days after the leaf emergence from the present results.

Effect of the amount of fertilizer, plant density, and harvesting time on the production of tobacco leaf protein and fresh biomass was investigated. Flue-cured tobacco(M tabacum, L., cv. NC 82) seedlings were transplanted in the field dressed 200kg N per ha at 1$\times$105, 3$\times$105, 5$\times$105, 7$\times$105 plants per ha, and were harvested at the time when 6 and 10 weeks after transplanting, respectively. Harvest at 10 weeks after transplanting increased greatly number of leaves per plant and fresh weight of a plant, Precentage of senescent leaf weight, but significantly decreased fresh weight of a leaf and total protein contents g-1 fresh weight of leaf and stalk over the amount obtained from the harvest at 6 weeks after transplanting. Also, fresh leaf numbers of a plant, fresh weight of a leaf and of a plant, and total protein contents g-1 fresh weight of biomass were more decreased, but percentage of senescent leaf weight were remarkably increased under higher plant density. Therefore, it was seemed that harvesting at 6 weeks after transplanting under 1$\times$105 plant density per ha is more effective for producing higher yield of biomass and protein per plant than 10 weeks harvesting with 7$\times$105 population per ha. A trend was observed that biomass and protein yields per ha are positively correlated with plant population. Biomass yield per ha was the greatest at 7$\times$105 density(80.5t), but the peak of protein yield was at the near of 5$\times$105 population(2454kg as total protein) per ha on the regression curve. It was assumed that if tobacco plants are transplanted under 5$\times$105 plant density at the mid of May, and thereafter harvest at 6 weeks repeatedly during the growing season, it is possible to harvest 2~3 times per year, and to yield more 6.024kg of protein and over 140me1ric tons of fresh biomass ha 1 year 1 statistically in the korea tobacco growing regions.

1. Average moisture content of tobacco in BIB silo was about 19: 1% until 4hours conditioned time, and then moisture variation of tobacco after 2hr conditioned was very small. 2. Application of mathematical model for ordering system. 1) The constant K in the exponential equation varies inversely with both relative humidity and equilibrium moisture. 2) Time needed to order blending tobacco leaves with standard moisture from bulking and blending silo was 4 hours. 3) Reconstituted tobacco sheet had higher moisture absorption ratio than Oriental and Burley tobacco. 4) For minimize of conditioning time in BIB silo, the values of K and Mo given in this study can be used in equation(1) to calculate moisture absorption ratio and optimum conditioning time. 3. Average moisture content and water activity of conditioned tobacco for 4 hours in BIB silo was about 20% and 0.65. In this condition. microbial life will inhibite 4. Physical properties of conditioned tobacco in bulking and blending silo for 4hours was virtually no change.

The chemical components of tobacco stalk, stems of tobacco caltivations, were analyzed and reconstituted tobacco sheet were made from the stalk and tobacco hyproducts by rolled and paper reconstitute tobacco sheet making process. The results were summarized as follow 1. In the viewpoint of chemical components, nicotine, total nitrogen and ash content of stalk were lower than those of stems, but crude fiber was two times higher than stems. 2. Reconstituted tobacco sheet of tobacco stalk blended were improved fragility and specific gravity than those of control. 3. Smoke components delivery of cigarette made from reconstituted tobacco sheet of tobacco stalk blended were similar to control cigarette. 4. According to the result of ranking preference test for control and sample cigarette, were not recognized significant at 5 percent level. 5. According to the result of areas test for control and sample cigarette, were not recognized significant at 5 percent level. 6. Optimum stalk blend ratio of reconstituted tobacco sheet manufacturing was from about 20 to 40% to the rolled sheet, and was from about 5 to 10% to the paper making process tobacco sheet.