The effects of elevated atmospheric CO2 on growth and photosynthesis of soybean (Glycine max Merr.) were investigated to predict its productivity under elevated CO2 levels in the future. Soybean grown for 6 weeks showed significant increase in vegetative growth, based on plant height, leaf characteristics (area, length, and width), and the SPAD-502 chlorophyll meter value (SPAD value) under elevated CO2 conditions (800 μmol/mol) compared to ambient CO2 conditions (400 μmol/mol). Under elevated CO2 conditions, the photosynthetic rate (A) increased although photosystem II (PS II) photochemical activity (Fv/Fm) decreased. The maximum photosynthetic rate (Amax) was higher under elevated CO2 conditions than under ambient CO2 conditions, whereas the maximum electron transport rate (Jmax) was lower under elevated CO2 conditions compared to ambient CO2 conditions. The optimal temperature for photosynthesis shifted significantly by approximately 3°C under the elevated CO2 conditions. With the increase in temperature, the photosynthetic rate increased below the optimal temperature (approximately 30°C) and decreased above the optimal temperature, whereas the dark respiration rate (Rd) increased continuously regardless of the optimal temperature. The difference in photosynthetic rate between ambient and elevated CO2 conditions was greatest near the optimal temperature. These results indicate that future increases in CO2 will increase productivity by increasing the photosynthetic rate, although it may cause damage to the PS II reaction center as suggested by decreases in Fv/Fm, in soybean.

Background : Management of air temperature are known to primarily affecting on physiological properties and yield in plant. Methods and Results : The effect of air temperature on characteristics of photosynthesis and chlorophyll fluorescence in Cnidium officinal were investigated using growth chamber after cultivating for 24 hours under controlled condition. Net photosyntheis rate, transpiration was measured at 1,000 μmol m-2 s-1 of photon flux density and chlorophyll fluorescence was analyzed by OJIP method. Net photosyntheis rate was highest in treatment of 25℃. Although transpiration rate was lowest, water use efficience was also in treatment of 25℃. Stomatal conductance was mainly influenced from ambient climatric factors such as vapor pressure deficit. As results of chlorophyll fluorescence by OJIP analysis, maximum quantum yield (Fv/Fm) of photosystem II (PSII), PIabs and the relative activities per reaction center such as ABS/RC, DIo/RC were not changed at air temperature. Therefore, elevated air temperatue during short term influence the dark reaction in photosystem through controlling a water use efficience and transpiration. Conclusion : This result show that 25℃ of air temperature may be a adequate temperature to improving the efficiency of photosynthesis in Cnidium officinale.

Grape cultivar “Campbell Early” account for 70% of table grape in Korea and Leaf Spot Disease caused by Pseudocercospora vitis is one of a major disease in greenhouse and field grown area during late summer season in both of organic and conventional grape farm. Leaf spot disease can cause lowing of sugar content in fruit and vine growth and very difficult to control especially in organic field. Photosynthesis ability and chemical components are compared between leaf spot disease infected leaves with degree of necrotic area. With increase of disease necrotic area, CO2 differential value, water use efficiency and CO2 assimilation and respiration ratio are decreased proportionally and on the other hand, stomatal conductance value is not affected by disease necrotic area. Chlorophyll contents are also decreased by 50% in heavily infected leaves and imply decrease of chlorophyll contents is a major source of photosynthesis ability decline. With increase of disease necrotic area in leaves, total nitrogen and phosphate contents are decreased and on the other side, total carbon, potassium, calcium and magnesium contents are increased. From this research, we can infer that not only chemical control program is important in control of leaf spot disease but also fertilizing program is significant especially in organic agronomical control of fungal disease in grape cultivar “Campbell Early”.

Background : Recently, some of the previous stuies reported that was useful technique on growth and yield of organically grown ginseng transplantation in a rain shelter greenhouse. This study was conducted to investigate the optimum method of greenhouse shading for ginseng(Panax ginseng C. A. Meyer) cultivaton in the northern area of Ganwon, Korea. Methods and Results : We carried out to select optimal shade materials and light-penetrated ratio among polyethylene film with two-layered polyethylene net(PEF+PEN) and blue-white duplicated PE film(BWD-PEF) in the condition of greenhouse for ginseng cultivation. The order of light-penentrated ratio by shade meterials was PEN(75%)+PEF 〉 PEN(85%)+PEF 〉BWD-PEF(85%) 〉BWD-PEF(90%) and the order of air temperature was BWD-PEF(85%) 〉BWD-PEF(90%) 〉PEN+PEF(85%) 〉PEN+PEF(75%). The net photosynthetic rate was higher in PEN(75%)+PEF than other shading material treatments during growth season including summer high-temperature period. The root weight and yield were increased by 31.2~55.0% and 25.6~52.2%, respectively under PEN+PEF(75%) compared to other shading materials. Conclusion : We concluded that the PEN+PEF(75%) could be a good shading meterails of the greenhouse for organic 4-year-old ginseng cultivation in northern area of Gangwon, Korea.

Plant biomass, photosystem II (PSII) photochemical activity, photosynthetic function, and zinc (Zn) accumulation were investigated in a sorghum-sudangrass hybrid (Sorghum bicolor × S. sudanense) exposed to various Zn concentrations to determine the elimination capacity of Zn from soils. Plant growth and biomass of the sorghum-sudangrass hybrid decreased with increasing Zn concentration. Symptoms of Zn toxicity, i.e., withering and discoloration of old leaves, were found at Zn concentrations over 800 ppm. PSII photochemical activity, as indicated by the values of Fv/Fm and Fv/Fo, decreased significantly three days after exposure to Zn concentrations of 800 ppm or more. Photosynthetic CO2 fixation rate (A) was high between Zn concentrations of 100-200 ppm (22.5 μmol CO2･m –2･s –1), but it declined as Zn concentration increased. At Zn concentrations of 800 and 1600 ppm, A was 14.1 and 1.8 μmol CO2･m –2･s –1, respectively. The patterns of stomatal conductance (gs), transpiration rate (E), and water use efficiency (WUE) were all similar to that of photosynthetic CO2 fixation rate, except for dark respiration (Rd), which showed an opposite pattern. Zn was accumulated in both above- and below-ground parts of plants, but was more in the below-ground parts. Magnesium (Mg) and iron (Fe) concentrations were significantly low in the leaves of plants, and symptoms of Mg or Fe deficiency, such as a decrease in the SPAD value, were found when plants were treated with Zn concentrations above 800 ppm. These results suggest that the sorghum-sudangrass hybrid is able to accumulate Zn to high level in plant body and eliminate it with its rapid growth and high biomass yield.

This study was conducted to elucidate the photosynthetic response to the environment and establish optimum cultivation conditions for the Korean endemic plant, Aster koraiensis. Photosynthetic characteristics according to growth stage, light, CO2, and soil water potential were investigated. During the first year of transplanting, photosynthetic rates were drastically increased until June, after which they slowly declined, During the second year, photosynthetic rates declined throughout the entire growth period. The highest level of light compensation point was shown the early growth stage. Photosynthetic rates affected by intercellular CO2 concentration were maintained or decreased over the CO2 saturation point. The lowest CO2 compensation point was 16.1 μmol･mol -1 during March. The morphological changes of leaves were observed due to shading with chlorophyll contents increasing. Photosynthetic rates were higher at 0% and 50% shading treatments than at 75%. There were rarely any morphological changes of leaves due to soil moisture, however, changes to leaf compactness were observed. Photosynthetic rate, apparent quantum yield, and respiration rate increased, whereas water use efficiency decreased over -25 kPa of soil moisture.

Background : In recent years, as the ginseng cultivation area using vinyl house is increasing, the demand of farmhouses for the studies of appropriate direct seeding cultivation and ginseng varieties for vinyl house cultivation is increasing, and there is a necessity to produce high quality clean ginseng in vinyl house in tandem with the consumers’ demand for pesticide-free ginseng and the supply-demand of ginseng seedling for sprout ginseng. Thus, the authors of this study analyzed the change of photosynthetic properties according to the cropping pattern and varieties with the aim to use the results of this study as the primary date for improving the quality of ginseng cultivated in vinyl house. Methods and Results : The authors analyzed the change of photosynthetic properties for the 3-year old ginseng cultivated through direct seeding according to the ginseng field levee height (10, 20, 30cm) and width (90, 100, 110, 120cm). The results suggested that with an increase in light intensity, the photosynthesis tends to increase regardless of levee height and width. When the levee width was 90cm, the photosynthesis increased as the levee height was reduced and it increased as the levee height increased when the levee width was 100cm. The photosynthesis was high when the levee height was 20cm for the levee width of 110cm and 120cm. The photosynthesis was analyzed for 11 varieties of 3-year old ginseng cultivated through direct seeding. The results suggested that the photosynthesis tends to increase as the light intensity increased in all 11 varieties, and the photosynthesis was the highest at 500PAR(ray source: 3.23umolCO2m-2s-1㎛ol) in the order of Cheonpoong, Yeonpoong, Cheongson and Sonwoon. Conclusion : The results of this study suggested that the photosynthesis according to the direct seeding cultivation in vinyl house increased as the levee height decreased for the levee width of 90cm and it was high when the levee height was 20cm for the levee width of 120cm. For the ginseng variety, Sonwon and Cheonpoong showed the highest photosynthesis.

Background : The research is designed to investigate the optimal cultivation technology and the growth of above-ground and below-ground sections as well as the photosynthetic characteristics for new ginseng variety “K-1” by differentiating the planting density under the conditions of transplanting and direct seedling. Methods and Results : The K-1 variety and hybrid variety (Jakyungjong) were selected for the research and the ginseng varieties were transplanted and directly sown in Yeoncheon area in 2013. The transplanting was made in the form of 5 lines × 9 rows (45 plants), 6 lines x 9 rows (54 plants), 7 lines × 9 rows (63 plants) and 8 lines × 9 rows (72 plants) in each lot (1.65㎡) while the direct seedling for testing was conducted three times in randomly blocked design in the form of 11 lines × 14 rows (154 plants), 12 lines × 14 rows (168 plants), 13 lines × 14 rows (182 plants). Various measures were collected from the 4-year transplanted ginseng and 3-year direct seedling ginseng in 2015 to find out the growth features and photosynthesis of above-ground section (rate of germination, leaf length, leaf width, stem length and leaf area index (LAI)) and the below-ground section (length, diameter, weight and class of roots). Conclusion : After the planting of the ginseng, the germination rate of K-1 for the transplanting was 85.1 ~ 92.0% across different plantation densities while that for the direct seedling was 67.7% ~ 77.9% across plantation densities, thus showing no significant difference between the two planting methods. LAI was higher for the higher planation density for both transplanting and direct seedling. As for the photosynthesis speed, the form of 6 lines × 9 rows showed the higher speed in transplanting while the form of 12 lines x 14 rows showed the higher speed in direct seedling. The photosynthesis of K-1 was higher than that of Jakyungjong. In the 4-year ginseng cultivated under the transplanting, diameter of roots, number of branch roots and weight of raw ginseng were the highest in the plantation density of 5 lines × 9 rows. The distribution of root weight was high with 23.3% and 20.0% for the 51~70g group and the 71g or above group, respectively, for the 4 year transplanted plants in the form of 5 lines × 9 rows. The growth for above-ground and below-ground sections for K-1 was better than that for Jakyungjong. As a result, it was found that the proper plantation density for the 4-year root in the transplanted K-1 was 5 lines × 9 rows considering the growth of the above-ground section, quantity and distribution of root weight.

Background : The ginseng cool-season and semi-shade plant undergoes photosynthesis smoothly at low temperature in the morning but its efficiency falls at high temperature in the afternoon. Therefore, if it is possible to control light transmission rates (LTR) every day, it will be able to draw an ideal result in the ginseng growth by attracting a lot of lights before 11am and attracting few lights after 11am which is the affect point of the photosynthetic efficiency. Methods and Results : While installing the sun shading facility that could control the light environment based on 11am and surveying the ginseng's growth and photosynthetic characteristics. The photosynthetic efficiency increased 2.81 times compared to conventional practices without the change of the chlorophyll content although LTR was high because of the low temperature in the morning. The aboveground part growth of the ginseng which adapted to the light environment increased to influence the root weight, when the ginseng was 4 years old, the fresh root weight was averagely 33.3g per plant which increased by 81% than 18.4g of conventional practices. Conclusion : If the light environment management according with the photosynthetic nature of the ginseng is conducted based on 11am, it will be possible to produce a large capacity and excellent-quality ginseng.

Background : Management of air temperature are known to primarily affecting on physiological properties and yield in plant. Methods and Results : The effect of air temperature on characteristics of photosynthesis and chlorophyll fluorescence in Schisandra chinensis Baillon were investigated under controlled temperature using growth chamber. Net photosyntheis rate, transpiration was measured at 1,000 μmol m-2 s-1 of photon flux density and chlorophyll fluorescence was analyzed by OJIP method. Net photosyntheis rate and transpiration rate was higher in treatment of 25℃. As results of chlorophyll fluorescence by OJIP analysis, maximum quantum yield (Fv/Fm) of photosystem II (PSII) and PIabs was higher in treatment of 25℃ which reflects the relative reduction state of PSII. But in treatment of 35℃ the relative activities per reaction center such as ABS/RC, DIo/RC were higher than in treatment of 25℃ which implied that the relative reduction of electron transport at PSI and increasement of photo inhibition at reaction center. Conclusion : This result implies that 25℃ of air temperature may be a adequate temperature to improving the efficiency of photosynthesis through controlling a photosystem in Schisandra chinensis Baillon.

Salvia miltiorrhiza has been used for treating heart and liver disease. In the present study, the influences of temperature on photosynthetical capacity of S. miltiorrhiza under controlled cultivation environment using growth chamber were investigated because of providing information about growth and secondary metabolite synthesis. And effect of harvesting time on growth properties and constituents such as salvianolic acid B, cryptotanshinone, tanshinone I, tanshinone IIA were evaluated. Maximum photosynthesis rate (5.102 μmol CO2/m2/s) and net apparent quantum yield (0.147 μmol CO2/m2/s), stomatal conductance (0.035 mmol/m2/s) and water use efficiency (7.108 μmol CO2/mmol H2O) was highest at 20℃. Results of chlorophyll fluorescence showed that elevated temperature had contributed to reduce a quantum yield and electron flux in photosystem. This result demonstrated that favorable temperature condition was determined at 20℃. Contents of salvianolic acid B, cryptotanshinone, tanshinone I and tanshinone IIA was highest in root sample harvested at 20 March, whereas growth and yield of S. miltiorrhiza had no significant differences with harvesting time. Therefore, this study shows that temperature play an important role in photosynthetic activity and harvesting time have influence upon accumulation of constituents in root of S. miltiorrhiza.

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature (27℃±4℃) treated both rice cultivars were decreased than those of control temperature (22℃±4℃) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

This study was carried out to determine the effects of light controls and leaf mold on root growth and physiological responses of Atractylodes japonica growing in forest farming. The experiment was performed by light controls (100%, 62.5%, 40.3% and 19.7% of full sunlight) and application of leaf mold to soil. Height, stem diameter, number of flower buds and root collar diameter were the highest in leaf mold within 62.5% of full sunlight (relative light intensity 62.5%). And these were the higher in leaf mold within each light level. As the shading level increased, light saturation point and maximum photosynthesis rate decreased. As the light level decreased, SPAD value increased in control and leaf mold. As a result of surveying the whole experiment, A. japonica was judged worse root growth under the lower light level. It was concluded that the light level was one of the most important factors to produce A. japonica. Also, producing high-quality of A. japonica with the price competitiveness by using leaf mold like the experiment can be an effective way to increase incomes for farmers.

This study was carried out in order to investigate the photosynthesis response and leaf characteristics of Peucedanum japonicum growing in forest farming. The experiment was performed by leaf mold (pine tree and chestnut tree) and shading levels (0%, 35%, 50% and 75% shading). Light relative intensity was 100% (full sunlight), 60.3% (35% shading), 35.1% (50% shading), and 17.4% (75% shading) respectively. Light response curves of pine-leaf mold and chestnut-leaf mold were the highest in control (full sunlight) and these were getting lower in the higher shading level. Photosynthesis capacity and light saturation point were indicated higher in chestnut-leaf mold within the same shading level. As the shading level increased, maximum photosynthesis rate decreased. And apparent quantum yield was not indicated statistically significant difference from all treatment. Leaf area, leaf length and leaf width were significant higher in 35% shading and control under chestnut-leaf mold in all treatment. As the shading level increased, LAR (leaf area ratio), SLA (specific leaf area) and SPAD value decreased in pine-leaf mold and chestnut-leaf mold. As a result of surveying the whole experiment, P. japonicum is judged better growth and higher yield by maintaining 35% shading (relative light intensity 60%) under chestnut-leaf mold in forest farming.

‘Hwasu 3551’(HS) 과 ‘White-Red Lip’(WR)을 대상으로 저 온이 호접란의 생육단계별 광합성에 미치는 영향을 알아보았다. 실 험에 사용하기 위해 조직배양을 통해 번식된 유묘들을 4주간 외부 환경에 순화시킨 후(1개월 묘), 28/26oC(HT)의 식물생육상에서 재배하였다. HT에서 0(1개월 묘), 2(3개월 묘), 4 개월(5개월 묘) 간 재배된 식물들을 21/19oC(LT)의 식물생육상으로 옮겨 3개월 간 저온처리 하였고, 각 식물생육상의 일장은 12시간(06시.18시), 광도는 110±10μmol·m-2·s-1 PPF를 유지하였다. 저온의 영향을 알 아보기 위해서 각 온도 및 생육단계별로 영양생장과 24시간 동안의 CO2흡수율을 측정하였다. 전반적으로 호접란의 광합성은 CO2흡 수 양상에 따라 페이즈 I부터 IV까지 나뉘어지는 전형적인 CAM 광합성을 보였으며, 3개월간 저온에서 재배 후 하루 동안 흡수한 총 CO2의 양과 영양생장의 증가정도는 HT 조건을 유지한 처리군에 비해 감소하였다. 특히 3개월 묘를 LT에서 3개월간 재배하였을 떄, HS, WR 두 품종의 페이즈 III 동안 CO2흡수율은 각각 -1.36, -0.60μmol·m-2·s-1까지 감소하여 CO2누출 (CO2 leakage)양상을 보였다. 이로 인해 낮 동안의 총 CO2흡수량이 감소하였고, 영양 생 장량 역시 감소하였다. 1개월 묘를 LT조건에서 재배하였을 때 신 엽의 발생은 통계적으로 유의성 있게 감소하였지만, 5개월 묘의 경 우에는 감소하지 않았고, 단지 엽장의 증가정도만 감소하였다. 이 러한 결과는 5개월 묘에서 저온의 영향이 작았고, 영양생장이 계속 유지되었다는 것을 나타낸다. 호접란의 재배에 있어서 이러한 접근 방식은 재배 스케줄을 조절하거나 기존의 방법을 개선하여 재배비 용을 절감하는 대에 도움이 될 수 있을 것이다.

국제적으로 지구온난화와 화석연류 고갈이라는 두 가지 이슈에 대한 관심이 증대되고 있다. 이에 따라 에너지원 다양화 및 대체 에너지 개발이 부각되면서 신･재생에너지에 관한 연구가 활발히 이루어지고 있다. 우리나라는 2015년까지 총 1차 에너지원의 4.3%, 2020년까지 6.1%, 2030년까지 11.0%를 신･재생에너지 공급을 목표로 하는 국가에너지 기본계획을 수립하고, 이에 따른 기술의 개발 및 산업육성에 주력하고 있다. 기후변화에 관한 국제 연합 기본 협약(UNFCCC; The United Nations Framework Convention Change)의 발표에 의하면 우리나라는 세계 10위의 온실가스 배출국으로서 수년이내에 온실가스 감축의무대상국으로 지정될 것이다. 따라서 친환경 청정에너지 보급을 보다 적극적으로 시행해야 한다. 신･재생에너지로는 태양광, 풍력, 수소연류전지, IGCC(석탄가스화 복합발전), 바이오디젤 등이 있다. 이중 바이오디젤은 동･식물성 유지(대두유, 유채유, 폐식용유, 우지 등)를 이용하여 생산하지만 농지면적과 식량에 대한 윤리적인 문제가 대두되고 있다. 미세조류는 앞에서 언급한 문제가 없으며 신･재생에너지로써의 바이오디젤 뿐만 아니라 산업적으로 건강식품, 화장품, 물고기 먹이 등으로 이용되며 탄소고정이라는 환경적인 면에서도 매력적인 유기자원이다. 조류는 태양에너지를 이용하여 이산화탄소(CO2)와 물(H2O)을 합성하여 다양한 생성물을 형성하는 미생물로써 조류의 자기균체 중 지질은 중량 대비 60% 이상을 생산하며, 이는 바이오디젤을 만드는데 사용되고 있다. 본 연구에서는 담수성 조류인 클로렐라 종(Chlorella vulgaris)을 실험 균주로 선정하였으며, 배양액은 BBM배지에서 working volume 200 ml, 인큐베이터 내부온도 25℃(±1)에서 실험하였다. 미세조류 성장에 가장 큰 영향을 미치는 광원의 종류는 차세대 조명이라고 각광받는 LED를 이용하였다. 실험 제어 인자는 빛의 파장(Rad, Blue, White), 빛의 주기{(24:0), (16:8), (14:10), (12:12)}, CO2 주입량(2%, 5%, 10%)으로 균체성장속도와 최대균체농도를 향상시킬 수 있는 미세조류의 최적배양조건과 최대지질 생산조건을 도출하여 기타 바이오에너지 이용에 대한 기초자료를 제공하고자 한다.

This study was performed to investigate the physiological responses of Oplopanax elatus by water condition.Drought stress was induced by withholding water for 26 days. The results show that PN max, SPAD, gs, E and Ci weresignificantly decreased with decreasing of soil moisture contents. However, AQY and WUE were decreased slightly only at26 day. This implies that photosynthetic rate is reduced due to an inability to regulate water and CO₂exchange through thestomatal. According to JIP analysis, ΦPO, ΨO, ΦEO and PIABS were dramatically decreased at 21 day and 26 day, whichreflects the relative reduction state of the photosystem II. On the other hand, the relative activities per reaction center suchas ABS/RC, TRo/RC were significantly increased at 26 day. Particularly, Dio/RC and DIo/CS increased substantially underdrought stress, indicating that excessive energy was consumed by heat dissipation. These results of chlorophyll a fluores-cence show that the sensitivity changes photosystem II activity. Thus, according to the results, O. elatus was exhibited astrong reduction of photosynthetic activity to approximately 10% soil moisture contents, and JIP parameters could be usefulindicator to monitor the physiological states of O. elatus under drought stress.

이 연구는 폐쇄형 식물공장 시스템 내에서 LED 펄스광의 튜티비 및 광도(PPFD)가 상추의 생장 및 광합성률에 미치는 영향을 구명하기 위해 수행하였다. 파종 3주 후 ‘청치마’ 및 ‘청치마’ 실생묘를 bar-type LED(red:blue:white = 5:2:1) 하에서 4주간 생육시켰다. LED 펄스(on/off) 간격은 연속조사(continuous), 200/200μs, 133/266μs, 100/300μs의 4가지로 설정하였는데, 이를 듀티비(duty ratio, DR, 한 주기 대비 점등시간 비율)로 표시하면 각각 100%, 50%, 33%, 25%였다. 이때 광도(PPFD)는 DR 100, 75, 50% 처리에서는 두 수준[고광(high light, HL), 저광(low light, LL)]으로 처리되었고, 광주기는 16시간이었다. 식물공장 내부의 온도는 주야간 20±2°°C, 상대습도는 약 70±10%로 유지되었다. 양액은 온도 20±2°C, EC는 1.2mS·cm-1, pH는 5.8±0.2로 유지되었고, NFT 방식으로 공급되었다. 처리 4주 후 ‘청치마’ 상추의 생체중과 건물중은 DR 100% HL 하에서 가장 높았고, DR 75% HL 및 DR 50% HL과는 유의차가 없었다. 엽수, 엽면적, 잎 두께(비엽면적의 역수)는 DR 100%, 75%, 50%의 HL처리에서 유의하게 큰 값을 나타내었다. 광이용효율(LUE)은 PPFD에 관계없이 연속광보다 펄스광 처리에서 높게 나타났으며, 특히 DR 25% HL 하에서 가장 높았고, DR 75% HL과 DR 50% HL 처리도 DR 100% HL보다 높은 값을 보였다. ‘적치마’ 상추의 생체중과 건물중은 DR 100% HL 하에서 가장 컸고, DR 100% LL, DR 75% HL, DR 50% HL 하에서 두번째로 컸다. LUE는 ‘청치마’와 같이 연속광보다 펄스광 하에서 높았다. 두 품종의 광합성 속도는 적산 PPFD에 비례하였으며, DR의 효과는 적었다. 결론적으로 펄스광은 상추의 LUE를 높이므로 LED를 광원으로 사용하는 폐쇄형 식물공장의 에너지 절감에 기여할 수 있을 것이다.

토마토 정식 전 후 묘령에 따른 토마토의 생육의 특성, 수량, 광합성 및 항산화 효소 활성을 알아보고자 본 실험을 수행하였다. 토마토 파종부터 정식시 까지 기간을 40, 45, 50, 55, 60일로 설정하였다. 육묘 기간이 50일(표준묘)보다 짧을수록 토마토 생장과 생육이 촉진된 반면에 육묘 일수가 길수록 생장과 생육이 감소하였다. 정식 후 4주는 묘령이 가장 짧은 40일묘에서 광합성량이 낮았지만 정식 후 8주는 차이를 보이지 않았다. CAT(Catalase), APX(Ascorbate peroxidase), POX(peroxidase) 들은 정식후 6주까지 증가하다가 8주부터 감소하였다. 정식후 4주는 SOD (Superoxide dismutase), CAT 활성은 묘령이 어릴수록 높은 경향을 보였고 반대로 정식 후 6주는 APX, POX는 육묘기간이 길수록 활성이 높았다. 토마토 수량도 표준묘와 비교해서 육묘 기간이 짧은 묘령에서 토마토 생산성이 높은 반면에 육묘기간이 길수록 생산이 감소하였다. 토마토의 생장과 수량의 관점에서 보면 육묘 기간은 40-50일 적합하다는 결과를 도출하였다. 따라서 토마토를 토경재배 할 경우 표준 묘령 50일보다 짧은 묘를 정식 후 생장과 생산성에서 유리할 뿐 아니라 육묘 시 발생되는 생산비의 절감에 유리할 것으로 사료된다.