• 한국작물학회지
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• 제40권2호
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• pp.255-259
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• 1995

콩의 수량에 대한 광합성 기관(source)과 광합성생물 수용기관(sink)이 미치는 영향을 살펴 보고자, 꼬투리의 크기에 비하여 종실 건물면적이 불량한 수집검정콩인 강릉재래 밀 금릉재래, 꼬투리의 비대가 충실한 백운콩 및 수원 168호를 공시하였다. 두 수준의 재식밀도(ha당 55,000, 110,000 개체)와 개화기 이후 등숙 기간 중 차광막을 설치하여 광합성 능력에 관여하는 환경요인을 변화시킴으로써 나타나는 건물중분배 및 개체수량 반응을 분석한 결과를 요약하면 다음과 같다. 1. 지상부 및 종실건물중의 품종간 광합성능력 변화를 위한 재식밀도 및 차광시 처리간 유의적인 차이가 인정되었고 품종 및 처리간 유의적인 상호작용 효과도 있었다. 2. 지상부 총건물중에 대한 종실건물중 비율은 품종간 차이가 인정되어, 수원 168호가 가장 높았으며, 광합성 능력을 변화시키기 위한 처리 가운데 극히 광이 부족한$S_2$를 제외한 나머지 세 처리간 차이는 없었다. 3. 등숙기간중에수량을 위한 source와 sink 능력을 광합성 기관 제한정도(source limitation value)에 의하여 품종간 비교하여 보면, 꼬투리에 종실이 충분히 면적되는 수원 168호는 source가, 수집검정콩인 강릉재래나 금릉재래는 sink의 기능이 수량에 있어서 제한요인으로 작용하였다.

• 한국기후변화학회지
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• 제7권1호
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• pp.9-17
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• 2016

Climate change affects plant responses on physiological characteristics and growth, and Pinus densiflora, one of the major tree species in Korea, are expected to be particularly vulnerable to rising temperature and increased precipitation. This study was conducted to investigate the effects of an open-field warming and precipitation manipulation on physiological characteristics and growth of P. densiflora seedlings. Seedlings of 2-year-old P. densiflora were planted in April, 2013, in open-field nursery located at Korea University. The air temperature of warmed plots had been set to be $3^{\circ}C$ higher than the control plots using infrared lamps. Precipitation was manipulated to be 30% lower or higher than the control, using transparent panels and drip irrigation. Net photosynthetic rate, total chlorophyll content, seedling height, root collar diameter and biomass were measured from April, 2014 to April, 2015. The increase in new shoot biomass from warming was statistically significant, with the biomass in warmed plots about 2-fold higher than in the control plots in 2014 and 2015. This result might be related to advanced bud burst and increased occurrence of abnormal new shoots in warmed plots. Meanwhile, the results of net photosynthetic rate, total chlorophyll content, seedling height, root collar diameter and total biomass from warming and precipitation manipulation were not statistically significant, but tendencies of lower net photosynthetic rate and higher seedling height and biomass in warmed plots compared to the control were shown. Such might be speculated as results of the extended growth period. When root to shoot (R/S) ratio was calculated from the biomass data obtained in April 2014 and April 2015, increased R/S ratio was observed regardless of the treatments applied. Drought tolerance of P. densiflora and particularly low annual precipitation observed in 2014 were suggested as the possible reasons.

• Journal of Microbiology and Biotechnology
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• 제13권2호
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• pp.165-174
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• 2003

Xanthophylls are oxygenated carotenoids that serve a variety of functions in photosynthetic organisms and are essential for survival of the organism. Within the last decade, major nor advances have been made in the elucidation of the molecular genetics and biochemistry of the xanthophyll biosynthesis pathway. Microalgae, yeast, or other microorganisms produce some of the xanthophylls that are being commercially used due to their own color and antioxidant properties. Currently, only a few microalgae are being considered or already being exploitd for the production of high-value xanthophylls. However, new developments in molecular biology have important implications for the commercialization of microalgae, and make the genetic manipulation of the xanthophyll content of microalgae mure attractive for biotechnological purposes. Accordingly, the current review summarizes the general properties of xanthophylls in microalgae and the recent developments in the biotechnological production of xanthophylls.

• Molecules and Cells
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• 제24권2호
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• pp.301-306
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• 2007

Tocopherols, essential components of the human diet, are synthesized exclusively by photosynthetic organisms. To increase tocopherol content by increasing total flux to the tocopherol biosynthetic pathway, genes encoding Arabidopsis homogentisate phytyltransferase (HPT/V-TE2) and tocopherol cyclase (TC/VTE1) were constitutively overexpressed in lettuce (Lactuca sativa L.). Total tocopherol content of the transgenic plants overexpressing either of the genes was increased by more than 2-fold mainly due to an increase in ${\gamma}$-tocopherol. However, chlorophyll content in the HPT/VTE2 and TC/VTE1 transgenic lines decreased by up to 20% and increased by up to 35%, respectively (P < 0.01). These results demonstrate that manipulation of the tocopherol biosynthetic pathway can increase or decrease chlorophyll content depending on the gene introduced.

• Journal of Plant Biotechnology
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• 제32권3호
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• pp.151-159
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• 2005

Injury caused by reactive oxygen species (ROS), known as oxidative stress, is one of the major damaging factors in plants exposed to environmental stress. Chloroplasts are specially sensitive to damage by ROS because electrons that escape from the photosynthetic electron transfer system are able to react with relatively high concentration of $O_2$ in chloroplasts. To cope with oxidative stress, plants have evolved an efficient ROS-scavenging enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), and low molecular weight antioxidants including ascorbate, glutathione and phenolic compounds. To maintain the productivity of plants under the stress condition, it is possible to fortify the antioxidative mechanisms in the chloroplasts by manipulating the antioxidation genes. A powerful gene expression system with an appropriate promoter is key requisite for excellent stress-tolerant plants. We developed a strong oxidative stress-inducible peroxidase (SWPA2) promoter from cultured cells of sweetpotato (Ipomoea batatas) as an industrial platform technology to develop transgenic plants with enhanced tolerance to environmental stress. Recently, in order to develop transgenic sweetpotato (tv. Yulmi) and potato (Solanum tuberosum L. cv. Atlantic and Superior) plants with enhanced tolerance to multiple stress, the genes of both CuZnSOD and APX were expressed in chloroplasts under the control of an SWPA2 promoter (referred to SSA plants). As expected, SSA sweetpotato and potato plants showed enhanced tolerance to methyl viologen-mediated oxidative stress. In addition, SSA plants showed enhanced tolerance to multiple stresses such as temperature stress, drought and sulphur dioxide. Our results strongly suggested that the rational manipulation of antioxidative mechanism in chloroplasts will be applicable to the development of all plant species with enhanced tolerance to multiple environmental stresses to contribute in solving the global food and environmental problems in the 21st century.