• Title/Summary/Keyword: leaf photosynthesis

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Effects of Antioxidants on the Photoinhibition in Panax ginseng C.A. Meyer (인삼의 광억제(Photoinhibition)에 대한 항산화제의 처리효과)

  • 양덕조;김명원
    • Journal of Ginseng Research
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    • v.17 no.3
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    • pp.232-235
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    • 1993
  • We investigated the effect of antioxidants (ascorbate, glutathione, and sodium azide), which efEectively inhibited the chlorophyll bleaching of Panax ginseng CA Meyer under the high light intensity, treated by folilar wiping on the early stage of photosynthesis and transpiration of ginseng in the 5000 $\mu$mol photon.$m^{-2}$.$s^{-1}$. Ascorbate and glutathione, endogenous antioxidant, completely recovered ginseng from the photoinhibition, but sodium azide, synthetic quencher, showed negative effect. We assumed that endogenous antioxidants could be available to the protection of the leaf-burning phenomenon of ginseng.

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Potassium Rate and Mowing Height for Kentucky Bluegrass Growth

  • Lee, Sang-Kook
    • Weed & Turfgrass Science
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    • v.5 no.4
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    • pp.268-273
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    • 2016
  • Potassium is well-known to improve turfgrass tolerance to environmental stresses such as low temperature and drought stress. Low mowing height reduces leaf area of turfgrass that is main place for photosynthesis and carbohydrate production. Closely-mowed turf would suffer from summer decline by low level of carbohydrate resulted from low photosynthesis of reduced leaf area. The objective of the study is to investigate K rate and mowing height for Kentucky bluegrass. The K rate treatments were 5, 10, and $20g\;K_2O\;m^{-2}$ for the low, medium and high K rates, respectively. The bi-weekly mowing treatment was made for treatments. Mowing was implemented at 40 and 100 mm using a rotary mower. Regardless K rates, the high mowing height would be required when the air temperature is higher than $28.5^{\circ}C$ and high turfgrass quality of Kentucky bluegrass is needed. When the air temperature is optimal for cool-season grass, the high mowing height and the low K rate is needed for the root length of Kentucky bluegrass.

Effects of Shading on Growth and Dry Matter Accumulation of Corn and Sorghum Species I. Effecs of shang on photosynthetic rate (차광정도가 옥수수와 수수속 작물의 생육 및 건물축적에 미치는영향 I. 광합성량에 미치는 차광의 영향)

  • 한흥전;류종원
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.8 no.1
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    • pp.61-65
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    • 1988
  • To examine the effects of light intensity on photosynthesis, corn and sorghum species were grown under shade cloths, which reduced light intensity by 25,50 and 75%. Photosynthetic rates were measured between 10 a.m. to noon on a clear day in early and mid - summer. 1. The degree of shading had a little effect on microenvironment. Air, soil and leaf temperatures were reduced as shade increased. 2. The degree of shading in early summer had relatively a little effect on photosynthesis of corn. However, the rates of photosynthesis in mid-summer decreased by 36%, 55% with relative light intensities of 50% and 25%, respectively. 3. The rate of photosynthesis was highly correlated with light intensity. The rates of photosynthesis with relative light intensities of 75,50 and 25% were decreased by 20, 40 and 5 4% in early summer, and by 17-53%, 36-64% and 5570% in mid-summer, respectively. 4. The 75% of light intensity had relatively little effect on dry matter yield of corn and sorghum species, however dry matter yield with 50 and 25% relative light intensities was decreased 17 and 36% in corn, 13-3 1 and 50-68% in sorghum species, respectively.

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Physiological Responses of Warm-Season Turfgrasses under Deficit Irrigation (소량관수로 인한 난지형 잔디의 생리적 반응)

  • Lee, Joon-Hee;Trenholm, Laurie. E.;Unruh, J. Bryan
    • Asian Journal of Turfgrass Science
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    • v.23 no.1
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    • pp.9-22
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    • 2009
  • Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore Paspalum(Paspalum vaginatumSwartz.), 'Empire' zoysiagrass(Zoysia japonica Steud.), and 'Pensacola' bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. 'Sealsle 1' and 'Palmetto' had a deeper root system than 'Empire' and 'Pensacola', while 'Floratam' had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

Cytohistological study of the leaf structures of Panax ginseng Meyer and Panax quinquefolius L.

  • Lee, Ok Ran;Nguyen, Ngoc Quy;Lee, Kwang Ho;Kim, Young Chang;Seo, Jiho
    • Journal of Ginseng Research
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    • v.41 no.4
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    • pp.463-468
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    • 2017
  • Background: Both Panax ginseng Meyer and Panax quinquefolius are obligate shade-loving plants whose natural habitats are broadleaved forests of Eastern Asia and North America. Panax species are easily damaged by photoinhibition when they are exposed to high temperatures or insufficient shade. In this study, a cytohistological study of the leaf structures of two of the most well-known Panax species was performed to better understand the physiological processes that limit photosynthesis. Methods: Leaves of ginseng plants grown in soil and hydroponic culture were sectioned for analysis. Leaf structures of both Panax species were observed using a light microscope, scanning electron microscope, and transmission electron microscope. Results: The mesostructure of both P. ginseng and P. quinquefolius frequently had one layer of non-cylindrical palisade cells and three or four layers of spongy parenchymal cells. P. quinquefolius contained a similar number of stomata in the abaxial leaf surface but more tightly appressed enlarged grana stacks than P. ginseng contained. The adaxial surface of the epidermis in P. quinquefolius showed cuticle ridges with a pattern similar to that of P. ginseng. Conclusion: The anatomical leaf structure of both P. ginseng and P. quinquefolius shows that they are typical shade-loving sciophytes. Slight differences in chloroplast structure suggests that the two different species can be authenticated using transmission electron microscopy images, and light-resistant cultivar breeding can be performed via controlling photosynthesis efficiency.

Growth Characteristics and Photosynthesis of Soybean Seedling to NaCl stress in Sand Culture (콩의 유묘기에 있어서 NaCl Stress에 의한 생육특성과 광합성 반응)

  • Cho, Jin-Woong;Kim, Choong-Soo
    • Korean Journal of Environmental Agriculture
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    • v.18 no.4
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    • pp.361-365
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    • 1999
  • This atudy was conducted to determine the growth characteristics and photosynthesis of soybean (Glycine max L. cv. Keumjongkongl) 30 day old seedling to 100mM NaCl concentration containing 1/2 Hoagland`s nutrient solution in sand culture. The nodule formation of root is not found perfectly with NaCl stress. The leaf dry matter weight (g/plant) of stressed plant is more reduction in 77% to control than any other characters. The water content (%) is tend to increase but water potential (MPa) is tend to decrease at NaCl stress. The chlorophyll content (SPAD) is tend to increase at growing leaf age of control but decrease at NaCl stress. The photosynthesis, stomatal conductance and transpiration are tend to decrease sharply at NaCl stress.

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Effect of Temperature on the Growth of Korean Valerian (Valeriana fauriei var. dasycarpa HARA) (온도가 한국산 쥐오줌풀의 생육에 미치는 영향)

  • Lee, Jong-Chul
    • Korean Journal of Medicinal Crop Science
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    • v.3 no.2
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    • pp.77-80
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    • 1995
  • This study was carried out to know the effect of air temperature on photosynthesis and growth of Korean Valerian (valeriana fauriei var. dasycarpa HARA). The results are as follows; 1. Photosynthesis of V fauriei had highly significant relation to temperature in a quadratic regression mo­del, from which the optimum temperature for the plant growth were estimated to be $17.7^{\circ}C$. During the day­time in the field condition, the photosynthesis rate was highest at 9 a.m, then reduced to minimum at 2 p.m., and increased again thereafter. 2. Number of stomata was about $25/mm^2$ on the upper side and $85/mm^2$ on the lower side of the leaf, and the size was $21{\sim}30/{\mu}m$ in diameter. 3. A highly significant quadratic regression was noted between temperature and leaf width or root weight of V. fauriei. It was estimated from the regression equation that the optimum temperature for root growth was $20.3^{\circ}C$.

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Photosynthesis rates, growth, and ginsenoside contents of 2-yr-old Panax ginseng grown at different light transmission rates in a greenhouse

  • Jang, In-Bae;Lee, Dae-Young;Yu, Jin;Park, Hong-Woo;Mo, Hwang-Sung;Park, Kee-Choon;Hyun, Dong-Yun;Lee, Eung-Ho;Kim, Kee-Hong;Oh, Chang-Sik
    • Journal of Ginseng Research
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    • v.39 no.4
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    • pp.345-353
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    • 2015
  • Background: Ginseng is a semishade perennial plant cultivated in sloping, sun-shaded areas in Korea. Recently, owing to air-environmental stress and various fungal diseases, greenhouse cultivation has been suggested as an alternative. However, the optimal light transmission rate (LTR) in the greenhouse has not been established. Methods: The effect of LTR on photosynthesis rate, growth, and ginsenoside content of ginseng was examined by growing ginseng at the greenhouse under 6%, 9%, 13%, and 17% of LTR. Results: The light-saturated net photosynthesis rate ($A_{sat}$) and stomatal conductance ($g_{s}$) of ginseng increased until the LTR reached 17% in the early stage of growth, whereas they dropped sharply owing to excessive leaf chlorosis at 17% LTR during the hottest summer period in August. Overall, 6-17% of LTR had no effect on the aerial part of plant length or diameter, whereas 17% and 13% of LRT induced the largest leaf area and the highest root weight, respectively. The total ginsenoside content of the ginseng leaves increased as the LTR increased, and the overall content of protopanaxatriol line ginsenosides was higher than that of protopanaxadiol line ginsenosides. The ginsenoside content of the ginseng roots also increased as the LTR increased, and the total ginsenoside content of ginseng grown at 17% LTR increased by 49.7% and 68.3% more than the ginseng grown at 6% LTR in August and final harvest, respectively. Conclusion: These results indicate that 13-17% of LTR should be recommended for greenhouse cultivation of ginseng.

Response of Korean Ginseng (Panax ginseng C. A. Meyer) to 2, 4- D II. Effects of 2, 4-D Foliar Application on Photosynthesis, Ethylene Gas Production and Plant Growth (제초제 2, 4-D에 대한 고려인삼의 반응 II. 2, 4-D의 경엽처리가 인삼엽의 광합성, 에칠렌가스 발생 및 지상부 생육에 미치는 영향)

  • 조재성;원준연;신최순
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.36 no.2
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    • pp.107-111
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    • 1991
  • This study was conducted to define the effect of 2, 4-D foliar application on the plant growth. photosynthesis ability and ethylene gas production of the ginseng plant. Neither abnomal foliar changes occured nor any inhibition in the leaf and stem growth was resulted for the plants treated with 2,4-D concentrated three times of the recommended dosage. The angle of petiole to the stem became wider by 2, 4-D foliar application. The higher concentration treatment of 2,4-D made the petiole angle significantly wider. Foliar application of the herbicide 2,4-D inhibited photosynthesis of the ginseng leaf. The inhibition rate of photosynthesis was significantly increased with the application concentration of 2, 4-D. Inhibition in photosyn-thesis ability by 2,4-D application with doubled concentration was recovered in three days after treatment. When 2,4-D was treated with a concentration tripled the recommended dosage, 12 days were needed to recover the photosynthesis ability of the ginseng leaf. Ethylene gas was not detected from the ginseng plants treated with 2 times concentrated 2, 4-D. However, the ginseng plants produced 0.03-0.04 ppm ethylene gas when the application rate was increased 3 times. The amount of ethylene gas produced by ginseng plant treated with 3 times concentrated 2, 4-D was only 1/20 compared with the amount produced by the soybean plant treated with the recommended dosage of 2, 4-D.

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