• 한국환경복원기술학회지
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• 제7권1호
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• pp.110-115
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• 2004

This experiment was conducted to investigate the effect of light intensities on the growth responses, carbohydrate contents and the characteristics of leaf gas exchange in Miscanthus sinensis and Pennisetum purpurascens. The plant height and leaf length were increased to about 30% in the sun. However, those were reduced severely in the shade, and leaf necrosis was also observed. The representative growth index and the dry weight of 2 species were 50% higher than shade and the rate was reduced according to the decrease of light intensities. Total carbohydrate contents showed very similar changes to that of dry weight. However, any notable influences were observed at above the light intensities of 250~500${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in the half shade. The size of spikes and the earliest spiking appeared in the sun and the spike color was decolorized as decreased in light intensities, irrespective of species. Photosynthetic rate of 2 species was 2 times higher in the sun than those in the shade, and it showed the typical photoresponses of sun plant. Stomatal conductances and intercelluar $CO_2$ concetration showed similar changes to that of photosynthetic rate. On the contrary, vapor pressure deficit was increased more in the shade than in the sun.

• Rapid Communication in Photoscience
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• 제3권3호
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• pp.53-55
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• 2014

The shade avoidance syndrome is a morphological and physiological response when plants are exposed to shade. Recent work in Arabidopsis had begun to define the molecular components of the shade avoidance syndrome in dicotyledonous model plant. However, little is known about the shade avoidance response networks in agriculturally important monocotyledon crops such as rice. Here, we found that the degree of bending at the lamina joint is inversely proportional to the R:FR ratio. To elucidate which phytochrome is involved in this response, we did lamina joint inclination assay with the rice phytochrome-deficient mutants (osphyA, osphyB, and osphyC) and the wild type plants. Whereas the osphyA and osphyC knockout mutants bent at the lamina joint in the far-red rich condition as the wild type plants, the osphyB knockout mutants no longer bent at the lamina joint in the far-red rich condition. These results suggest that PHYB acts as a sole photoreceptor in the lamina joint inclination response in rice.

• 한국자원식물학회지
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• 제24권5호
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• pp.613-621
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• 2011

인삼의 시설생산을 위하여 배지 조성 및 차광 정도를 달리한 환경조건 하에서의 생육특성과 생리활성 변화를 검토하고자 온실 및 실내시험을 수행하였다. 적정한 배지 조합은 차광 정도에 따라 달랐는데 무차광에서는 coco peat 단독, 50% 차광에서는 coco peat와 perlite를 50:50으로 혼합하였을 때, 70% 차광에서는 perlite 단독배지에서 유의적으로 높은 생육을 보였다(P<0.05). 차광은 엽면적, 엽록소 함량, 근장, 지상부 및 지하부 생체중을 유의적으로 감소시켰다. 총 페놀 함량은 지상부(20.7~23.8 $mg{\cdot}kg^{-1}$)보다는 지하부(25.8~28.4 $mg{\cdot}kg^{-1}$)에서, 무차광(20.7~25.8 $mg{\cdot}kg^{-1}$)보다는 차광(23.7~28.4 $mg{\cdot}kg^{-1}$)에서 높게 나타났다. 총 플라보노이드 함량은 지하부(6.9~7.0 $mg{\cdot}kg^{-1}$)보다는 지상부에서(17.4~26.8 $mg{\cdot}kg^{-1}$), 무차광보다는 차광에서 높게 검출되었다. 반면, DPPH 라디컬 소거능 측정을 통한 항산화성은 추출물 농도가 증가할수록 높은 활성을 보였고, 지하부(24.9~28.7%)보다는 지상부에서(31.1~36.5%), 차광보다는 무차광에서 다소 높은 활성을 보였다. 결론적으로 차광은 비닐하우스 조건하에서 재배된 인삼의 생육과 생리활성에 영향을 미치는 것으로 나타났다.

• Plant Resources
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• 제7권1호
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• pp.77-86
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• 2004

The reduced ratio of red:far-red (R:FR) light acts as a measure of the proximity of competitors and plants can detect the potentially competing neighbor plants by perceiving reflected R:FR signals and initiate the response of “shade avoidance” before actual shading occurs. The phytochrome system is responsible for monitoring the changes in the R:FR and initiating the shade avoidance response. The response to low R:FR ratio was studied in a white aspen Populus alba clone ‘Bolleana’ using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were 27 ％ taller than trees grown inside the FR-blocking filter chambers. Stem taper of clear chamber trees was 16％ less than the FR-blocking filter trees. Low R:FR also induced 22％ more stem dry weight and 13％ greater petiole length per leaf compared to the FR-blocking filter trees. There were no statistically significant differences in leaf area, leaf number increment, and total dry weight between the two light filter treatments.

• 한국작물학회지
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• 제61권3호
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• pp.196-207
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• 2016

In monsoon climates, persistent shade is a troublesome weather condition with an impact on the growth and yield of corn (Zea mays L.). We imposed 7, 14, 21, and 28 days of consecutive shade (CS) on Gwangpyeongok and P3394 corn hybrids at the beginning of the kernel filling stages. Shade had little impact on leaf area and dry matter accumulation in the stem and leaves. However, dry matter accumulation in the ear was severely reduced by approximately 28% and 53% after 14 and 28 days of CS, respectively. For the components of grain yield, 7 and 14 days of shade did irreparable damage to the number of filled kernels, the kernel number per ear row, and the percent of filled kernels, but did little damage or reversible damage after removal of the shade to the 100-grain weight and the row number per ear. Shade significantly reduced the relative growth rate (RGR) due to a decrease in the net assimilation rate (NAR). These results suggest that source activity limitation by shade during the kernel filling stages leads to the inhibition of sink activity and size. The yield of biomass, ear, and grain logistically declined as the length of CS increased. Probit analysis revealed that the number of days of CS needed to cause 25% and 50% reductions in grain yield were 3.7 and 23.1, respectively. These results suggest that the plant yield loss induced by shade at the beginning of the kernel filling stages is mainly achieved within the first 7 days of consecutive shade.

• Journal of Ginseng Research
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• 제6권1호
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• pp.84-99
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• 1982

Water content and its seasonal change in reprodltctive organs were reviewed in relation to cultivation practice s. Precipitati on and humidity under shade roof were reviewed in relation to shading ,jystem and environmental factors. High water content of reproductive organs suggests vulnerability to water stress during reproductive growth stage. Watering during dehisconce treat menu seems to keep optimum temperature but cnoventional practice seems to be too often In watering. Information effe on water physiology of seeds is too rare to develop seed storing method and ctive seed use. Dehiscent mechanism was considered in terms of water absorption of embryo. Precipitation rate of conventional shade roof reaclled to 38% and at line level 50% and varied with shade patterns. Precipitation rate under shade has been investigated for itself but should be investigated in relation to light intensity and soil moisture content Relative humidity under shade depends mainly on air humidity and soil moisture, considerably on shade materials and lithe on pole height, bed width or plant density. Since relative humidity was lower in afternoon it was often less than 50% even in summer with high temperature suggesting possible disorder of phi biological function especially in photosynthesis. More information was needed on optimum humidity for productive physiological function of leaf.

• Journal of Plant Biology
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• 제33권2호
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• pp.147-150
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• 1990

Different species with similar niches can coexist in the same community if disturbances prevent compeptitive exclusion of competitively inferior species. Disturbances which open up gaps are common in all kind of community. Even in virgin forests without any artificial disturbance, there exist a significant proportion of trees of early successional shade-in-tolerant species in addition to the dominant late successional shade-tolerant species. In forest ecosystems, most canopy tree species including shade-tolerant ones require one or more gaps in their life-time to reach the canopy. Because of these frequent disturbances, forests can be considered of dynamic mosaics of patches of different ages and with different species composition which are in certain stages of recovery from disturbances. Disturbances temporarily increase the availability of resources such as light, water and soil nutrient for other in dividuals through the death of one or more canopy trees.

• Journal of Photoscience
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• 제10권1호
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• pp.157-164
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• 2003

Light exerts two primary roles in plant growth and development. Plants acquire all biochemical energy required for growth and propagation solely from light energy via photosynthesis. In addition, light serves as a medium through which plants recognize environmental fluctuations, such as photoperiod and presence of neighboring animals and plants. Plants therefore constantly monitor the direction, intensity, duration, and wavelength of environmental light and integrate these light signals into the intrinsic regulatory programs to achieve an optimized growth in a given light condition. Although light regulates all aspects of plant growth and developmental aspects, the molecular mechanisms and signaling cascades involved have not been well established until recently. However, recent advances in genetic tools and plant transformation techniques greatly facilitated the elucidation of molecular events in plant photomorphogenesis. This mini-review summarizes the gist of recent findings in deetiolation and suppression of shade avoidance response as classic examples of the phytochrome-mediated photomorphogenesis.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2003년도 제10차 국제학술회의 및 추계정기 학술발표회
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• pp.50-56
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• 2003

우리나라 남부도서지역인 진도지방에서 울금 다수확의 기초 자료를 얻고자 차광재배를 실시한 결과는 다음과 같다. 진도지역에서 울금을 4월 20일 정식할 경우 4주 지난 후에 출현되고, 출현율은 83~88%이었다. 초장은 129cm~147cm 이였고, 차광의 정도가 높을수록 초장이 커지는 경향이었다. 엽장은 47.5cm~49.4cm로 차광 30~60%에서 약간 양호하였다. 또한 엽폭은 16.9~17.9cm로 차광이 높을수록 짧아지는 경향이었으나 유의성은 인정되지 않았다. 울금의 1주 근경중는 941~993g로 비대가 잘 되었고, 10a당 3,980~4,200kg을 생산 할 수 있었으며, 15%와 30% 차광이 수량이 약간 증수되었으나 45%이상의 차광에서는 오히려 감소되는 경향으로 차광의 효과는 인정되지 않았다. 이러한 결과로 보아 울금을 재배할 경우 15%차광에서 생육이 가장 양호한 것으로 나타나고, 근경수량이 약간 증수되나 경제성으로 고려하여 재배하여야 할 것으로 생각된다.

• 한국자원식물학회지
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• 제16권3호
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• pp.207-211
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• 2003

우리나라 남부 도서지역인 진도 지방에서 울금 다수확의 기 초 자료를 얻고자 차광 재배를 실시 한 결과는 다음과 같다. 진도 지역에서 울금을 4월 20일 정식할 경우 4주 지난 후에 출현되고, 출현율은 83­88%이었다. 초장은 129cm­147cm이였고, 차광의 정도가 높을수록 초장이 커지는 경향이었다. 엽장은 47.5cm­49.4cm로 차광 30­60%에서 약간 양호하였다. 또한 엽폭은 16.9­17.9cm로 차광이 높을수록 짧아지는 경향이었으나 유의성은 인정되지 않았다. 울금의 1주 근경중은 941­993g으로 비대가 잘되었고, 10a당 3,980­4,200kg을 생산 할 수 있었으며, 15%와 30%차광이 수량이 약간 증수되었으나 45%이상의 차광에서는 오히려 감소되는 경향으로 차광의 효과는 인정되지 않았다. 이러한 결과로 보아 울금을 재배할 경우 15%차광에서 생육이 가장 양호한 것으로 나타나고, 근경 수량이 약간 증수되나 경제성을 고려하여 재배하여야 할 것으로 생각된다.