• Title/Summary/Keyword: light leaf respiration

Search Result 52, Processing Time 0.022 seconds

The Effect of Greenhouse Climate Change by Temporary Shading at Summer on Photo Respiration, Leaf Temperature and Growth of Cucumber (여름철 수시차광에 의한 온실 환경변화가 오이의 광호흡, 엽온, Thermal breakdown 등 생육에 미치는 영향)

  • Kim, Dong Eok;Kwon, Jin Kyung;Hong, Soon Jung;Lee, Jong Won;Woo, Young Hoe
    • Journal of Bio-Environment Control
    • /
    • v.29 no.3
    • /
    • pp.306-312
    • /
    • 2020
  • This study was conducted to investigate cucumber plants response to greenhouse environments by solar shading in greenhouse in the summer. In order to estimate heat stress reduction of cucumber plants by solar shading in greenhouse, we measured and analyzed physiological conditions of cucumber plants, such as leaf temperature, leaf-air temperature, rubisco maximum carboxylation rate, maximum electron transport rate, thermal breakdown, light leaf respiration, etc. Shading levels were 90% mobile shading of full sunlight, 40% mobile shading of full sunlight and no shading(full sunlight). The 90% shading screen was operated when the external solar radiation is greater than 650 W·m-2. Air temperature, solar radiation, leaf temperature, leaf-air temperature and light leaf respiration in the 90% shading of full sunlight was lower than those of 40% shading and no shading. Rubisco maximum carboxylation rate, arrhenius function value and light leaf respiration of the 90% shading were significantly lower than those of 40% shading and no shading. The thermal breakdown, high temperature inhibition, of 90% shading was significantly higher than that of 40% shading and no shading. Therefore, these results suggest that 90% mobile shading made a less stressful growth environment for cucumber crops.

Effect of Leaf Temperature on Light Response and Respiration in Panax ginseng C. A. Meyer (고려인삼에서 광반응 및 호흡에 미치는 잎온도의 영향)

  • 현동윤;유남희
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.41 no.6
    • /
    • pp.725-728
    • /
    • 1996
  • This study was conducted to investigate effect of leaf temperature on light response and respiration during short-term exposure to a sequnce of PPFD cycle(100-200-300-400$\mu$ mol m$^{-2}$ s$^{-1}$ ) under increasing leaf temperature sequnce up to 3$0^{\circ}C$ and in dark condition, increasing up to 46$^{\circ}C$ with step size (1$^{\circ}C$) in Panax ginseng C. A. Meyer. When leaflet exposed to low light intensity and temperature, Rubisco activity was higher than remained activity in high condition. Leaves adapted to 100$\mu$mol m$^{-2}$ s$^{-1}$ PPFD had a peak response similar to that of 200$\mu$mol m$^{-2}$ s$^{-1}$ at 18$^{\circ}C$, but in above PPFD cycle(300, 400$\mu$mol m$^{-2}$ s$^{-1}$ ) it represented at 17$^{\circ}C$ and 16$^{\circ}C$, re-spectively. $CO_2$ evolution in dark condition increased rapidly when leaf temperature was increased up to 28$^{\circ}C$ and then 'dipped' below steady-state level from above 4$0^{\circ}C$. Thus, Pananx ginseng is able to take advantage of irradiance increase and decrease of $CO_2$ evolution in dark condition to control leaf temperature.mperature.

  • PDF

Influence of Monochromatic Light on Photosynthesis and Leaf Bleaching in Panax species (단색광이 인삼속 식물의 광합성과 잎표백화에 미치는 영향)

  • Lee Sung-Sik;Proctor John T.A.;Choi Kwang-Tae
    • Journal of Ginseng Research
    • /
    • v.23 no.1 s.53
    • /
    • pp.1-7
    • /
    • 1999
  • Photosynthetic rates and leaf bleaching were measured under light of far-red, red, orange, green, blue and white in order to clarify the effect of light qualities on photosynthesis in Panax species, P. ginseng and P. quinquefolium. Photosynthetic rate of P. ginseng and P. quinquifolium showed higher in the order under the light of red > orange > blue > white > green. Degree of leaf bleaching in P. quinquifolium showed severer in the order under the light of far-red > red > white > blue > orange > green. These suggest that shading material with blue or orange color is good for ginseng growth. As for the effect of temperature, the photosynthesis was increased with increasing temperature untill $25^{\circ}C$ and thereafter decreased. Therefore, it was clarified that the optimum temperature for photosynthesis of P. ginseng and P. quinquefolium was $25^{\circ}C$. And the dark respiration rate of ginseng leaf also increased with increasing air temperature. Especially, the dark respiration rate increased by $80\%$ for P. ginseng and by $73\%$ for P.quinquefolium at above $30^{\circ}C$ as compared with $25^{\circ}C$. In general, the photosynthesis rate was higher in P. quinquifolium than in P. ginseng and ranged from 3.54 to 4.04 mg $(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. quinquefolium and from 2.08 to 2.59 mg$(CO_2{\cdot}dm^{-2}{\cdot}hr^{-1})$ for P. ginseng.

  • PDF

Effect of Light Pretreatment on Photosynthetic Characteristics of Leaf Blade in Japonica and Tongil Type Rice (벼 자포니카와 통일형 품종간 광전역에 따른 엽신의 광합성특성 차이)

  • 허훈;류경열
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.39 no.4
    • /
    • pp.307-316
    • /
    • 1994
  • To investigate the effect of light pretreatment on photosynthetic characteristics of leaf blade of rice, 2 varieties of japonica type and 2 varieties of tongil type were grown under 30% or 70% shading conditions from tillering stage to heading stage. Shading treatment of 70% at the heading stage produced low dry matter, and higher LAR and SLA compared with other combination of shading treatment and growing stage did. Photosynthetic activity was lower in order of 0%, 30% and 70% shading treatment under the low light intensity(5Klux) but significantly high in 30% shading treatment under the high light intensity (33Klux) at tillering stage. Photosynthetic activity under low(5Klux) and high(33Kluk) light intensity were higher in order of 70%, 30% and 0% shading treatment at heading stage. Respiration /photosynthesis ratio was lower in shading treatment than in control. CGR, RGR and NAR decreased in shading treatment. Shading treatment reduced the number of ripened grain per panicle and decreased the harvesting index.

  • PDF

Characteristics of Photosynthesis among New Cultivars of Ginseng (Panax ginseng C.A. Meyer) (인삼 신품종의 광합성 특성)

  • Lee, Sung-Sik
    • Journal of Ginseng Research
    • /
    • v.26 no.2
    • /
    • pp.85-88
    • /
    • 2002
  • This study was carried out to obtain information of the photosynthetic rate at various temperature and light intensity, stomata, chlorophyll, specific leaf weight, characteristics of aerial part and root in ginseng new cultivars developed by pure line selection. The light saturation point of leaves in new cultivars and Jakyungjong were 15,000 lux, and the optimum air temperature on the photosynthesis of new cultivars and Jakyungjong were 20$\^{C}$. The photosynthetic rates were increased in order of Jakyungjong, Gopoong, Chunpoong and Yunpoong. The dark respiration rate of leaves in ginseng cultivars were increased according to the increasing of temperature, and the dark respiration rate of leaves of Yunpoong was the highest among cultivars. The specific leaf weight (SLW) were increased in order of Jakyungjong, Yunpoong, Gopoong, Chunpoong, but total chlorophyll contents were not different among cultivars. Stomata frequency of Yunpoong was the highest being 69.2ea among cultivars, while the length of stomata was reverse. Yunpoong was superior in aerial part among ginseng cultivars : the number of stem was 1.8ea, the number of palmately leaves was 7.7ea, the number of leaflets was 41.0ea, leaf area was 12.3 dm$^2$ The root weight were increased in order of Jakyungjong, Gopoong, Chunpoong and Yunpoong. Chunpoong and Gopoong hove good root shape the length of tap root in Chunpoong and Gopoong were the longest being 6.5 cm and 6.8 cm respectively, but that in Yunpoong was the shortest being 4.4 cm.

Effects of Teaching Based on Driver's Conceptual Change Model on Rectifying High School Students' Misconception of Photosynthesis and Respiration (Driver의 개념변화 학습 모형을 적용한 수업이 고등학생들의 식물의 광합성과 호흡의 오개념 교정에 미치는 효과)

  • Kim, Dong-Ryeul
    • Journal of The Korean Association For Science Education
    • /
    • v.29 no.6
    • /
    • pp.712-729
    • /
    • 2009
  • This study aims to research high school students' misconception of botanic photosynthesis and respiration, and as the measure of rectifying the misconception, to develop the teaching program based on Driver's conceptual change model, applying it to classes and observing the effect. Selected as the research subject was sixty-six students in 1st year of a highschool located in Busan who had chosen Biology Learning as discretionary subject, with their conceptual level on botanic photosynthesis and respiration researched through tests in drawing and descriptive writing. As a consequence of applying drawing as a way of classifying the levels of students' misconception on photosynthesis and respiration, many students' drawings included their misconception caused by textbooks or scientists, but after application of Driver's conceptual change model, they drew scientific drawings including the fundamental factors of botanic photosynthesis and respiration such as light, carbon dioxide, water, glucose, oxygen, leaf, chloroplast, mitochondria, stoma, and energy. Likewise, as a result of the descriptive writing test implemented for researching the students' conception on the various aspects of botanic photosynthesis and respiration, many students in the pretest showed misconception on the point of time and location at which botanic photosynthesis and respiration occur, botanic nutrient, the role of a leaf in photosynthesis, and the relation between botanic photosynthesis and respiration, but after teaching based on Driver's conceptual change model, their misconceptions on photosynthesis and respiration were rectified to a high degree.

Changes of Characteristics Related to Photosynthesis in Synurus deltoides under Different Shading Treatments (차광처리에 따른 수리취의 광합성 관련 특성 변화)

  • Lee, Kyeong-Cheol;Noh, Hee-Sun;Kim, Jong-Whan;Ahn, Soo-Yong;Han, Sang-Sup
    • Korean Journal of Medicinal Crop Science
    • /
    • v.20 no.5
    • /
    • pp.320-330
    • /
    • 2012
  • This study was conducted to investigate the changes of chlorophyll contents, chlorophyll fluorescence, photosynthetic parameters, and leaf growth of Synurus deltoides under different shading treatments. S. deltoides was grown under non-treated (full sunlight) and three different shading conditions (Shaded 88~93%, 65~75%, and 45%~55%). Light compensation point ($L_{comp}$), dark respiration ($D_{resp}$), maximum photosynthesis rate ($Pn_{max}$), photo respiration rate ($P_{resp}$), carboxylation efficiency ($\Phi_{carb}$), and photochemical efficiency were decreased with increasing shading level; However, $CO_2$ compensation point ($CO_{2\;comp}$), total chlorophyll content, and specific leaf area (SLA) were shown the opposite trend. S. deltoides under 88~93% treatment showed the lowest photosynthetic activity such as maximum photosynthetic rate ($Pn_{max}$), photochemical efficiency, and $CO_2$ compensation point ($CO_{2\;comp}$). Therefore, photosynthetic activity will be sharply decreased with a long period of 8~12% of full sunlight. With the shading level decreased, carotenoid content and non-photochemical fluorescence quenching (NPQ) increased to prevent excessive light damage. This result suggested that growth and physiology of S. deltoides adapted to high light intensity through regulating its internal mechanism.

Physiological Response and Growth Performance of Parasenecio firmus under Different Shading Treatments (차광처리에 따른 병풍쌈의 생리반응 및 생장특성)

  • Lee, Kyeong-Cheol;Lee, Hak-Bong;Park, Wan-Geun;Han, Sang-Sup
    • Korean Journal of Agricultural and Forest Meteorology
    • /
    • v.14 no.2
    • /
    • pp.79-89
    • /
    • 2012
  • This study was conducted to investigate the chlorophyll contents, photosynthetic characteristics, chlorophyll fluorescence, and growth performance of Parasenecio firmus under changing light environment. Parasenecio firmus was grown under non-treated (full sunlight) and three different shading conditions (88~93%, 65~75% and 45%~55% of full sunlight) for the experiment. Total chlorophyll content, photochemical efficiency (Fv/Fm), T/R ratio, specific leaf area (SLA), leaf area ratio (LAR), and leaf weight ratio (LWR) were increased with increasing shading level, but decreased dark respiration. Therefore, light absorption and light utilization efficiency were improved under the low intensity light. Plants under 65~75% of full sunlight had best maximum photosynthetic rate and net apparent quantum yield in May. On the other hand, the non-treated plants had lower maximum photosynthetic rate, photochemical efficiency, and chlorophyll content than the treated ones. Parasenecio firmus considered to be a sciophyte, is fairly sensitive to high intensity light. If 88-93% of full sunlight lasts for a long period, photosynthetic capacity will be sharply decreased, though limiting light. These results suggest that growth of Parasenecio firmus adapted to 65~75% of full sunlight.

Studies on the Photosynthesis of Korean Ginseng III. Effects of the Light Transparent Rate of Shading on the Photosynthesis Ability of Korean Ginseng Plant (Panax ginseng C. A. Meyer) (고려인삼엽의 광합성능력에 관한 연구 III. 투광율이 광합성 능력에 미치는 영향)

  • 조재성;원준연;목성균
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.31 no.4
    • /
    • pp.408-415
    • /
    • 1986
  • This study was conducted to define the effects of light transparent rate of the shading on the photosynthesis ability of the ginseng leaves and their seasonal changes. Regardless the effects of light transparent rate of shading and age of ginseng plant, 10,000 lux was the most adequate light intensity for the maximum photosynthesis of ginseng leaves and seasonal difference was not significant. The ginseng plants which were grown under 10 to 15 percent light transparent shading showed the highest photosynthesis ability. The photosynthesis ability of ginseng leaves was significantly decreased in September than June and the decreasing rate was higher at the ginseng plants planted on back rows than front rows. In June, the ginseng plants grown under 10 to 15 percent light transparent shading showed high respiration amount but in September, those grown under 20 to 25% light transparent shading showed the highest respiration. The amount of chlorophyll of ginseng leaf was significantly decreased by increasing light transparent rate of shading.

  • PDF

Alteration of Gas Exchange in Rice Leaves Infected with Magnaporthe grisea

  • Yun, Sung-Chul;Kim, Pan-Gi;Park, Eun-Woo
    • The Plant Pathology Journal
    • /
    • v.16 no.5
    • /
    • pp.257-263
    • /
    • 2000
  • Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

  • PDF