• Title/Summary/Keyword: stomatal response

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Effects of the Light Source of LEDs on the Physiological and Flowering Response of Endangered Plant Silene capitata Kom. (LED광질에 따른 분홍장구채(Silene capitata Kom.)의 생리 및 개화 반응)

  • Park, Jae Hoon;Lee, Eung Pill;Lee, Soo In;Jang, Rae Ha;An, Kyung Ho;You, Young Han
    • Korean Journal of Environment and Ecology
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    • v.30 no.5
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    • pp.821-828
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    • 2016
  • We examed physiological and flowering response of S. capitata, the endangered plant in Korea, under LED light conditions in plant factory to cultivate artificially for conservation. We cultivated S. capitata and measured its physiological responses and the number of flowers under red, blue, white, red+far-red mixed, red+blue mixed, and red+blue+white mixed light. The results showed that its photosynthetic rate and chlorophyll content were recorded relatively high in red+blue+white and red+blue mixed light respectively. Transpiration rate and stomatal conductance appeared relatively high in the white single light while water use efficiency was no difference. Photochemical efficiency of photochemical photosystem II by minimum and maximum chlorophyll fluorescence was the highest in the red+blue+white mixed light condition than other ones. The number of flowers of S. capitata was at its peak under the red light or red+far-red mixed light. Therefore, we conclude that the most efficient way to grow for flowering of S. capitata is to provide red light or red+far-red mixed light in the plant factory.

Physiological Response and Cadmium Accumulation of MuS1 Transgenic Tobacco Exposed to High Concentration of Cd in Soil: Implication to Phytoremediation of Metal Contaminated Soil (토양 중 고농도 카드뮴에 노출된 MuS1 형질전환 담배 (Nicotiana tabacum cv. Xanthi)의 생리적 반응 및 카드뮴 축적: 식물학적 오염토양정화를 위한 형질전환 식물 탐색)

  • Jeoung, Yoon-Hwa;Kim, Young-Nam;Kim, Kwon-Rae;Kim, Kye-Hoon
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.1
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    • pp.58-64
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    • 2013
  • The objective of this study was to understand the physiological response and cadmium accumulation of MuS1 transgenic tobacco exposed to high concentration of Cd in soil. For this, a pot experiment was carried out in a greenhouse for a month, with two lines of MuS1 transgenic tobaccos (S4 and S6) and non-transgenic tobacco cultivated in the soils spiked at three different Cd concentrations (0, 60 and 180 mg $kg^{-1}$). Both transgenic and non-transgenic tobacco showed visible toxic symptoms such as chlorosis and leaf roll as treated concentration increased. The net photosynthetic rates of MuS1 plants (S4 and S6) exposed at 180 mg $kg^{-1}$ Cd were 6.3 and $7.7{\mu}mol\;m^{-2}s^{-1}$, being higher than those of the non-transgenic plant ($4.8{\mu}mol\;m^{-2}s^{-1}$). Values of stomatal conductance of MuS1 transgenic plants (0.05 and 0.008 mmol $H_2O\;m^{-2}s^{-1}$) were also higher than those of non-transgenic plant (0.03 mmol $H_2O\;m^{-2}s^{-1}$). In addition, fresh and dry weights of MuS1 transgenic plants were heavier than those of non-transgenic plant. Likewise, MuS1 transgenic plants appeared to be better physiological performance than non-transgenic tobacco when exposed at high concentration of Cd in soil. With regard to metal accumulation, MuS1 transgenic tobaccos accumulated more Cd in their roots than non-transgenic tobacco implying that MuS1 transgenic tobacco is suggested to be used for phytostabilization of heavy metals.

Growth and Physiological Response in Container of Daphniphyllum macropodum by Shading Level (피음 수준에 따른 굴거리나무의 용기 내 생장 및 생리적 반응)

  • Song, Ki Seon;Kim, Jong Jin
    • Journal of Korean Society of Forest Science
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    • v.106 no.1
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    • pp.33-39
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    • 2017
  • This study was carried out in order to closely examine the growth and the physiological response by shading levels of a container seedling of Daphniphyllum macropodum which is known as the species of having shade tolerance in a warm temperature evergreen broad-leaved tree. The shading treatment was regulated with the shading level of full sunlight, and 35%, 55%, 75% of full sunlight. As a result of surveying the height and the root collar diameter growth by the shading level, the height was the highest with 13.2 cm under 35% of shading. The root collar diameter was the highest with 4.99 mm under full sunlight. The organ-based (leaves, shoot and root) dry mass production and the whole dry mass production were higher with 1.38 g, 0.47 g, 0.87 g, 2.72 g, respectively, in order of 35% shading. As for chlorophyll a, b, and the total chlorophyll content, the highest chlorophyll content was shown under 75% of shading with the relatively highest shading level. The ratio of chlorophyll a to chlorophyll b (a/b) was the highest under 35% of shading. The photosynthetic rate, stomatal conductance and water use efficiency were the highest with $12.3{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$, $0.27molH_2O{\cdot}m^{-2}{\cdot}s^{-1}$, $3.53{\mu}molCO_2{\cdot}mmol^{-1}H_2O$, respectively, under 35% of shading. As a result of surveying the whole experiment, D. macropodum grows nicely by maintaining 35% shading.

Growth and Physiological Adaptations of Tomato Plants (Lycopersicon esculentum Mill) in Response to Water Scarcity in Soil (토양 수분 결핍에 따른 토마토의 생육과 생리적응)

  • Hwang, Seung-Mi;Kwon, Taek-Ryun;Doh, Eun-Soo;Park, Me-Hea
    • Journal of Bio-Environment Control
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    • v.19 no.4
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    • pp.266-274
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    • 2010
  • This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.

Effect of Light Conditions on Photoinhibition of Ginseng and Tobacco (광조건이 인삼과 잎담배의 광저해에 미치는 영향)

  • ;Il Hou
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.30 no.2
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    • pp.126-130
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    • 1985
  • Photoinhibition studies were conducted with ginseng (Panax ginseng) grown under shade and tobacco (N. tobaccum cv. Bulgaria) grown under full sunlight. The plants were exposed to light intensity of 580, 1280, 1770, 2580 ${\mu}$E/㎡/sec in normal air for 3.6 9 hours. Light saturation of ginseng was observed at 550 ${\mu}$E/㎡/sec and that of tobacco was at 1600 ${\mu}$E/㎡/sec. Tobacco exposed to high light intensity and long duration of light irradiation didn't show entire reduction in photosynthetic capacity. But in ginseng, 20.3% of photosynthesis was reduced in light intensity of 2,580 ${\mu}$E/㎡/sec during 9 hours. Light response in photosynthesis differed considerably between tobacco and ginseng, and ginseng exposed to high light intensity showed remarkable reduction in photosynthesis. The extent of photoinhibition of ginseng was dependent on the length of exposure to the high light intensity. Stomatal resistance of ginseng seemed not to be changed by photoinhibition but mesophyll resistance was increased.

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Gravitropism in the Salt-Stressed Primary Root of Maize (Zea mays) (염분 스트레스에 노출된 옥수수(Zea mays) 뿌리의 굴중성 반응)

  • Han, Du-Yeol;Lee, Young-Na;Kim, Yeo-Jae;Park, Woong-June
    • Journal of Life Science
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    • v.18 no.8
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    • pp.1164-1168
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    • 2008
  • We investigated gravitropic responses in the primary root of maize (Zea mays) seedlings which were exposed to salt stress. The maize roots salt-stressed with higher than 100 mM NaCl or KCl started to reveal enhanced gravitropic curvature after 2 hours form the gravi-stimulation. Such a promotion was not caused by sodium phosphate, but invoked by potassium phosphate, indicating the active component is $K^{+}$. Because NaCl increased gravitropic curvature, despite that $Na^{+}$ did not played any role, we evaluated the role for $Cl^{-}$ by comparing the effects of $MgCl_2$ and $MgSO_4$. The enhancement of the curvature only with $MgCl_2$ revealed that $Cl^{-}$ played a role in the gravi-response, indicating the involvement of anion channels. These results suggest that both of $K^{+}$ and $Cl^{-}$ play roles in the regulation of osmosis that is required for cell expansion in gravitropism as well as in nyctinasty and stomatal opening.

Influence of Drought and High Temperature on the Physiological Response and Yield in Hot Pepper (토양 건조 스트레스와 기온상승에 의한 고추의 생리반응 및 생산량 변화)

  • Lee, Sang Gyu;Lee, Hee Ju;Kim, Sung Kyeom;Mun, Bo heum;Lee, Jin Hyoung;Lee, Hee Su;Do, Kyung Ran
    • Journal of Environmental Science International
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    • v.27 no.4
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    • pp.251-259
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    • 2018
  • This study was conducted to determine the effects of combination of air temperature and soil water content on the growth, physiological disorder rate, and yield of hot peppers. The study was carried out in a typical plastic house (open on one side and with ventilation fans on the other side), which was maintained with gradient air temperature (maximum difference in air temperature: $6^{\circ}C$). The deficit irrigation (DI) treatment commenced 65 days after transplanting. The height of plant and fresh and dry weights of the stem increased at high air temperature (ambient + $6^{\circ}C$, extreme high temperature; EHT). Furthermore, the leaf area decreased significantly with the DI treatment. There were no significant differences in the stem diameter, number of branches, and fresh and dry weights of the leaves among all the treatments. The net photosynthesis rate of the full irrigation (FI) treatment was higher than that of the DI treatment. The photosynthesis rate at ambient air temperature was $19.7{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$, the highest among all the treatments; however, the photosynthesis rate of the EHT treatment decreased by 60% ($12.3{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$). Additionally, the formation of guard cells in the leaf was abnormal with the EHT treatment, and there was a decrease in translocation efficiency. The effects of air temperature treatment were more pronounced on the physiological disorder rate and yield. The physiological disorder rate of the EHT treatment was the highest under the DI treatment condition. The yield of the AFI (ambient air temperature with full irrigation) treatment was 3,771 kg/10a, the highest among all the treatments; however, the yield of the EHT treatment with DI and FI was 1,282 and 1,327 kg/10a, respectively. These results indicate that growth and physiological disorder rate improved with the EHT treatment; however, there was a decrease in yield. Furthermore, the formation of guard cells was abnormal and malfunctional.

Changes in Photosynthesis and Carbohydrate Reserves of 'Fuji'/M9 Apple trees in Response to Early Defoliation at Growing Period (생육기 조기낙엽에 따른 사과 '후지'/M9의 광합성과 탄수화물의 변화)

  • Jeong, Jae Hoon;Han, Jeom Hwa;Ryu, Suhyun;Han, Hyun Hee;Kwon, YongHee;Do, Gyung-Ran;Yim, Sun-Hee;Lee, Han-Chan
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.291-296
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    • 2017
  • This study was conducted to evaluate the influence of early defoliation on photosynthesis and carbohydrate reserves when the source leaves of 'Fuji'/M9 apple (Malus domestica Borkh.) trees were removed during the growing period. Bud regrowth rates of 80%, 50% defoliation and non-defoliation treatments were significantly different 82.7%, 45.9% and 2.1% respectively at 30 days after treatment. In all treatments, sucrose and starch concentrations in remaining leaves decreased non-significantly during the 14-day period. No significant changes were observed for total soluble carbohydrates in non-defoliation and 50% defoliation. However, in 80% defoliated treatments, concentrations of sorbitol and total soluble carbohydrates in remaining leaves declined steadily during the 14-day period. It is thought that high sink strength increases the requirements of carbohydrate from remaining leaves more than non-defoliated. The concentrations of starch in the roots tend to decrease non-significantly as percentage of defoliation increased. Photosynthesis of remaining leaves was monitored during the 14-day period after partial defoliation treatments. Net photosynthetic rates (Pn) and stomatal conductance were significantly enhanced in the 80% defoliation. The observed photosynthetic enhancement following partial defoliation may have been due to the enhancement of osmotic potential in leaves. These results were estimated that increasing of photosynthetic rate in the partial defoliation is due to the sink carbohydrate requirements for the current year's secondary growth of buds.

Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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Evaluation of Photochemical Reflectance Index (PRI) Response to Soybean Drought stress under Climate Change Conditions (기후변화 조건에서 콩 한발스트레스에 대한 광화학 반사 지수 반응 평가)

  • Sang, Wan-Gyu;Kim, Jun-Hwan;Shin, Pyeong;Baek, Jae-Kyeong;Lee, Yun-Ho;Cho, Jung-Il;Seo, Myung-Chul
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.21 no.4
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    • pp.261-268
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    • 2019
  • Climate change and drought stress are having profound impacts on crop growth and development by altering crop physiological processes including photosynthetic activity. But finding a rapid, efficient, and non-destructive method for estimating environmental stress responses in the leaf and canopy is still a difficult issue for remote sensing research. We compared the relationships between photochemical reflectance index(PRI) and various optical and experimental indices on soybean drought stress under climate change conditions. Canopy photosynthesis trait, biomass change, chlorophyll fluorescence(Fv/Fm), stomatal conductance showed significant correlations with midday PRI value across the drought stress period under various climate conditions. In high temperature treatment, PRI were more sensitive to enhanced drought stress, demonstrating the negative effect of the high temperature on the drought stress. But high CO2 concentration alleviated the midday depression of both photosynthesis and PRI. Although air temperature and CO2 concentration could affect PRI interpretation and assessment of canopy radiation use efficiency(RUE), PRI was significantly correlated with canopy RUE both under climate change and drought stress conditions, indicating the applicability of PRI for tracking the drought stress responses in soybean. However, it is necessary to develop an integrated model for stress diagnosis using PRI at canopy level by minimizing the influence of physical and physiological factors on PRI and incorporating the effects of other vegetation indices.