The Experts below are selected from a list of 1533 Experts worldwide ranked by ideXlab platform
Ichiro Terashima - One of the best experts on this subject based on the ideXlab platform.
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apoplastic mesophyll signals induce rapid stomatal responses to co2 in Commelina communis
New Phytologist, 2013Co-Authors: Takashi Fujita, Ko Noguchi, Ichiro TerashimaAbstract:Summary Previous studies have suggested that the mesophyll contributes to stomatal CO2 responses. The effects of changes in CO2 concentration (100 or 700 ppm) on stomatal responses in red or white light were examined microscopically in a leaf segment, an epidermal strip and an epidermal strip placed on a mesophyll segment of Commelina communis, all mounted on a buffer-containing gel. In both red and white light, stomata of the leaf segment opened/closed rapidly at low/high CO2. In red light, epidermal strip stomata barely responded to CO2. In white light, they opened at low CO2, but hardly closed at high CO2. Stomata of the epidermal strip placed on the mesophyll responded in the same manner as those on the leaf segment. Insertion of a doughnut-shaped cellophane spacer (but not polyethylene spacer) between the epidermal strip and the mesophyll hardly altered these responses. Stomata in leaf segments treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), a photosynthesis inhibitor, did not open in red light, but opened/closed at low/high CO2 in white light. These results indicate that the apoplast transfer of ‘mesophyll signals’ and the stomatal opening at low CO2 are dependent on photosynthesis, whereas the stomatal closure at high CO2 is independent of photosynthesis.
Takashi Fujita - One of the best experts on this subject based on the ideXlab platform.
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apoplastic mesophyll signals induce rapid stomatal responses to co2 in Commelina communis
New Phytologist, 2013Co-Authors: Takashi Fujita, Ko Noguchi, Ichiro TerashimaAbstract:Summary Previous studies have suggested that the mesophyll contributes to stomatal CO2 responses. The effects of changes in CO2 concentration (100 or 700 ppm) on stomatal responses in red or white light were examined microscopically in a leaf segment, an epidermal strip and an epidermal strip placed on a mesophyll segment of Commelina communis, all mounted on a buffer-containing gel. In both red and white light, stomata of the leaf segment opened/closed rapidly at low/high CO2. In red light, epidermal strip stomata barely responded to CO2. In white light, they opened at low CO2, but hardly closed at high CO2. Stomata of the epidermal strip placed on the mesophyll responded in the same manner as those on the leaf segment. Insertion of a doughnut-shaped cellophane spacer (but not polyethylene spacer) between the epidermal strip and the mesophyll hardly altered these responses. Stomata in leaf segments treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), a photosynthesis inhibitor, did not open in red light, but opened/closed at low/high CO2 in white light. These results indicate that the apoplast transfer of ‘mesophyll signals’ and the stomatal opening at low CO2 are dependent on photosynthesis, whereas the stomatal closure at high CO2 is independent of photosynthesis.
Ko Noguchi - One of the best experts on this subject based on the ideXlab platform.
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apoplastic mesophyll signals induce rapid stomatal responses to co2 in Commelina communis
New Phytologist, 2013Co-Authors: Takashi Fujita, Ko Noguchi, Ichiro TerashimaAbstract:Summary Previous studies have suggested that the mesophyll contributes to stomatal CO2 responses. The effects of changes in CO2 concentration (100 or 700 ppm) on stomatal responses in red or white light were examined microscopically in a leaf segment, an epidermal strip and an epidermal strip placed on a mesophyll segment of Commelina communis, all mounted on a buffer-containing gel. In both red and white light, stomata of the leaf segment opened/closed rapidly at low/high CO2. In red light, epidermal strip stomata barely responded to CO2. In white light, they opened at low CO2, but hardly closed at high CO2. Stomata of the epidermal strip placed on the mesophyll responded in the same manner as those on the leaf segment. Insertion of a doughnut-shaped cellophane spacer (but not polyethylene spacer) between the epidermal strip and the mesophyll hardly altered these responses. Stomata in leaf segments treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), a photosynthesis inhibitor, did not open in red light, but opened/closed at low/high CO2 in white light. These results indicate that the apoplast transfer of ‘mesophyll signals’ and the stomatal opening at low CO2 are dependent on photosynthesis, whereas the stomatal closure at high CO2 is independent of photosynthesis.
Bing Feihong - One of the best experts on this subject based on the ideXlab platform.
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Protective effect of homonojirimycin from Commelina communis (dayflower) on influenza virus infection in mice.
Phytomedicine, 2013Co-Authors: Guo-bin Zhang, Liao Yifan, Li Jing, Lian-qi Tian, Bing FeihongAbstract:The effects of homonojirimycin (HNJ), one of alkaloids from Commelina communis L., on protection against influenza virus infection in mice were investigated. HNJ was found to improve the survival rate, prolong the mean survival time and reduce virus yields in lungs on days 4 and 6 post-infection (p.i.), after the agent had been orally administered to the mice from 2 days before infection to 6 days p.i. Administration of HNJ (1 mg/kg) significantly increased interferon (IFN)-γ and interleukin (IL)-10 levels but decreased tumor necrosis factor (TNF)-α and IL-6 levels in serum and lungs of influenza-infected mice on days 2, 4 or 6 p.i. These results showed that HNJ exerted protection against influenza virus infection and produced effective immune responses in vivo.
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Effect of total alkaloids from Commelina communis L. on lung damage by influenza virus infection.
Microbiology and Immunology, 2010Co-Authors: Guo-bin Zhang, Bing Feihong, Liu Jun, Liao Yifan, Li Jing, Chang-yuan DongAbstract:Whether administration of total alkaloids from Commelina communis L. (TAC) reduces lung damage in influenza virus-infected mice was investigated. Compared with untreated mice, significantly less severe damage was found in the lungs of mice administered TAC at 8 mg/kg per day for 6 days. TAC significantly decreased viral loads in the lungs. The concentrations of IFN-γ in the serum of TAC-treated mice were significantly lower than those of virus control mice at 4 and 6 days post-infection. The results indicate that TAC imparted partial protection to the mice by reducing pulmonary viral loads and limiting lesions in the lungs.
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Anti-influenza-virus activity of total alkaloids from Commelina communis L.
Archives of Virology, 2009Co-Authors: Bing Feihong, Liu Jun, Guo-bin Zhang, Liao Yifan, Li Jing, Chang-yuan DongAbstract:The antiviral activity of total alkaloids from Commelina communis L. (TAC) against influenza virus A/PR/8/34 (H1N1) was investigated in vitro and in vivo. TAC exhibited an inhibitory action on the growth of influenza virus in Madin-Darby canine kidney cells when added before or after viral infection. In mice infected with influenza virus, orally administered TAC at 8, 16 or 32 mg/kg per day for 6 days significantly increased the survival rate, prolonged the mean survival time and reduced the viral titers in the lung and the lung index, compared with that of the untreated virus control. The results obtained suggest that TAC has a pronounced protective effect against infection by influenza A virus.
Sarah M. Assmann - One of the best experts on this subject based on the ideXlab platform.
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Effects of light quantity and quality during development on the morphology and stomatal physiology of Commelina communis.
Oecologia, 1992Co-Authors: Sarah M. AssmannAbstract:The effects on plant growth and stomatal physiology of alterations in light quantity and quality during development were investigated in the C3 monocot, Commelina communis. Reduction in light intensity resulted in decreased branching and stem elongation, with effects more severe under “neutral shade” (R:FR≥1.0) than under “leaf shade” (R:FR≤0.4) conditions. Shade treatments had no effect on the leaf area or stomatal density of newly expanded leaves. Gas exchange measurements on leaves that had expanded under the different treatments indicated that a reduction in light intensity decreased the magnitude and slowed the kinetics of stomatal responses to pulses of blue light, particularly in plants from the neutral shade treatment. These results indicate that the specific stomatal response to blue light is plastic, and is modulated by the light environment prevailing during leaf development.
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Vanadate inhibition of stomatal opening in epidermal peels of Commelina communis
1990Co-Authors: Amnon Schwartz, Nitza Illan, Sarah M. AssmannAbstract:An H+ ATPase at the plasma-membrane of guard cells is thought to establish an electrochemical gradient that drives K+ and Cl− uptake, resulting in osmotic swelling of the guard cells and stomatal opening. There are, however, conflicting results regarding the effectiveness of the plasma-membrane H+-ATPase inhibitor, vanadate, in inhibiting both H+ extrusion from guard cells and stomatal opening. We found that 1 mM vanadate inhibited light-stimulated stomatal opening in epidermal peels of Commelina communis L. only at KCl concentrations lower than 50 mM. When impermeant n-methylglucamine and HCl (pH 7.2) were substituted for KCl, vanadate inhibition was still not observed at total salt concentrations≥50 mM. In contrast, in the absence of Cl−, when V2O5 was used to buffer KOH, vanadate inhibition of stomatal opening occurred at K+ concentrations as high as 70 mM. Partial vanadate inhibition was observed in the presence of the impermeant anion, iminodiacetic acid (100 mM KHN(CH2CO2H)2). These results indicate that high concentrations of permeant anions prevent vanadate uptake and consequently prevent its inhibitory effect. In support of this hypothesis, an inhibitor of anion uptake, anthracene-9-carboxylic acid, partially prevented vanadate inhibition of stomatal opening. Other anion-uptake inhibitors (1 mM 4,4-diisothiocyanatostilbene-2,2′-disulfonic acid, 1 mM 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonic acid, 200 μM Zn2+) were not effective. Decreased vanadate inhibition at high Cl−/vanadate ratios may result from competition between vanadate and Cl− for uptake. Unlike metabolic inhibitors, vanadate did not affect the extent of stomatal closure stimulated by darkness, further indicating that the observed action of vanadate represents a specific inhibition of the guard-cell H+ ATPase.