Stimulation of Net Photosynthesis in Cucumber Leaf Discs: Effect of K-Glyoxylate and KCL

1984 ◽  
Vol 35 (7) ◽  
pp. 941-947 ◽  
Author(s):  
MONICA MADORE ◽  
BERNARD GRODZINSKI
Keyword(s):  
Net Photosynthesis ◽  
Leaf Discs ◽  
Stimulation Of

Techniques for Detecting Grass Tolerance to Sethoxydim and Fenoxaprop-Ethyl Herbicides

Weed Science ◽  
1991 ◽  
Vol 39 (4) ◽  
pp. 548-552 ◽  
Author(s):  
Joanna Hubbard ◽  
Ted Whitwell
Keyword(s):  
Rapid Detection ◽  
Net Photosynthesis ◽  
Rapid Screening ◽  
Leaf Photosynthesis ◽  
Screening Technique ◽  
Leaf Discs ◽  
Solute Leakage ◽  
Leaf Chlorophyll ◽  
Leaf Segments

Measurements of net photosynthesis, chlorophyllafluorescence and solute leakage were evaluated as techniques for rapid detection of grass tolerance to fenoxaprop-ethyl and sethoxydim. Net photosynthesis measured as net CO2uptake of the youngest fully expanded leaf ofCalamagrostis arundinacea‘Karl Foerster’ (Feather Reed Grass) detected tolerance to fenoxaprop-ethyl and susceptibility to sethoxydim 4 days after treatment and prior to the observation of visual injury. Sethoxydim reduced photosynthesis compared to untreated controls but fenoxaprop-ethyl did not. Measurements of older leaf (second most recently fully expanded leaf) photosynthesis were less consistent than those of the younger leaf. Chlorophyllafluorescence ofCalamagrostisleaf segments following treatment with fenoxaprop-ethyl and sethoxydim was ineffective for detecting grass tolerance. Solute leakage from leaf discs treated with 50 to 500 μg ml−1fenoxaprop–ethyl and 10 to 100 μg ml−1sethoxydim indicated differential tolerance ofCalamagrostisand johnsongrass to fenoxaprop–ethyl and centipedegrass and johnsongrass to sethoxydim. Fenoxaprop–ethyl increased solute leakage from susceptible johnsongrass at 100 μg ml−1while the 500 μg ml−1concentration was required to cause substantial solute leakage from tolerantCalamagrostis. Sethoxydim caused greater leakage from johnsongrass than from centipedegrass at 50 and 100 μg ml−1. The best potential rapid screening technique was solute leakage measurements.

scholarly journals Atmospheric CO2 availability induces varying responses in net photosynthesis, toxin production and N2 fixation rates in heterocystous filamentous Cyanobacteria (Nostoc and Nodularia)

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Nicola Wannicke ◽  
Achim Herrmann ◽  
Michelle M. Gehringer
Keyword(s):  
Nitrogen Availability ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Toxin Production ◽  
Oxygenic Photosynthesis ◽  
List Type ◽  
Filamentous Cyanobacteria ◽  
Biological Nitrogen ◽  
Stimulation Of

AbstractHeterocystous Cyanobacteria of the genus Nodularia form major blooms in brackish waters, while terrestrial Nostoc species occur worldwide, often associated in biological soil crusts. Both genera, by virtue of their ability to fix N2 and conduct oxygenic photosynthesis, contribute significantly to global primary productivity. Select Nostoc and Nodularia species produce the hepatotoxin nodularin and whether its production will change under climate change conditions needs to be assessed. In light of this, the effects of elevated atmospheric CO2 availability on growth, carbon and N2 fixation as well as nodularin production were investigated in toxin and non-toxin producing species of both genera. Results highlighted the following: Biomass and volume specific biological nitrogen fixation (BNF) rates were respectively almost six and 17 fold higher in the aquatic Nodularia species compared to the terrestrial Nostoc species tested, under elevated CO2 conditions. There was a direct correlation between elevated CO2 and decreased dry weight specific cellular nodularin content in a diazotrophically grown terrestrial Nostoc species, and the aquatic Nodularia species, regardless of nitrogen availability. Elevated atmospheric CO2 levels were correlated to a reduction in biomass specific BNF rates in non-toxic Nodularia species. Nodularin producers exhibited stronger stimulation of net photosynthesis rates (NP) and growth (more positive Cohen’s d) and less stimulation of dark respiration and BNF per volume compared to non-nodularin producers under elevated CO2 levels. This study is the first to provide information on NP and nodularin production under elevated atmospheric CO2 levels for Nodularia and Nostoc species under nitrogen replete and diazotrophic conditions.

Stimulation of ACC-dependent ethylene production in citrus leaf discs by light

1990 ◽  
Vol 80 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Lorenzo Zacarias ◽  
Darius Hidela ◽  
Eduardo Primo-Millo
Keyword(s):  
Ethylene Production ◽  
Leaf Discs ◽  
Citrus Leaf ◽  
Stimulation Of

Stimulation of ACC-dependent ethylene production in citrus leaf discs by light

1990 ◽  
Vol 80 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Lorenzo Zacarias ◽  
Darius Tudela ◽  
Eduardo Primo-Millo
Keyword(s):  
Ethylene Production ◽  
Leaf Discs ◽  
Citrus Leaf ◽  
Stimulation Of

scholarly journals Stimulation of Ethylene Production in Citrus Leaf Discs by Mannitol

1982 ◽  
Vol 70 (1) ◽  
pp. 142-146 ◽  
Author(s):  
Joseph Riov ◽  
Shang Fa Yang
Keyword(s):  
Ethylene Production ◽  
Leaf Discs ◽  
Citrus Leaf ◽  
Stimulation Of

Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

1971 ◽  
Vol 29 ◽  
pp. 570-571
Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman
Keyword(s):  
Chemical Composition ◽  
Rat Liver ◽  
Future Study ◽  
Mode Of Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Effective Inhibitor ◽  
Biochemical Effects ◽  
Glycerophosphate Dehydrogenase ◽  
Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

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