THE EFFECT OF LEAF WATER BALANCE ON THE SUSCEPTIBILITY OF FRENCH BEAN TO TOBACCO NECROSIS VIRUS

1967 ◽  
Vol 45 (11) ◽  
pp. 2115-2118 ◽  
Author(s):  
W. C. Kimmins ◽  
R. E. Litz
Keyword(s):  
Relative Humidity ◽  
Turgor Pressure ◽  
Continuous Light ◽  
French Bean ◽  
Tobacco Necrosis Virus ◽  
Culture Solution ◽  
Pressure Measurements ◽  
Necrosis Virus ◽  
Continuous Darkness ◽  
High Suction

French beans were germinated under constant temperature, relative humidity, and day period, and were transferred to Hoagland's culture solution. Variations of the preinoculation treatment were begun at an age of 10 days for a period of 24 h. Treatments were selected which would induce turgor changes in the primary leaves.It was observed that susceptibility to tobacco necrosis virus infection was increased by preinoculation conditions of continuous darkness, high relative humidity, and low suction tension of the culture solution. Susceptibility was lowered by preinoculation conditions of continuous light, low relative humidity, and high suction tension of the culture solution.Diffusion pressure deficit, osmotic pressure, and turgor pressure measurements were made with the primary leaves at time of inoculation. Considerable agreement was noted between turgor changes and susceptibility.Preinoculation treatments such as darkening will alter susceptibility through changes in turgor pressure. It is suggested that there may be a direct effect of leaf turgor on the number of infectible sites.

Stipple streak disease of French bean caused by a tobacco necrosis virus in Queensland

1968 ◽  
Vol 19 (5) ◽  
pp. 731 ◽  
Author(s):  
GM Behncken
Keyword(s):  
French Bean ◽  
Tobacco Necrosis Virus ◽  
Serological Evidence ◽  
Necrosis Virus ◽  
Leaf Vein ◽  
Satellite Virus ◽  
Vein Necrosis ◽  
Stem Necrosis ◽  
Olpidium Brassicae

A disease of beans in the Nambour district of Queensland has been shown to be stipple streak disease caused by a tobacco necrosis virus. Symptoms include leaf vein necrosis, stem necrosis, and occasionally necrotic lesions on the pods. In glasshouse tests symptoms developed more rapidly, and were more severe, at temperatures of 80–88°F than at 62–70°. The virus was readily transmitted by zoospores of a lettuce isolate of the fungus Olpidium brassicae (Wor.) Dang. Serological evidence is presented which indicates that the virus is an "A" serotype strain of tobacco necrosis virus. No evidence for the presence of an associated satellite virus was found.

THE EFFECT OF DARKENING ON THE SUSCEPTIBILITY OF FRENCH BEAN TO TOBACCO NECROSIS VIRUS

1967 ◽  
Vol 45 (5) ◽  
pp. 543-553 ◽  
Author(s):  
W. C. Kimmins
Keyword(s):  
Carbon Dioxide ◽  
Light Intensity ◽  
French Bean ◽  
Tobacco Necrosis Virus ◽  
Plant Water ◽  
Necrosis Virus ◽  
Free Air ◽  
Detached Leaves ◽  
Resistance To Infection ◽  
Increased Susceptibility

Darkening of plants of Phaseolus vulgaris var. Prince for 3–108 h before inoculation with tobacco necrosis virus increased the susceptibility of the primary leaves to infection. The maximum number of lesions was obtained when plants were in darkness for 96 h. Darkening produced similar results on detached leaves and decapitated plants. The largest differences in susceptibility between shaded and illuminated plants were found in plants 9–12 days old. In plants 22–24 days old, darkening did not increase susceptibility. When 10-day-old plants were darkened for 24 h, the increased susceptibility that resulted persisted up to 6–8 h after the plants had been returned to light. Short periods (1, 10, and 20 min) of light given at varying times throughout a 24-h period of darkening did not alter susceptibility. Lowering of the light intensity to 250 lumens/ft2 failed to reduce resistance to infection. However, below 250 lumens/ft2 susceptibility increased with decreasing light intensity. Plants in the light or dark were more susceptible when supplied with carbon dioxide free air. When a relative humidity of 20% was used, darkening the plants no longer increased their susceptibility.It is suggested that there are a greater number of infectible sites present in darkened plants, and that this situation may be effected through some aspect of plant water relationships.

scholarly journals Effect of relative humidity, temperature, light and plant age on infection of lowbush blueberry by Sphaerulina vaccinii

Plant Disease ◽  
2021 ◽  
Author(s):  
Pervaiz Abbasi ◽  
Paul Hildebrand ◽  
Shawkat Ali ◽  
Debra Moreau ◽  
Willy Renderos
Keyword(s):  
Relative Humidity ◽  
Continuous Light ◽  
Free Water ◽  
Stem Canker ◽  
Plant Age ◽  
Continuous Darkness ◽  
Lowbush Blueberry ◽  
Close Proximity ◽  
The Impact ◽  
Humid Period

Leaf spot and stem canker caused by Sphaerulina vaccinii is associated with premature defoliation in lowbush blueberry resulting in reduced yields. In this study, we investigated the impact of free water, relative humidity (RH), temperature, light, and plant age on leaf infection under controlled conditions. On potato dextrose agar, germination of conidia was usually polar. Growth was minimal at 5 and 10°C, increased at 15 and 20°C, was maximal at 25°C and decreased at 30°C. Percentage of germinated conidia on inoculated blueberry leaves incubated in dark controlled-humidity chambers for 3 days (25°C) was 86.0, 90.5, 81.3 and 28.3% in free water, 100, 97.5 or 95% relative humidity (RH), respectively. Germination did not occur at 90 or 85% RH. Infection of inoculated plants, however, was not favored by free water, but rather by high RH (>95%) and a 14-h photoperiod (180 µmol/m2/s). Infection failed in continuous darkness, continuous light or continuous darkness followed by 4, 8 or 12 h of light. Light and scanning electron microscopy showed that hyphal penetration into stomata on abaxial leaf surfaces was strongly tropic. When germ tubes grew in close proximity to a stomate, a penetration hypha formed at about 90° angles to the germ tube and took the closest path to the stomate. Stomatal penetration was usually direct, but occasionally appressorium-like hyphal swellings formed over stomatal openings. When inoculated plants were exposed to high RH (>95%) at various temperatures, infection occurred after 4 days at 10°C, after 3 days at 15°C and after 1 day at 20 and 25°C. Infection failed to occur at 30°C. Disease severity also increased with duration of the humid period. When leaves were examined microscopically, those that had been incubated for 6 days showed a substantially greater network of epiphytic growth with more stomatal penetrations compared to those incubated for 3 days. Infection was substantially reduced when the humid period was interrupted by alternating days of low RH (60%). Two-week-old leaves were 2.7 times more susceptible than 8-week-old leaves.

scholarly journals Regioselective Base-induced Condensations of Acrylic Acid Derivatives

1999 ◽  
Vol 23 (3) ◽  
pp. 174-175
Author(s):  
E. Abdel-Ghani
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Dicarboxylic Acid ◽  
Ethyl Acetoacetate ◽  
Tobacco Necrosis Virus ◽  
Necrosis Virus ◽  
Antiviral Activities

The orientation of cyclization of the reaction of methyl aroylacrylate (1) and aroylacrylic acid (8) with ethyl acetoacetate and/or thiourea leading to the formation of 4-aroylmethylcyclopentane-1,3-dione (2) 5-aryl-3-oxocyclohexene-1,2-dicarboxylic acid (9), 2-imino-5-aroylmethylthiazolidin-4-one (11) and 6-aryl-2-sulfonylpyrimidine-4-carboxylic acid (14) depends on the medium employed; some compounds show moderate antiviral activities against tobacco necrosis virus.

Direct turgor pressure measurements in individual leaf cells of Tradescantia virginiana

Planta ◽  
1980 ◽  
Vol 149 (5) ◽  
pp. 445-453 ◽  
Author(s):  
U. Zimmermann ◽  
D. H�sken ◽  
E.-D. Schulze
Keyword(s):  
Turgor Pressure ◽  
Pressure Measurements ◽  
Tradescantia Virginiana ◽  
Individual Leaf
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