Factors affecting infection of sunflowers by Plasmopara halstedii

1973 ◽  
Vol 51 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Yigal Cohen ◽  
W. E. Sackston
Keyword(s):  
Systemic Infection ◽  
Optimum Temperature ◽  
Plasmopara Halstedii ◽  
Factors Affecting ◽  
Leaf Stage ◽  
Apical Bud ◽  
Apical Buds ◽  
Local Lesions ◽  
Young Leaves ◽  
Incubation Temperatures

Systemic infection of sunflowers by Plasmopara halstedii occurs much more readily through hypocotyls than through roots, and through apical buds than through leaves.Systemic symptoms rarely develop from belowground infections of plants past the four-leaf stage, and from apical bud infections of plants past the eight-leaf stage. Necrotic lesions may occur and the pathogen may sporulate on hypocotyls and roots of plants with no typical systemic symptoms.Infection by sporangia produces local lesions in young leaves; some of these infections may become systemic.Immersion of 3-day-old seedlings in inoculum for 1 min resulted in some infection; highest infection resulted from 3- to 6-h exposure.Systemic infection resulted from apical bud inoculation with suspensions averaging one sporangium per plant.Optimum temperature during inoculation of 3-day-old seedlings was 15°, and during incubation was 20° to 25 °C. Optimum temperature during bud inoculation was 15°; incubation temperatures from 15° to 25 °C gave essentially similar results.

Disappearance of IAA in the presence of tissues of sunflowers infected by Plasmopara halstedii

1974 ◽  
Vol 52 (4) ◽  
pp. 861-866 ◽  
Author(s):  
Yigal Cohen ◽  
W. E. Sackston
Keyword(s):  
Indoleacetic Acid ◽  
Stem Elongation ◽  
Plasmopara Halstedii ◽  
Positive Correlation ◽  
Leaf Stage ◽  
Apical Buds ◽  
Leaf Tissues ◽  
Highly Correlated ◽  
Stem Slices

Stem elongation of sunflower plants inoculated at the two-leaf stage through apical buds with Plasmopara halstedii was greatly inhibited. Systemically infected plants did not show normal phototropic and negative-geotropic responses. There was a positive correlation between stunting of infected plants and ability of stem slices to remove indoleacetic acid (IAA) from test solutions. IAA disappearance in the presence of stem slices of infected plants was also highly correlated with area of mildew symptoms on leaves. Although IAA disappeared in the presence of all diseased tissues, leaf tissues were least active. No IAA disappeared in the presence of sporangia of the pathogen. These results explain reduced levels of IAA observed in mildew-infected sunflowers in earlier studies and may account for the characteristic stunting of systemically infected plants.

scholarly journals New contribution to the survey of the acrotony theory on the branch of one year grapevine: III - Role of buds and leaves in development, application in the vineyard of results obtained in laboratory and greenhouse

OENO One ◽  
2001 ◽  
Vol 35 (1) ◽  
pp. 1
Author(s):  
Béchir Ezzili ◽  
M. Bejaoui
Keyword(s):  
Second Phase ◽  
Second Stage ◽  
Apical Bud ◽  
Apical Buds ◽  
Stage Of Development ◽  
Cytokinin Treatment ◽  
Young Leaves ◽  
One Year ◽  
Development Application

<p style="text-align: justify;">The respective influences of the bud and leaves on stimulation of acrotony phenomenon was studied. Defoliation (all leaves at the stage budbursted + 30 days) and various bud ablation were made : buds 9, 10 ; 7, 8, 9, 10 ; 5, 6, 7, 8, 9, 10 ; 3, 4, 5, 6, 7, 8, 9, 10.</p><p style="text-align: justify;">Concerning the phenomen of acrotony, the role of apical bud and leaves developped on at 10 and 30 days after budburst were determined.</p><p style="text-align: justify;">The effect produced by excision of the apical buds shows that the two subadjacent buds were developped. All decapitation did not increase the percentage of budbreak.</p><p style="text-align: justify;">In all decapitations, the subadjacent buds were developped however, buds below were inhibed. The effect produced by excision of leaves in the second stage of development did not promote budbreak.</p><p style="text-align: justify;">On 10 bud canes, auxins synthesized in the developing young leaves seem to exercise their inhibiting effect on the budbreak of the subjacent buds.</p><p style="text-align: justify;">Cytokinins managed by the means of our operatory mode seem to reach the subjacents buds, modify the expression of the ramification of the canes with regard to the system usual acrotony and limit the inhibition basipetally. The budburst of the canes at a temperature of 18°C seems to be more important than that at 30°C day/ 20°night. Thus, the acrotony phenomenon decreases. When the apical branches are in second phase of growth, the size of the leaves become large. It seems that the leaves would exercise their inhibitions on the subjacent buds by the slant of the synthesized gibberillins and auxins. Cytokinins have no further role to play during this phase of growth and do not thwart anymore the inhibition. In the vineyard, the ANA treatment is totally inhibiting at 20 and 50 mg/l doses. In contrast, the 6BAP treatment at 20 mg/l shortly before budburst increases the budburst percentage for Muscatel of Italy.</p><p style="text-align: justify;">When the last treatment is performed during 25 days followed by a cytokinin treatment we notice budburst. The mechanism of these different growth regulators on the acrotony phenomenon has been discussed .</p>

scholarly journals Survival characteristics of Salmonella enterica serovar Enteritidis in chicken egg albumen

2006 ◽  
Vol 134 (5) ◽  
pp. 967-976 ◽  
Author(s):  
H. KANG ◽  
C. LOUI ◽  
R. I. CLAVIJO ◽  
L. W. RILEY ◽  
S. LU
Keyword(s):  
Salmonella Enterica ◽  
Iron Acquisition ◽  
Foodborne Pathogen ◽  
Human Infection ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Factors Affecting ◽  
Chicken Egg ◽  
Egg Albumen ◽  
High Concentrations ◽  
Incubation Temperatures

Salmonella enterica serovar Enteritidis (SE) is a major foodborne pathogen primarily causing human infection through contaminated chicken eggs. To understand how SE survives in chicken egg albumen, we systematically and quantitatively analysed the survival properties of SE in egg albumen and identified factors affecting its survival. Survival assays of SE in egg indicate that egg albumen restricted the growth of SE. A major factor that controlled SE's growth in egg albumen was iron restriction, since egg albumen supplemented with iron allowed SE to grow, and iron acquisition mutants of SE showed decreased survival in egg albumen. In addition, low pH of albumen, high concentrations of bacteria and low incubation temperatures of bacteria with albumen facilitates the survival of SE. Our results suggest that egg albumen uses multiple mechanisms to control SE including iron limitation, surface interaction and possible enzymatic activities.

A further note on the viruses affecting Atropa belladonna and a description of a virus complex attacking Hyoscyamus niger

Parasitology ◽  
1945 ◽  
Vol 36 (3-4) ◽  
pp. 209-210 ◽  
Author(s):  
Kenneth M. Smith
Keyword(s):  
Potato Virus ◽  
Systemic Infection ◽  
Nicotiana Sylvestris ◽  
Hyoscyamus Niger ◽  
Atropa Belladonna ◽  
Naturally Occurring ◽  
Local Lesions ◽  
Virus Complex ◽  
Solanaceous Plants

It has been shown that Atropa belladonna acts as a symptomless carrier of Hyosoyamus Virus I. Some symptoms caused by this virus on other solanaceous plants are described.A naturally occurring virus complex in Hyoscyamus niger was found to consist of Solanum Virus I (potato virus X) and Brassica Virus I. During the course of the investigation it was found that potato virus X forms local lesions on the cotyledons of ridge cucumber without systemic infection and that Brassica Virus I behaves similarly on the inoculated leaves of Nicotiana sylvestris.

scholarly journals Some Variables Affecting the Use of Cowpea as an Assay Host for Cucumber Mosaic Virus

1954 ◽  
Vol 7 (2) ◽  
pp. 141 ◽  
Author(s):  
NC Crowley
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Vigna Sinensis ◽  
Factors Affecting ◽  
Local Lesions

A study was made of the factors affecting the production of local lesions by cucumber mosaic virus on cowpea (Vigna sinensis (L.) Endl. ex Hassk.).

Notes on Lygus simonyi, Reut. (Capsidae), a Cotton Pest in Uganda

1935 ◽  
Vol 26 (4) ◽  
pp. 429-438 ◽  
Author(s):  
G. L. R. Hancock
Keyword(s):  
Climatic Factors ◽  
Severe Damage ◽  
Apical Buds ◽  
Young Leaves ◽  
Cotton Pest

Lygus simonyi has been found to cause serious damage to cotton in Uganda, by sucking the young leaves and apical buds, by retarding the growth of the branches, and by sucking the young bolls.There are indications that soil and climatic factors are of importance in controlling this insect ; excessive succulence of the plant appears to be one factor associated with severe damage.

scholarly journals Strawberry latent ringspot virus Infecting Roses in India

Plant Disease ◽  
2004 ◽  
Vol 88 (1) ◽  
pp. 86-86 ◽  
Author(s):  
S. Kulshrestha ◽  
V. Hallan ◽  
G. Raikhy ◽  
R. Ram ◽  
A. A. Zaidi
Keyword(s):  
Plant Viruses ◽  
Ringspot Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chain Reaction ◽  
Specific Primers ◽  
Chenopodium Amaranticolor ◽  
Elisa Kit ◽  
Local Lesions ◽  
Young Leaves ◽  
Polymerase Chain

Rose is an economically important crop of India and the world. A survey of rose plantations in and near the Kangra Valley of Himachal Pradesh, India, showed virus-like symptoms, including yellow flecking in young leaves and reduction in leaflet size, while some were symptomless. These symptoms are similar to those for Strawberry latent ringspot virus (SLRSV) (1). Sap inoculation from symptomatic and some symptomless leaves to Chenopodium amaranticolor resulted in chlorotic local lesions followed by systemic chlorosis. SLRSV was detected in this indicator host and six rose cultivars (Happiness, Iceberg, First Prize, Ganga, Pink Panther, and Oklahoma) showing characteristic symptoms of SLRSV using enzyme-linked immunosorbent assay (ELISA) with ELISA kit (DSMZ, Braunschweig, Germany). Reverse transcription-polymerase chain reaction was performed with SLRSV-specific primers (2), and a product of the expected size of ˜181 bp was amplified. The authenticity of the fragment was confirmed by sequencing. Isolated SLRSV was also inoculated to seed-grown rose seedlings and after 20 days postinoculation the same symptoms (yellow flecking in young leaves) were observed. These results established the identity of the virus that caused yellow flecking on rose leaves in India as SLRSV. To our knowledge, this is the first report of SLRSV infecting rose in India. References: (1) A. F. Murant. Strawberry latent ringspot virus. No. 126 in: Description of Plant Viruses, CMI/AAB, Surrey, U.K., 1974. (2) E. Bertolini et al. J. Virol. Methods 96:33, 2001.

Factors Affecting the Herbicidal Activity of TCA on Green Foxtail

Weed Science ◽  
1972 ◽  
Vol 20 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Paul N. P. Chow
Keyword(s):  
High Temperature ◽  
Light Intensity ◽  
Sodium Salt ◽  
Trichloroacetic Acid ◽  
High Light ◽  
Herbicidal Activity ◽  
Setaria Viridis ◽  
Factors Affecting ◽  
Leaf Stage ◽  
Green Foxtail

Growth of green foxtail (Setaria viridis (L.) Beauv.) was effectively controlled in the greenhouse by applying the sodium salt of trichloroacetic acid (TCA) as a postemergence treatment, when a rate of 0.84 kg/ha was used; when application preceded the two-leaf stage; and when 2.54 mm of water were available daily for moving TCA into the soil. There were significant interactions of TCA rate with light intensity, temperature, and source of seeds on the response of green foxtail. Seedhead production was curtailed at rates of 0.56 kg/ha or above when plants were grown under high light intensities (19,250 to 22,000 lux) and at moderate temperatures (20 to 22 C). Rates of 1.68 kg/ha or more were required to stop heading of foxtail grown at high temperature (27 C).

Factors Affecting Seed Germination and Seedling Emergence of Asia Minor Bluegrass (Polypogon fugax)

Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 440-447 ◽  
Author(s):  
Xian Wu ◽  
Jun Li ◽  
Hongle Xu ◽  
Liyao Dong
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Late Summer ◽  
Asia Minor ◽  
Burial Depth ◽  
Optimum Temperature ◽  
Large Area ◽  
Factors Affecting ◽  
Temperature Regimes ◽  
Grass Weed

Little published information is available related to seed germination and seedling establishment of Asia Minor bluegrass, a problematic grass weed in some regions of China. The objective of this study was to examine the effects of different environmental factors on Asia Minor bluegrass seed germination. The optimum temperature for germination was around 10 to 20 C, and more than 90% of seeds germinated under 20/10 and 25/15 C temperature regimes. Also, light and pH did not appear to have any effect on seed germination. Asia Minor bluegrass was sensitive to osmotic stress, but tolerant of NaCl. No seedlings emerged when seeds were buried 4 cm deep. The result suggested that Asia Minor bluegrass has the potential to spread into a large area in China. To prevent its spreading, measures such as soil cultivation can be used to limit seed germination from increased burial depth and/or nonselective herbicides can be applied to kill early-germinating weed seedlings in late summer.

scholarly journals Presence of Anti-cystatin C–positive Dendritic Cells or Macrophages and Localization of Cysteine Proteases in the Apical Bud of the Enamel Organ in the Rat Incisor

2005 ◽  
Vol 53 (5) ◽  
pp. 643-651 ◽  
Author(s):  
Sumio Nishikawa
Keyword(s):  
Dendritic Cells ◽  
Cystatin C ◽  
Cysteine Protease ◽  
Cathepsin L ◽  
Cysteine Proteases ◽  
Cysteine Protease Inhibitor ◽  
Enamel Organ ◽  
Apical Bud ◽  
Apical Buds ◽  
Proliferation And Differentiation

Cystatin C, a cysteine protease inhibitor, was examined in the apical buds of rat incisors by immunohistochemistry, because in transition and maturation zones most of the dendritic cells in the papillary layer are anti-cystatin C–positive. Anti-cystatin C–labeled cells were sparse and localized to the proliferation and differentiation zones, constituting the apical bud of 5-week-old rat incisors. These cells were considered macrophages or dendritic cells, based on their reactivity with OX6 and ED1, as well as their ultrastructure. Basement membrane at the periphery of apical bud was also labeled by anti-cystatin C antibody. The apical buds included a few apoptotic fragments and weak reactivity with antibody to cathepsin L, a cysteine protease. Reactivity to anti-cystatin C and anti-cathepsin ∗∗∗L antibodies was also detected in the apical bud of newborn rat incisors. These results suggest that the cystatin C–positive macrophages or dendritic cells are involved in normal incisor formation. They may be related to the clearance of apoptotic cells or protection from putative cysteine protease activity.

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