EFFECT OF CROP DEBRIS, PLANT ROOTS, AND CROP SEQUENCE ON THE MICROBIAL FLORA OF THE SOIL IN RELATION TO ROOT ROT IN CEREAL CROPS

1948 ◽  
Vol 26c (1) ◽  
pp. 86-93 ◽  
Author(s):  
L. E. Tyner
Keyword(s):  
Barley Straw ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Fallow Soil ◽  
Helminthosporium Sativum ◽  
Plate Counts ◽  
Oat Straw ◽  
Field Plots ◽  
Penicillium Spp ◽  
Crop Sequence

The decomposition of wheat, oat, or barley straw in soil caused a marked increase in the microflora, as indicated by plate counts. The oat straw compost yielded significantly more colonies of fungi than either the wheat or barley straw composts. The population of bacteria and actinomycetes was increased to about the same degree by all three of the composts.In another laboratory experiment, wheat, oats, barley, and beans were planted in various rotations in pots of soil from field plots known to be heavily infested with the root-rotting pathogens Helminthosporium sativum P. K. and B., Ophiobolus graminis Sacc., and Fusarium spp. Fungi, mostly Penicillium spp. and Mucor spp., were up to 15 times more abundant from the rhizosphere of wheat roots than from the rhizosphere of oat, barley, or bean roots, regardless of crop sequence. It is assumed that the higher counts of saprophytic fungi obtained from the rhizosphere of wheat seedlings were directly correlated with the greater amount of dead root tissue on this crop, since disease on the wheat seedlings was more severe than on the other hosts. In a duplicate experiment in fallow soil, the rhizospheres of wheat, oats, barley, and beans yielded about equal numbers of fungi.

THE EFFECT OF CROP DEBRIS ON THE PATHOGENICITY OF CEREAL ROOT-ROTTING FUNGI

1940 ◽  
Vol 18c (7) ◽  
pp. 289-306 ◽  
Author(s):  
L. E. Tyner
Keyword(s):  
Plant Pathogens ◽  
Fusarium Culmorum ◽  
Barley Straw ◽  
Seedling Vigour ◽  
Wheat Seedlings ◽  
Helminthosporium Sativum ◽  
Nitrogen Ratio ◽  
Oat Straw ◽  
Micro Organisms ◽  
Cereal Root

The effect of wheat, oat, and barley straw, composted with soil, on the development of disease on the basal parts of wheat seedlings was studied in a series of greenhouse experiments during three seasons. The pathogens used were Ophiobolus graminis Sacc., Helminthosporium sativum P. K. and B., and Fusarium culmorum (W. G. Sm.) Sacc. The wheat-straw composts were distinctly more favourable to the development of disease than the composts of either oat or barley straw. The least injury occurred on seedlings grown in composts of oat straw. It is suggested that the micro-organisms associated with the decomposition of oat straw bring about some degree of biological control of the plant pathogens also present.Although the amount of straw applied sometimes influenced severity of disease, the effects were not consistent from planting to planting. Apparently the actual carbon to nitrogen ratio had less effect upon disease development than did the chemical nature of the straw.The kind and amount of straw in the composts also influenced seedling vigour. This vigour was, in general, inversely proportional to the degree of infection.The introduction of a short fallow period between plantings decreased infection somewhat and increased vigour.The pathogenicity of the artificial inoculum added at the first planting was practically vitiated before the second planting. Subsequently, the infection ratings tended to increase and were about the same as those in the uninoculated series.

Intact soil-core microcosms compared with multi-site field releases for pre-release testing of microbes in diverse soils and climates

2001 ◽  
Vol 47 (3) ◽  
pp. 237-252 ◽  
Author(s):  
Joel V Gagliardi ◽  
J Scott Angle ◽  
James J Germida ◽  
R Campbell Wyndham ◽  
Christopher P Chanway ◽  
...  
Keyword(s):  
Low Cost ◽  
Soil Microbiology ◽  
Soil Core ◽  
Wheat Roots ◽  
Fallow Soil ◽  
Site Field ◽  
Intact Soil Core ◽  
Regression Slopes ◽  
Field Plots ◽  
Intact Soil

Intact soil-core microcosms were used to compare persistence of Pseudomonas chlororaphis 3732RN-L11 in fallow soil and on wheat roots with field releases at diverse sites. Parallel field and microcosm releases at four sites in 1996 were repeated with addition of one site in 1997. Microcosms were obtained fresh and maintained at 60% soil water holding capacity in a growth chamber at 70% relative humidity, a 12-hour photoperiod, and constant temperature. Persistence of 3732RN-L11 was measured at each site in field plots and microcosms at 7–21 day intervals, and in duplicate microcosms sampled at an independent laboratory. Linear regression slopes of field plot and microcosm persistence were compared for each site, and between identical microcosms sampled at different sites, using log10transformed plate counts. Microcosm persistence closely matched field plots for wheat roots, but persistence in fallow soil differed significantly in several instances where persistence in field plots was lower than in microcosms. Analysis of weather variations at each site indicated that rainfall events of 30–40 mm caused decreased persistence in fallow soil. Cooler temperatures enhanced persistence in field plots at later time points. Inter-laboratory comparison of regression slopes showed good agreement for data generated at different sites, though in two instances, longer sampling periods at one site caused significant differences between the sites. Soil characteristics were compared and it was found that fertility, namely the carbon to nitrogen ratio, and the presence of expanding clays, were related to persistence. These microcosm protocols produced reliable data at low cost, and were useable for pre-release risk analyses for microorganisms.Key words: microcosm, soil, microbiology, risk assessment, 3732RN-L11.

THE EFFECT OF INFECTION BY HELMINTHOSPORIUM SATIVUM ON THE AMINO ACID CONTENT OF WHEAT ROOTS

1954 ◽  
Vol 32 (5) ◽  
pp. 571-575 ◽  
Author(s):  
S. B. Hrushovhtz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Content ◽  
Dry Weight ◽  
Weight Basis ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Aggregate Content ◽  
Maximum Extraction ◽  
Helminthosporium Sativum

The amino acids present in roots of healthy and diseased (Helminthosporium sativum P. K. & B.) wheat seedlings were determined by paper chromatography. Treatment of dried roots with 80% ethanol followed by acid hydrolysis effected maximum extraction of the amino acids. Eleven free and 13 combined amino acids were identified on the chromatograms, and four unidentified fractions were indicated. Total nitrogen of the diseased roots was higher on a dry weight basis than that of healthy roots. The aggregate content of both free and combined amino acids was slightly higher in the diseased roots than in the healthy ones. However, the concentrations of free alanine, serine, and asparagine in the diseased roots were twice those in the healthy ones.

Effect of 24-epibrassinolide on localization of ABA, AZP, and dehydrins in wheat plant roots during dehydration

Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 329-336
Author(s):  
A.R. Lubyanova ◽  
F.M. Shakirova ◽  
M.V. Bezrukova
Keyword(s):  
Triticum Aestivum ◽  
Wheat Germ ◽  
Wheat Plant ◽  
Triticum Aestivum L ◽  
Immunohistochemical Localization ◽  
Plant Roots ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Apoplastic Barrier ◽  
Protective Proteins

We studied the immunohistochemical localization of abscisic acid (ABA), wheat germ agglutinin (WGA) and dehydrins in the roots of wheat seedlings (Triticum aestivum L.) during 24-epibrassinolide-pretreatment (EB-pretreatment) and PEG-induced dehydration. It was found coimmunolocalization of ABA, WGA and dehydrins in the cells of central cylinder of basal part untreated and EB-pretreated roots of wheat seedlings under normal conditions and under osmotic stress. Such mutual localization ABA and protective proteins, WGA and dehydrins, indicates the possible effect of their distribution in the tissues of EB-pretreated wheat roots during dehydration on the apoplastic barrier functioning, which apparently contributes to decrease the water loss under dehydration. Perhaps, the significant localization of ABA and wheat lectin in the metaxylem region enhances EB-induced transport of ABA and WGA from roots to shoots under stress. It can be assumed that brassinosteroids can serve as intermediates in the realization of the protective effect of WGA and wheat dehydrins during water deficit.

scholarly journals Plant Cell Wall Changes in Common Wheat Roots as a Result of Their Interaction with Beneficial Fungi of Trichoderma

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2319
Author(s):  
Aneta Basińska-Barczak ◽  
Lidia Błaszczyk ◽  
Kinga Szentner
Keyword(s):  
Cell Wall ◽  
Common Wheat ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Plant Cell Walls ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Trichoderma Species ◽  
Defense Strategies

Plant cell walls play an important role in shaping the defense strategies of plants. This research demonstrates the influence of two differentiators: the lifestyle and properties of the Trichoderma species on cell wall changes in common wheat seedlings. The methodologies used in this investigation include microscopy observations and immunodetection. In this study was shown that the plant cell wall was altered due to its interaction with Trichoderma. The accumulation of lignins and reorganization of pectin were observed. The immunocytochemistry indicated that low methyl-esterified pectins appeared in intercellular spaces. Moreover, it was found that the arabinogalactan protein epitope JIM14 can play a role in the interaction of wheat roots with both the tested Trichoderma strains. Nevertheless, we postulate that modifications, such as the appearance of lignins, rearrangement of low methyl-esterified pectins, and arabinogalactan proteins due to the interaction with Trichoderma show that tested strains can be potentially used in wheat seedlings protection to pathogens.

THE NATURAL MICROFLORA OF THE SOIL IN RELATION TO THE FOOT-ROT PROBLEM OF WHEAT

1931 ◽  
Vol 4 (1) ◽  
pp. 69-77 ◽  
Author(s):  
A. W. Henry
Keyword(s):  
Marked Effect ◽  
Black Soil ◽  
Plant Diseases ◽  
Foot Rot ◽  
Wheat Seedlings ◽  
Helminthosporium Sativum ◽  
Natural Microflora ◽  
Loam Soil ◽  
Unsterilized Soil ◽  
Inhibitive Action

In these studies the natural microflora of the black loam soil typical of the Edmonton district of Alberta had a marked inhibitive action on the development of the wheat foot-rotting fungus Helminthosporium sativum when the latter was grown directly in this soil. The severity of foot-rot infection of wheat seedlings caused by this pathogene was correspondingly reduced as a result of this action. A trace of unsterilized soil serving as a source of the saprophytic soil organisms had almost as great an influence as a relatively large amount. A similar effect on Fusarium graminearum, another fungous pathogene which causes loot-rot of wheat, is indicated.Bacteria, actinomycetes and fungi isolated from black soil each had a suppressive action on H. sativum in the soil and reduced the severity of foot-rot infection caused by it, but the fungi were considerably more effective than the bacteria and actinomycetes tested. A combination of all of these organisms produced the most marked effect and one equivalent to that produced by the organisms of unsterilized soil.The significance of the results in connection with the foot-rot problem of wheat is briefly discussed and their possible bearing on other plant diseases caused by soil-borne pathogenes is mentioned.

VARIABILITY IN ASSOCIATION EFFECTS OF OTHER SOIL FUNGI ON THE VIRULENCE OF HELMINTHOSPORIUM SATIVUM ON WHEAT SEEDLINGS

1940 ◽  
Vol 18c (11) ◽  
pp. 562-565 ◽  
Author(s):  
G. B. Sanford ◽  
M. W. Cormack
Keyword(s):  
Pure Culture ◽  
Plant Pathogens ◽  
Soil Fungi ◽  
Culture Conditions ◽  
Wheat Seedlings ◽  
Helminthosporium Sativum ◽  
Preliminary Study

Random isolates of Penicillium, Actinomyces, and certain miscellaneous soil-inhabiting fungi were tested in steam sterilized soil, under pure culture conditions, for their association effects on the virulence of Helminthosporium sativum P. K. and B. on wheat seedlings. Certain isolates of the first two genera mentioned exerted a marked degree of suppression, some had no effect, while others increased the virulence. Similarly, these effects varied widely within certain species of Penicillium. This preliminary study indicates that the random isolates of many genera and species of fungi may differ widely in ability to affect the virulence of certain plant pathogens.

Changes in the Ultrastructure of the Root Tip of Wheat Following Exposure to Aluminium

1994 ◽  
Vol 21 (1) ◽  
pp. 85 ◽  
Author(s):  
MLD Lima ◽  
L Copeland
Keyword(s):  
Triticum Aestivum ◽  
Prolonged Exposure ◽  
Morphological Changes ◽  
Triticum Aestivum L ◽  
Root Tip ◽  
Cortical Layers ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Meristematic Cells ◽  
Fermentative Metabolism

Investigations have been carried out on morphological changes induced by aluminium ions in roots of wheat seedlings (Triticum aestivum L. cv. Vulcan). Lesions were evident on the surface of the roots after 4-8 h of exposure, and within 24 h there was increased vacuolation, loss of turgor, and severe cytoplasmic disorganisation in epidermal and peripheral cap cells. The central cap and cortical layers were also severely damaged by aluminium, but changes in the meristematic cells became evident only after more prolonged exposure of roots to aluminium. Mobilisation of starch in amyloplasts of peripheral and central cap cells of aluminium-stressed roots was particularly noticeable, and this was accompanied by an increase in the amount of extractable activity of starch-degrading enzymes. The possibility that the mobilisation of starch is linked to a coincident increase in fermentative metabolism in Al-stressed wheat roots is considered.

scholarly journals Transcriptome analysis of osmotic-responsive genes in ABA-dependent and -independent pathways in wheat (Triticum aestivum L.) roots

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6519 ◽  
Author(s):  
Chunxi Li ◽  
Wenli Zhang ◽  
Meng Yuan ◽  
Lina Jiang ◽  
Bo Sun ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Calcium Binding ◽  
Molecular Mechanisms ◽  
Soluble Sugars ◽  
Triticum Aestivum L ◽  
Wheat Roots ◽  
Wheat Growth ◽  
Wheat Seedlings ◽  
Yield And Quality ◽  
Trehalose Biosynthesis

Bread wheat is one of the most important crops in the world. However, osmotic stress significantly inhibits wheat growth and development, and reduces crop yield and quality. Plants respond to osmotic stress mainly through abscisic acid (ABA)-dependent and -independent pathways. In this study, root transcriptome profiles of wheat seedlings exposed to osmotic stress and exogenous ABA were analysed to identify osmotic-responsive genes belonging to the ABA-dependent or -independent pathways. We found that osmotic stress promoted proline biosynthesis in the ABA-dependent pathway, and trehalose biosynthesis is likely promoted among soluble sugars to maintain protein bioactivity under osmotic stress. In wheat roots subjected to osmotic stress, calcium ions, and glutathione exert their functions mainly through calcium-binding protein (CaM/CML) and glutathione-S-transferase, respectively, depending on both pathways. In addition, a complex relationship among phytohormones signal transduction was observed in response to osmotic stress. The findings of this study deepen our understanding of the molecular mechanisms of osmotic-stress resistance, and provide several candidate osmotic-responsive genes for further study.

INFLUENCE OF WILD AND CULTIVATED PLANTS ON THE MULTIPLICATION, SURVIVAL AND SPREAD OF CEREAL FOOT-ROTTING FUNGI IN THE SOIL

1935 ◽  
Vol 12 (5) ◽  
pp. 575-589 ◽  
Author(s):  
G. W. Padwick
Keyword(s):  
Bromus Inermis ◽  
Cultivated Plants ◽  
Wheat Seedlings ◽  
Helminthosporium Sativum ◽  
Soil Infestation ◽  
Loam Soil ◽  
Unsterilized Soil ◽  
Take All ◽  
Do So

Using the severity of infection of wheat seedlings as a measure of soil infestation, it is shown that susceptible grasses such as Agropyron tenerum, A. cristatum, A. repens and Bromus inermis encourage the multiplication and survival of inoculum of the take-all fungus Ophiobolus graminis in both sterilized and unsterilized soil. The same grasses also aided the survival of Helminthosporium sativum in sterilized soil. In these experiments, however, only one, namely B. inermis, appeared to favor the survival of Fusarium graminearum.The fungus O. graminis, which failed to spread laterally to any appreciable extent in bare, unsterilized black loam soil of the Edmonton district of Alberta, was able to do so when such soil was occupied by living, susceptible plants.

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