scholarly journals Methods suitable for estimation of infection of bean seeds by Colletotrichum lindemuthianum and fungi of the genus Fusarium

2014 ◽  
Vol 11 (2) ◽  
pp. 79-91
Author(s):  
Barbara Łacicowa ◽  
Zofia Machowicz ◽  
Danuta Sułek
Keyword(s):  
Low Temperature ◽  
Plant Material ◽  
Agar Medium ◽  
Colletotrichum Lindemuthianum ◽  
Genus Fusarium ◽  
Moist Sand

Bean seeds were analyzed for infection by <i>Colletotrichum lindemuthianum</i> and fungi of the genus <i>Fusarium</i> using the method of isolation on maltose medium and by means of planting the seeds in moist sand. 38 samplesof seed from various varieties of beans were examined. Both methods proved to be suitable for the detection of fungi, but the percentage of seeds infected by <i>Colletotrichum lindemuthianum</i> and fungi of the <i>Fusarium</i> genus can be estimated more precisely by determining the number of infected seedlings obtained from material planted in the sand. On the agar medium used the growth of <i>Colletotrichum lindemuthanum</i> and fungi from the <i>Fusarium</i> genus was impossible due to other fungi present in the plant material. Treatment of the bean seeds with a low temperature (-16ºC for 12 hours) in necessary before using the method of isolation on maltose medium.

scholarly journals Bacterial Streak and Bulb Rot of Onion: I. A Diagnostic Medium for the Semiselective Isolation and Enumeration of Pseudomonas viridiflava

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 897-900 ◽  
Author(s):  
R. Gitaitis ◽  
D. Sumner ◽  
D. Gay ◽  
D. Smittle ◽  
G. McDonald ◽  
...  
Keyword(s):  
Low Temperature ◽  
Plant Material ◽  
No Reduction ◽  
Agar Medium ◽  
Penicillin G ◽  
Phenol Red ◽  
Pseudomonas Viridiflava ◽  
Infested Field ◽  
History Of ◽  
Bulb Rot

A semiselective, diagnostic agar medium (T-5) and low temperature incubation technique were developed for recovering Pseudomonas viridiflava from the environment or plant material. Medium T-5 contains the following per liter: NaCl, 5.0 g; NH4H2PO4, 1.0 g; K2HPO4, 1.0 g; MgSO4·H2O, 0.2 g; D-tartaric acid, 3.0 g; phenol red, 0.01 g; agar, 20.0 g; bacitracin, 10 mg; vancomycin, 6 mg; cycloheximide, 75 mg; novobiocin, 45 mg; penicillin G, 5 mg. The pH is adjusted to 7.4. Antibiotics are added aseptically after autoclaving. P. viridiflava recovery from artificially infested, field-soil (Tifton loamy-sand), with a cropping history of no onion production, was high, with a corresponding reduction of 99.99% of nontarget bacteria. However, soils from fields with a long history of onion production, near Vidalia, Georgia, contained significantly larger populations of background microflora that grew on medium T-5. Incubation at 5°C reduced contaminating microflora 1,000- to 10,000-fold with no reduction in recovery of the target organism. However, this low temperature incubation required an increased incubation period of 3 weeks and reduced the level of fluorescence of P. viridiflava.

Changes in Fumitory Achenes During Low Temperature After-Ripening

Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 310-313 ◽  
Author(s):  
Larry S. Jeffery ◽  
John D. Nalewaja
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Low Temperature ◽  
Ethyl Alcohol ◽  
Longitudinal Section ◽  
Soluble Carbohydrates ◽  
Ripening Period ◽  
Embryo Size ◽  
Moist Sand ◽  
Fumaria Officinalis

Fumitory (Fumaria officinalisL.) achenes were after-ripened in moist sand at 4 C for 0, 15, 30, 45, and 60 days. Embryo size in longitudinal section increased 14 times during after-ripening. The percentage of ether soluble lipids and their fatty acids remained constant during the entire after-ripening period. Soluble carbohydrates were the highest at the 45-day period of after-ripening when embryo growth was rapid. The concentration of 70% ethyl alcohol soluble amino acids increased gradually over the first 45 days of after-ripening and decreased over the last 15 days as embryo growth became more rapid.

scholarly journals Comparative Cold Tolerance in Diverse Turf Quality Genotypes of Perennial Ryegrass

HortScience ◽  
2002 ◽  
Vol 37 (5) ◽  
pp. 826-830 ◽  
Author(s):  
J.S. Ebdon ◽  
R.A. Gagne ◽  
R.C. Manley
Keyword(s):  
Low Temperature ◽  
Perennial Ryegrass ◽  
Plant Material ◽  
High Performance ◽  
Temperature Tolerance ◽  
Low Temperature Tolerance ◽  
Turf Quality ◽  
Freeze Stress ◽  
Turfgrass Quality ◽  
Low Performance

Turf loss from freezing injury results in costly reestablishment, especially with turfgrasses such as perennial ryegrass (Lolium perenne L.) having poor low-temperature tolerance. However, no studies have been conducted to investigate the relative importance of low-temperature tolerance and its contribution to turfgrass quality (performance) in northern climates. The objective of this research was to compare critical freezing thresholds (LT50) of 10 perennial ryegrass cultivars representing contrasting turf-quality types (five high- and five low-performance cultivars). Cultivar selection was based on turfgrass quality ranking (top and bottom five) from the 1997 National Turfgrass Evaluation Program (NTEP) trial conducted at the Maine (Orono) location. Ten freeze-stress temperatures (-3 to -21 °C) and a nonfrozen control (5 °C) were applied to 5-month-old plants. Acclimated (AC) plant material maintained in an unheated polyhouse during the fall and winter in Massachusetts was compared to nonacclimated (NA) plant material (grown at 18 °C minimum in a greenhouse). Low-temperature tolerance was assessed using whole-plant survival and electrolyte leakage (EL). Estimates of LT50 were derived from fitted EL and survival curves using nonlinear regression. High-performance cultivars were able to tolerate significantly lower freeze-stress temperatures indicated by less EL and greater survival compared to low-performance cultivars. The EL method had good predictive capability for low-temperature survival. Acclimated tissues and high-performance cultivars had significantly flatter EL curves and lower mortality rates. These results underscore the importance of selecting cold-tolerant perennial ryegrass genotypes for adaptation to northern climates.

scholarly journals Quantification of Seed Dormancy of Deciduous Orchard Species

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 908A-908
Author(s):  
Schuyler D. Seeley
Keyword(s):  
Low Temperature ◽  
Plant Material ◽  
Temperature Response ◽  
Woody Species ◽  
Normal Growth ◽  
Response Curves ◽  
Naturally Occurring ◽  
Breaking Dormancy ◽  
Temporary Growth ◽  
Per Se

Forcing plant material has long been used to determine dormancy intensity (DI) in woody species. Forcing with growth regulators may enhance this ability. Some forcing with naturally occurring hormones may be showing us the actual DI of certain materials. But, measurements of DI that use caustic, near-lethal treatments, or metabolic agents may be all or nothing breaking indicators acting on mechanisms other than the dormancy mechanism and thus not as useful in determining DI. It is possible to cause a meristem to break without completely breaking dormancy. Measurement of normal post-dormancy growth is necessary to determine the effect of a DI agent. DI breaking treatments that act on the dormancy mechanism can cause a temporary growth flush, but, unless the extent of that growth flush is measured and compared with the growth flush of the same normally broken plant material, its true effect remains unknown. In some plant material, the safest way to determine DI is to determine the chilling required to produce normal growth. This assumes that the vernalization requirement and temperature response curves are known for the plant in question. In peach, for instance, vernalization at 2C will cause seeds to germinate, but the resulting seedlings will be physiologically dwarfed. Vernalization at 6C or at 2C cycled with higher temperatures within the vernalization range results in normal seedlings. This indicates that, for chilling to progress normally, vernalization per se must be interspersed or concomitant with growth heat units. Vernalization, therefore, has a low temperature driven component and a heat requiring development and/or growth component. Vernalization driving conditions are slowly being elucidated. Each clarification requires modification of dormancy models. DI does not equal dormancy status!

THE EVALUATION OF COLD AND DROUGHT STRESS OF TURFGRASSES BY ELECTROLYTIC AND NINHYDRIN METHODS

1966 ◽  
Vol 46 (4) ◽  
pp. 337-342 ◽  
Author(s):  
W. E. Cordukes ◽  
J. Wilner ◽  
V. T. Rothwell
Keyword(s):  
Drought Stress ◽  
Low Temperature ◽  
Plant Material ◽  
Laboratory Tests ◽  
Close Agreement ◽  
Kentucky Bluegrass ◽  
Reliable Estimate ◽  
Visual Recovery ◽  
Red Fescue ◽  
Low Temperature Treatments

Electrolytic analyses of fresh blade tissue provided a rapid and reliable estimate of cold or drought stress of several turfgrasses in artificial laboratory tests. Resistance and conductivity readings and ninhydrin analyses were in close agreement with visual recovery of plant material following artificial low temperature treatments. In drought tests, electrolytic analyses clearly indicated the superiority of creeping red fescue over Kentucky bluegrass in drought tolerance.

Mycoparasitism of sclerotia of Sclerotinia and Sclerotium species by Sporidesmium sclerotivorum

1979 ◽  
Vol 25 (1) ◽  
pp. 17-23 ◽  
Author(s):  
W. A. Ayers ◽  
P. B. Adams
Keyword(s):  
Biological Control ◽  
Agar Medium ◽  
Macrophomina Phaseolina ◽  
Parasitic Fungus ◽  
Natural Soil ◽  
Northeastern United States ◽  
Sclerotium Cepivorum ◽  
Moist Sand ◽  
Asexual Spore ◽  
Cornmeal Agar

Sclerotia of Sclerotinia sclerotiorum in soil were invaded by a destructive fungus that was isolated and identified as Sporidesmium sclerotivorum. The parasitic fungus grew slowly on an autoclaved agar medium made from comminuted sclerotia of S. sclerotiorum and on cornmeal agar but failed to germinate or grow on many common mycological media. Macroconidia of S. sclerotivorum germinated adjacent to sclerotia on water agar or moist filter paper, colonized the sclerotia, and developed two distinctive asexual spore states by which it could be recognized. In moist sand, steamed soil, and natural soil the mycoparasite infected and destroyed more than 95% of the amended (1% w/w) sclerotia of S. sclerotiorum in 10 weeks or less at 25 °C. Sclerotia killed by autoclaving were poorly colonized. Sclerotia of Sclerotium cepivorum were attacked by the mycoparasite more slowly than those of S. sclerotiorum. Sclerotia of Macrophomina phaseolina apparently were not parasitized. The mycoparasite was isolated from soils from three different areas of the northeastern United States. The prolific development of the mycoparasite in soil containing sclerotia of susceptible species and its ability to spread through soil by growth from one sclerotium to another suggest that S. sclerotivorum is an important contributor to the natural destruction of sclerotia in.soil and that it may have high potential as an applied agent of biological control of sclerotial fungi.

THE FORMATION OF STROMA-LIKE STRUCTURES IN CULTURES OF A STERILE LOW-TEMPERATURE BASIDIOMYCETE

1964 ◽  
Vol 42 (8) ◽  
pp. 1025-1030 ◽  
Author(s):  
E. W. B. Ward
Keyword(s):  
Low Temperature ◽  
Yeast Extract ◽  
Mycelial Growth ◽  
Agar Medium ◽  
Extract Agar ◽  
Factors Influencing ◽  
Dense Mass ◽  
Yeast Extract Agar

A study was made of factors influencing the formation and development of stroma-like structures in cultures of a sterile low-temperature basidiomycete. The stromata grow from the surface of the colony at various inclinations, usually concentrically around and close to the inoculum plug. They are club-shaped, dull white in color, and composed of a dense mass of interwoven hyphae. Most extensive development occurred on a malt – yeast extract agar medium. Light, which retards mycelial growth, greatly stimulated stroma formation, and development was also influenced by temperature, pH, and composition of the medium.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

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