Factors affecting spread of Cronartiumcomptoniae on the sweetfern host

1981 ◽  
Vol 11 (2) ◽  
pp. 401-409 ◽  
Author(s):  
Dale L. K. Smeltzer ◽  
D. W. French
Keyword(s):  
Spore Germination ◽  
Free Water ◽  
Dispersal Distance ◽  
Growth Chamber ◽  
Spore Viability ◽  
Factors Affecting ◽  
Temperature Range ◽  
Field Plots

Infection of sweetfern plants (Comptoniaperegrina (L.) Coult.) by Cronartiumcomptoniae Arth. was observed at a maximum of 30 m from the aeciospore source on two field plots in northeastern Minnesota, U.S.A. Amount of infection per spores trapped decreased significantly as dispersal distance increased from the source of inoculum. Infection of sweetfern was limited most by the decrease in spore viability, but lack of rain may have limited infection at least twice during the summer. Inoculations of sweetfern with aeciospores and uredospores in a growth chamber resulted in infection at 0–28 °C, a wider temperature range than for spore germination on agar. Infection occurred after 1 h in a humid chamber and was inhibited by light, especially high intensities. Free water and spores on the undersurface of the sweetfern leaf were required for infection.

Environmental factors affecting germination of Cronartium comandrae aeciospores

1974 ◽  
Vol 52 (3) ◽  
pp. 659-667 ◽  
Author(s):  
J. M. Powell
Keyword(s):  
Environmental Factors ◽  
Germ Tube ◽  
Free Water ◽  
Direct Sunlight ◽  
Factors Affecting ◽  
Temperature Range ◽  
Ph Range ◽  
Germ Tubes ◽  
Germ Tube Elongation

Cronartium comandrae Pk. aeciospores germinated over the temperature range 1 to 30 °C, but germination outside the range 5 to 22 °C was poor. Optimum for germination was about 15 °C, although initial germination was better at 20 °C. Some aeciospores germinated after 1 h of incubation and most within 4 to 5 h. The rate of germ tube elongation was reduced after 8 h, and generally had ceased after 24 h. Each spore produced an average of two germ tubes, but only one developed. Appressoria usually formed only at 15 and 20 °C. Free water was apparently necessary for germination. Hydration of spores initially improved germination but extended periods of hydration decreased it. Viable spores swelled more than non-viable spores. Aeciospores germinated well in the dark and in light but not in direct sunlight. Fresh aeciospores germinated on media with a pH range of 4.5 to 8.0, but did best between pH 6.0 and 6.5. Germination results are compared with those reported for other Cronartium rusts.

Dynamic Study on Vacuum Pyrolysis Reaction of Chinese Fir Sawdust Biomass

2012 ◽  
Vol 512-515 ◽  
pp. 375-378
Author(s):  
Su Wen Yang ◽  
Jian Min Yi ◽  
Ke Qiang Qiu ◽  
Xin Deng ◽  
Jian Shan Chen
Keyword(s):  
Heating Rate ◽  
Free Water ◽  
Chinese Fir ◽  
Peak Temperature ◽  
Gravimetric Analysis ◽  
Water Desorption ◽  
Exponential Factor ◽  
Pyrolysis Reaction ◽  
Temperature Range ◽  
Vacuum Pyrolysis

This thesis does thermal gravimetric analysis（TGA）studies on Chinese fir sawdust biomass by integrated thermal analyzer under vacuum conditions. Through the analysis on lostmass curve at different heating rate of 10, 15, 20 and 30°C/min, we found the process of Chinese fir sawdust vacuum pyrolysis can be mainly divided into three stages: evaporation of free water and combined water desorption, rapid lostmass of pyrolysis and slow decomposition of residues. The lostmass major temperature range is between 250 ~ 450°C, the peak temperature is between 365 ~ 400°C. When the pyrolysis temperature is 500°C, vacuum pyrolysis reaction of Chinese fir sawdust has basically completed. As the heating rate rises, the lostmass curve is moving to the right, the peak temperature is shifting to higher temperature, and the temperature range of thermal decomposition reaction widens significantly. According to experimental datas, we tried to obtain the vacuum pyrolysis dynamic parameters of Chinese fir sawdust, and the results are that the apparent activation energy of vacuum pyrolysis reaction of Chinese fir sawdust biomass is 128.34kJ/mol, with the pre-exponential factor being 6.42×109 and reaction order being 1.08, similar to first order reaction.

RATE OF EVAPORATION FROM A FREE-WATER SURFACE AS INFLUENCED BY EXPOSURE

1961 ◽  
Vol 41 (1) ◽  
pp. 199-203 ◽  
Author(s):  
A. C. Carder
Keyword(s):  
Water Surface ◽  
Meteorological Factors ◽  
Free Water ◽  
Water Evaporation ◽  
High Wind ◽  
Progressive Decrease ◽  
Factors Affecting ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
Low Rate

In a 3-year free-water evaporation study, an evaporimeter tank in the open field lost 34.5 per cent more water than a tank sheltered by buildings and trees. Meteorological factors responsible for this difference appear to be high wind velocities and long daily periods of sunshine. Changes in temperature regime had no effect.Difference in evaporation from the two tanks led to examination of data obtained over 35 years from the sheltered tank. It was found that, although there was a progressive decrease in amount of evaporation over the years from this tank, rainfall at the same time had increased and that the effect of this increase on evaporation was roughly equal to that of all other factors affecting evaporation, such as a change in exposure, etc. Thus, the comparatively low rate of evaporation from the sheltered tank was undoubtedly due in part to the proximity of buildings and trees which had been established.

Factors affecting vegetative growth and the production of perithecia in culture by Ophiobolus graminis. II. Variations in light and temperature

1970 ◽  
Vol 18 (1) ◽  
pp. 11 ◽  
Author(s):  
G Weste
Keyword(s):  
Vegetative Growth ◽  
Unit Area ◽  
Red Light ◽  
Light Period ◽  
Factors Affecting ◽  
Temperature Range ◽  
Temperature Controlled

Sixty-one isolates of O. graminis were shown to be obligate photosporulators. Fertile perithecia developed only when the cultures were exposed to light of between 65 and 360 f.c., with a maximum at 200 f.c. The temperature range for the production of fertile perithecia was between 13 and 24°c, with the optimum at 20°. Studies on the interaction of light and temperature showed that when cultures received sufficient light, temperature controlled perithecial numbers. Light most effective in photosporulation was of wavelengths between 390 and 450 mμ. Red light neither inhibited nor stimulated reproduction. At least 12 hr of illumination was required, and perithecial numbers per unit area increased with increasing light period until the cultures dried out.

Factors Affecting Prolonged Spore Viability in Herbarium Collections of Three Species of Pellaea

1986 ◽  
Vol 76 (3) ◽  
pp. 141 ◽  
Author(s):  
Michael D. Windham ◽  
Paul G. Wolf ◽  
Thomas A. Ranker
Keyword(s):  
Spore Viability ◽  
Factors Affecting ◽  
Herbarium Collections

Study of the hydraulic regime of the St. Lawrence River between Montreal and the city of Québec

1992 ◽  
Vol 19 (1) ◽  
pp. 78-85 ◽  
Author(s):  
S. Robert ◽  
D. Plotte ◽  
J.-C. Rassam ◽  
R. Boivin ◽  
R. Larivière ◽  
...  
Keyword(s):  
Numerical Model ◽  
River Flow ◽  
Free Water ◽  
Water Levels ◽  
Factors Affecting ◽  
Model Study ◽  
Hydraulic Regime ◽  
The City ◽  
Numerical Model Study ◽  
St Lawrence River

This paper presents the results of a numerical model study of the St. Lawrence River flow from the Beauharnois–Les Cèdres and Carillon hydroelectric complexes, just upstream from the Montreal Archipelago, to the city of Québec. The main factors affecting the water levels in the river under free water surface conditions, and their degree of influence, were estimated. In particular, the effects of the flows, local inflows, flow variations, and tide on the water levels along the St. Lawrence maritime channel were analyzed. The daily average flows are of utmost importance, other parameters being adjusting factors. Key words: St. Lawrence River, water level prediction, numerical model.

scholarly journals ROOT HARDINESS OF GRAPE CULTIVARS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1136F-1136
Author(s):  
M. Ahmedullah ◽  
C. R. Rom
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Free Water ◽  
Extracellular Water ◽  
Triphenyltetrazolium Chloride ◽  
Temperature Range ◽  
Survival Test ◽  
One Year ◽  
Grape Cultivars

Roots of one year old grape cvs. Concord, White Riesling, Grenache and Semillon were frozen to 0, -5, -10, -15 and -20°C in a programmable freezer. The tops were protected from cold by insulating them. For survival test, 4 plants of each cv. were planted in the greenhouse and their growth observed. Differential thermal analysis (DTA), using a computer attached to a programmable freezer was performed on roots. To aid in the interpretation of DTA, triphenyltetrazolium chloride (TTC) was performed. Hardiness determinations were based on DTA, TTC and the survival tests. DTA patterns representing exothermic response showed an exotherm associated with extracellular free water in tissue which appeared at about the same temperature range for all cvs. This is not associated with hardiness. Additional minor exotherms related to hardiness appeared at lower temperatures than the extracellular water exotherm. Their location differed from one cv. to another. Based on these tests, Concord roots appear to be hardier than other cvs. with important but minor differences in the hardiness of other cvs.

scholarly journals Factors affecting strength of clays in the temperature range 110 to 800%

2017 ◽  
Vol 7 (079) ◽  
pp. 26
Author(s):  
W. H. Sutton ◽  
F. R. Matson
Keyword(s):  
Factors Affecting ◽  
Temperature Range

Not available

Sign in / Sign up

Export Citation Format

Share Document