FACTORS AFFECTING THE VIABILITY AND GERMINATION BEHAVIOR OF CONIFEROUS SEED: PART II: CONE AND SEED MATURITY, PSEUDOTSUGA MENZIESII (Mirb.) FRANCO

1958 ◽  
Vol 34 (3) ◽  
pp. 275-282 ◽  
Author(s):  
G. S. Allen
Keyword(s):  
Pseudotsuga Menziesii ◽  
Factors Affecting ◽  
Seed Maturity

scholarly journals FACTORS AFFECTING THE VIABILITY AND GERMINATION BEHAVIOR OF CONIFEROUS SEED: PART I: CONE AND SEED MATURITY, TSUGA HETEROPHYLLA (RAFN.) SARG.

1958 ◽  
Vol 34 (3) ◽  
pp. 266-274 ◽  
Author(s):  
G. S. Allen
Keyword(s):  
Marked Effect ◽  
Relative Rate ◽  
Germination Rate ◽  
Tsuga Heterophylla ◽  
Germination Capacity ◽  
Factors Affecting ◽  
Seed Processing ◽  
Seed Maturity ◽  
Commercial Seed ◽  
Basic Studies

The following three papers show that both germination capacity and germination behavior are influenced markedly by maturity of cones and seed, and by various treatments, all of which can be controlled. Basic studies to discover the reasons for the radical changes in germination rate described herein are indicated.Commercial cone and seed processing often reduces germination capacity and increases the absolute or relative rate of germination. Dewinging, particularly if prolonged or if done in the presence of hard and sharp debris, has a marked effect upon both seed characteristics.High kiln temperatures (above 52 °C.), impact, and other "drastic" treatments reduce viability and increase germination rate. Seed that has been affected in these ways usually produces germinates whose radicles are discolored and subject to decay in the incubator. The seed itself tends to darken abnormally during stratification and/or incubation, and usually becomes contaminated quickly during incubation. Commercial seed that shows evidence of harmful treatment is usually dull and dusty and produces similar symptoms of weakness during incubation.

Factors affecting seed set in Douglas-fir (Pseudotsuga menziesii)

1991 ◽  
Vol 69 (2) ◽  
pp. 229-238 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli ◽  
Sheila J. Morris
Keyword(s):  
Reproductive Success ◽  
Pseudotsuga Menziesii ◽  
Low Temperatures ◽  
Seed Set ◽  
Douglas Fir ◽  
Ovule Development ◽  
High Moisture ◽  
Embryo Abortion ◽  
Factors Affecting ◽  
Major Loss

Cone and seed development in Douglas-fir were studied from pollination until seed release in 1986. Cone abortion at, and shortly after, pollination was high, resulting from a combination of low temperatures and possibly high moisture and populations of microorganisms on cones. Seed potential averaged about 75 seeds per cone with 31 filled seed per cone, giving an average seed efficiency of 39%. The major loss of seed resulted from insufficient pollen in the ovules. Other causes were ovule and embryo abortion at various stages of development. The effects of prezygotic and postzygotic events on seed set are discussed with respect to the reproductive success of Douglas-fir. Key words: Douglas-fir, seed set, cone, ovule, development, abortion.

scholarly journals FACTORS AFFECTING THE VIABILITY AND GERMINATION BEHAVIOR OF CONIFEROUS SEED. V. SEED MOISTURE CONTENT DURING STRATIFICATION AND SECONDARY STORAGE, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO

1962 ◽  
Vol 38 (3) ◽  
pp. 303-312 ◽  
Author(s):  
G. S. Allen
Keyword(s):  
Moisture Content ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Secondary Storage ◽  
Seed Moisture Content ◽  
Factors Affecting ◽  
Seed Moisture ◽  
And Storage ◽  
Post Stratification

Two seedlots of Douglas fir were each soaked to two levels of moisture content, stratified for 20-120 days at 0-2 °C., subjected to post-stratification storage, and incubated at 10°, 15°, and 25 °C. The higher moisture content (60-70 per cent) was superior for both seedlots particularly when the seed was subjected to drying and storage after stratification. The ability of Douglas fir seed to withstand stratification, drying, and storage for a total time of 240 days, without loss of germinative capacity or vigor, is shown.

scholarly journals FACTORS AFFECTING THE VIABILITY AND GERMINATION BEHAVIOR OF CONIFEROUS SEED. VI. STRATIFICATION AND SUBSEQUENT TREATMENT, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO

1962 ◽  
Vol 38 (4) ◽  
pp. 485-496 ◽  
Author(s):  
G. S. Allen
Keyword(s):  
Pseudotsuga Menziesii ◽  
Subsequent Treatment ◽  
Duration Of Treatment ◽  
Factors Affecting ◽  
Seed Testing ◽  
Stratification Effect ◽  
Incubation Temperatures ◽  
And Storage ◽  
Post Stratification

Stratification effects increase with duration of treatment; short treatments accelerate germinaion markedly for incubation at 25 °C but longer treatments are necessary for rapid germination at 15° or 10 °C. Post stratification drying and storage reduce the stratification effect, particularly at low incubation temperatures, but do not adversely affect germinative capacity. Implications for seed testing and nursery practice are discussed.

Factors affecting seed and cone development in Pacific silver fir (Abies amabilis)

1998 ◽  
Vol 28 (8) ◽  
pp. 1146-1163 ◽  
Author(s):  
John N Owens ◽  
Sheila J Morris
Keyword(s):  
Anatomical Study ◽  
Silver Fir ◽  
Insect Damage ◽  
Factors Affecting ◽  
Abies Amabilis ◽  
Seed Loss ◽  
Seed Maturity ◽  
Cone Axis ◽  
Cone Development ◽  
Filled Seeds

The reproductive development from pollination until seed maturity for Pacific silver fir (amabilis fir; Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) was studied at two sites in British Columbia. Ten trees growing at varying elevations at each site were flagged and two or more cones were collected from each tree every 1 or 2 weeks. Following size measurements, cones were dissected and 20 ovules from each cone were sampled, fixed, embedded in paraffin, sectioned, and stained for anatomical study. Ovule, megagametophyte, and embryo size was measured and stage of ovule or seed and embryo was determined. At both sites the phenology and details of development were similar. The major causes of cone loss were frost at pollination and insect damage following pollination. The seed potential per cone was 359-408, but the filled seeds per cone based on cutting tests and X-raying was only 18-22%. The major causes of seed loss were insect damage (32-39%) during ovule and seed development and failure of ovules to be pollinated (26-31%). Although the amount of insect damage was similar at both sites, damage at Site 1 was primarily caused by Megastigmus sp. larvae in the seeds whereas at Site 2, damage was to seeds, scales, and the cone axis and due to Earomyia abietum larvae. Megagametophyte and embryo development is described and the time and causes of the seed loss are related to development. Anomalous types of development are described and possible causes discussed.

Some effects of soil and air temperature on growth of Agropyron spicatum following clipping or burning

1980 ◽  
Vol 58 (5) ◽  
pp. 568-573 ◽  
Author(s):  
W. Willms ◽  
A. W. Bailey ◽  
A. McLean
Keyword(s):  
Pseudotsuga Menziesii ◽  
Air Temperature ◽  
Ground Surface ◽  
Agropyron Cristatum ◽  
Late Winter ◽  
Rapid Rate ◽  
Apparent Effect ◽  
Factors Affecting ◽  
Agropyron Spicatum ◽  
Made In

Studies were made in both the Artemisia tridentata and Pseudotsuga menziesii communities to examine some factors affecting available growth in spring. The appearance of tillers was examined in relation to species (Agropyron spicatum. Agropyron cristatum. Poa sandbergii) and temperature. The rate of tiller elongation in Agropyron spicatum was studied in relation to temperature and fall clipping or burning while tiller length was examined in relation to fall or late-winter burning. Tiller development in all species appeared within the same week. The community had no apparent effect on tiller initiation. However, growth in Agropyron spicatum was arrested for 1 week in the Pseudotsuga menziesii community after the tillers appeared at the ground surface. The rate of tiller elongation was not affected by clipping. However, burning resulted in a more rapid rate at cool temperatures and a slower rate at warm temperatures. Tillers were shorter in plants burned in late winter than in plants burned in fall.

EVALUATION OF FACTORS AFFECTING TREE AND STAND SUSCEPTIBILITY TO THE DOUGLAS-FIR BEETLE (COLEOPTERA: SCOLYTIDAE)

1999 ◽  
Vol 131 (6) ◽  
pp. 831-839 ◽  
Author(s):  
T.L. Shore ◽  
L. Safranyik ◽  
W.G. Riel ◽  
M. Ferguson ◽  
J. Castonguay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Process Model ◽  
Cross Validation ◽  
Biological Process ◽  
Douglas Fir ◽  
Bark Thickness ◽  
Dendroctonus Pseudotsugae ◽  
Factors Affecting ◽  
Site Characteristics ◽  
Tree Characteristics

AbstractTree and site characteristics were compared between 19 groups of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested by Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, and 19 uninfested groups to identify individual or combinations of characteristics associated with Douglas-fir beetle attacks. Of the tree characteristics, diameter, height, age, phloem thickness, bark thickness, and a standardized variable consisting of diameter divided by the last 10 years growth rate (DBHTYG) showed significant differences. None of the site characteristics showed significant differences between infested and uninfested areas. Two models, identified through discriminant analysis, placed 84 and 87% of the data in the correct infestation groups. These models included the variables diameter, height, phloem thickness, aspect, and DBHTYG in various combinations. The results were confirmed using a jackknifed cross-validation approach. These variables have potential for use in the development of a biological process model of tree and stand susceptibility to the Douglas-fir beetle.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

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