GREEN FOXTAIL: SEED DORMANCY, GERMINATION AND GROWTH

1971 ◽  
Vol 51 (1) ◽  
pp. 53-59 ◽  
Author(s):  
W. H. VANDEN BORN
Keyword(s):  
Seed Germination ◽  
Light Intensity ◽  
Western Canada ◽  
Field Crops ◽  
Green Foxtail ◽  
Wide Range ◽  
Moist Storage ◽  
Competitive Efficiency ◽  
Germination And Growth ◽  
Reduced Temperature

Green foxtail seed exhibited complete or near-complete dormancy when freshly harvested. This dormancy was overcome most readily during moist storage at 6 C for three to six weeks. Seed germination occurred over a wide range of temperature, but most rapidly at or above 25 C. Seedlings emerged readily from planting depths up to 8 cm. Plants emerging as late as the end of July could still produce seeds during the same season. Implications of the findings for green foxtail control are discussed. Severely restricted growth of green foxtail under reduced temperature and light intensity is considered to account for at least part of the reported low competitive efficiency of green foxtail infestations in field crops in western Canada.

Seed germination ecology of Sumatran fleabane (Conyza sumatrensis) in relations to various environmental parameters

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Gulshan Mahajan ◽  
Asheneel Prasad ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Seed Germination ◽  
Light Intensity ◽  
Chloride Concentration ◽  
Soil Surface ◽  
Control Treatment ◽  
Effect Of Temperature ◽  
Burial Depth ◽  
Germination Ecology ◽  
Wide Range ◽  
Dark Conditions

Abstract Sumatran fleabane [Conyza sumatrensis (Retz.) Walker] is an emerging weed in the Australian cropping region. Populations resistant to glyphosate have evolved in Australia, creating the demand for information regarding the seed germination ecology of glyphosate-resistant (R) and glyphosate susceptible (S) populations of C. sumatrensis. A study was conducted to examine the effect of temperature, light intensity, salt stress, osmotic stress, and burial depth on the germination and emergence of two populations (R and S) of C. sumatrensis. Both populations were able to germinate over a wide range of alternating day/night temperatures (15/5 to 35/25 C). In light/dark conditions, the R population had higher germination than the S population at 20/10 and 35/25 C. In the dark, the R population had higher germination than the S population at 25/15 C. In the dark, germination was inhibited at 30/20 C and above. Averaged over populations, seed germination of C. sumatrensis was reduced by 97% at zero light intensity (completely dark conditions) compared with full light intensity. Seed germination of C. sumatrensis reduced by 17 and 85% at an osmotic potential of −0.4, and −0.8 MPa, respectively, compared with the control treatment. The R population had lower germination (57%) than the S population (72%) at a sodium chloride concentration of 80 mM. Seed germination was highest on the soil surface and emergence was reduced by 87 and 90% at burial depths of 0.5 and 1.0 cm, respectively. Knowledge gained from this study suggests that a shallow-tillage operation to bury weed seeds in conventional tillage systems, and retention of high residue cover in a zero-till system on the soil surface may inhibit the germination of C. sumatrensis. This study also warrants that the R population may have a greater risk of invasion over a greater part of a year due to germination over a broader temperature range.

THE INFLUENCE OF THE EXTRACT OF SOME CROPS AND SOIL RESIDUES ON GERMINATION AND GROWTH

1960 ◽  
Vol 40 (1) ◽  
pp. 188-197 ◽  
Author(s):  
K. F. Nielsen ◽  
W. B. Woods ◽  
T. F. Cuddy
Keyword(s):  
Seed Germination ◽  
Root Length ◽  
Deionized Water ◽  
The Other ◽  
Percentage Germination ◽  
Soil Extracts ◽  
Field Crops ◽  
Time Required ◽  
Germination And Growth ◽  
Germinated Seeds

Six plant species were germinated in sand wetted with water extracts of tissues of five field crops and three soils. Deionized water was used as a check f he study was conducted using standard seed germination techniques.Alter 7 to 10 days all of the germinated seeds were harvested and measurements made of the shoot and root lengths.Alfalfa extract caused the greatest reduction in shoot and root length as well as m percentage germination. It caused the greatest increase in the time required for germination. Timothy extract was not quite as harmful as the alfalfa. Extracts of oats, corn and potatoes were still less harmful with potato extract causing the least effect.The soil extracts generally had very little effect when compared with deionized water.Plant species showed marked differences in tolerance to the extracts alfalfa being the most resistant and timothy the least.Where water alone was used rate of germination and per cent germination were as high or higher than with the other extracts, but the root and shoot lengths were not always the greatest.

Germination and Growth of Leafflower (Phyllanthus urinaria) as Affected by Cultural Conditions and Herbicides

1992 ◽  
Vol 6 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Glenn R. Wehtje ◽  
Charles H. Gilliam ◽  
Jesse A. Reeder
Keyword(s):  
Seed Germination ◽  
Light Intensity ◽  
Deep Layer ◽  
Seedling Development ◽  
Factors Affecting ◽  
Cultural Conditions ◽  
Phyllanthus Urinaria ◽  
Germination And Growth ◽  
Reduced Light ◽  
Osmotic Potentials

Factors affecting the germination and seedling growth of leafflower were evaluated. Germination required exposure to light. Seeds covered with a 1-cm deep layer of pine bark mulch failed to emerge. Maximum seedling development occurred in full exposure to sunlight; shading that reduced light intensity more than 26% was inhibitory. Maximum seed germination (79%) occurred between 25 and 35 C; temperatures outside this range were inhibitory. Germination was strongly influenced by osmotic potential. Osmotic potentials of 0, 304, and 507 kPa resulted in 85, 24 and 14% germination, respectively. PRE applications of either granular formulated oxadiazon at 4.5 kg ha–1, or premixed granular formulated oxyfluorfen + oryzalin at 4.6 + 2.3 kg ha–1, provided a minimum of 85% control. The following POST treatments provided a minimum of 90% control of mature plants: paraquat at 0.21 kg ha–1, glyphosate at 0.56 kg ha–1, oxyfluorfen at 1.12 kg ha–1, and acifluorfen at 2.24 kg ha–1.

scholarly journals TEMPERATURE - GERMINATION RESPONSES OF SUNFLOWER (Helianthus annuus L.) GENOTYPES / GERMINACION COMO REACCION A LA TEMPERATURA EN LOS GENOTIPOS DEL GIRASOL (Helianthus annuus L.) / GERMINATION - RÉACTION À LA TEMPÉRATURE DANS LES GÉNOTYPES DE TOURNESOL (Helianthus annuus L.)

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 97-104
Author(s):  
F.M. Khalifa ◽  
A.A. Schneiter ◽  
E.I. El Tayeb
Keyword(s):  
Seed Germination ◽  
Helianthus Annuus ◽  
Maximum Rate ◽  
Germination Rate ◽  
Thermal Time ◽  
Large Temperature ◽  
Climatic Zones ◽  
Helianthus Annuus L ◽  
Wide Range ◽  
Cardinal Temperature

SUMMARY Seed germination of six sunflower (Helianthus annuus L.) hybrids was investigated across a range of eleven constant temperatures between 5°C and 45°C. Large temperature differences in germination rate 1/t (d-1), cardinal temperature (°C) and thermal time θ (°cd) were observed among hybrids. Base temperatures (Tb) varied between 3.3°C and 6.7°C whereas maximum germination temperatures (Tm) varied between 41.7°C and 48.9°C. Final germination fraction was attained at 15°C - 25°C whereas the maximum rate of germination was attained at 30.4°C - 35.6°C. The maximum germination rate of hybrid USDA 894, the cultivar with the slowest germination rate, was only 50% of that of hybrid EX 47. The low Tb and high Tm of sunflower appear to be one of the factors which explain the successful adaptation of sunflower to a wide range of temperature. These findings are discussed in relation to the origin of the crop and its wide adaptations in diverse habitats and climatic zones.

scholarly journals Studies of Flows Through N-Sequential Orifices

1983 ◽  
Vol 105 (3) ◽  
pp. 297-302 ◽  
Author(s):  
R. C. Hendricks ◽  
T. T. Stetz
Keyword(s):  
Mass Flux ◽  
Critical Mass ◽  
Pressure Profile ◽  
Profile Data ◽  
Axial Pressure ◽  
Reduced Pressure ◽  
Wide Range ◽  
Good For ◽  
Critical Regions ◽  
Reduced Temperature

Critical mass flux and axial pressure profile data for fluid nitrogen are presented for N = 20, 15, 10, and 7 N-sequential-orifice-inlet configurations uniformly spaced at 15.5 cm. These data correlate well over a wide range in reduced temperature (0.7 < Tr, 0 < ambient) and reduced pressure (to Pr = 2) and are in general agreement with previous studies of one to four inlets. Experimental and theoretical agreement is good for liquid and gas critical mass flux, but inconclusive in the near-thermodynamic critical regions.

scholarly journals The effect of five kinds of colloidal polymers for seed germination and growth in sand

2021 ◽  
Vol 804 (4) ◽  
pp. 042036
Author(s):  
Wenxu Zhang ◽  
Lulu Guo ◽  
Jing Chen ◽  
Shengfang Liu ◽  
Yifan Wang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Germination And Growth

Analysis of high yielding maize production - a study based on a commercial crop

2008 ◽  
Vol 48 (3) ◽  
pp. 296 ◽  
Author(s):  
C. J. Birch ◽  
G. McLean ◽  
A. Sawers
Keyword(s):  
Retrospective Analysis ◽  
Environmental Conditions ◽  
Sowing Date ◽  
Plant Population ◽  
Higher Plant ◽  
Maize Crop ◽  
Wide Range ◽  
Commercial Crop ◽  
Reduced Temperature

This paper reports on the use of APSIM – Maize for retrospective analysis of performance of a high input, high yielding maize crop and analysis of predicted performance of maize grown with high inputs over the long-term (>100 years) for specified scenarios of environmental conditions (temperature and radiation) and agronomic inputs (sowing date, plant population, nitrogen fertiliser and irrigation) at Boort, Victoria, Australia. It uses a high yielding (17 400 kg/ha dry grain, 20 500 kg/ha at 15% water) commercial crop grown in 2004–05 as the basis of the study. Yield for the agronomic and environmental conditions of 2004–05 was predicted accurately, giving confidence that the model could be used for the detailed analyses undertaken. The analysis showed that the yield achieved was close to that possible with the conditions and agronomic inputs of 2004–05. Sowing dates during 21 September to 26 October had little effect on predicted yield, except when combined with reduced temperature. Single year and long-term analyses concluded that a higher plant population (11 plants/m2) is needed to optimise yield, but that slightly lower N and irrigation inputs are appropriate for the plant population used commercially (8.4 plants/m2). Also, compared with changes in agronomic inputs increases in temperature and/or radiation had relatively minor effects, except that reduced temperature reduces predicted yield substantially. This study provides an approach for the use of models for both retrospective analysis of crop performance and assessment of long-term variability of crop yield under a wide range of agronomic and environmental conditions.

Factors affecting red-osier dogwood seed germination

1992 ◽  
Vol 70 (5) ◽  
pp. 1012-1016 ◽  
Author(s):  
S. N. Acharya ◽  
C. B. Chu ◽  
R. Hermesh ◽  
G. B. Schaalje
Keyword(s):  
Seed Germination ◽  
Germination Percentage ◽  
Collection Site ◽  
Moisture Condition ◽  
Seed Formation ◽  
Factors Affecting ◽  
Year Effect ◽  
Wide Range ◽  
Cornus Stolonifera ◽  
Moisture Conditions

Seeds from 55 populations of native Alberta red-osier dogwood (Cornus stolonifera Michx.) were collected over 2 years (1984 and 1985) to determine the range of variability for seed germination and the effect of ecoregion and moisture conditions in the collection sites on this trait. Each year the unscarified seeds were stored at 3 °C for 30 days, stratified at 3 °C for an additional 30 days and then incubated on an 8 h light: 16 h dark cycle at a temperature of 25:10 °C (light:dark) for germination. A wide range of germination percentages was observed among populations collected in any 1 year. However, the variability was not due to the ecoregion or moisture condition of the collection site. Germination percentage of populations collected in 1984 and 1985 formed five and seven groups, respectively. A study involving eight sites that were common to 1984, 1985, and 1986 revealed a significant effect of population on seed germination. This population effect was not obscured by the combined effects of year, precipitation, temperature, and seed size. The year effect was significant only when population was used as a covariate. Precipitation during seed formation significantly influenced germination performance even after adjustments were made for population and year. Seed germination in red-osier dogwood appears to be influenced by the population from which the seeds are collected and by yearly environmental fluctuations. Therefore, germination studies in this species must include seeds from diverse populations collected over several years. Key words: red-osier dogwood, Cornus stolonifera Michx., germination, population, environment.

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