The Invasion of Molehills by Weeds as a Possible Factor in the Degeneration of Reseeded Pasture. I. The Buried Viable Seed Population of Molehills from Four Reseeded Pastures in West Wales

1975 ◽  
Vol 12 (2) ◽  
pp. 643 ◽  
Author(s):  
Monica C. Jalloq
Keyword(s):  
Viable Seed ◽  
Seed Population

Seventeen Years of Cropping Systems and Tillage Affect Velvetleaf (Abutilon theophrasti) Seed Longevity

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 82-86 ◽  
Author(s):  
William E. Lueschen ◽  
Robert N. Andersen ◽  
Thomas R. Hoverstad ◽  
Brian K. Kanne
Keyword(s):  
Cropping Systems ◽  
Rapid Decline ◽  
Continuous Cropping ◽  
No Tillage ◽  
Viable Seed ◽  
Tillage Practices ◽  
Seed Population ◽  
Time Required ◽  
A Site ◽  
Chemical Fallow

Velvetleaf is difficult to control in corn and soybean and the seed can persist in soil for many years. Seven cultural and tillage practices were established in 1974 on a site heavily infested with velvetleaf to determine the time required to eradicate velvetleaf seed from the soil. A rapid decline in velvetleaf seed population in the top 23 cm of soil occurred during the first 5 yr of this study. In the fifth year, the chemical fallow and continuous alfalfa treatments had 37 and 56% of the original velvetleaf seed population remaining, respectively. In the 17th year, soils in these treatments that had received no tillage since study initiation still contained 15 and 25% of the original velvetleaf seed population, respectively. Systems involving moldboard plowing with continuous-tillage fallow, continuous cropping of corn or oat, or an annual corn and soybean rotation had a more rapid decline in the velvetleaf seed population in soil compared to the chemical fallow and continuous alfalfa treatment. After 17 yr, soil in any system that had received at least one moldboard plowing per year still contained 1 to 3 million velvetleaf seed ha−1, which is only 0.8 to 2.5% of the initial viable seed population. Nearly 100% of the seed remaining in the soil in the 17th year for all treatments was still viable.

scholarly journals Spatiotemporal analysis of the runaway distribution function from synchrotron images in an ASDEX Upgrade disruption

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
M. Hoppe ◽  
L. Hesslow ◽  
O. Embreus ◽  
L. Unnerfelt ◽  
G. Papp ◽  
...  
Keyword(s):  
Radial Profile ◽  
Spatiotemporal Analysis ◽  
High Energy ◽  
Synchrotron Emission ◽  
Analytic Model ◽  
Runaway Electrons ◽  
Radial Density ◽  
Radial Density Profile ◽  
Argon Injection ◽  
Seed Population

Synchrotron radiation images from runaway electrons (REs) in an ASDEX Upgrade discharge disrupted by argon injection are analysed using the synchrotron diagnostic tool Soft and coupled fluid-kinetic simulations. We show that the evolution of the runaway distribution is well described by an initial hot-tail seed population, which is accelerated to energies between 25–50 MeV during the current quench, together with an avalanche runaway tail which has an exponentially decreasing energy spectrum. We find that, although the avalanche component carries the vast majority of the current, it is the high-energy seed remnant that dominates synchrotron emission. With insights from the fluid-kinetic simulations, an analytic model for the evolution of the runaway seed component is developed and used to reconstruct the radial density profile of the RE beam. The analysis shows that the observed change of the synchrotron pattern from circular to crescent shape is caused by a rapid redistribution of the radial profile of the runaway density.

scholarly journals Selection and Micropropagation of an Elite Melatonin Rich Tulsi (Ocimum sanctum L.) Germplasm Line

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 207
Author(s):  
Mukund R. Shukla ◽  
Annaliese Kibler ◽  
Christina E. Turi ◽  
Lauren A. E. Erland ◽  
J. Alan Sullivan ◽  
...  
Keyword(s):  
In Vitro Selection ◽  
Integrated Approach ◽  
Antioxidant Potential ◽  
Ocimum Sanctum ◽  
Natural Health Products ◽  
Seed Population ◽  
Health Products ◽  
Potential Applications ◽  
Medicinal Properties

Tulsi (Ocimum sanctum L.) is a sacred plant of medicinal and spiritual significance in many cultures. Medicinal properties of Tulsi are ascribed to its phytochemicals with antioxidant capabilities. The current study was undertaken to screen a large seed population of Tulsi to select germplasm lines with high antioxidant potential and to standardize protocols for micropropagation and biomass production to produce a phytochemically consistent crop. A total of 80 germplasm lines were established under in vitro conditions and screened for their antioxidant potential determined with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) bioassay. The micropropagation of a selected line, named Vrinda, was established using nodal cultures grown on Murashige and Skoog medium containing benzylaminopurine (1.1 µM), gibberellic acid (0.3 µM), and activated charcoal (0.6%). The antioxidant phytohormones melatonin and serotonin were quantified in the field and greenhouse grown tissues of Vrinda and melatonin levels were found to be consistent in both conditions with higher serotonin levels under field conditions. This integrated approach combining the in vitro selection and propagation offers potential applications in the development of safe, effective, and novel natural health products of Tulsi, and many other medicinal plant species.

scholarly journals Do applications of systemic herbicides when green fruit are present prevent seed production or viability of Alliaria petiolata (garlic mustard)?

2021 ◽  
pp. 1-17
Author(s):  
Leo Roth ◽  
José Luiz C. S. Dias ◽  
Christopher Evans ◽  
Kevin Rohling ◽  
Mark Renz
Keyword(s):  
Seed Production ◽  
Seed Viability ◽  
Early Spring ◽  
Alliaria Petiolata ◽  
Late Spring ◽  
Garlic Mustard ◽  
Viable Seed ◽  
Application Timing ◽  
Control Seed ◽  
Second Year

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) postemergence to established, second-year A. petiolata populations at three locations when petals were dehiscing, and evaluated control, seed production and seed viability. Postemergence glyphosate applications at this timing provided 100% control of A. petiolata by 4 weeks after treatment at all locations whereas triclopyr efficacy was variable, providing 38-62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, we found a 71-99% reduction in number of viable seed produced plant-1 regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals were dehiscing is a viable alternative to cutting or hand-pulling at this timing as it substantially decreased viable A. petiolata seed production. Management Implications Postemergence glyphosate and triclopyr applications in the early spring to rosettes are standard treatments used to manage A. petiolata. However, weather and other priorities limit the window for management, forcing field practitioners to utilize more labor-intensive methods such as hand-pulling. It is not known how late in the development of A. petiolata these herbicides can be applied to prevent viable seed production. Since prevention of soil seedbank replenishment is a key management factor for effective long-term control of biennial invasive species, we hypothesized late spring foliar herbicide applications to second year A. petiolata plants when flower petals were dehiscing could be an effective management tool if seed production or viability is eliminated. Our study indicated that glyphosate applications at this timing provided 100% control of A. petiolata plants by 4 weeks after treatment at all locations, whereas triclopyr efficacy was inconsistent. Although both glyphosate and triclopyr decreased viable seed production to nearly zero at one of our three study locations, the same treatments produced significant amounts of viable seed at the other two locations. Our findings suggest late spring glyphosate and triclopyr applications should not be recommended over early spring applications to rosettes for A. petiolata management, as our late spring application timing did not prevent viable seed production, and may require multiple years of implementation to eradicate populations. Nonetheless, this application timing holds value in areas devoid of desirable understory vegetation compared to no management practices or mechanical management options including hand-pulling when fruit are present, as overall viable seed production was reduced to similar levels as these treatments.

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Husrev Mennan ◽  
Mathieu Ngouajio
Keyword(s):  
Soil Depth ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Soil Surface ◽  
Burial Depth ◽  
Galium Aparine ◽  
Wild Mustard ◽  
Seed Population ◽  
Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

Buried seed populations in the montane, subalpine, and alpine belts of Mont Jacques-Cartier, Quebec

1988 ◽  
Vol 66 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Hubert Morin ◽  
Serge Payette
Keyword(s):  
Seed Bank ◽  
Linear Correlation ◽  
Altitudinal Gradient ◽  
Number Of Species ◽  
Significant Linear Correlation ◽  
Seed Population ◽  
Close Relationship ◽  
Buried Seed ◽  
Study Sites ◽  
Number Of Seeds

The analysis of the total buried seed population along an altitudinal gradient in the Mont Jacques-Cartier area, southern Quebec, reveals a close relationship between buried seed flora and aboveground vegetation. Eighty-one percent of the species present in the total buried seed population were present in the aboveground vegetation of the study sites. The total number of seeds in the buried seed population, the number of species in the total buried seed population, and the number of seeds and species in the seed bank did not show any significant linear correlation with altitude. A shift from a boreal to an arctic–alpine buried seed population with increasing altitude was observed, instead of a decrease in seed bank size.

FUNGI ASSOCIATED WITH HOT SPOTS IN FARM STORED GRAIN

1962 ◽  
Vol 42 (1) ◽  
pp. 130-141 ◽  
Author(s):  
H. A. H. Wallace ◽  
R. N. Sinha
Keyword(s):  
Hot Spots ◽  
Viable Seed ◽  
Stored Grain ◽  
Surface Layers ◽  
Bulk Heating ◽  
Storage Fungi ◽  
Grain Bulks ◽  
Penicillium Spp ◽  
Water Contents

The temperature, moisture, germination and fungal relationships of normal and heated wheat and oats collected from grain bulks in 13 granaries in Manitoba and Saskatchewan were determined during the falls and winters of 1957–60. Eight bulks were studied in detail. It was found that hot spots could develop anywhere in a bin. Temperatures up to 53 °C. (in winter) were obtained and were usually highest at the base of the bulk. Heating grain was relatively dry (less than 11 per cent) except along the surface. The highest water contents (27 per cent) in the bulks always occurred in the gram along the surface layers. Loss of germinability could occur anywhere in the bulk. Field fungi, such as Alternaria, were common in viable seed, but negligible in heated grain. The seeds in hot spots were predominantly infected by storage fungi, among which Penicillium spp. were the most abundant, even in relatively dry grain at the 6-foot depth. Other fungi commonly found were Aspergillus spp., especially A. flavus Link, A. fumigatus Fresenius, A. versicolor (Vuillemin) Tiraboschi and Absidia spp. Actinomycetes (Streptomyces) were common in some heating grain bulks.

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