Secondary dormancy of seeds in relation to the Bromus tectorum&ndash;Pyrenophora semeniperda pathosystem

Bromus tectorum is a highly invasive annual grass. The fungal pathogen Pyrenophora semeniperda can kill a large fraction of B. tectorum seeds. Outcomes in this pathosystem are often determined by the speed of seed germination. In this paper we extend previous efforts to describe the pathosystem by characterising secondary dormancy acquisition of B. tectorum. In the laboratory approximately 80% of seeds incubated at –1.0 MPa became dormant. In the field, seeds were placed in the seed bank in late autumn, retrieved monthly and dormancy status determined. The field study confirmed the laboratory results; ungerminated seeds became increasingly dormant. Our data suggest that secondary dormancy is much more likely to occur at xeric sites.

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Seed germination, seedling emergence, and seed bank ecology of sweet fern (Comptonia peregrina(L.) Coult.)

Canadian Journal of Botany ◽

10.1139/b99-081 ◽

1999 ◽

Vol 77 (9) ◽

pp. 1378-1386

Author(s):

Melissa A Dow ◽

Christa R Schwintzer

Keyword(s):

Seed Germination ◽

Seed Bank ◽

Temperature Fluctuation ◽

Seedling Emergence ◽

Chilling Temperature ◽

Secondary Dormancy ◽

Forest Sites ◽

Moist Chilling ◽

Adjacent Field ◽

Dormancy Cycles

We examined seed-bank seeds of sweet fern (Comptonia peregrina (L.) Coult.), an actinorhizal nitrogen-fixing shrub, to determine their distribution in the soil and to identify the factors that stimulate them to germinate following removal of the vegetation. Seeds were extracted from the soil of adjacent field and forest sites currently lacking sweet fern in Orono, Maine. Both sites contained approximately 2000 seeds·m-2with the greatest concentration at a depth of 60-80 mm. The seeds were 4.0-5.5 mm long, enclosed by a pitted, woody pericarp, and 8% contained embryos. Many seedlings emerged in disturbed plots (vegetation removed and upper soil mixed) in May and June 1997, but none appeared after 24 July. Seeds collected in May and June germinated readily in a growth chamber (30-45% germination) whereas only 2-5% of July- and August-collected seeds germinated indicating induction of secondary dormancy. August-collected seeds showed strong germination after >=15 days of moist chilling at 4°C indicating relief of secondary dormancy by chilling. Temperature fluctuation with an amplitude of 10°C strongly stimulated germination. Presence of annual secondary dormancy cycles and stimulation by strong temperature fluctuation assures that seed-bank seeds germinate under conditions that allow the seedlings to become established.Key words: actinorhizal plants, Comptonia peregrina, germination ecophysiology, secondary dormancy, seed bank, seedling emergence.

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Is Pyrenophora semeniperda the Cause of Downy Brome (Bromus tectorum) Die-offs?

Invasive Plant Science and Management ◽

10.1614/ipsm-d-12-00043.1 ◽

2013 ◽

Vol 6 (1) ◽

pp. 105-111 ◽

Cited By ~ 16

Author(s):

Owen W. Baughman ◽

Susan E. Meyer

Keyword(s):

Seed Bank ◽

Fungal Pathogen ◽

Bromus Tectorum ◽

Seed Banks ◽

Causal Agent ◽

Western North America ◽

Downy Brome ◽

Winter Annual ◽

Persistent Seed Bank ◽

Semi Arid

AbstractDowny brome (cheatgrass) is a highly successful, exotic, winter annual invader in semi-arid western North America, forming near-monocultures across many landscapes. A frequent but poorly understood phenomenon in these heavily invaded areas is periodic ‘die-off’ or complete stand failure. The fungal pathogen Pyrenophora semeniperda is abundant in cheatgrass seed banks and causes high mortality. To determine whether this pathogen could be responsible for stand failure, we quantified late spring seed banks in die-off areas and adjacent cheatgrass stands at nine sites. Seed bank analysis showed that this pathogen was not a die-off causal agent at those sites. We determined that seed bank sampling and litter data could be used to estimate time since die-off. Seed bank patterns in our recent die-offs indicated that the die-off causal agent does not significantly impact seeds in the persistent seed bank.

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Research Article: A study of Bromus tectorum L. seed germination in the Gunnison Basin, Colorado

BIOS ◽

10.1893/0005-3155(2006)77[07:raasob]2.0.co;2 ◽

2006 ◽

Vol 77 (1) ◽

pp. 7-12 ◽

Cited By ~ 2

Author(s):

Caley Gasch ◽

Robin Bingham

Keyword(s):

Seed Germination ◽

Bromus Tectorum ◽

Research Article

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Cover-based allometric estimate of aboveground biomass of a non-native, invasive annual grass (Bromus tectorum L.) in the Great Basin, USA

Journal of Arid Environments ◽

10.1016/j.jaridenv.2021.104582 ◽

2021 ◽

Vol 193 ◽

pp. 104582

Author(s):

Adam L. Mahood ◽

Erica Fleishman ◽

Jennifer K. Balch ◽

Frank Fogarty ◽

Ned Horning ◽

...

Keyword(s):

Great Basin ◽

Aboveground Biomass ◽

Bromus Tectorum ◽

Annual Grass ◽

Native Invasive

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Effects of heat and smoke on germination of soil-stored seed in a south-eastern Australian sand heathland

Australian Journal of Botany ◽

10.1071/bt01017 ◽

2002 ◽

Vol 50 (2) ◽

pp. 197 ◽

Cited By ~ 31

Author(s):

Timothy J. Wills ◽

Jennifer Read

Keyword(s):

Seed Germination ◽

Seed Bank ◽

Soil Seed Bank ◽

Seedling Emergence ◽

Type Systems ◽

Treated Soil ◽

South Eastern ◽

Heat Treated ◽

Eastern Australia ◽

And Control

Various fire-related agents, including heat, smoke, ash and charred wood, have been shown to break dormancy and promote germination of soil-stored seed in a broad range of species in mediterranean-type systems. However, relatively little work has been conducted in south-eastern Australian heathlands. This study examined the effects of heat and smoked water on germination of the soil seed bank in a mature sand heathland within the Gippsland Lakes Coastal Park, in south-eastern Australia. Heat was clearly the most successful treatment for promoting seed germination, followed by smoked water, then controls, with 55% of species present in the germinable soil seed bank requiring a heat or smoke stimulus to promote seed germination. Mean species richness of the germinable soil seed bank was found to be significantly higher in heat-treated soil than in smoke and control treatments. Seedling density of heat-treated soil was almost 10 times that of controls, while smoke-treated soil was almost five times that of controls. Seedling emergence was fastest in heat-treated soil, followed by smoke and control soils. Of the species found in the soil seed bank, 25% were absent from the extant vegetation, suggesting the existence of post-fire colonisers in the soil seed bank. The results have implications for the design of soil seed bank experiments and the use of fire as a tool in vegetation management.

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Seed Storage and Germination Performance in Knema attenuata - an Endemic Medicinal Tree of Western Ghats, India

Journal of Non Timber Forest Products ◽

10.54207/bsmps2000-2021-u31w16 ◽

2021 ◽

Vol 27 (3) ◽

pp. 162-166

Author(s):

Abdul Azeez Hussain ◽

◽

Ramachandra Kurup Rajvikraman ◽

Keyword(s):

Seed Germination ◽

Relative Humidity ◽

Moisture Content ◽

Seed Bank ◽

Tree Species ◽

Western Ghats ◽

Climatic Condition ◽

Seed Storage ◽

Medicinal Tree

Detailed study on seed storage and germination trailed in Knema attenuata (Wall. ex Hook. f. & Thomson) Warb.– the IUCN Red Listed ‘least concern’ medicinal tree species revealed that seeds were of recalcitrant nature. Viability of the seeds could be maintained for a longer period of up to 6 months with 47% Moisture content (mc) when kept in closed polycarbonate bottles at seed bank condition [20±20C Temp. and 40% Relative Humidity (RH)]. The 55% seed germination under normal climatic condition could be enhanced to a much higher percentage (75±5) inside the mist house chamber (34±30C Temp. and 70-80% RH).

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Seed Germination Ecophysiology of Meadow Salsify (Tragopogon pratensis) and Western Salsify (T. dubius)

Weed Science ◽

10.1017/s0043174500052061 ◽

1993 ◽

Vol 41 (3) ◽

pp. 362-368 ◽

Cited By ~ 16

Author(s):

Meiqin Qi ◽

Mahesh K. Upadhyaya

Keyword(s):

Seed Germination ◽

Storage Temperature ◽

Seedling Emergence ◽

Separate Study ◽

Optimum Temperature ◽

Seedling Mortality ◽

Secondary Dormancy ◽

Persistence Strategies

To understand persistence strategies of meadow and western salsify, ecophysiological characteristics of their seed germination were studied. Anaerobiosis (immersion in deoxygenated water) induced secondary dormancy in seeds of both species. Dormancy could be induced in 86% of meadow salsify seeds and in 65% of western salsify seeds by a 1-d anaerobiosis treatment. The induced dormancy was gradually released during storage of air-dried secondary dormant meadow salsify seeds, and the rate of this release was influenced by storage temperature; 30 C was more effective than 10 or 20 C in releasing secondary dormancy. These results suggest that the two species may rely on induced dormancy as an option in their persistence strategy. The optimum temperature for germination of nondormant seeds of both species was 15 C. Maximum germination percentages for both species were established within 4 to 6 d of incubation at 15 C and within 14 to 28 d of incubation at 25 C. Nondormant seeds did not germinate below 10 or above 30 C. Stratification (at 5 C for 2 to 10 wk) stimulated germination of secondary dormant seeds of meadow salsify. This stratification requirement can be important in preventing germination of dormant salsify seeds in the fall, thereby avoiding high seedling mortality in the winter. Light (red and far-red) had no effect on germination of seeds in secondary dormancy. In a separate study, seeds of both species were planted in pots at depths of 2 to 14 cm and seedling emergence was observed. Maximum emergence occurred when seeds were buried 2 cm deep. Seeds planted 8 cm or deeper germinated but did not emerge.

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Fall-Grazing and Grazing-Exclusion Effects on Cheatgrass (Bromus tectorum) Seed Bank Assays in Nevada, United States

Rangeland Ecology & Management ◽

10.1016/j.rama.2020.01.012 ◽

2020 ◽

Vol 73 (3) ◽

pp. 343-347

Author(s):

Barry L. Perryman ◽

Brad W. Schultz ◽

Michelle Burrows ◽

Teshome Shenkoru ◽

Jon Wilker

Keyword(s):

United States ◽

Seed Bank ◽

Bromus Tectorum ◽

Grazing Exclusion

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Seedling establishment from seeds and seed banks in forests under long-term pollution stress: a potential for vegetation recovery

Canadian Journal of Botany ◽

10.1139/b94-019 ◽

1994 ◽

Vol 72 (2) ◽

pp. 143-149 ◽

Cited By ~ 28

Author(s):

M. Komulainen ◽

M. Vieno ◽

V. T. Yarmishko ◽

T. D. Daletskaja ◽

E. A. Maznaja

Keyword(s):

Seed Germination ◽

Seed Bank ◽

Coniferous Forest ◽

Calluna Vulgaris ◽

Seed Banks ◽

Pollution Source ◽

Average Density ◽

Vegetation Recovery ◽

Ground Vegetation ◽

Empetrum Nigrum

Seed germinability of some common dwarf shrubs and seed-bank composition were studied in young pine forests along a pollution gradient from Severonickel smelter in Monchegorsk, northern Russia. Samples for seed germination and seed-bank trials were taken from sites representing different zones of pollution. Generally, germinability of dwarf shrub seeds was not affected by distance from pollution source, except for Empetrum nigrum ssp. hermaphroditium. The average density per site of seedlings that emerged from seed-bank samples varied between 278 and 416 seedlings/m2. Empetrum nigrum ssp. hermaphroditum and Betula sp. dominated in seed banks. Calluna vulgaris was also numerous at one site. As a whole, seed-bank taxa were well represented in the above ground vegetation. There were no significant differences in seedling density between sites for dominant taxa. Our results indicate that seeds can retain viability even under a heavy pollution load and thus form a potential for vegetation recovery in polluted sites. Key words: seed germination, seed bank, recovery, pollution, coniferous forest.

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Downy Brome (Bromus tectorum) Vernalization: Variation and Genetic Controls

Weed Science ◽

10.1017/wsc.2018.1 ◽

2018 ◽

Vol 66 (3) ◽

pp. 310-316 ◽

Cited By ~ 1

Author(s):

Nevin C. Lawrence ◽

Amber L. Hauvermale ◽

Ian C. Burke

Keyword(s):

North America ◽

Bromus Tectorum ◽

Brachypodium Distachyon ◽

Western North America ◽

Downy Brome ◽

Annual Grass ◽

Vernalization Gene ◽

Greenhouse Experiments ◽

Winter Annual

AbstractDowny brome (Bromus tectorumL.) is a widely distributed invasive winter annual grass across western North America.Bromus tectorumphenology can vary considerably among populations, and those differences are considered adaptively significant. A consensus hypothesis in the literature attributes the majority of observed differences inB. tectorumphenology to differing vernalization requirements among populations. A series of greenhouse experiments were conducted to identify differences inB. tectorumvernalization requirements and link vernalization to expression of annual false-brome [Brachypodium distachyon(L.) P. Beauv.]-derived vernalization gene homolog (BdVRN1). Results from this study indicate that variation in time to flowering is partially governed by differing vernalization requirements and that flowering is linked to the expression ofBdVRN1.

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