Impact of heat on seed germination of three perennial grasses in the semiarid region in Central Argentina

2016 ◽  
Vol 64 (5) ◽  
pp. 451 ◽  
Author(s):  
Alicia G. Kin ◽  
Carla E. Suárez ◽  
Claudia C. Chirino ◽  
Patricia L. Ávila ◽  
Ernesto F. A. Morici
Keyword(s):  
Heat Shock ◽  
Seed Germination ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Seed Viability ◽  
High Heat ◽  
Perennial Grasses ◽  
Semiarid Region ◽  
Central Argentina ◽  
Negative Effect

Fire is an important factor affecting the viability and germination of seeds in the soil seed bank. We evaluated the effects of heat on germination and seed viability of three native perennials winter grasses of central Argentina. Seeds of two palatable grasses Piptochaetium napostaense (Speg.) Hack, Nassella tenuis (Phil.) Barkworth and a non-palatable Jarava ichu Ruiz & Pav. were exposed to different heat shock treatments resulting from a combination of temperature: 70, 90, 120, 140 and 170°C and three exposure times (5, 10 or 20 min) and a control (no heat) treatment. All control treatments had a high percentage of seed viability (>97%). Germination of P. napostaense was not affected by mild heat shock (70 and 90°C) but it was sensitive to higher temperatures: no seeds survived the exposure to 140 and 170°C. Seeds of this species have awns that facilitate the burring of seeds in the soil, which can reduce fire exposure. N. tenuis and J. ichu were less sensitive to heat. High heat shock reduced seed germination but not seed viability. These experiments show that seeds of P. napostaense, the target species for management on these grasslands, were the most sensitive to heat treatments. Our results show that heat shock can have a negative effect on the soil seed bank of P. napostaense (palatable and dominant species), but does not have significant effects on J. ichu seeds (unpalatable species). Thus, we suggest that the current management recommendations for the use of controlled fire to promote palatable species may not be optimal for these species.

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

2002 ◽  
Vol 50 (2) ◽  
pp. 197 ◽  
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.

scholarly journals Viability of recalcitrant Araucaria angustifolia seeds in storage and in a soil seed bank

2019 ◽  
Vol 31 (6) ◽  
pp. 2413-2422 ◽  
Author(s):  
Ezequiel Gasparin ◽  
José M. R. Faria ◽  
Anderson C. José ◽  
Olivia A. O. Tonetti ◽  
Rodrigo A. de Melo ◽  
...  
Keyword(s):  
Water Content ◽  
Seed Bank ◽  
Forest Cover ◽  
Soil Seed Bank ◽  
Natural Habitat ◽  
Seed Viability ◽  
Germplasm Conservation ◽  
Forest Edge ◽  
Araucaria Angustifolia ◽  
Subsequent Decrease

Abstract Araucaria angustifolia (Bertol.) Kuntze is a representative species of the Mixed Ombrophilous Forest in the Atlantic Forest Biome of Brazil. The development of a germplasm conservation protocol for long-term seed bank storage is compromised for this species, as it is sensitive to desiccation. Furthermore, in situ establishment of a soil seed bank in its natural habitat may be limited. This study evaluates the storability of two provenances of A. angustifolia seeds and their behavior in an artificial soil seed bank in two forest environments (understory and edge). Results show that both seed provenances may be stored at 5 °C for approximately 12 months, retaining high viability. The subsequent decrease in germination was associated with a reduction and an increase in seed water content, as well as with increased electrical conductivity. In the understory environment, seed viability was above 85% for the first 60 days, and at the end of the experiment (270 days), seedlings emerged. However, at the forest edge, there was a total loss of seed viability after 120 days associated with a reduction in water content and high predation. It is concluded, therefore, that short-term storage of A. angustifolia seeds is possible in a cold room, which is fundamental to supply seed demand outside the production period. Forest cover conservation is important for regeneration and conservation of the species.

scholarly journals Seed bank modelling of volunteer oil seed rape: from seeds fate in the soil to seedling emergence

2013 ◽  
Vol 31 (2) ◽  
pp. 267-279 ◽  
Author(s):  
E. Soltani ◽  
A. Soltani ◽  
S. Galeshi ◽  
F. Ghaderi-Far ◽  
E. Zeinali
Keyword(s):  
Oilseed Rape ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Burial Depth ◽  
Soil Seed Banks ◽  
Seed Bank Dynamics ◽  
Autumn And Winter ◽  
Lower Slope

Studies were conducted to estimate parameters and relationships associated with sub-processes in soil seed banks of oilseed rape in Gorgan, Iran. After one month of burial, seed viability decreased to 39%, with a slope of 2.03% per day, and subsequently decreased with a lower slope of 0.01 until 365 days following burial in the soil. Germinability remained at its highest value in autumn and winter and decreased from spring to the last month of summer. Non-dormant seeds of volunteer oilseed rape did not germinate at temperatures lower than 3.8 ºC and a water potential of -1.4 MPa ºd. The hydrothermal values were 36.2 and 42.9 MPa ºd for sub- and supra-optimal temperatures, respectively. Quantification of seed emergence as influenced by burial depth was performed satisfactorily (R² = 0.98 and RMSE = 5.03). The parameters and relationships estimated here can be used for modelling soil seed bank dynamics or establishing a new model for the environment.

scholarly journals Establishment of native and exotic grasses on mine overburden and topsoil in the Hunter Valley, New South Wales

2005 ◽  
Vol 27 (2) ◽  
pp. 73 ◽  
Author(s):  
C. H. A. Huxtable ◽  
T. B. Koen ◽  
D. Waterhouse
Keyword(s):  
Seed Bank ◽  
Native Species ◽  
Soil Seed Bank ◽  
Coal Mines ◽  
Climatic Conditions ◽  
Perennial Grasses ◽  
Grass Species ◽  
Native Grasses ◽  
Exotic Grasses ◽  
Mine Rehabilitation

Native grasses have an important role to play in mine rehabilitation throughout Australia, but there have been few scientifically designed studies of field establishment of native grasses from sown seed in this country. Current recommendations for rehabilitation of open-cut coal mines in the Hunter Valley involve the sowing of exotic pasture species to reinstate mined land to Class IV and V under the Rural Land Capability System. Despite the importance of native grasses in the pre-mined landscape, they are currently not widely included in mine rehabilitation. To address this issue a project was conducted between 1994 and 2000 to research the use of native grasses for rehabilitation of open-cut coal mines in the Hunter Valley. This paper reports on 2 mine site experiments that aimed to assess establishment and persistence of a broad range of native and exotic grass species from an autumn sowing in both topsoil and raw spoil over a period of 61 months. The most promising natives in terms of early establishment, persistence and spread over time, included six C3 accessions (five Austrodanthonia spp. and Austrostipa bigeniculata) and one C4 accession (Cynodon dactylon). Persistence of these accessions was better in raw spoil than topsoil, despite initial low numbers, due to a lack of weed competition and their ability to spread by self-seeding. In topsoil, and in the absence of any biomass reduction, native species were mostly out-competed by vigorous exotic perennial grasses which were sown in these experiments and from seed influx from adjacent rehabilitation areas or from the soil seed bank. The effects of climatic conditions and differences in soil physical, chemical and seed bank characteristics at the 2 mine sites are also discussed.

scholarly journals Regulation of seed germination by diurnally alternating temperatures in disturbance-adapted banana crop wild relatives (Musa acuminata)

2020 ◽  
Vol 30 (4) ◽  
pp. 238-248
Author(s):  
Simon Kallow ◽  
Rachael Davies ◽  
Bart Panis ◽  
Steven B. Janssens ◽  
Filip Vandelook ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Crop Wild Relatives ◽  
Musa Acuminata ◽  
Wild Relatives ◽  
Temperature Cycles ◽  
Thermal Requirements ◽  
Alternating Temperature ◽  
Banana Crop

AbstractSeed conservation of banana crop wild relatives (Musa L. spp.) is limited because of lack of knowledge about their germination ecology. Musa acuminata Colla, the most important banana crop wild relative, is distributed in tropical and subtropical Asian and Pacific rainforests and colonizes disturbed sites. The role of temperature in stimulating/inhibiting germination to detect disturbance when canopy gaps are formed is not well known. We assessed seed germination thermal requirements of three subspecies of M. acuminata using nine seed accessions which had been stored in the Millennium Seed Bank. Diurnally alternating temperature cycles were almost completely essential for germination compared with constant temperatures. Germination was optimal when the upper temperature of a diurnal cycle was at 35°C; the lower temperature of the cycle was less important. Subspecies occurrence coordinates were used to extract climate temperature data which were then compared against the temperature requirements for germination from our experiment results. Maximum temperatures of the warmest month across subspecies ranges were close to but below optimal germination temperatures, as were diurnal ranges, suggesting soil-warming at the micro-climate level following gap creation is important for M. acuminata seed germination. Additionally, pre-treatment for 3 months at 60% relative humidity at constant 25°C improved germination from 14 ± 10 (mean, standard deviation) to 41 ± 29% suggesting a period in the soil seed bank under the canopy may increase sensitivity to alternating temperature cycles. Overall viability was low (49 ± 28%), and considerable variance was caused by the different accessions. Germination remained somewhat inconsistent.

scholarly journals Seed Longevity of Spotted Spurge and Wild Poinsettia Under Diverse Environmental Conditions

2020 ◽  
Vol 38 ◽  
Author(s):  
R. ASGARPOUR ◽  
R. GHORBANI ◽  
M. KHAJEH-HOSSEINI ◽  
F. GOLZARDI ◽  
M.N. ILKAEE
Keyword(s):  
Seed Germination ◽  
Exotic Species ◽  
Seed Bank ◽  
Environmental Conditions ◽  
Crop Residue ◽  
Soil Seed Bank ◽  
Seed Longevity ◽  
Water Flooding ◽  
Golestan Province ◽  
Soil Effects

ABSTRACT: Seed longevity under different environmental conditions is considered as one of the most important factors in the spread and persistence of an exotic species. The Experiments were conducted to determine seed persistence in soil, effects of submergence in water, flooding of the soil, and high temperatures on germination and viability of spotted spurge (Chamaesyce maculata) and wild poinsettia (Euphorbia heterophylla) as two exotic species in different regions of Golestan province. Spotted spurge seeds buried at depth of 10 cm maintained their viability above 95% after a year, while wild poinsettia seeds were destroyed completely after exhuming the soil. Seeds of both species were unable to germinate under submergence, but 92% of the spotted spurge seeds remained viable under this condition for 14 d. No germination was observed after 9 weeks submersion. Submersion duration drastically affected seed germination of wild poinsettia, so that no germination occurred after 6 d submersion. Twelve days after flooding, spotted spurge emergence decreased by 57% compared to the control. Ten percentage of wild poinsettia seedlings emerged when flooding was kept up to 12 d after sowing, while control had 96% emergence. Germination of spotted spurge seeds subjected to 140 oC for 5 min was 5%. Viability of wild poinsettia seed was completely lost at 120 and 140 C for 5 min. These results suggest that spotted spurge is capable of forming persistent seedbank. Seeds of spotted spurge were partially tolerant to submersion in water, but wild poinsettia seed are susceptible to submergence. The burning of crop residue could also prevent augmenting the soil seed bank of both species.

scholarly journals Longevidad y germinación de semillas de Syagrus romanzoffiana (Arecaceae) y sus implicaciones ecológicas

2015 ◽  
Vol 63 (2) ◽  
pp. 333 ◽  
Author(s):  
Túlio Gabriel Soares Oliveira ◽  
Anderson Cleiton José ◽  
Leonardo Monteiro Ribeiro ◽  
José Marcio Rocha Faria
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Palm Tree ◽  
Forest Fragment ◽  
Seedling Mortality ◽  
Viable Seeds ◽  
One Year ◽  
Syagrus Romanzoffiana

<strong><em>Syagrus romanzoffiana</em> is a palm tree native and widely distributed of South America.</strong> <strong>The present study investigated the longevity and germination of the buried seeds of this species in an experimental seed bank.</strong> <strong>Laboratory germination and</strong> <strong>viability tests were performed for comparison with field results. Pyrenes (seeds enclosed by the endocarp) were buried in a forest fragment edge in July (dry season) in July 2012 and exhumed monthly during one year, for the assessment of water content</strong> <strong>and percentage of germinated and viable seeds.</strong> <strong>Germination tests</strong> <strong>were conducted in a Mangelsdorf-type germinator at 30°C under constant light and the viability was </strong><strong>assessed by the tetrazolium test. An additional sample of</strong> <strong>pyrenes was buried to evaluate the percentage of seedling emergence and survival. Climatic</strong> <strong>and soil moisture</strong> <strong>data</strong> <strong>were recorded.</strong> <strong>In the laboratory, the pyrenes were stored for one year in a temperature-controlled room at 20ºC and 75% (±10%) relative air humidity to assess changes in the percentage of germination and viability over time.</strong> <strong>In the field, a reduction in seed viability</strong> <strong>was observed over the study period, with a total loss of viability of non-germinated seeds at seven months after burial.</strong> <strong>The maximum germination (close to 26%) was observed in the samples that were exhumed between five and seven months after burial. In the field, seedling emergence did not exceed 10% and seedling mortality was not observed. The percentages of germination and of viable seeds decreased both in burial and stored seeds. The stored seeds maintained viability at up to six months, with marked reduction thereafter. After the germination tests (four months) in the laboratory, all of the remaining seeds were nonviable. The ecological, physiological</strong> <strong>and reproductive characteristics of the species are discussed, and we concluded that</strong> <strong><em>S. romanzoffiana</em></strong> <strong>seeds have short longevity after imbibition, and low potential for soil seed bank formation.</strong>

scholarly journals Soil Seed Bank and Aboveground Vegetation in Grazing Lands of Southern Marmara, Turkey

2011 ◽  
Vol 39 (1) ◽  
pp. 96 ◽  
Author(s):  
Altıngül ÖZASLAN PARLAK ◽  
Ahmet GÖKKUŞ ◽  
Hasan Can DEMİRAY
Keyword(s):  
Species Richness ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Common Species ◽  
Seed Banks ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Vegetation Survey ◽  
Soil Seed Banks ◽  
Grazing Lands

The composition and conservation of plant communities is greatly influenced by the soil seed bank. Information on the soil seed banks and the remaining vegetation in these ecosystems is crucial for guiding the restoration efforts. This study examines the size, species richness, diversity, uniformity, and similarity of soil seed banks and aboveground vegetation in 6 different grazing lands including coastal pasture, reseeded pasture, artificial pasture, lowland shrubland, ungrazed pasture, and hillside shrubland. Forty-eight soil samples were taken by cores with a diameter and depth of 10 cm from each of grazing lands in August of 2007. A vegetation survey was conducted using a 0.5 x 0.5-m quadrant in both the spring and fall. Eighty species were observed in soil seed banks and aboveground vegetation. The largest seed bank was observed in reseeded pasture (7,715 seed/m2), while the smallest seed bank was found in coastal pasture (2,755 seed/m2). Coastal pasture also possessed the least amount of aboveground vegetation (131 plants/m2). The most aboveground vegetation was found in ungrazed pasture (155 plants/m2). The most common species in seed banks were annual and perennial grasses in reseeded pasture, annual forbs in artificial pasture and hillside shrubland, and perennial forbs in low shrubland and ungrazed pasture. Species richness, diversity, and uniformity in seed banks were highest in lowland shrubland and lowest in artificial pasture. The seed bank and aboveground vegetation were similar in ungrazed pasture, coastal pasture, reseeded pasture, low shrubland, hillside shrubland and artificial pasture. Shrublands play an important role in species richness and the number of germinated seeds from seed banks of grazing lands in southern Marmara. The results showed that reseeding or a decrease in grazing pressure may improve the condition of grazing lands.

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