Seed heteromorphy influences seed longevity in Aegilops

2018 ◽  
Vol 28 (4) ◽  
pp. 277-285 ◽  
Author(s):  
Filippo Guzzon ◽  
Simone Orsenigo ◽  
Maraeva Gianella ◽  
Jonas V. Müller ◽  
Ilda Vagge ◽  
...  
Keyword(s):  
Seed Germination ◽  
Field Experiments ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Longevity ◽  
Ex Situ ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Seed Conservation ◽  
Germination Phenology

AbstractThe genus Aegilops belongs to the secondary gene pool of wheat and has great importance for wheat cultivar improvement. As a genus with only annual species, regeneration from seeds in Aegilops is crucial. In several species in Aegilops, spikes produce different seed morphs, both in size and germination patterns. However, little is known about the ecology of seed germination, nor about the seed longevity in this genus. Here we investigated the germination phenology of Ae. neglecta under laboratory and field conditions and assessed longevity of different seed morphs of five additional Aegilops species using controlled ageing tests. Large seeds were short-lived and germinated faster than small seeds in most of the species. Field experiments with Ae. neglecta showed that large seeds of the dimorphic pair germinated 3 months after dispersal in contrast to 14 months for smaller seeds. Differences in longevity were detected not only in dimorphic seed pairs, but also among seeds from different positions on the spike. Our results indicate that different longevities in seed morphs of Aegilops may reflect a different soil seed bank persistence, with smaller seeds able to maintain a higher viability after dispersal than larger ones, thereby spreading seedling emergence over two years. Differences of seed germination and longevities between seed morphs in Aegilops may have important implications for ex situ seed conservation and reinforce the hypothesis of a bet-hedging strategy in the germination ecology of this genus.

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 Effects of Environmental Factors on Seed Germination and Emergence of Velvetleaf (Abutilon theophrasti)

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
RC. XIONG ◽  
Y. MA ◽  
HW. WU ◽  
WL. JIANG ◽  
XY. MA
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Field Experiments ◽  
Cropping Systems ◽  
Control Strategies ◽  
Seedling Emergence ◽  
Central China ◽  
Burial Depth ◽  
Temperature Regimes ◽  
Alternating Temperature

ABSTRACT: Velvetleaf, an annual broadleaf weed, is a common and troublesome weed of cropping systems worldwide. Laboratory and field experiments were conducted to determine the effects of environmental factors on germination and emergence of velvetleaf. Seeds germinated over a range of constant temperatures from 10 to 40 oC regardless of light conditions, but no germination occurred at temperature below 5 oC and beyond 50 oC. Seeds germinated at alternating temperature regimes of 15/5 to 40/30 oC, with maximum germination (>90%) at alternating temperatures of 40/30 oC. Germination was sensitive to water stress, and only 0.4% of the seeds germinated at the osmotic potential of -0.4 MPa. There was no germination at ? 0.6 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ³ 150 mM NaCl or ³ 200 mM NaHCO3 concentrations. However, pH values from 5 to 9 had no effect on seed germination. Seedling emergence was significantly affected by burial depth and maximum emergence (78.1-85.6%) occurred at the 1-4 cm depth. The results of this study have contributed to our understanding of the germination and emergence of velvetleaf and should enhance our ability to improve control strategies in cropping systems in central China.

Factors affecting seed germination of annual sowthistle (Sonchus oleraceus) in southern Australia

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 854-860 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Field Experiments ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Factors Affecting ◽  
Control Programs ◽  
Buried Seed ◽  
Ph Range

Annual sowthistle has become more abundant under no-till systems in southern Australia. Increased knowledge of germination biology of annual sowthistle would facilitate development of effective weed control programs. The effects of environmental factors on germination and emergence of annual sowthistle seeds were examined in laboratory and field experiments. Seeds of annual sowthistle were able to germinate over a broad range of temperatures (25/15, 20/12, and 15/9 C day/night temperatures). Seed germination was favored by light; however, some germination occurred in the dark as well. Greater than 90% of seeds germinated at a low level of salinity (40 mM NaCl), and some seeds germinated even at 160 mM NaCl (7.5%). Germination decreased from 95% to 11% as osmotic potential increased from 0 to −0.6 MPa and was completely inhibited at osmotic potential greater than −0.6 MPa. Seed germination was greater than 90% over a pH range of 5 to 8, but declined to 77% at pH 10. Seedling emergence was the greatest (77%) for seeds present on the soil surface but declined with depth, and no seedlings emerged from a soil depth of 5 cm. In another experiment in which seeds were after-ripened at different depths in a field, seed decay was greater on the soil surface than at 2 or 5 cm depth. At the end of the growing season, there was a much greater persistence of buried seed (32 to 42%) than seeds present on the soil surface (8%). Greater persistence of buried seed could be due to dormancy enforced by dark in this species.

scholarly journals Establishing field stands of Russian dandelion (Taraxacum Kok-saghyz) from seed in southern Ontario, Canada

2016 ◽  
Vol 96 (5) ◽  
pp. 887-894 ◽  
Author(s):  
A. Moussavi ◽  
S.Z.H. Cici ◽  
C. Loucks ◽  
R.C. Van Acker
Keyword(s):  
Seed Germination ◽  
Sandy Soil ◽  
Soil Type ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Loamy Soil ◽  
Southern Ontario ◽  
Low Field ◽  
New Crop

Taraxacum Kok-saghyz (L.E. Rodin) (TKS) is a natural source of rubber. There is a rising interest in TKS establishment as a new crop in Ontario. Trials were conducted at Simcoe and Guelph, Ontario between 2013 and 2014 to explore the possibility of establishing TKS plants from seed in fields in Ontario. The effects of seeding depth, watering regimes, polymer, and covering mulch on the recruitment of TKS were explored. It was found that TKS displays very low field recruitment levels regardless of treatment. KNO3 did not have any significant effect on TKS seed germination. Seedling emergence was greatest when seeds were placed on the soil surface and decreased with increasing seeding depth. Two years of field experiments highlighted that TKS seedlings recruit better in moderate conditions when the temperature is optimum for TKS germination (warm but not hot, <25 °C). TKS seedlings recruited better at Simcoe (with a sandy soil type) than at Guelph (with a loamy soil type). Overall, however, field recruitment from seed was low (15% at best) and these results suggest that establishing TKS from seed in Ontario fields remains a challenge.

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 An ABA-GA bistable switch can account for natural variation in the variability of Arabidopsis seed germination time

2020 ◽  
Author(s):  
Katie Abley ◽  
Pau Formosa-Jordan ◽  
Hugo Tavares ◽  
Emily Chan ◽  
Ottoline Leyser ◽  
...  
Keyword(s):  
Seed Germination ◽  
Phenotypic Variability ◽  
Time Variability ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Bistable Switch ◽  
Germination Time ◽  
Arabidopsis Seed ◽  
Recombinant Inbred Population ◽  
Exogenous Addition

AbstractGenetically identical plants growing in the same conditions can display heterogeneous phenotypes. Whether this phenotypic variability is functional and the mechanisms behind it are unclear. Here we use Arabidopsis seed germination time as a model system to examine phenotypic variability. We show extensive variation in seed germination time variability between Arabidopsis accessions, and use a multi-parent recombinant inbred population to identify two loci involved in this trait. Both loci include genes implicated in ABA signalling that could contribute to seed germination variability. Modelling reveals that the GA/ABA bistable switch underlying germination can amplify variability and account for the effects of these two loci on germination distributions. The model predicts the effects of modulating ABA and GA levels, which we validate genetically and by exogenous addition of hormones. We confirm that germination variability could act as a bet hedging strategy, by allowing a fraction of seeds to survive lethal stress.

Effects of Sand Burial and Water Regimes on Seed Germination and Seedling Emergence of Two Desert Species

2011 ◽  
Vol 356-360 ◽  
pp. 2465-2472
Author(s):  
Fei Peng ◽  
Wataru Tsuji ◽  
Tao Wang ◽  
Atsushi Tsunekawa
Keyword(s):  
Seed Germination ◽  
Water Supply ◽  
Water Regime ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Burial Depth ◽  
Dune System ◽  
Sand Burial ◽  
Water Regimes ◽  
Simulated Precipitation

Reaumuria songarica (Pall.) Maxim and Nitraria tangutorum Bobr. are two species growing on nebkhas in dune system. But N. tangutorum distributes more widely than R. songarica does. Sand burial and drought are two major disturbing factors in the field. Experiments were conducted under controlled conditions to investigate sand burial depth and simulated precipitation amount on seed germination, seedling emergence and seedling mass of the two shrubs to explain the dominance of N. tangutorum over R. songarica. Seeds were buried at 6 depths (0, 0.5, 1.5, 3, 5, 8 cm) and irrigated with 3 water regimes (5, 7, 10 mm) in plastic pots (8 cm in diameter and 11 cm in height) under the same light intensity and alternating temperature in an environment controlled growth chamber. R. songarica has a greater germination percentage than N. tangutorum under each burial depth with any water regime. R songarica seed germination increased with burial depth at each water regime and when depth is deeper than 1.5 cm all the seeds germinated under 7 and 10 mm water treatment. N. tangutorum seed germination increased until an optimal burial depth and then decreased. The optimal burial depth shifts with water regime. Seedling emergence of R songarica did not occur at depth deeper than 1.5 cm under any water regime. N. tangutorum seedling emergence maximized at 3, 1.5 and 0.5 cm with 5, 7 and 10 mm water supply regime respectively. Under all the treatments, N. tangutorum seedlings had larger dry mass than R. songarica seedlings. Higher N. tangutorum seedling emergence percentage and seedling mass with given water supply enhance its possibility to appear on nebkhas in the study area.

Emergence of wheat may be reduced by seed weather damage and azole fungicides and is related to coleoptile length

1988 ◽  
Vol 28 (2) ◽  
pp. 253 ◽  
Author(s):  
GM Murray ◽  
J Kuiper
Keyword(s):  
Seed Germination ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Controlled Environment ◽  
Wheat Cultivars ◽  
Moist Soil ◽  
Coleoptile Length ◽  
Dry Soil ◽  
Weather Damage ◽  
Azole Fungicides

Seed germination, seedling emergence and coleoptile length of sound and weather-damaged seed of 8 wheat cultivars, which had been treated with twice the recommended rates of the seed dressings Le-san E11, Pano-ram 25, Vitavax 750L, Baytan and Erex, were studied in a sand-perlite substrate at 13�C and in 2 field experiments. Germination was not affected by the dressings. Baytan and Erex delayed and reduced the emergence of all cultivars at 13�C, but in the field only some cultivars had emergence reduced by seed dressings. Weather damage reduced the germination of some cultivars but the results were not consistent. The emergence of damaged seed of some cultivars was further reduced by Baytan and Erex when sown deeply in dry soil. In the cvv. Banks and Osprey, weather damage and Erex shortened coleoptiles of seed that was germinated on moist soil in darkness at 13�C. Emergence was positively related with coleoptile length, and, in the controlled environment test, it declined markedly when coleoptiles were less than 5 cm.

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