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1

Scott, Andrew J., i John W. Morgan. "Germination strategies of annual forbs from south-eastern Australian semiarid grasslands". Australian Journal of Botany 60, nr 4 (2012): 340. http://dx.doi.org/10.1071/bt12027.

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Germination is a key process driving the composition and dynamics of annual-forb communities and soil seed banks. We tested the germination biology of 20 annual forbs from semiarid grasslands in southern Australia, under a single temperature regime (20/10°C) in either constant darkness or 12-h diurnal light, to assess whether their laboratory germination responses are consistent with transient seed banks and rapid field emergence. Germination in the light was generally moderate to high, with most (70%) species achieving >35% final germination. Additionally, most (90%) species began germinating within 5 days, and all species achieved at least 50% of final germination within 10 days, suggesting that rapid and synchronous germination is the main strategy of annual forbs in this region. However, several species had seeds that continued to germinate for a prolonged period, and in most species, a fraction of seeds did not germinate, demonstrating risk-spreading strategies. Additionally, the germination of most (79%) species was significantly inhibited by continuous darkness. Despite the potential for the formation of large persistent seed banks through low germination in some species and dark inhibition in most, rapid germination and prevailing environmental conditions apparently prevent this in the field.
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Olff, H., D. M. Pegtel, J. M. Van Groenendael i J. P. Bakker. "Germination Strategies During Grassland Succession". Journal of Ecology 82, nr 1 (marzec 1994): 69. http://dx.doi.org/10.2307/2261387.

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Mathias, Andrea, i Éva Kisdi. "Adaptive diversification of germination strategies". Proceedings of the Royal Society of London. Series B: Biological Sciences 269, nr 1487 (22.01.2002): 151–55. http://dx.doi.org/10.1098/rspb.2001.1867.

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Xu, Xinyu, Lorne Wolfe, Jeffrey Diez, Yi Zheng, Hui Guo i Shuijin Hu. "Differential germination strategies of native and introduced populations of the invasive species Plantago virginica". NeoBiota 43 (19.03.2019): 101–18. http://dx.doi.org/10.3897/neobiota.43.30392.

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Germination strategies are critically important for the survival, establishment and spread of plant species. Although many plant traits related to invasiveness have been broadly studied, the earliest part of the life cycle, germination, has received relatively little attention. Here, we compared the germination patterns between native (North America) and introduced (China) populations of Plantagovirginica for four consecutive years to examine whether there has been adaptive differentiation in germination traits and how these traits are related to local climatic conditions. We found that the introduced populations of P.virginica had significantly higher germination percentages and faster and shorter durations of germination than native populations. Critically, the native populations had a significantly larger proportion of seeds that stayed dormant in all four years, with only 60% of seeds germinating in year 1 (compared to >95% in introduced populations). These results demonstrate striking differences in germination strategies between native and introduced populations which may contribute to their successful invasion. Moreover, the germination strategy of P.virginica in their native range exhibited clear geographical variation across populations, with trends towards higher germination percentages at higher latitudes and lower annual mean temperatures and annual precipitation. In the introduced range, however, their germination strategies were more conserved, with less variation amongst populations, suggesting that P.virginica may have experienced strong selection for earlier life history characteristics. Our findings highlight the need to examine the role of rapid evolution of germination traits in facilitating plant invasion.
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Cuello, William S., Jennifer R. Gremer, Pete C. Trimmer, Andrew Sih i Sebastian J. Schreiber. "Predicting evolutionarily stable strategies from functional responses of Sonoran Desert annuals to precipitation". Proceedings of the Royal Society B: Biological Sciences 286, nr 1894 (16.01.2019): 20182613. http://dx.doi.org/10.1098/rspb.2018.2613.

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For many decades, researchers have studied how plants use bet-hedging strategies to insure against unpredictable, unfavourable conditions. We improve upon earlier analyses by explicitly accounting for how variable precipitation affects annual plant species’ bet-hedging strategies. We consider how the survival rates of dormant seeds (in a ‘seed bank’) interact with precipitation responses to influence optimal germination strategies. Specifically, we incorporate how response to resource availability (i.e. the amount of offspring (seeds) generated per plant in response to variation in desert rainfall) influences the evolution of germination fractions. Using data from 10 Sonoran Desert annual plants, we develop models that explicitly include these responses to model fitness as a function of precipitation. For each of the species, we identify the predicted evolutionarily stable strategies (ESSs) for the fraction of seeds germinating each year and then compare our estimated ESS values to the observed germination fractions. We also explore the relative importance of seed survival and precipitation responses in shaping germination strategies by regressing ESS values and observed germination fractions against these traits. We find that germination fractions are lower for species with higher seed survival, with lower reproductive success in dry years, and with better yield responses in wet years. These results illuminate the evolution of bet-hedging strategies in an iconic system, and provide a framework for predicting how current and future environmental conditions may reshape those strategies.
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Zhou, Daowei, Tianhui Wang i Ian Valentine. "Phenotypic plasticity of life-history characters in response to different germination timing in two annual weeds". Canadian Journal of Botany 83, nr 1 (1.01.2005): 28–36. http://dx.doi.org/10.1139/b04-148.

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An experimental manipulation was conducted to test whether germination timing influences the post-germination life-history characters in Amaranthus retroflexus L. and Chenopodium glaucum L. Seeds were sown in spring, late spring, and summer. Life-history characters of both phenology and morphology were measured, and dry masses of roots, stems, leaves, and reproductive organs were determined. Life-history characters showed high plasticity in response to different sowing dates. Later germinating plants had relatively faster growth rates and smaller sizes at reproduction than earlier germinating plants. Delaying germination led to relatively earlier reproduction and a relatively greater allocation to reproduction. Much of the variation (60%) could be explained by a single axis of a principal component analysis. The attributes on this axis were similar to the C–R axis of Grime's C–S–R model. Further, the sowing dates of these two species were aggregated on this axis such that spring germinators tended towards the competitor strategy (C), late-spring germinators tended towards a mixed competitive–ruderal strategy (C–R), and summer germinators tended towards a ruderal strategy (R). Different germination timing led to different life-history strategies in the established phase. This kind of phenotypic plasticity in life history results from the plant adapting to regeneration strategies of different germination timing.Key words: Amaranthus retroflexus, Chenopodium glaucum, phenotypic plasticity, life-history characters, plant strategies, germination timing.
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Kettner, Keith, i Hector Eduardo Pérez. "Dose–response of germinating Rudbeckia mollis (Asteraceae) seeds exposed to various thermal scenarios". Seed Science Research 22, nr 3 (8.06.2012): 191–97. http://dx.doi.org/10.1017/s0960258512000086.

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AbstractTemperature is a key environmental signal regulating germination. A thorough understanding of how seed populations respond to various temperatures can inform end-users regarding effective establishment strategies and forms the basis for questions related to a taxon's thermo-biology. Although abundant information exists regarding germination responses of economically important crops to several temperature scenarios, much less is known concerning the seed biology of wild germplasm. To address this, we examined the germination response of non-dormant Rudbeckia mollis seeds to various doses of constant or simulated seasonal diel temperatures. Germination response was sigmoidal. Seeds of R. mollis were capable of germinating within a few days to high percentages (>95%) at relatively cool constant (15–25°C) or 12-hour alternating (22/11–33/24°C) temperatures, with optimum temperatures for germination occurring at 25°C or 29/19°C. Germination was inhibited as temperatures increased to 30°C or 33/24°C with early and late germinating phenotypes displaying differential responses at these temperatures. No germination occurred at 35°C. Results are discussed in terms of seedling establishment of R. mollis outside its natural range and implications of climate change on germination.
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Gul, Bilquees, Raziuddin Ansari, Timothy J. Flowers i M. Ajmal Khan. "Germination strategies of halophyte seeds under salinity". Environmental and Experimental Botany 92 (sierpień 2013): 4–18. http://dx.doi.org/10.1016/j.envexpbot.2012.11.006.

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Wu, Gao-Lin, Guo-Zhen Du i Zhi-Hua Shi. "Germination strategies of 20 alpine species with varying seed mass and light availability". Australian Journal of Botany 61, nr 5 (2013): 404. http://dx.doi.org/10.1071/bt12119.

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Seed germination is a central component of plant life history. To investigate the proposed role of seed size on germination strategy in plant communities, a semifield experiment was conducted in alpine meadow of the Qinghai–Tibetan Plateau, China. Interspecies relationships of seed mass and seed germination characteristics were studied under semifield conditions with different light availability. Light availability and seed mass had significant effects on final germination percentage and time to germination for studied species. There was a significant negative correlation between the strength of light required for germination and seed mass. Fifteen study species (e.g. Ligularia przewalskii, Artemisia sieversiana Willd, Tripolium vulgare Ness. and Saussurea morifolia Chen) exhibited a synchronous germination strategy. Seeds from large-seeded species, such as Dracocephalum ruyschiana, Laniophlomis rotate (Benth.) and Salvia przewalskii Maxim., were less likely to require light for germination than those of small-seeded species, such as A. sieversiana Willd, Senecio diversipinnus Ling and Saussurea mongolica (Franch.). We propose that germination strategies of small-seeded species are well suited to unpredictable environmental variation in this alpine grassland community.
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10

McClure, Allison W., Katherine C. Jacobs, Trevin R. Zyla i Daniel J. Lew. "Mating in wild yeast: delayed interest in sex after spore germination". Molecular Biology of the Cell 29, nr 26 (15.12.2018): 3119–27. http://dx.doi.org/10.1091/mbc.e18-08-0528.

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Studies of laboratory strains of Saccharomyces cerevisiae have uncovered signaling pathways involved in mating, including information-processing strategies to optimize decisions to mate or to bud. However, lab strains are heterothallic (unable to self-mate), while wild yeast are homothallic. And while mating of lab strains is studied using cycling haploid cells, mating of wild yeast is thought to involve germinating spores. Thus, it was unclear whether lab strategies would be appropriate in the wild. Here, we have investigated the behavior of several yeast strains derived from wild isolates. Following germination, these strains displayed large differences in their propensity to mate or to enter the cell cycle. The variable interest in sex following germination was correlated with differences in pheromone production, which were due to both cis- and trans-acting factors. Our findings suggest that yeast spores germinating in the wild may often enter the cell cycle and form microcolonies before engaging in mating.
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11

Norman, H. C., P. S. Cocks, F. P. Smith i B. J. Nutt. "Reproductive strategies in Mediterranean annual clovers: germination and hardseededness". Australian Journal of Agricultural Research 49, nr 6 (1998): 973. http://dx.doi.org/10.1071/a97105.

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Clovers from 6 sites in the eastern and western Mediterranean were examined for germination and seed dormancy strategies. At least 2 species were collected from each site, such that 4 strategies were compared in 14 accessions of 11 species. The first trait was initial and final hardseededness after 1 summer-autumn (long-term hardseededness), the second was the pattern of hardseed breakdown during this period (short-term hardseededness), the third was the rate of germination at temperatures ranging from 5ºC to 30ºC, and the fourth was the degree to which germination proceeded at high temperatures. Logistic curves were used to describe short-term hardseededness and germination rates, and to calculate half-lives. The seeds of all species exhibited some form of protection against out-of-season rains. In accessions from the eastern Mediterranean the most common strategy was delayed breakdown of hard seed, where most seeds remained hard until mid-to-late autumn. This was the strategy used by Trifolium lappaceum, T. glanduliferum, T. clusii, and T. purpureum. In the western Mediterranean, the accessions also employed slow germination and high temperature dormancy. Examples were T. obscurum and T. clypeatum (slow germination) and T. cherleri and T. isthmocarpum (high temperature dormancy). It was clear that no single germination-regulating mechanism applied to genotypes collected from any 1 site. However, individual species growing at different sites tended to exhibit the same strategies. The results supported the idea of substitutability in reproductive traits, developed by ecological modellers. The efficacy of the 60º/15ºC alternating temperature oven in predicting loss of hardseededness by the clovers in the field was poor except for T. cherleri. The alternating temperature ovens, which are used to predict hardseed breakdown of subterranean clover, are unsatisfactory for most other clovers.
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12

Ishikawa, Shizuko, i June Abe. "Germination Strategies of Capsella bursapastoris in the Orchard." Journal of Weed Science and Technology 40, nr 3 (1995): 209–14. http://dx.doi.org/10.3719/weed.40.209.

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Valleriani, Angelo. "Evolutionarily stable germination strategies with time-correlated yield". Theoretical Population Biology 70, nr 3 (listopad 2006): 255–61. http://dx.doi.org/10.1016/j.tpb.2006.07.008.

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Zogas, Alexander, Evsey Kosman i Marcelo Sternberg. "Germination strategies under climate change scenarios along an aridity gradient". Journal of Plant Ecology 13, nr 4 (29.06.2020): 470–77. http://dx.doi.org/10.1093/jpe/rtaa035.

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Abstract Aims Climate change in the eastern Mediterranean region will have a strong impact on ecosystem functioning and plant community dynamics due to a reduction in annual rainfall and increased variability. We aim to understand the role of seed banks as potential buffers against climatic uncertainty determined by climate change. Methods We examined germination strategies of 18 common species present along an aridity gradient. Data were obtained from soil seed banks germinated during nine consecutive years from arid, semi-arid, Mediterranean and mesic Mediterranean ecosystems. At the semi-arid and Mediterranean sites, rainfall manipulations simulating 30% drought and 30% rainfall increase were applied. Germination strategies were tested under optimal irrigation conditions during three consecutive germination seasons to determine overall seed germinability in each soil sample. Changes in germination strategy were examined using a novel statistical approach that considers the climatic and biotic factors that may affect seed germinability. Important Findings The results showed that dominant species controlled their germination fractions by producing seeds with a different yearly germination fraction probability. The amount of rainfall under which the seeds were produced led to two major seed types with respect to germinability: high germinability, seeds leading to transient seed banks, and low germinability, seeds leading to persistent seed banks. We conclude that differential seed production among wet and dry years of both seed types creates a stable balance along the aridity gradient, enabling the soil seed bank to serve as a stabilizing mechanism buffering against rainfall unpredictability. Additionally, we present a general model of germination strategies of dominant annual species in Mediterranean and arid ecosystems that strengthens the notion of soil seed banks as buffers against climatic uncertainty induced by climate change in the region.
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Bombo, Aline Bertolosi, Tuane Santos de Oliveira, Beatriz Appezzato-da-Glória i Ana Dionísia da Luz Coelho Novembre. "Seed germination of Brazilian Aldama species (Asteraceae)". Journal of Seed Science 37, nr 3 (wrzesień 2015): 185–91. http://dx.doi.org/10.1590/2317-1545v37n3146138.

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Brazilian samples from the Aldama genus (Asteraceae) could not propagate vegetatively despite their thickened underground system; thus, this study on sexual propagation is critical given the lack of data on reproductive strategies for such species. The aim for this research was to assess the optimal temperature for Aldama arenaria, A. filifolia, A. linearifolia, A. robustaand A. trichophylla seed germination. Seed germination was evaluated at the constant temperatures 20, 25 and 30 °C and the alternating temperatures 15-35, 20-30 and 20-35 °C with an 8-h daily photoperiod, using fluorescent-lamp. The ungerminated seeds were evaluated for embryo viability. The A. filifolia seed health was also evaluated. The optimal temperatures for germination are 20 and 25 °C for Aldama arenaria, A. filifolia, A. robusta and A. trichophylla seeds and 20 °C for A. linearifoliaseeds. The alternating temperature 15-35 °C is not recommended for germinating seeds from these species. The six fungi taxa studied herein did not affect A. filifolia seed germination.
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Mehmeti, A., A. Demaj i R. Waldhardt. "Germination traits of three weed species in Kosovo". Web Ecology 10, nr 1 (15.02.2010): 15–22. http://dx.doi.org/10.5194/we-10-15-2010.

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Abstract. Amaranthus retroflexus, Echinochloa crus-galli and Datura stramonium are the most important weed species in Kosovo. They cause severe yield depression, contaminate fodder and negatively affect growth and reproduction of other weed species. To counteract these problems, specific strategies need to be developed. Such strategies should consider information on species germination traits. In this context, our study provides information on temperature requirements for germination. Seeds of A. retroflexus, E. crus-galli and D. stramonium were harvested in two sub-regions of Kosovo (western and eastern parts) differing in climate and land use. They were set for germination experiments in growth chambers at temperatures ranging from 3 to 35 °C and under field conditions. In both experiments, the germination rate differed between species and provenances. In the growth chamber experiment, germination of all three species was negligible below 15 °C and reached the highest rates between 24 and 30 °C. Seeds originating from the western part of Kosovo had higher germination rates and required a lower temperature for germination than seeds originating from the eastern part. In the field experiment, the time-dependent germination behaviour of D. stramonium differed between provenances. In general, germination started when soil temperature was above 18 °C and continued as long as the soil was moist. The results are discussed in the context of the need to develop weed management strategies against these weeds in Kosovo.
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Anderson, T. Michael, Martin Schütz i Anita C. Risch. "Endozoochorous seed dispersal and germination strategies of Serengeti plants". Journal of Vegetation Science 25, nr 3 (1.08.2013): 636–47. http://dx.doi.org/10.1111/jvs.12110.

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Kohler, L. J., A. V. Quirk, S. L. Welkos i C. K. Cote. "Incorporating germination-induction into decontamination strategies for bacterial spores". Journal of Applied Microbiology 124, nr 1 (5.11.2017): 2–14. http://dx.doi.org/10.1111/jam.13600.

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Cote, C. K., J. Bozue, N. Twenhafel i S. L. Welkos. "Effects of altering the germination potential of Bacillus anthracis spores by exogenous means in a mouse model". Journal of Medical Microbiology 58, nr 6 (1.06.2009): 816–25. http://dx.doi.org/10.1099/jmm.0.008656-0.

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Inhalational anthrax is the most severe form of anthrax. It has been shown in small-animal and non-human primate models that relatively large pools of ungerminated Bacillus anthracis spores can remain within the alveolar spaces for days to weeks post-inhalation or until transported to areas more favourable for germination and bacillary outgrowth. In this study, spores of the Ames strain that were exposed to germination-inducing media prior to intranasal delivery were significantly less infectious than spores delivered in either water or germination-inhibitory medium. The effect of manipulating the germination potential of these spores within the lungs of infected mice by exogenous germination-altering media was examined. The data suggested that neither inducing germination nor inhibiting germination of spores within the lungs protected mice from the ensuing infection. Germination-altering strategies could, instead, significantly increase the severity of disease in a mouse model of inhalational anthrax when implemented in vivo. It was shown that germination-altering strategies, in this study, were not beneficial to the infected host and are impractical as in vivo countermeasures.
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Martínez-García, F., S. Guerrero-García i F. Pérez-García. "Evaluation of reproductive success and conservation strategies for Senecio coincyi (Asteraceae), a narrow and threatened species". Australian Journal of Botany 60, nr 6 (2012): 517. http://dx.doi.org/10.1071/bt12109.

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Senecio coincyi is a threatened endemic plant of central western Spain, with a very narrow extent of occurrence. The reproductive success and germination behaviour of this species were studied. The area of occupancy, habitat types and size of 13 known subpopulations of S. coincyi were evaluated. The number of individuals that form all these subpopulations was counted. In addition, the number of flowers and cypselas per fruit head and the number of fruit heads per individual plant were recorded in a subset of subpopulations. Germination tests were carried out to evaluate the effect of temperature and light regimes on, and possible intraspecific variation in, cypsela germination. Cypselas reached very high germination percentages (90–100%) from 15°C to 30°C. However, the germination decreased (19%) at 10°C. The light conditions assayed (16-h light photoperiod and complete darkness) did not significantly affect cypsela germination. In general, there was no intraspecific variability in germination patterns of S. coincyi cypselas. Livestock is the most important factor that can be a threat for this species. S. coincyi showed high reproductive success and, therefore, its conservation problems are not due to agents related to its reproduction, but rather to other factors such as alteration of its habitat caused by the presence of livestock.
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Figueroa, J. A., i J. J. Armesto. "Community-wide germination strategies in a temperate rainforest of Southern Chile: ecological and evolutionary correlates". Australian Journal of Botany 49, nr 4 (2001): 411. http://dx.doi.org/10.1071/bt00013.

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Delayed seed germination (‘dispersal in time’), as a component of a plant’s germination strategy, was studied in dicotyledoneous species of a temperate rainforest flora in Chiloé Island (42°30′S), southern Chile. The objective of this investigation was to assess, for this temperate rainforest flora, what proportion of interspecific variation in the time of seed germination—measured in days since the onset of seed dispersal in space—could be attributed to the plants’ historical and phylogenetic background and what proportion was associated with life history and ecological attributes such as seed mass, life form, dispersal syndromes and dispersal periods. To characterise germination times for 44 species from Chiloé forests (n = 150 seeds sowed per species in laboratory assays), we computed the mean germination time (GT), in days since sowing, for all seeds germinated of each species. Seeds were taken from the plants at the onset of dispersal and germinated in Petri dishes at 10/20°C. Considering all species, GTs varied between 3 and 385 days and presented an L-shaped frequency distribution. One-way ANOVAs measured the effects of each factor across all other variables. Two-way ANOVAs were used to assess significant interactions between factors. Multifactorial ANOVAs were used to evaluate the independent effects of each of six historical, phylogenetic and ecological factors on GT and to detect associations between factors. In one-way ANOVAs, phylogenetic grouping (at or above order) explained 12% of the variance in GT; dispersal period (summer v. mainly autumn dissemination of ripe seeds), biogeographic element (endemic, austral, neotropical or cosmopolitan) and dispersal syndrome (fleshy v. dry propagules) explained 7, 6 and 5% of the variance in GT, respectively. The factors life form (trees, shrub and woody vines combined, herbs and non-woody epiphytes) and seed mass (light v. heavy) explained the 4 and 2% of the variance in GT, respectively. Taxa related to Ranunculales presented the longest mean GT (148 days). Endozoochorous species had a more delayed germination than species with other dispersal syndromes. Herbs and non-woody epiphyte species showed mean GT (41 days) significantly shorter than trees and shrubs plus woody vines combined (86 and 85 days, respectively). All interactions in two-way ANOVAs were significant. Multifactorial ANOVAs revealed that the three major factors contributing to differences in GT in this temperate rainforest flora were phylogenetic relatedness, dispersal syndromes and life form (7, 6 and 6% of the interspecific variation, respectively). In this analysis, biogeographic element, dispersal period and seed mass were not significantly related to GT. For the factors examined, failure-time analysis, which takes into account all viable seeds not germinating in laboratory assays, confirmed results from multifactorial ANOVAs.
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Kleemann, Samuel G. L., Bhagirath S. Chauhan i Gurjeet S. Gill. "Factors Affecting Seed Germination of Perennial Wall Rocket (Diplotaxis tenuifolia) in Southern Australia". Weed Science 55, nr 5 (październik 2007): 481–85. http://dx.doi.org/10.1614/ws-06-197.1.

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Germination response of perennial wall rocket to temperature, light, osmotic potential, and depth of burial emergence was evaluated under controlled environmental conditions. The effect of seed burial depth on seedling recruitment in the field was also investigated at Roseworthy, South Australia. Under optimal conditions (30 C, light/dark) germination of perennial wall rocket was rapid, with 90% of seeds germinating within 48 h of imbibition. Germination was reduced (20%) at lower, suboptimal temperatures (10 to 20 C) when seeds of perennial wall rocket were exposed to light. Germination declined with increasing osmotic potential and was completely inhibited at osmotic potentials of −1.5 MPa. Perennial wall rocket emergence was greatest from seeds placed on the soil surface, but some seedlings (< 10%) emerged from a depth of 0.5 to 2 cm. Under both field and growth-cabinet conditions, the greatest seedling emergence of perennial wall rocket occurred from seed present on the soil surface; however, the level of absolute recruitment from the seed bank was much lower (< 5%). Information gained from this study will further improve our understanding of the germination behavior of perennial wall rocket and contribute to developing sustainable strategies for its control.
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Vander Kloet, Sam P., i Nick M. Hill. "Bacca quo vadis: Regeneration niche differences among seven sympatric Vaccinim species on headlands of Newfoundland". Seed Science Research 10, nr 1 (marzec 2000): 89–97. http://dx.doi.org/10.1017/s0960258500000106.

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AbstractOn headlands in Newfoundland, four of the seven sympatric Vaccinium species co-occur frequently at the quadrat level in tundra communities. We hypothesized that differentiation at the regeneration niche level was a prerequisite for the coexistence of these sympatric congeners. After a description and quantification of parameters affecting whole berry and seed dispersal and those affecting seed germination, differentiation at these two levels of the regeneration niches of the seven Vaccinia was investigated using numerical clustering techniques. Differentiation patterns were similar in both the germination and the dispersal dendrograms; three species were most dissimilar (viz. V. angustifolium, V. boreale and V. uliginosum), and the remaining four were separated into single species groups at the 62% and 75% similarity levels by the germination and dispersal dendrograms, respectively. Overall, patterns reflect divergence in dispersal mechanisms and germination abilities among the seven species, in support of the thesis that sympatric congeners have varied regeneration strategies. Differences in the germination success observed after testing natural dispersal units (e.g. seed from scat and seed within whole berries) points to the need to conduct germination trials in ecologically relevant ways. This approach reveals how divergent regeneration strategies are possible in species having similar, palatable baccate fruits (e.g. V. angustifolium and V. uliginosum) and highlights our lack of insight into regeneration strategies of the groups. The cranberry seeds, despite germination success gauged by results from standard germination protocols, exhibit no germination in trials conducted with the natural dispersal unit, the whole berry.
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Mahmood, Ako H., Singarayer K. Florentine, Bhagirath S. Chauhan, David A. McLaren, Grant C. Palmer i Wendy Wright. "Influence of Various Environmental Factors on Seed Germination and Seedling Emergence of a Noxious Environmental Weed: Green Galenia (Galenia pubescens)". Weed Science 64, nr 3 (wrzesień 2016): 486–94. http://dx.doi.org/10.1614/ws-d-15-00184.1.

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Green galenia is a South African woody prostrate perennial that was first recorded in Australia in the early 1900s and has since become a serious threat to indigenous temperate grasslands and surrounding agricultural areas. Laboratory and field based experiments were conducted to examine the effect of environmental factors on the germination and viability of green galenia seed. It was shown that green galenia was able to germinate over a broad range of temperatures, but short bursts (5 min) of high temperatures (80 C to 120 C replicating possible exposures to a fire) reduced seed germination. Seed germination was positively favored by light, declined rapidly in darkness, and decreased by > 80% at a depth of only 0.5 cm in soil. Water stress greatly reduced seed germination (45% germination at osmotic potentials below −0.2 MPa). Germination was completely inhibited at water potentials of −0.4 to −1.0 MPa. This species is moderately tolerant to salinity, with over 50% of seeds germinating at low levels of salinity (60 mM NaCl), and moderate germination (49%) occurring at 120 mM NaCl, it can germinate well in both alkaline (pH 10–83%) and acidic (pH 4–80%) conditions. The results of this study have contributed to our understanding of the germination and emergence of green galenia, and this will assist in developing tools and strategies for the long term management of this noxious weed in Victoria and other parts of Australia.
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Bose, Utpal, Angéla Juhász, James A. Broadbent, Setsuko Komatsu i Michelle L. Colgrave. "Multi-Omics Strategies for Decoding Smoke-Assisted Germination Pathways and Seed Vigour". International Journal of Molecular Sciences 21, nr 20 (12.10.2020): 7512. http://dx.doi.org/10.3390/ijms21207512.

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The success of seed germination and the successful establishment of seedlings across diverse environmental conditions depends on seed vigour, which is of both economic and ecologic importance. The smoke-derived exogenous compound karrikins (KARs) and the endogenous plant hormone strigolactone (SL) are two classes of butanolide-containing molecules that follow highly similar signalling pathways to control diverse biological activities in plants. Unravelling the precise mode-of-action of these two classes of molecules in model species has been a key research objective. However, the specific and dynamic expression of biomolecules upon stimulation by these signalling molecules remains largely unknown. Genomic and post-genomic profiling approaches have enabled mining and association studies across the vast genetic diversity and phenotypic plasticity. Here, we review the background of smoke-assisted germination and vigour and the current knowledge of how plants perceive KAR and SL signalling and initiate the crosstalk with the germination-associated hormone pathways. The recent advancement of ‘multi-omics’ applications are discussed in the context of KAR signalling and with relevance to their adoption for superior agronomic trait development. The remaining challenges and future opportunities for integrating multi-omics datasets associated with their application in KAR-dependent seed germination and abiotic stress tolerance are also discussed.
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Nara, Kazuhide. "Spores of ectomycorrhizal fungi: ecological strategies for germination and dormancy". New Phytologist 181, nr 2 (16.12.2008): 245–48. http://dx.doi.org/10.1111/j.1469-8137.2008.02691.x.

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Gutterman, Yitzchak. "Strategies of seed dispersal and germination in plants inhabiting deserts". Botanical Review 60, nr 4 (październik 1994): 373–425. http://dx.doi.org/10.1007/bf02857924.

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Albrecht, Matthew A., i Quinn G. Long. "Germination niche of the permanent wetland specialist, Parnassia grandifolia DC". Seed Science Research 24, nr 3 (22.05.2014): 239–45. http://dx.doi.org/10.1017/s0960258514000166.

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AbstractTemperate wetland species often require light and warm temperatures for seed germination. However, recent studies indicate that species which specialize on permanently saturated wetlands that are maintained by groundwater discharge (fens, seeps and mountain springs), rather than wetlands with surface-water-driven hydrologic regimes, diverge from the typical wetland germination niche by germinating at cool temperatures and lacking photoblastic seeds. We conducted laboratory experiments that manipulated stratification conditions (non-stratified versus cold stratification in light and darkness), thermal regime (15/6, 25/15 and 35/20°C), and light (14 h photoperiod versus continuous darkness) to test whether seeds of the North American calcareous fen specialist Parnassia grandifolia diverged from the typical temperate wetland germination niche. After 30 d, fresh seeds were conditionally dormant and could only germinate to high percentages in light at 25/15°C. During 16 weeks of incubation, non-stratified seeds germinated to low percentages ( < 40%) at all thermal regimes in darkness. In contrast, cold-stratified seeds germinated to high percentages in both light and darkness at all thermal regimes, although germination was incomplete (no cotyledon emergence) at 35/20°C. Further, seeds did not require light during cold stratification to germinate to high percentages when incubated in light or darkness. Thus, seeds diverged from the typical temperate wetland germination syndrome in lacking a light and warm temperature requirement for germination. Our results reinforce previous work from European fens and Mediterranean wetlands. This indicates that multiple germination strategies are found in fen wetlands that are maintained by the continuous or near-continuous discharge of cool groundwater.
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Schütz, Wolfgang. "Are germination strategies important for the ability of cespitose wetland sedges (Carex) to grow in forests?" Canadian Journal of Botany 75, nr 10 (1.10.1997): 1692–99. http://dx.doi.org/10.1139/b97-883.

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The seed germination behaviour of six cold-temperate, cespitose Carex species occurring either in wet forests or wet, open habitats was investigated under different light and temperature conditions. Germination tests were conducted in the laboratory with cold and wet stratified seeds in light and darkness, under four constant-temperature regimes and one fluctuating regime. Other germination tests were carried out in an experimental garden where freshly matured seeds sown on the soil surface were exposed to conditions typical for a sun-exposed site and a shaded (forest) site for 2 years. In the garden experiments, seeds at the sun-exposed site germinated soon after sowing in three species, whereas late-shedding species or species exhibiting primary dormancy germinated the following spring. Under the dense leaf canopy at the forest site, germination was inhibited completely during the first season in all species. Wet-forest species (Carex elongata, Carex remota) germinated the following spring before the leaf canopy closed, whereas the sedges adapted to open habitats (Carex canescens, Carex cespitosa, Carex pseudocyperus, Carex paniculata) failed to germinate, or only a low percentage germinated. Following transfer of ungerminated seeds from the shaded site to the sun-exposed site in the summer of the second year of the investigation, almost all of the hitherto ungerminated seeds germinated within 10 days. Results of laboratory experiments supported the findings in the garden experiments. At low mean temperatures (7 and 10 °C) in light, sedges adapted to open habitats did not germinate at all or showed a low percentage of germination, whereas forest sedges showed good germination. A high diurnal temperature amplitude and (or) a high constant temperature was needed to trigger the germination of a fraction of the seeds in dark treatments. It is suggested that the forest sedges are adapted to using a brief temporal regeneration niche during mid-spring, when mean temperatures are close to 10 °C and the leaf canopy has yet to close in central European, wet deciduous forests. In contrast, sedges adapted to open habitats probably fail to germinate under forest conditions because of their higher temperature requirements. Key words: Carex, germination, light, temperature, dormancy.
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Budisavljević, Alan, Dubravka Sandev, Marko Randić, Vanja Stamenković i Sanja Kovačić. "Seed dormancy and germination of five selected NATURA-2000 plant species from Croatia showing different germination strategies". Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology 155, nr 1 (26.02.2020): 116–27. http://dx.doi.org/10.1080/11263504.2020.1727978.

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Han, Chengchou, i Stephen L. Young. "Ecology of Musk Thistle (Carduus nutans) Seed Germination for Grasslands of Temperate Climates". Weed Science 61, nr 4 (grudzień 2013): 549–56. http://dx.doi.org/10.1614/ws-d-13-00015.1.

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Musk thistle is an invasive weed that is widely distributed throughout much of North America, including grasslands in temperate climates of the midwest USA. A series of laboratory and greenhouse experiments were conducted to determine the effect of various environmental factors on germination of musk thistle seeds. In temperature-fluctuation experiments, seed germination was greater than 65% in both alternating (30/20 C) and constant (20 or 25 C) temperature regimes with an 8-h day but less (33%) in warmer regimes (35/20 C). Germination of musk thistle seeds was 37% in alternating temperature regimes of 30/20 C in total darkness, but less than 67% in pots in the greenhouse. Differences of 10 and 15 C between day and night temperatures resulted in 91 and 75% maximum germination of musk thistle, respectively. Increasingly dryer soils reduced germination of musk thistle seeds from 35% (−0.03 MPa) to 0% (−1.2 MPa), whereas saline soils (> 80 mM) reduced maximum germination to less than 10%. Musk thistle seeds collected from populations in a bare-ground area had 96% germination, which was greater than that of seeds collected from populations growing in a perennial grass pasture (71%). A residence time (i.e., period that seeds remained on the parent plant) of 9 to 12 wk after capitulum maturity resulted in seeds germinating more quickly than those dispersed earlier. Overall, reduced light levels, cool and fluctuating temperatures, and amount of time seeds remained in residence are some of the most important factors that contribute to germination of musk thistle seeds. Information on germination dynamics of musk thistle seeds provides an understanding of the interactions that affect this process and underscores the importance of timely management strategies in temperate grasslands.
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Liu, Wenting, Tianle Wang, Shuang Zhang, Lijun Ding i Zhijun Wei. "Grazing influences Stipa breviflora seed germination in desert grasslands of the Inner Mongolia Plateau". PeerJ 6 (1.03.2018): e4447. http://dx.doi.org/10.7717/peerj.4447.

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Seed germination plays an important role in determining the composition and regeneration of plant populations (Stipa breviflora). However, the influencing factors and strategies employed for seed germination in desert grasslands under grazing remain unknown. Therefore, in this study, the reproductive allocation, seed density, seed properties, and corresponding seed germination rates of S. breviflora were examined. Possible situations encountered during dispersal were also simulated to determine their effects on seed germination. The results showed that reproductive individual density not subjected to grazing were significantly higher than those subjected to moderate and heavy grazing. For seed density and seed bank in soil, the highest values were observed for the no grazing treatment, followed by the moderate and heavy grazing treatments. The seed density for germination of soil seed banks was nearly one-fourth of seed density during the growing season. In addition, grazing treatments affected the phenotypic characteristics of seeds and reduced the lower limit of the weight of germinable seeds. Awn removal significantly increased germination. The longest germination time was observed for seeds that entered the soil at an angle of 0°. Our research demonstrated that grazing negatively affected the desert grassland edificator. Individual plants adopted different adaptation strategies under different grazing intensities; for example, a fixed proportion of the seed number and seed germination number of S. breviflora in the soil seed bank was maintained by exceeding the minimum weight of a seed for seed germination. During seed dispersion, the awn effectively prevented germination under unfavourable conditions and helped seeds enter the soil at an optimal angle for promoting germination.
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Alipour, Shirin, Karolina Bilska, Ewelina Stolarska, Natalia Wojciechowska i Ewa Marzena Kalemba. "Nicotinamide adenine dinucleotides are associated with distinct redox control of germination in Acer seeds with contrasting physiology". PLOS ONE 16, nr 1 (27.01.2021): e0245635. http://dx.doi.org/10.1371/journal.pone.0245635.

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Seed germination is a complex process enabling plant reproduction. Germination was found to be regulated at the proteome, metabolome and hormonal levels as well as via discrete post-translational modification of proteins including phosphorylation and carbonylation. Redox balance is also involved but less studied. Acer seeds displaying orthodox and recalcitrant characteristics were investigated to determine the levels of redox couples of nicotinamide adenine dinucleotide (NAD) phosphate (NADP) and integrated with the levels of ascorbate and glutathione. NAD and NADP concentrations were higher in Norway maple seeds and exceptionally high at the germinated stage, being the most contrasting parameter between germinating Acer seeds. In contrast, NAD(P)H/NAD(P)+ ratios were higher in sycamore seeds, thus exhibiting higher reducing power. Despite distinct concentrations of ascorbate and glutathione, both seed types attained in embryonic axes and cotyledons had similar ratios of reduced/oxidized forms of ascorbate and half-cell reduction potential of glutathione at the germinated stage. Both species accomplished germination displaying different strategies to modulate redox status. Sycamore produced higher amounts of ascorbate and maintained pyridine nucleotides in reduced forms. Interestingly, lower NAD(P) concentrations limited the regeneration of ascorbate and glutathione but dynamically drove metabolic reactions, particularly in this species, and contributed to faster germination. We suggest that NAD(P) is an important player in regulating redox status during germination in a distinct manner in Norway maple and sycamore seeds.
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SIKIN, ADI MD, CLAIRE ZOELLNER i SYED S. H. RIZVI. "Current Intervention Strategies for the Microbial Safety of Sprouts". Journal of Food Protection 76, nr 12 (1.12.2013): 2099–123. http://dx.doi.org/10.4315/0362-028x.jfp-12-437.

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Sprouts have gained popularity worldwide due to their nutritional values and health benefits. The fact that their consumption has been associated with numerous outbreaks of foodborne illness threatens the $250 million market that this industry has established in the United States. Therefore, sprout manufacturers have utilized the U.S. Food and Drug Administration recommended application of 20,000 ppm of calcium hypochlorite solution to seeds before germination as a preventative method. Concentrations of up to 200 ppm of chlorine wash are also commonly used on sprouts. However, chlorine-based treatment achieves on average only 1- to 3-log reductions in bacteria and is associated with negative health and environmental issues. The search for alternative strategies has been widespread, involving chemical, biological, physical, and hurdle processes that can achieve up to 7-log reductions in bacteria in some cases. The compilation here of the current scientific data related to these techniques is used to compare their efficacy for ensuring the microbial safety of sprouts and their practicality for commercial producers. Of specific importance for alternative seed and sprout treatments is maintaining the industry-accepted germination rate of 95% and the sensorial attributes of the final product. This review provides an evaluation of suggested decontamination technologies for seeds and sprouts before, during, and after germination and concludes that thermal inactivation of seeds and irradiation of sprouts are the most practical stand-alone microbial safety interventions for sprout production.
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Martínez-Berdeja, Alejandra, Michelle C. Stitzer, Mark A. Taylor, Miki Okada, Exequiel Ezcurra, Daniel E. Runcie i Johanna Schmitt. "Functional variants of DOG1 control seed chilling responses and variation in seasonal life-history strategies in Arabidopsis thaliana". Proceedings of the National Academy of Sciences 117, nr 5 (21.01.2020): 2526–34. http://dx.doi.org/10.1073/pnas.1912451117.

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The seasonal timing of seed germination determines a plant’s realized environmental niche, and is important for adaptation to climate. The timing of seasonal germination depends on patterns of seed dormancy release or induction by cold and interacts with flowering-time variation to construct different seasonal life histories. To characterize the genetic basis and climatic associations of natural variation in seed chilling responses and associated life-history syndromes, we selected 559 fully sequenced accessions of the model annual species Arabidopsis thaliana from across a wide climate range and scored each for seed germination across a range of 13 cold stratification treatments, as well as the timing of flowering and senescence. Germination strategies varied continuously along 2 major axes: 1) Overall germination fraction and 2) induction vs. release of dormancy by cold. Natural variation in seed responses to chilling was correlated with flowering time and senescence to create a range of seasonal life-history syndromes. Genome-wide association identified several loci associated with natural variation in seed chilling responses, including a known functional polymorphism in the self-binding domain of the candidate gene DOG1. A phylogeny of DOG1 haplotypes revealed ancient divergence of these functional variants associated with periods of Pleistocene climate change, and Gradient Forest analysis showed that allele turnover of candidate SNPs was significantly associated with climate gradients. These results provide evidence that A. thaliana’s germination niche and correlated life-history syndromes are shaped by past climate cycles, as well as local adaptation to contemporary climate.
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Quinn, Michael P., Don W. Morishita i William J. Price. "Determining Physiological Maturation of Jointed Goatgrass (Aegilops cylindricaHost) Caryopses". Weed Technology 20, nr 4 (grudzień 2006): 921–33. http://dx.doi.org/10.1614/wt-05-159.1.

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Information on jointed goatgrass caryopsis development is currently lacking in published literature. It is hoped that through a better understanding of jointed goatgrass caryopsis ontogeny more effective weed-management strategies will be developed. Greenhouse experiments were initiated in fall 2002 and 2003 and completed the following spring seasons. Jointed goatgrass plants were started from spikelets, vernalized for 8 wk at 4 C, and grown in a greenhouse. Treatments were the number of days after anthesis (DAA) that a spike was allowed to remain on the plant before harvesting and ranged from 2 to 34 DAA, in increments of 1 (2002) or 2 (2003) d. Individual spikes were divided at harvest into three sections: top, middle, and bottom, disarticulated from the rachis, placed into a germinator, and germination recorded each day. Goatgrass spikelets germinated as early as 2 DAA, although spikelets harvested <7 DAA had <3% germination for all spike sections and were extremely variable, especially for the middle and bottom sections. Time to germination was similar for all sections of the spike. Maximum average germination of the top section was 72% compared with 86% for the bottom and middle sections. Our data suggest that factors other than developmental rate (i.e., dormancy) may affect germination in sections of the spike. A second year of the experiment was conducted for validation. Model validation suggested that although trends were similar in both years, variation in germination response might be too great for accurate, predictive model construction. The early germination shown in this research demonstrates that control measures must be implemented earlier than previously prescribed to prevent jointed goatgrass reproduction.
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RIBEIRO, KAROLINE APARECIDA FELIX, CRISTIAN MADEIRA DE MEDEIROS, JOSÉ ÁNGEL SÁNCHEZ-AGUDO i JOSÉ SÁNCHEZ-SÁNCHEZ. "Seed germination of Carex lainzii Luceño, E. Rico & T. Romero: An endemic Spanish endangered species". Biodiversitas Journal of Biological Diversity 20, nr 3 (20.02.2019): 704–11. http://dx.doi.org/10.13057/biodiv/d200313.

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Abstract. Ribeiro KAF, Madeira de Medeiros C, Agudo JAS, Sánchez JS. 2019. Seed germination of Carex lainzii Luceño, E. Rico & T. Romero: An endemic Spanish endangered species. Biodiversitas 20: xxxx. Strategies to halt the decline of biodiversity include: in-situ and ex-situ conservation, the latter already considered at the global level essential in conservation programs. The results of the germinative responses of Carex lainzii Luceño, E. Rico & T. Romero (Cyperaceae), an endemic Spanish endangered species, are presented in this work, to different trials carried out in the laboratory with seeds harvested in the two known populations of that community. Treatments with and without 0.2% potassium nitrate (KNO3) were tested for four, six and eight months in cold stratification at 5 °C in two germination chambers at different temperatures (22/10 °C and 27/15 °C with a photoperiod of 12/12 hours). The results indicate that there is a large difference in germination rates between the two populations. The use of KNO3 did not increase germination rates in any case, but differences were found between periods of cold stratification, with six months being the most effective. On the other hand, the germination rates of both populations remain low (17.58% and 2%) compared to the obtained rate of seed viability. With this first approach to the understanding of the germination requirements of C. lainzii, it becomes clear that new essays are needed to obtain better results, in order to effectively implement the protection plans of C. lainzii populations.
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Martínez-García, Felipe, Silvia Guerrero-García i Félix Pérez-García. "Evaluation of reproductive success and conservation strategies for Senecio coincyi (Asteraceae), a narrow and threatened endemic plant of central western Spain". Archives of Biological Sciences 64, nr 3 (2012): 1001–16. http://dx.doi.org/10.2298/abs1203001g.

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Senecio coincyi (Asteraceae) is a threatened endemic plant of central western Spain. The reproductive biology of this species in relation to the characteristics of its habitats and the possible strategies for its conservation, were studied. The area of occupancy, habitat types and size of 13 known subpopulations of S. coincyi was evaluated. Germination tests were carried out to assess the effect of temperature and light regimes, and the possible intraspecific variation on the cypsela germination. Cypselas reached very high germination percentages (90-100%) from 15?C to 30?C. However, the germination decreased (by about 19%) at 10?C. The light conditions assayed did not significantly affect cypsela germination. In conclusion, S. coincyi showed high sexual reproduction ability, and therefore its conservation problems are not due to agents related to its reproductive biology, but to others, such as the alteration of its habitat caused by the presence of livestock.
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39

Wong, Bryant M., Gregory R. Houseman, Sarah E. Hinman i Bryan L. Foster. "Targeting Vulnerable Life-Stages of Sericea Lespedeza (Lespedeza cuneata) with Prescribed Burns". Invasive Plant Science and Management 5, nr 4 (grudzień 2012): 487–93. http://dx.doi.org/10.1614/ipsm-d-12-00002.1.

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AbstractThere is growing interest in whether invasive species may be controlled by utilizing management strategies that target vulnerable life stages. We manipulated the timing of fire and measured its effects on sericea lespedeza germination and seedling survival. Although fire strongly decreased germination in the laboratory, fire increased germination under field conditions. Additionally, fire caused small decreases in seedling survival in the field. Therefore, controlled burns are likely to encourage spread of sericea lespedeza and are unlikely to effectively control this invasive species. Although targeting vulnerable life stages is a promising strategy for invasive species control, our results illustrate that system-specific studies may be needed to unravel potentially complex interactions between biotic and abiotic factors before effective control strategies can be devised.
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40

Han, Z. Q., X. L. Zeng, T. Liu, B. L. Li i Q. M. Sun. "ESS germination strategies in Gurbantunggut Desert under the global climate change". Procedia Environmental Sciences 13 (2012): 1893–901. http://dx.doi.org/10.1016/j.proenv.2012.01.183.

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Lewandrowski, Wolfgang, Todd E. Erickson, Emma L. Dalziell i Jason C. Stevens. "Ecological niche and bet-hedging strategies for Triodia (R.Br.) seed germination". Annals of Botany 121, nr 2 (27.12.2017): 367–75. http://dx.doi.org/10.1093/aob/mcx158.

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Baskin, Carol C., i J. M. Baskin. "Ecology and evolution of specialized seed dispersal, dormancy and germination strategies". Plant Species Biology 15, nr 2 (sierpień 2000): 95–96. http://dx.doi.org/10.1046/j.1442-1984.2000.00030.x.

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Ellner, Stephen. "ESS germination strategies in randomly varying environments. I. Logistic-type models". Theoretical Population Biology 28, nr 1 (sierpień 1985): 50–79. http://dx.doi.org/10.1016/0040-5809(85)90022-x.

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Suzuki, Wajirou. "Germination Traits and Adaptive Regeneration Strategies of the Three Carpinus Species". Journal of Forest Research 5, nr 3 (sierpień 2000): 181–85. http://dx.doi.org/10.1007/bf02762399.

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45

Li, Li, i Zhang XiMing. "Germination strategies of two halophytes in Salt Desert of northwestern China". Science in China Series D: Earth Sciences 50, S1 (czerwiec 2007): 115–21. http://dx.doi.org/10.1007/s11430-007-5004-7.

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Barga, Sarah, Thomas E. Dilts i Elizabeth A. Leger. "Climate variability affects the germination strategies exhibited by arid land plants". Oecologia 185, nr 3 (21.09.2017): 437–52. http://dx.doi.org/10.1007/s00442-017-3958-5.

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47

Tanveer, A., M. Tasneem, A. Khaliq, M. M. Javaid i M. N. Chaudhry. "Influence of seed size and ecological factors on the germination and emergence of field bindweed (Convolvulus arvensis)". Planta Daninha 31, nr 1 (marzec 2013): 39–51. http://dx.doi.org/10.1590/s0100-83582013000100005.

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An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 ºC, with optimum germination between 20 and 25 ºC. Time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased with an increase in temperature from 20 ºC, salinity and osmotic stress. However, germination was tolerant to low salt (25 mM) or osmotic stress (0.2 MPa), but as salinity and osmotic stress increased, germination percentage and germination index decreased. Seeds of C. arvensis placed at soil surface showed maximum emergence and decreased as seeding depth increased. Seeds of C. arvensis germinated over a wide range of pH (4 to 9) but optimum germination occurred at pH 6 to 8. Under highly alkaline and acidic pH, time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased. Increase in field capacity caused decreased time to start germination, time to 50% germination and mean germination time but increased germination percentage and germination index. Bigger seeds had low time to start germination, time to 50% germination and mean germination time but high germination percentage and germination index. Smaller seeds were more sensitive to environmental factors as compared to larger or medium seeds. It can be concluded that except for pH, all environmental factors and seed sizes adversely affect C. arvensis as regards seed germination or emergence and germination or emergence traits, and larger seeds result in improved stand establishment and faster germination than small seeds, regardless of moisture stress or deeper seeding depth.
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48

Logan, D. C., i G. R. Stewart. "Germination of the seeds of parasitic angiosperms". Seed Science Research 2, nr 4 (grudzień 1992): 179–90. http://dx.doi.org/10.1017/s0960258500001367.

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AbstractTotalling more than 3000 species, parasitic angiosperms are a most diverse group of organisms. Classified as either shoot or root parasites according to site of attachment, plant parasites are further classified, according to the degree of parasitism, into one of two divisions: holoparasitic or hemiparasitic. Within these divisions, angiosperm parasites are either obligate or facultative.Obligate parasites cannot survive to maturity without attaching to a host plant, thus the need to germinate in close proximity to a host first characterizes the specialized germination and seed dispersal strategies of these plants. However, seeds of all species of the rootholoparasitic Orobanchaceae and four genera within the Scrophulariaceae have evolved very specialized germination strategies. Once the seeds have undergone an after-ripening period, they require a prolonged imbibition period at temperatures of approx. 30°C before they acquire the potential to germinate. Minute seeds with very little reserves, they must germinate within millimetres of the host root for successful host attachment and continued survival. To this end, germination only occurs in responseto specific chemical germination triggers released from the host root. InStriga hermonthica(Del.) Benth., the perception of the host-derived trigger results in stimulation of endogenous ethylene production and it is this ethylene that initiates germination. It is proposed that the chemical triggers released from the host be consideredas ‘elicitors’ which function primarily as allelochemicals and that the parasite seeds have become adapted in such a way as to have an absolute requirement for external germination triggers.
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Phillips, Nathan C., Daniel T. Drost, Bill Varga, Leila Shultz i Susan E. Meyer. "(231) Habitat-correlated Germination and Growth Characteristics in Intermountain Allium (Liliaceae)". HortScience 41, nr 4 (lipiec 2006): 1025D—1025. http://dx.doi.org/10.21273/hortsci.41.4.1025d.

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Seed germination timing strategies and seedling growth characteristics in wild populations have evolved in response to their life history, ecology, and habitat. In this study, we examined the ecophysiological aspects of seed germination and growth in three Allium species native to the Intermountain West (A. acuminatum, A. brandegei, and A. passeyi). Three populations of each species were studied along an elevation gradient resulting in low, mid, and high elevation sites for each species. We investigated seed dormancy patterns within and among species and their relation to habitat. Seeds collected at the study sites were subjected to cold (3 °C) moist stratification in low light to simulate the natural winter environment under snow. Stratification periods ranged from 0 to 24 weeks. After stratification, seeds were placed in lighted growth chambers at 8 °C to simulate the natural spring environment. Germination was observed for 4 weeks. Germinated seeds were then grown at either 12 °C or 16 °C until leaf senescence. Destructive sampling occurred at 2, 4, and 8 weeks. Bulb mass and water content were also assessed after leaf senescence. In the germination experiment, all species responded favorably to cold moist stratification, suggesting physiological seed dormancy. Germination percentages among species varied greatly with 98% germination in A. acuminatum, but only 33% in A. brandegei. Seedling survival and growth varied among species and in response to growing temperature. Observed patterns in seed germination and growth are typical of survival strategies in other spring ephemerals. Seed dormancy traits and seedling growth characteristics in these species have evolved to allow optimal success for their specific habitat.
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Bhowmik, Prasanta C. "Weed biology: importance to weed management". Weed Science 45, nr 3 (czerwiec 1997): 349–56. http://dx.doi.org/10.1017/s0043174500092973.

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Knowledge of weed biology is essential for development of both economically and environmentally acceptable weed management systems. Weed biology relates to plant attributes such as morphology, seed dormancy and germination, physiology of growth, competitive ability, and reproductive biology. Concepts of population biology such as seedbank dynamics for annuals and root reserves, dormancy, and longevity of vegetative propagules for perennials can be used to predict weed infestations better and to evaluate sustainable management strategies. Integrated approaches that give priority to depletion of root reserves or seedbanks through interfering with dormancy or germination requirements have great potential to enhance weed management strategies in the future.
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