Academic literature on the topic 'Germination strategies'
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Journal articles on the topic "Germination strategies"
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Scott, Andrew J., and John W. Morgan. "Germination strategies of annual forbs from south-eastern Australian semiarid grasslands." Australian Journal of Botany 60, no. 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, and J. P. Bakker. "Germination Strategies During Grassland Succession." Journal of Ecology 82, no. 1 (March 1994): 69. http://dx.doi.org/10.2307/2261387.
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Mathias, Andrea, and Éva Kisdi. "Adaptive diversification of germination strategies." Proceedings of the Royal Society of London. Series B: Biological Sciences 269, no. 1487 (January 22, 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, and Shuijin Hu. "Differential germination strategies of native and introduced populations of the invasive species Plantago virginica." NeoBiota 43 (March 19, 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, and 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, no. 1894 (January 16, 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, and Ian Valentine. "Phenotypic plasticity of life-history characters in response to different germination timing in two annual weeds." Canadian Journal of Botany 83, no. 1 (January 1, 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 CR axis of Grime's CSR 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 competitiveruderal strategy (CR), 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, and Hector Eduardo Pérez. "Dose–response of germinating Rudbeckia mollis (Asteraceae) seeds exposed to various thermal scenarios." Seed Science Research 22, no. 3 (June 8, 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, and M. Ajmal Khan. "Germination strategies of halophyte seeds under salinity." Environmental and Experimental Botany 92 (August 2013): 4–18. http://dx.doi.org/10.1016/j.envexpbot.2012.11.006.
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Wu, Gao-Lin, Guo-Zhen Du, and Zhi-Hua Shi. "Germination strategies of 20 alpine species with varying seed mass and light availability." Australian Journal of Botany 61, no. 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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McClure, Allison W., Katherine C. Jacobs, Trevin R. Zyla, and Daniel J. Lew. "Mating in wild yeast: delayed interest in sex after spore germination." Molecular Biology of the Cell 29, no. 26 (December 15, 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.
Dissertations / Theses on the topic "Germination strategies"
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Meaney, Carolyn Anne. "Strategies for the control of germination and outgrowth of Group I Clostridium botulinum in food products." Thesis, University of Nottingham, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716472.
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The spore-forming bacterium Clostridium botulinum is the causative agent of food- borne botulism, infant botulism and wound botulism. Botulinum neurotoxin (BoNT) is one of the most lethal substances known to man. Whilst the pathogenesis of C. botulinum is generally ascribed to BoNT, it is the capacity to produce endospores that lies at the heart of botulism. Spores enable the organism to persist in the environment and be transmitted from soil to foods and subsequently from person to person. Germination is the initial and perhaps most important step for the progression of disease. Understanding the molecular mechanisms of germination of C. botulinum spores is a major focus of research for the food industry due to C. botulinum group I proteolytic strain being a causative agent of a potentially fatal food poisoning. It occurs in low-acid canned foods of pH >4.6. Incidences of such food poisoning are rare due to adequate existing sterilisation and preservation systems. However, development of novel preservative systems and preventative strategies remains a target for the food industry with knowledge of the genetics of germination having direct applications in future disease prevention. This study encompassed four main areas of focus. These included (i) determination of appropriate germination conditions for spores of C. botulinum and evaluation of media suitable for the production of spores (ii) the use of reverse genetics and ClosTron technology followed by characterisation of three genes, sleB, cwlJ and ypeB thought to play a role in the critical stage of spore cortex lysis occurring during spore germination (iii) development of a system of forward genetics with the implementation of mariner-based random mutagenesis in C. botulinum and (iv) evaluation of the role of four small acid soluble protein (SASP) genes of the a/p- type in the protection of C. botulinum spores against heat and various chemicals. This study has culminated with the establishment of conditions specific for the germination of spores of C. botulinum ATCC 3502 strain. Combinations of nutrient germinants proved optimal with sodium bicarbonate playing a significant role functioning as a germinant itself or as a germinant co-factor. Evaluation of suitable sporulation media suggested the choice of medium for the production of spores to be a critical consideration for the performance of subsequent phenotyping and characterisation assays. Insertional mutagenesis using ClosTron technology uncovered a potential contributory role for SleB and YpeB in the spore cortex lysis stage of spore germination. A cell wall hydrolase, CwlJ is likely to be a minor cortex lytic enzyme during germination. The implementation of a system of random mutagenesis was successful in C. botulinum and future refinements of the protocol will be required to optimise all necessary requirements of a fully functional mariner-based mutagenesis system. The role of the four individual SASP genes in protection of spores against heat was difficult to ascertain but two genes, CBO1789 and CBO1790 have been implicated as having a role to play in the spore’s resistance to the DNA damaging chemical, nitrous acid. Collectively, this study has contributed and expanded our knowledge of current germination mechanisms of spores of the Group I proteolytic C. botulinum strain. It is hoped that continued study with this organism will lead to the design of either inhibitors of germination or artificial germinants that could allow spore killing under milder conditions.
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Clauss, Maria Johanna. "Life history strategies in variable environments: Demography, delayed germination and bet-hedging in a desert annual Plantago." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/282885.
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Temporal variability in the environment can affect population dynamics and life history strategies. Annual plants in desert environments are subject to large fluctuations in precipitation, both within and among years. I used a combination of field and laboratory studies to characterize variability in the populations dynamics and life history of a desert winter annual plant. I conducted demographic studies over four seasons in four populations of Plantago insularis Eastw. [Plantaginaceae] located along a precipitation gradient in the Sonoran Desert. I quantified the fates of germinated and non-germinated individuals by monitoring permanent quadrats and repeatedly sampling the soil seed bank. A fraction of seeds in all populations delayed germination and formed a persistent seed bank. Populations with more among-year variation in precipitation had greater variability in reproductive success for germinated seedlings, and the population in the most xeric environment was the most variable. Survival of non-germinated seeds was less variable than reproductive success of germinated seeds in all populations. Thus, non-germinating seeds reduced temporal variation in population dynamics by increasing population growth in dry years and decreasing growth in wet years. In this field study, populations in historically more xeric environments had lower mean germination fractions. Using geometric mean growth rate as an estimate of fitness, I demonstrate that germination fractions less than one were adaptive in three of four populations. Results of experimental studies with up to twelve populations of P. insularis, suggest that field germination responses emerged from a combination of two processes. Lower water availability during germination resulted in lower germination fractions. When water was amply available, all populations could express high germination fractions. A pattern of delayed germination consistent with bet-hedging as an adaptation to temporal variability in reproductive success arose in the field, in part, because frequencies of wet and dry germination conditions differed among populations. Phenotypic plasticity in germination response for seeds in the most xeric, environment conferred greater fitness than would have been possible with any one constant germination fraction.
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Blomqvist, Elin. "Evaluation of two potential management strategies for garden lupin (Lupinus polyphyllus) in road verges." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-82565.
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Invasiva växtarter är ett globalt problem som hotar inhemska ekosystem. Blomsterlupinen (Lupinus polyphyllis) är en invasiv flerårig växt som erhåller flera egenskaper som bidrar till dess framgångsrika etablering och spridning. Vägkanter agerar som landskapskorridorer för exotiska arter samtidigt som det är en viktig habitatrefug för många ängsväxter. För att effektivisera bevarandeåtgärder behövs en gedigen kunskap om målarten och dess egenskaper. Syftet med den här studien var att utvärdera två potentiella hanteringsmetoder av blomsterlupin i vägkanter. Slåtter är en redan etablerad strategi, men för att ta reda på om olika skördintensiteter påverkar återväxten av biomassa på olika sätt jämfördes en kontrollgrupp (ej skörd) och tre skördgrupper (1–3 skördar) med avseende på bladbiomassa, stambiomassa, blomställningsbiomassa och plantans totala biomassa. En annan potentiell hanteringsmetod utvärderades med fokus på fröbanken. Frön från blomsterlupin värmebehandlades i 40°C, 50°C och 70°C, och jämfördes mot frön utsatta för kontrolltemperatur (20°C). Varaktigheten för värmebehandlingar var 1, 5 och 15 minuter. Några frön utsattes för vattenbehandling innan värmebehandlingen för att bryta den fysiska vilan. Blomsterlupinfrön jämfördes mot tre andra arter i familjen ärtväxter (Fabaceae); blodklöver (Trifolium incarnatum), blålusern (Medicago sativa) och (Louts corniculatus). Det fanns en signifikant effekt beroende av skördintensitet på återväxt av stambiomassa, blomställningsbiomassa och plantans totala biomassa. Gällande bladbiomassa fanns ingen skillnad mellan grupperna. Faktumet att blomsterlupinen primärt investerar mer resurser på produktion av bladbiomassa kan anses positivt ur ett åtgärdsperspektiv. Återväxten av biomassa var emellertid beroende av plantans ursprungliga storlek, således skulle effekten av slåtter kunna skilja sig mellan individer i en population. Vattenbehandlingen bröt inte den fysiska vilan hos blomsterlupinfrön. Men en ökad temperatur under värmebehandlingen verkade ha en hämmande effekt för antalet grodda frön och MGT. Trots det återfanns ett relativt stort antal levande blomsterlupinfrön efter den sista observationsdagen. Det kan indikera att många frön skulle överleva en värmebehandling av fröbanken om behandlingen skulle implementeras som åtgärdsmetod. Metoden skulle förmodligen vara tidskrävande och dyr i förhållande till den önskade reducerande effekten på levande blomsterlupinfrön. För att utveckla resurseffektiva åtgärder för artens fröbank krävs mer kunskap. Slåtter verkar vara en bättre åtgärdsmetod om det genomförs vid rätt tidpunkt två gånger om året.Invasive plant species are a global problem that threaten native ecosystems. The garden lupin (Lupinus polyphyllus) is an invasive perennial herb and possesses several traits, which enables successful establishment and dispersal. Road verges serve as landscape corridors for exotic species, as well as being an important refuge habitat for many grassland species. To make conservation managements more efficient, an extensive knowledge of the target species and it’s traits is required. The aim of this study was to evaluate two potential management strategies for garden lupin in road verges. Mowing is an established strategy already, but to find out if different cutting intensities will affect biomass regrowth differently, one control group (no cut) and three harvest groups (1-3 cuts) were compared regarding leaf biomass, stem biomass, inflorescence biomass and total plant biomass. Another potential management strategy was evaluated focusing on the seed bank. Seeds of garden lupin were heat treated at 40 °C, 50 °C, and 70 °C and compared to control seeds (20 °C). Duration of treatments was 1, 5, and 15 minutes. Some seeds were watered before the heat treatment to break physical dormancy. Seeds of garden lupin were compared to three other species in the Fabaceae family: Trifolium incarnatum, Medicago sativa, and Lotus corniculatus. I found a significant effect of cutting frequency on regrowth of stem biomass, inflorescence biomass, and total plant biomass. Regarding leaf biomass, there was no difference between harvest groups. The fact that garden lupin plants primarily invest more resources in leaf biomass regrowth can be regarded as positive from a management point of view. However, biomass regrowth was depended on initial plant size, and the mowing response might differ between individual plants in populations. The water treatment did not break the physical dormancy of garden lupin seeds. Increased temperatures during heat treatments seemed to have an inhibiting effect on both seed germination and mean germination time. However, a high number of vital garden lupin seeds were remaining after the last observation. This might indicate that many seeds would remain vital if seed bank heat treatments were implemented as a management strategy. The strategy would probably be time consuming and expensive in relation to the desired reducing effect on vital garden lupin seeds. To develop resource efficient management actions on the species’ seed bank, more knowledge is needed. Mowing seems like a better management option if it is implemented at the right time twice a year.
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Waller, Penelope Anne. "Towards ecological restoration strategies for Peninsula Shale Renosterveld: testing the effects of disturbance-intervention treatments on seed germination on Devil's Peak, Cape Town." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6606.
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The ecological restoration of Peninsula Shale Renosterveld is essential to redress its conservation target shortfall. The ecosystem is Critically Endangered and, along with all other renosterveld types in the Cape lowlands, declared 'totally irreplaceable'. Further to conserving all extant remnants, ecological restoration is required to play a critical part in securing biodiversity and to meeting conservation targets. Remnants of Peninsula Shale Renosterveld are situated either side of the Cape Town city bowl and, despite formal protection, areas of the ecosystem are degraded and require restoration intervention. The body of research addressing restoration in renosterveld is small, yet growing, and seed-based restoration efforts have achieved limited success. This study primarily set out to further understand community recovery through determining the effects of interventions, implemented to mimic ecological drivers, on several seed germination criteria. Thirty-two interventions (comprised of five, crossed factors: burning, tillage, herbicide-application, rodent-exclusion and seeding) were incorporated into a field experiment situated in an area that was most likely ploughed over a century ago and is currently dominated by alien, annual grasses. Additional aspects of the study included determining the physiological status of the seed from 31 harvested species (through viability and germinability tests) towards identifying key restoration species, and, assessing intervention costeffectiveness as a measure of intervention feasibility. The majority of the harvested species exhibited moderate to high levels of viability and germinability and occurred in the middle or upper key-restoration-species index range, indicating their potential for use in future restoration efforts. Seeding contributed considerably to overall community attributes, significantly increasing indigenous seedling density, species richness and canopy cover. Due to the dominance of alien, annual grasses, seeding alone was relatively ineffectual and recruitment was considerably improved when seeding was implemented in conjunction with one or more of the other interventions. These findings indicate that a lack of available seed is not the only barrier to community recovery and that competition exerted by the alien grass component plays a large role in inhibiting seedling recruitment of desirable species. Intervention effectiveness increased with the number of factors per intervention yet, fortuitously, the most effective interventions were not necessarily the most costly. Some interventions resulted in good performances and have the potential to restore self-perpetuating communities with a semblance of ecosystem composition, structure and function. There is a clear and promising way forward incorporating these findings into feasible, implementable, landscape-scale, ecological restoration strategies for Peninsula Shale Renosterveld and potentially other Critically Endangered and 'totally irreplaceable' renosterveld ecosystems.
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Easton, Lyndlee Carol, and lyndlee easton@flinders edu au. "LIFE HISTORY STRATEGIES OF AUSTRALIAN SPECIES OF THE HALOPHYTE AND ARID ZONE GENUS FRANKENIA L. (FRANKENIACEAE)." Flinders University. Biological Sciences, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20081124.105244.
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This thesis is a comparative study of the life history strategies, and in particular seed germination requirements, in Australian species of the halophyte plant genus Frankenia L. (Frankeniaceae). Frankenia is a cosmopolitan genus that occurs in Mediterranean, semi-arid, and arid regions on distinctive soil types commonly on saline, sodic or gypseous soils in habitats such as coastal cliffs, and on the margins of salt lakes, salt-pans and saltmarshes (Summerhayes 1930; Barnsley 1982). The plants are small shrubs or cushion-bushes with pink, white or pale purple flowers, and salt-encrusted recurved leaves.
This project investigates germination requirements for Frankenia in relation to seed age, light requirements, temperature preferences, salinity tolerance, and soil characteristics. It also explores two divergent reproductive strategies notably seed packaging strategies in relation to environmental variables. Within the 46 currently recognized endemic Australia species, some species have a few ovules per flower and produce only a few larger seeds per fruit, while other species have many ovules per flower and produce many small seeds per fruit. Large-seededness is thought to increase the probability of successful seedling establishment in drought and salt-stressed environments. As both larger- and smaller-seeded species of Frankenia co-occur in close geographical proximity, hypotheses regarding the advantages of large-seededness in stress environments can be tested. By restricting the analysis of seed mass variation to similar habitats and within a single plant genus, it is possible to test ecological correlates that would otherwise be masked by the strong effects of habitat differences and phylogenetic constraints.
Overall, larger-seeded Frankenia species were demonstrated to be advantageous for rapid germination after transitory water availability, and for providing resources to seedlings if resources became limiting before their successful establishment. Smaller-seeded species delayed germination until both soil-water availability and cooler temperatures persisted over a longer time period, improving chances of successful establishment for the more slowly growing seedlings that are more reliant on their surroundings for resources.
This study produces information on the seed and seedling biology of many Australian species of Frankenia including several that are of conservation significance, e.g. F. crispa with its isolated populations, and the rare and endangered F. plicata. This information is important for the development of conservation management plans for these and other arid zone, halophyte species. In addition, the results of this study are of practical significance in determining the suitability of Frankenia for inclusion in salinity remediation and mine-site rehabilitation projects, and for promoting Frankenia as a drought and salt tolerant garden plant.
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Löbel, Swantje. "Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes." Doctoral thesis, Uppsala universitet, Ekologisk botanik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-106847.
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The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. Epiphytes must track this dynamic habitat network for their long-term survival. Community patterns at different spatial scales were explored and linked to regional metapopulation processes and local population dynamics. Spatial structuring in species richness both at a local and regional scale indicated stronger dispersal limitation but lower sensitivity to habitat quality in species with large asexual than in species with small sexual diaspores. In sexually dispersed species, a strong rescue effect was indicated by a bimodal frequency distribution of the species and by increasing local abundance with increasing patch connectivity. Present connectivity to other deciduous forest patches had positive effects on richness of asexually dispersed species, whereas richness of sexually dispersed species was instead related to the landscape connectivity 30 years ago. A study of local growth and reproduction suggested that this is caused by delayed sexual, but not asexual, reproduction. Habitat conditions affected the production of sporophytes, but not of asexual diaspores. No differences in either growth rates or competitive abilities among species with different dispersal and life-history strategies were found. In vitro experiments showed that establishment is higher from large asexual diaspores than from small sexual. Establishment of all diaspore types was limited by pH. There were indications of trade-offs between high germination and protonemal growth rates, desiccation tolerance and a rapid development of shoots from protonema. The results indicated that the epiphyte metacommunity is structured by two main trade-offs: dispersal distance (diaspore size) versus age at first reproduction, and dispersal distance versus sensitivity to habitat quality. Trade-offs in species traits may have evolved as a consequence of conflicting selection pressures imposed by habitat turnover, connectivity and irregular water supply rather than by species interactions. Syndromes of interrelated species traits imply that fairly small changes in habitat conditions can lead to distinct changes in metacommunity diversity: the results indicate that increasing distances among patches cause most harm to asexually dispersed species, whereas cuttings of forests of high age and quality as well as increasing patch dynamics are most harmful to sexually dispersed species.Senarelagd disputation från: 2009-09-26, Lindahlsalen, EBC, Villavägen 9, 75236 Uppsala, Uppsala, 10:00
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Balole, Thabsile Virginia. "Strategies to improve yield and quality of sweet sorghum as a cash crop for small scale farmers in Botswana." Diss., Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-05032002-082332.
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Castro, Tatiana Carvalho de. "Produção de plantas e metabólitos de Cleome dendroides Schult. & Schult. f. (Cleomaceae) utilizando diferentes sistemas de cultivo in vitro." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9245.
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Cleome dendroides é uma espécie endêmica da Mata Atlântica dos estados do Rio de Janeiro e Espírito Santo, bioma alterado por intensa atividade antrópica, o que constitui uma ameaça à preservação de suas populações. Não existem estudos dos pontos de vista fisiológico, biotecnológico, fitoquímico ou farmacológico sobre a espécie. Considerando-se o perfil fitoquímico e o potencial medicinal do gênero, torna-se relevante definirem-se protocolos para a produção de plantas e metabólitos de C. dendroides utilizando diferentes sistemas de cultivo in vitro. No presente trabalho, foram realizados estudos sobre a germinação in vivo da espécie, avaliando-se a influência do substrato, temperatura e luz. Não se observou qualquer tipo de dormência, sendo as temperaturas de 20, 25 e 20-30C, em areia ou vermiculita, apropriadas para a germinação in vivo. Definiu-se também uma metodologia eficiente de germinação sob condições in vitro, e as plântulas obtidas foram utilizadas como fonte de explantes para os estudos de propagação in vitro. A resposta morfogênica foi avaliada considerando-se a origem e tipo do explante, tipos e concentrações de reguladores de crescimento e número de subculturas. A metodologia empregada mostrou-se eficiente para a produção de brotos e manutenção de estoques de plantas in vitro que serviram como fonte de explantes. A melhor condição para a propagação in vitro foi definida em meio solidificado contendo BA, independentemente do tipo de explante e da origem. Os brotos obtidos foram alongados, enraizados e aclimatizados. Também foi estabelecida a cultura de raízes e a regeneração de brotos a partir destas culturas. Avaliou-se o efeito da origem do explante, assim como dos tipos e concentrações de fitorreguladores sobre a proliferação de raízes e a regeneração de brotos. O fitorregulador AIB propiciou maior multiplicação das raízes, enquanto BA mostrou-se eficiente na regeneração de brotos a partir das raízes recém-formadas. Foi estabelecido ainda um protocolo de cultura de calos e de suspensões celulares. Avaliou-se o efeito da origem e do tipo de explante, dos tipos e das concentrações de fitorreguladores sobre a calogênese. A combinação de PIC com KIN foi a mais eficiente para a indução de calos em explantes de plântulas obtidas a partir de germinação in vitro, produzindo calos que foram mantidos por pelo menos dois anos. As suspensões celulares também foram estabelecidas em meio contendo PIC + KIN, mantendo uma produção de biomassa de cerca de cinco vezes o peso fresco inicial por três sucessivas subculturas. Análises histoquímicas e fitoquímicas revelaram a presença de alcaloides nos calos e nas suspensões celulares. Foram realizadas análises fitoquímicas de plantas de campo, plantas aclimatizadas, plantas mantidas em estoque in vitro e culturas de raízes, as quais indicaram a presença de derivados de glicosinolatos. Os resultados demonstraram a viabilidade de produção de material vegetal de C. dendroides por meio de métodos biotecnológicos e a produção in vitro de metabólitos de importância medicinalCleome dendroides is an endemic species of the Atlantic Forest of Rio de Janeiro and Espírito Santo states, biome changed by intense human activities that threaten its populations. There are no physiological, biotechnological, phytochemical or pharmacological studies of this specie. Considering the phytochemical profile and the medical potential of the genus, it becomes relevant to establish protocols for the production of plants and metabolites of C. dendroides using different in vitro culture systems. In this work, studies were performed on the in vivo germination of the species evaluating the influence of the substrate, temperature and light. There was no dormancy, and germination was achieved at 20, 25 and 20-30C, on sand or vermiculite substrates. An efficient methodology of germination under in vitro conditions was defined by comparing the different stages of post-seminal development with seedlings from germination under in vivo conditions. The plantlets obtained from the in vitro germination were used as a source of explants for in vitro propagation system. The morphogenic response was evaluated considering the source and type of explant, types and concentrations of growth regulators and number of subcultures. The methodology was efficient for the production of shoots and maintenance of in vitro plants. The best condition for in vitro propagation was using solidified medium supplemented with BA, regardless of the tested explants. The shoots were efficiently elongated, rooted and acclimatized. It was also established an efficient protocol for root culture and shoots regeneration from these cultures. The effect of source of explant, the types and growth regulator concentrations on the proliferation of roots and shoot regeneration was evaluated. IBA provided higher multiplication rates of the roots, whereas BA was effective in the regeneration of shoots from the newly formed roots. A protocol of callus culture and cell suspension culture was established. The effect of the origin and type of explant, the types and concentrations of growth regulators on callus formation was evaluated. PIC + KIN was the most efficient combination for callus induction from explants derived from in vitro germinated seedlings. Callus cultures were maitained for at least two years. Cell suspension cultures were established with the same combination of growth regulators (PIC + KIN), maintaining a biomass of about five times the initial fresh weight of three successive subcultures. Histochemical and phytochemical analysis revealed the presence of alkaloids in callus and suspension cell cultures. Phytochemical analyses of field plants, acclimatization in vitro plant and culture roots were performed, which indicated the presence of glucosinolate derivatives. The results demonstrated the possibility of producing medicinal important metabolites from C. dendroides by biotechnological methods
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Bithell, S. L. "An evaluation of Solanum nigrum and S. physalifolium biology and management strategies to reduce nightshade fruit contamination of process pea crops." Lincoln University, 2004. http://hdl.handle.net/10182/1160.
Full textAbstract:
The contamination of process pea (Pisum sativum L.) crops by the immature fruit of black nightshade (Solanum nigrum L.) and hairy nightshade (S. physalifolium Rusby var. nitidibaccatum (Bitter.) Edmonds) causes income losses to pea farmers in Canterbury, New Zealand. This thesis investigates the questions of whether seed dormancy, germination requirements, plant growth, reproductive phenology, or fruit growth of either nightshade species reveal specific management practices that could reduce the contamination of process peas by the fruit of these two weeds. The seed dormancy status of these weeds indicated that both species are capable of germinating to high levels (> 90%) throughout the pea sowing season when tested at an optimum germination temperature of 20/30 °C (16/8 h). However, light was required at this temperature regime to obtain maximum germination of S. nigrum. The levels of germination in the dark at 20/30 °C and at 5/20 °C, and in light at 5/20 °C, and day to 50 % germination analyses indicated that this species cycled from nondormancy to conditional dormancy throughout the period of investigation (July to December 2002). For S. physalifolium, light was not a germination requirement, and dormancy inhibited germination at 5/20 °C early in the pea sowing season (July and August). However, by October, 100% of the population was non-dormant at this test temperature. Two field trials showed that dark cultivation did not reduce the germination of either species. Growth trials with S. nigrum and S. physalifolium indicated that S. physalifolium, in a non-competitive environment, accumulated dry matter at a faster rate than S. nigrum. However, when the two species were grown with peas there was no difference in dry matter accumulation. Investigation of the flowering phenology and fruit growth of both species showed that S. physalifolium flowered (509 °Cd, base temperature (Tb) 6 °C) approximately 120 °Cd prior to S. nigrum (633 °Cd). The fruit growth rate of S. nigrum (0.62 mm/d) was significantly faster than the growth rate of S. physalifolium (0.36 mm/d). Because of the earlier flowering of S. physalifolium it was estimated that for seedlings of both species emerging on the same date that S. physalifolium could produce a fruit with a maximum diameter of 3 mm ~ 60 °Cd before S. nigrum. Overlaps in flowering between peas and nightshade were examined in four pea cultivars, of varying time to maturity, sown on six dates. Solanum physalifolium had the potential to contaminate more pea crops than S. nigrum. In particular, late sown peas were more prone to nightshade contamination, especially late sowings using mid to long duration pea cultivars (777-839 °Cd, Tb 4.5 °C). This comparison was supported by factory data, which indicated that contamination of crops sown in October and November was more common than in crops sown in August and September. Also, cultivars sown in the later two months had an ~ 100 °Cd greater maturity value than cultivars sown in August and September. Nightshade flowering and pea maturity comparisons indicated that the use of the thermal time values for the flowering of S. nigrum and S. physalifolium can be used to calculate the necessary weed free period required from pea sowing in order to prevent the flowering of these species. The earlier flowering of S. physalifolium indicates that this species is more likely to contaminate pea crops than is S. nigrum. Therefore, extra attention may be required where this species is present in process pea crops. The prevention of the flowering of both species, by the maintenance of the appropriate weed free period following pea sowing or crop emergence, was identified as potentially, the most useful means of reducing nightshade contamination in peas.
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Tauer, Pamela Kay. "Strategies for successful germination of Rocky Mountain juniper (Juniperus scopulorum Sarg.) in an Oklahoma nursery." 2010. http://digital.library.okstate.edu/etd/Tauer_okstate_0664M_10840.pdf.
Full textBook chapters on the topic "Germination strategies"
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Gutterman, Yitzchak. "Germination Adaptations, Strategies and Influences on Germination During Seed Wetting." In Adaptations of Desert Organisms, 211–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-55974-7_6.
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Lombardi, Tiziana, and Stefano Bedini. "Seed Germination Strategies of Mediterranean Halophytes Under Saline Condition." In Handbook of Halophytes, 1–19. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-17854-3_119-1.
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Lombardi, Tiziana, and Stefano Bedini. "Seed Germination Strategies of Mediterranean Halophytes Under Saline Condition." In Handbook of Halophytes, 1685–703. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57635-6_119.
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Gutterman, Y. "Genotypic, Phenotypic and Opportunistic Germination Strategies of Some Common Desert Annuals Compared with Plants with Other Seed Dispersal and Germination Strategies." In Basic and Applied Aspects of Seed Biology, 611–22. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5716-2_68.
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Gutterman, Yitzchak. "Strategies of Phenotypic Plasticity of Germination: Dormancy After Seed Maturation." In Adaptations of Desert Organisms, 127–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-55974-7_4.
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Gutterman, Yitzchak. "Strategies of Phenotypic Plasticity of Germination During Seed Development and Maturation." In Adaptations of Desert Organisms, 65–125. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-55974-7_3.
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Marques da Silva, José Rafael, and Manuela Correia. "The soil-water-plant agrisystem:a little about soil, water and plants." In Manuali – Scienze Tecnologiche, 7. Florence: Firenze University Press, 2020. http://dx.doi.org/10.36253/978-88-5518-044-3.07.
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Soil and water are essential for plants to grow. By analysing a Vegetation Index map of a corn field after emergency we are going to observe different concentrations of chlorophyll across the field. We will try to identify possible causes for those differences and discuss the strategies to solve any problems that are occurring. These problems can be related with soil characteristics, irrigation, plant germination capacity, nutrition, etc., highlighting the importance of soil-water-plant agrisystem.
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Skordilis, A., and C. A. Thanos. "Comparative Ecophysiology of Seed Germination Strategies in the Seven Pine Species Naturally Growing in Greece." In Basic and Applied Aspects of Seed Biology, 623–32. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5716-2_69.
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R. Qasem, Jamal. "Weed Seed Dormancy: The Ecophysiology and Survival Strategies." In Seed Dormancy and Germination. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.88015.
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Fernández-Aparicio, M., and D. Rubiales. "Advances in understanding plant root response to weedy root parasites." In Understanding and improving crop root function, 215–30. Burleigh Dodds Science Publishing, 2021. http://dx.doi.org/10.19103/as.2020.0075.11.
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This chapter addresses advances in understanding plant root responses to weedy root parasites. It begins by reviewing host-parasitic weed interactions, focusing specifically on seed dispersal and germination and the possibility of host infection as a consequence of germination. The chapter then moves on to discuss host plant pre-penetration and post-penetration defence mechanisms. It concludes by emphasising the importance of developing management strategies for parasitic weed management.
Conference papers on the topic "Germination strategies"
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Jan, Nurhidaya Mohamad, Fong Wan Heng, Nor Haniza Sarmin, and Sherzod Turaev. "Watson-Crick Petri net languages: The effect of labeling strategies." In PROCEEDINGS OF THE 21ST NATIONAL SYMPOSIUM ON MATHEMATICAL SCIENCES (SKSM21): Germination of Mathematical Sciences Education and Research towards Global Sustainability. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4887673.
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Ghazali, Munirah, Hafezali Iqbal Hussain, and Ayminsyadora Ayub. "A comparative study on the counting strategies of students in year 1 and 2 in Malaysia." In PROCEEDINGS OF THE 21ST NATIONAL SYMPOSIUM ON MATHEMATICAL SCIENCES (SKSM21): Germination of Mathematical Sciences Education and Research towards Global Sustainability. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4887685.
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Kiram, Johannah Jamalul, Jumat Sulaiman, Suyansah Swanto, and Wardatul Akmam Din. "The relationship between English language learning strategies and proficiency of pre-university students: A study case of UMS." In PROCEEDINGS OF THE 21ST NATIONAL SYMPOSIUM ON MATHEMATICAL SCIENCES (SKSM21): Germination of Mathematical Sciences Education and Research towards Global Sustainability. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4887688.
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