Filters: Tags: dormancy (X)43 results (392ms)
Annual dormancy cycle and influence of flooding in buried seeds of mudflat populations of the summer annual Leucospora multifida
Assessment of the influence of recruitment from the sediment on the development of planktonic populations of cyanobacteria in a temperate mesotrophic lake.
Seasonal relationships between cyst germination and vegetative population of Scrippsiella trochoidea (Dinophyceae)
Seed production and seedling establishment of a Southwest riparian tree, Arizona walnut (Juglans major ).
Assessment of the importance of resting eggs for the evolutionary success of Mesozoic non--marine cypridoidean Ostracoda (Crustacea)
Impact of the pathogen Pyrenophora semeniperda on Bromus tectorum seedbank dynamics in North American cold deserts
Bromus tectorum is a dominant winter annual weed in cold deserts of western North America. We followed patterns of seed carry-over and abundance of the pathogen Pyrenophora semeniperda over 5 years at B. tectorum-dominated shadscale (Atriplex confertifolia) and sagebrush (Artemisia tridentata) sites in southern Idaho. We hypothesised that more seeds could potentially carry over at the drier shadscale site because of minimal autumn precipitation, but that P. semeniperda, a pathogen that primarily kills dormant seeds, would have more impact at the drier site, where a higher density of dormant seeds would likely be present in the early spring seedbank. Successful first-year seed carry-over was higher in years with...
Fecundity, phenology, and seed dormancy of F sub(1) wild-crop hybrids in sunflower (Helianthus annuus, Asteraceae)
Longest Insect Dormancy: Yucca Moth Larvae (Lepidoptera: Prodoxidae) Metamorphose After 20, 25, and 30 Years in Diapause
In annual plants, increased competitive advantage has often been attributed to rapid germination and early establishment. In contrast, many annual species exhibit some degree of delayed germination (i.e., seed dormancy) that results in the formation of age structure within the seed population. Delayed germination can be an effective bet-hedging strategy in variable or unpredictable environments as a seed bank can buffer against years with reproductive failures and reduce the probability of local extinction. However, there has been little consideration of the direct effects of aging within the seed pool although the potential demographic costs of such a strategy (e.g., mortality in the seed bank or delayed reproduction)...
Cheatgrass (Bromus tectorum L., Poaceae), an introduced winter annual, has invaded a variety of habitats in western North America. This study examines variation in cheatgrass germination response and after-ripening patterns that are related to differences in habitat and to yearly differences in weather conditions during seed maturation. Seeds collected from five contrasting populations in 1992 and 1993 were subjected to controlled dry storage and then incubated across a range of temperatures. Recently harvested seeds were dormant and germinated slowly, while fully after-ripened seeds were nondormant and germinated rapidly. The optimal incubation temperature for mean germination time shifted from 5:15 to 20:30 Â°C...
Habitat-correlated variation in blackbrush (Coleogyne ramosissima: Rosaceae) seed germination response
Blackbrush is a dominant shrub species in the transition zone between North American warm and cold deserts. Its seeds are dormant at dispersal and lose dormancy in response to moist chilling. Seeds from warmer low-elevation habitats have shorter chilling requirements and a higher optimum chilling temperature than those from colder habitats where winter snow regularly occurs. This ecotypic variation functions to time germination optimally in habitats with contrasting chilling regimes. Regulation of germination phenology is an important feature of the life history of this ecotonal species, which must be able to migrate elevationally through recruitment from seed in response to long-term climatic shifts in order to...
Seed dormancy pattern and seed reserves as adaptations of the endemic winter annual Lesquerella lescurii (Brassicaceae) to its floodplain habitat.
Seed germination regulation and field seed bank carryover in shadscale (Atriplex confertifolia: Chenopodiaceae)
In laboratory germination studies with 15 collections ofAtriplex confertifolia, a dominant shrub of North American salt deserts, we found that seeds were dormant and largely unresponsive to chilling at dispersal but became chilling-responsive through dry after-ripening. Collections from warm desert habitats were more chilling-responsive and after-ripened more rapidly than those from cold desert habitats. In a field seed bank experiment, germination did not take place until the second spring, and 30% of the seeds remained viable and ungerminated after five springs. Cold desert collections showed highest seed bank carryover. Spring germination and seed bank carryover across years are important aspects of shadscale...