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Filters: partyWithName: Garvin, Susan C (X) > Types: Citation (X)

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Seed gennination of Atriplex confertifolia (shadscale) has been studied sporadically since 1900, with little progress in understanding the mechanisms responsible for seed donnancy or in overcoming these obstacles for the purpose of successfully seeding shadscale in restoration projects. Most work has concentrated on the indurated bracteoles and their role in inhibiting gennination, but no conclusive evidence has been presented to show that the bracts must disintegrate to allow germination. Experiments show that moist chilling offresh seeds for 12 weeks allowed gennination of up to 66 percent offresh fruits and up to 85 percent of 3 year old fruits. No gennination occurred in unchilled fruit. A preliminary trial...
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...
Shadscale (Atriplex confertifolia (Torr. & Frem.) Wats.) is a dominant shrub species of western North American deserts. Its one-seeded utricles are enclosed in bracteoles, and its seeds are highly dormant at dispersal. We examined the role of soluble inhibitors, bracteole effects, after-ripening, and chilling in regulating dormancy for six shadscale populations. Seeds in bracteole-enclosed fruits required chilling to become germinable, and the fraction responsive to chilling was small for recently harvested seeds. This fraction increased during dry storage for 24 weeks, but the rate of increase decreased asymptotically. After-ripening rate was an exponential function of storage temperature over the range 22?50�C....