Seed Germination of American Pokeweed (Phytolacca americana). I. Laboratory Techniques and Autotoxicity

Edwards, Maurice E.; Harris, Elizabeth; Wagner, Frederic H.; Cross, M. Catherine; Miller, Gregory S.

doi:10.2307/2444734

Cited by 12 publications

(10 citation statements)

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“…Other mechanisms that create highly competitive seedling neighborhoods may also select for accelerated germination. For example, P. americana may reduce germination of conspecific seeds by allelopathy (Edwards et al, 1988); seeds that do not germinate quickly may be prevented from germinating at all (Tielbörger and Prasse, 2009). Ultimately, future laboratory and field studies are needed to examine whether labile germination strategies are common mechanisms to escape allelopathic inhibition.…”

Section: Discussionmentioning

confidence: 99%

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Density of intraspecific competitors determines the occurrence and benefits of accelerated germination

Orrock

Christopher

2010

American J of Botany

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Germination is a key process in plant recruitment and population dynamics, and seeds are expected to be under strong selection pressure to germinate under conditions that maximize subsequent plant survival. Increased rates of germination (i.e., accelerated germination) may occur in competitive environments. We examined the effects of conspecific density on the timing of germination of seeds of a bird-dispersed plant, Phytolacca americana (Phytolaccaceae, L.), in three different competitive environments. By comparing germination of seeds sown at the same time at different densities, we quantify the benefits of accelerated germination under conditions in which differences in performance among seedlings are attributable to germination timing only, and not to being sown at different times. We find that although the probability of germination is unchanged, the time to initiation of germination is significantly shorter when competition is greater. We also show that plants that germinate earlier are larger and have higher growth rates because they have more time to grow without competitors. Our work demonstrates that shifts in germination timing in response to competition can yield significant dividends for seeds that germinate earliest, but we caution that the magnitude and consequences of accelerated germination will likely depend on the competitive neighborhood.

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Section: Discussionmentioning

confidence: 99%

“…This regime reflects conditions used in other germination studies of P . americana (Farmer and Hall, 1970; Edwards et al, 1988; Orrock et al, 2003, 2006). Seeds were checked daily, and distilled water was added as necessary to maintain soil moisture.…”

Section: Methodsmentioning

confidence: 99%

Density of intraspecific competitors determines the occurrence and benefits of accelerated germination

Orrock

Christopher

2010

American J of Botany

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“…However, this explanation is not supported by field data, as there was no significant difference in precipitation during the study in 2000 and 2001 (t test, t ϭ 0.72, df ϭ 233, P ϭ 0.48). Third, P. americana seedlings may exhibit density-dependent germination inhibition via allelopathy, as extracts from mature P. americana are known to inhibit germination (Edwards et al 1988), and seedlings may become microsite limited when many emerge during pulses of germination (Maron and Simms 1997). Although we removed germinants as soon as we found them, our rate of removal may not have been sufficient to avoid germination inhibition of remaining seeds.…”

Section: Discussionmentioning

confidence: 99%

Spatial Ecology of Predator–prey Interactions: Corridors and Patch Shape Influence Seed Predation

Orrock

Danielson

Burns

et al. 2003

Ecology

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Corridors that connect patches of disjunct habitat may be promising tools for mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes, we examined how corridors affect the impact of invertebrate, rodent, and avian seed predators on pokeweed, Phytolacca americana. Over 13 months in 2000 and 2001, we quantified the effects of patch shape, connectivity, and predator type on the number of seeds germinating in the field (germinants), seed removal, and the viability of remaining seeds.Corridors did not affect the number of P. americana germinants in experimental exclosures or the viability of seeds remaining in exclosures. However, corridors affected the removal of seeds in a predator-specific manner: invertebrates removed more seeds in unconnected patches, whereas rodents removed more seeds in connected patches. Seed removal by birds was similar in connected and unconnected patches. Total seed removal by all seed predators was not affected by corridors, because invertebrates removed more seeds where rodents removed fewer seeds, and vice versa. Overall, seed predation significantly reduced the number and viability of remaining seeds, and reduced the number of germinants in 2000 but not in 2001. The abundance of naturally occurring P. americana plants in our experimental patches in 2000 decreased with increasing seed removal from exclosures but was not related to viability or germinants in 2000, suggesting that seed removal may shape the distribution and abundance of this species.Complementary patterns of seed removal by rodents and invertebrates suggest that corridors alter the effects of these predator taxa by changing the relative amounts of edge and core (nonedge) habitats in a patch. Because invertebrates and rodents do not completely overlap in the seeds they consume, corridors may change predation pressure on seeds that are primarily consumed by one predator type, with potential consequences for the composition of plant and seed predator communities.

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“…Furthermore, it could be used for the phytoextraction of manganese and rare earth elements from contaminated soils. [14][15][16] Seeds of pokeweed were treated with concentrated sulfuric acid for 15 min to promote germination, [17] then they were sown in sand in a plastic basin. After germination in the dark (about 1 week), the seedlings were cultivated in hydroculture in a green house with supplementary light to provide a 16-hr photoperiod and with the temperature controlled at 25 C day=20 C night and a relative humidity (RH) of 70-75%.…”

Section: Plant Materials and Collection Of Plant Xylem Sap Samplesmentioning

confidence: 99%

Simultaneous Extraction and Determination of Organic Acids in Xylem Saps by Rp-HPLC After Solid-Phase Extraction With Smaller Particle-Sized Hydroxyapatite Nanocrystals

Wei

Zhang

Cui

et al. 2010

Journal of Liquid Chromatography & Related Technologies

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& A simple and reliable RP-HPLC method based on solid-phase extraction with smaller particle sized hydroxyapatite nanocrystals was developed for the simultaneous extraction and determination of oxalic, malic, and citric acids in xylem saps of pokeweed. The smaller particle sized hydroxyapatite nanocrystals exhibited greater surface area and more active sites on the surface, consequently, higher adsorption ability to organic acids, which was proved to be an effective solid-phase extractor for the simultaneous extraction of organic acids in xylem saps. Oxalic, malic, and citric acids were determined by RP-HPLC at the optimum chromatographic conditions after the solid-phase extraction procedure. The accuracy of the method was confirmed with an average recovery ranging between 94.2% and 97.9%, the relative standard deviations (RSD) were less than 2.0%. This method was successfully applied to determine the organic acids in xylem saps of pokeweed.

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Seed Germination of American Pokeweed (Phytolacca americana). I. Laboratory Techniques and Autotoxicity

Cited by 12 publications

References 0 publications

Density of intraspecific competitors determines the occurrence and benefits of accelerated germination

Density of intraspecific competitors determines the occurrence and benefits of accelerated germination

Spatial Ecology of Predator–prey Interactions: Corridors and Patch Shape Influence Seed Predation

Simultaneous Extraction and Determination of Organic Acids in Xylem Saps by Rp-HPLC After Solid-Phase Extraction With Smaller Particle-Sized Hydroxyapatite Nanocrystals

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