The role of natural agents in the removal of coat-imposed dormancy in Dichrostachys cinerea (L.) Wight et Arn. seeds

Staden, J. Van; Kelly, Kathleen; Bell, W. E.

doi:10.1007/bf00024141

Cited by 17 publications

(14 citation statements)

References 9 publications

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“…However, the seed coat fracture as a result of fire and the following germination depend on the fire's intensity (temperature, duration) and on the species of seed. Conversely, some studies indicated the negative impact of fire on seed germination while others reported minimal or no effect (Brown, 1993;Van Staden et al, 1994). Thus, the questions are: i) do different hard-seeded legume species have the same response to heat shock?…”

Section: Discussionmentioning

confidence: 99%

The effect of fire on the dormancy break of annual legume seeds

et al. 2011

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Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm) and subjected to fires at two different intensities (high and low). As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C) for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50%) remained non-germinated in the soil.

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Section: Discussionmentioning

confidence: 99%

The effect of fire on the dormancy break of annual legume seeds

et al. 2011

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“…A relatively high proportion of empty and insect-damaged seeds contributed to this low success. However, unlike A. altissima and U. pumila, R. pseudoacacia seeds present dormancy, which can be broken by natural processes, such as the passage through the digestive track of animals, fires, or abrasion with soil particles [64]. Even if dormancy depresses germination success of a seed cohort in the short term, at longer time scales it may increase reproductive success by extending the temporal window for germination [22].…”

Section: International Journal Of Ecologymentioning

confidence: 99%

Potential Germination Success of Exotic and Native Trees Coexisting in Central Spain Riparian Forests

Cabra-Rivas

Castro‐Díez

2016

International Journal of Ecology

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We compared potential germination success (i.e., percentage of produced seeds that germinate under optimal conditions), the percentage of empty and insect-damaged seeds, germinability (Gmax), and time to germination (Tgerm) between the exoticsAilanthus altissima,Robinia pseudoacacia,andUlmus pumilaand two coexisting native trees (Fraxinus angustifoliaandUlmus minor) in the riparian forests of Central Spain. Additionally, we tested the effect of seed age, seed bank type (canopy or soil) and population onGmaxandTgermofA. altissimaandR. pseudoacacia, which are seed-banking species. Species ranked by their potential germination success wereA. altissima>U. pumila>R. pseudoacacia>U. minor>F. angustifolia. The combination of a highGmaxand negligible seed insect-damage providedA. altissimawith a potential germination advantage over the natives, which were the least successful due to an extremely high percentage of empty seeds or a very lowGmax.R. pseudoacaciashowed high vulnerability to insect seed predation which might be compensated with the maintenance of persistent seed banks with highGmax.GmaxandTgermwere strongly affected by seed age in the seed-banking invaders, but between-seed bank variation ofGmaxandTgermdid not show a consistent pattern across species and populations.

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“…The seeds of D. cinerea are impermeable to water and dormant at release (van Staden et al 1994b;Witkowski and Garner 2000). Dormancy is mainly broken through diurnal temperature fluctuations, by scarification through ingestion and by bruchid exit holes (van Staden et al 1994b …”

Section: Study Sitementioning

confidence: 99%

“…Fire may additionally promote the regeneration of woody plant species by promoting the release and germination (Brown and van Staden 1997;Keeley and Fortheringham 2000;Brown et al 2003) of seeds. Consumption of seed pods followed by defecation of intact seeds by browsers can also promote shrub recruitment (Brown and Archer 1987;Reyes et al 1994) as scarification through ingestion is known to break seed dormancy (van Staden et al 1994b). On the other hand, large herbivores can inhibit tree establishment directly through browsing, uprooting or trampling of seedlings (Dublin et al 1990;Mwalyosi 1990;Sinclair 1995).…”

Section: Introductionmentioning

confidence: 99%

Interacting effects of grass height and herbivores on the establishment of an encroaching savanna shrub

Hagenah¹,

Munkert²,

Gerhardt³

et al. 2008

Herbaceous Plant Ecology

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Shrub encroachment is a widely observed problem in Southern African savannas.Although the effects of herbivory and grass height on woody species recruitment have been studied individually, little information exists about how these factors interact. In this study seeds and seedlings of the encroaching shrub Dichrostachys cinerea were planted in clipped and unclipped grass plots, with and without large herbivores present. Seed germination, seedling survival and seedling predation were monitored for 8 months. Germination started earlier in plots where herbivores were excluded. Overall, the earlier the seeds germinated, the longer the seedlings survived. Clipping positively affected the number of germinated seeds, seedling growth and survival but effects varied among herbivore exclusion treatments and sites. Invertebrates caused the majority of the seedling damage. We conclude the recruitment of D. cinerea is influenced by the interplay of grass height and herbivory. In this study, the presence of large herbivores early in the wet season, and the absence of simulated grazing later on, affected the regeneration of D. cinerea negatively. However, differences in effects among sites suggest that the mechanisms found here may work differently in other habitats.

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The role of natural agents in the removal of coat-imposed dormancy in Dichrostachys cinerea (L.) Wight et Arn. seeds

Cited by 17 publications

References 9 publications

The effect of fire on the dormancy break of annual legume seeds

The effect of fire on the dormancy break of annual legume seeds

Potential Germination Success of Exotic and Native Trees Coexisting in Central Spain Riparian Forests

Interacting effects of grass height and herbivores on the establishment of an encroaching savanna shrub

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