Investigating seed dormancy in switchgrass (Panicum virgatum L.): understanding the physiology and mechanisms of coat-imposed seed dormancy

Duclos, Denise V.; Ray, Dennis T.; Johnson, Daniel J.; Taylor, A.G.

doi:10.1016/j.indcrop.2013.01.005

Cited by 30 publications

(33 citation statements)

References 35 publications

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“…In panicoid grasses, these structures are even more likely to affect germination, because the coleorhiza must emerge through a rigid lemma by opening a hinged flap named 'the germination lid' (Haar et al, 2014). Previous results in these species showed that extraction of the covering structures strongly promotes germination (Duclos et al, 2013), and the extraction of only the lemma had a similar or higher effect to the removal of both lemma and palea on germination in Digitaria sanguinalis (L.) Scop. (Gallart et al, 2008) and Paspalum notatum Flüggé (West and Marousky, 1989).…”

Section: Differential Incidence Of Lemma On Germinationmentioning

confidence: 91%

“…These results suggest that seed covering structures delay water uptake but they are not an impermeable barrier for any of the genotypes evaluated. In other panicoid species, with similar results, it was concluded that seed dormancy expressed in each genotype is not due to a water uptake impediment by their covering structures (Huarte et al, 2007;Duclos et al, 2013). After the imbibition assays, seeds were tested for germination at 32 °C.…”

Section: Germination Was Not Associated To Water Uptake Dynamicsmentioning

confidence: 96%

“…In Panicum virgatum, it was suggested that dormancy at the caryopsis level is controlled by the caryopsis coat (pericarp/ testa complex) and even a slight disruption may cause an increase in germination, depending on the genotype (Duclos et al, 2013). More evidence is necessary to support the putative role of the caryopsis coat on seed dormancy in P. dilatatum.…”

Section: Flavescensmentioning

confidence: 99%

“…Dry storage time, which causes after-ripening (a reduction in seed dormancy) in several panicoid grasses (Duclos et al, 2013;Glison et al, 2015), caused an increase in germination in almost all treatments for pentaploid clones (Figure 2), but no significant effect was observed on Virasoro and Flavescens (p > 0.05). However, after-ripening was evident for both sexual biotypes in the ABA sensitivity assays, since after 5 months of dry storage no effect of ABA on G tot or G 7 was observed on WOL or control seeds ( Figure 3B).…”

Section: Effect Of Dry Storagementioning

confidence: 99%

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Differential incidence of the lemma on seed germination among different Paspalum dilatatum genotypes

2017

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-Paspalum dilatatum Poir. is a promising perennial summer grass forage for temperate regions, but among other factors, slow stand establishment has hindered its adoption. One of the reasons may be seed dormancy. Intraspecific variability in seed dormancy has been reported in P. dilatatum, but the mechanisms underlying this variability remain unclear. In this paper, we focus on the role of seed external covering structures on germination, particularly the lemma. Seeds of apomictic and sexual biotypes of P. dilatatum were subjected to acid scarification and removal of the lemma to study their germination, imbibition rate and sensitivity to ABA. Seeds without lemma showed higher germination than other treatments in dormant genotypes. We found that the lemma delayed but did not prevent water uptake in any genotype. Comparing sexual biotypes, P. dilatatum subsp. flavescens showed higher lemma-imposed dormancy than P. dilatatum "Virasoro", and also higher seed dormancy at the caryopsis level. The thickness of the lemma was not different between these biotypes, so this trait did not explain differences in dormancy. Intraspecific variability of seed dormancy in this species may be attributable to the lemma incidence, however differences in the caryopsis component of seed dormancy should be considered.Index terms: perennial warm-season forage grasses, seed dormancy, seed covering structures, acid scarification.Impacto diferencial da lema sobre a germinação de sementes entre diferentes genótipos de Paspalum dilatatum RESUMO -Paspalum dilatatum Poir. é uma gramínea forrageira perene de regiões temperadas, mas sua utilização é limitada pelo seu estabelecimento lento, entre outros fatores. Uma razão pode ser a dormência das sementes. Tem sido relatada variabilidade intraespecífica da dormência em P. dilatatum, mas os mecanismos envolvidos nesta variabilidade não são claros. Neste trabalho estudamos o papel das coberturas externas sobre a germinação, particularmente da lema. Sementes de biótipos sexuais e apomíticos de P. dilatatum foram submetidos à escarificação ácida e remoção da lema para estudar a germinação, a taxa de embebição e a sensibilidade ao ABA. As sementes sem lema mostraram maior germinação que outros tratamentos em genótipos com dormência. Ainda, a lema retarda, mas não impede a entrada de água. Comparando genótipos sexuais, P. dilatatum subsp. flavescens apresentou uma maior dormência imposta pela lema que P. dilatatum "Virasoro", e também dormência mais elevada ao nível do cariopse. A espessura da lema não foi diferente entre estes genótipos, e portanto esta não explicou as diferenças na dormência. A variabilidade intraespecífica da dormência nesta gramínea panicóide pode ser atribuída às diferenças na incidência da lema. Contudo, diferenças na dormência ao nível da cariopse devem ser consideradas.Termos de indexação: gramínea forrageira perene estival, dormência das sementes, coberturas externas das sementes, escarificação ácida.

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Section: Differential Incidence Of Lemma On Germinationmentioning

confidence: 91%

Section: Germination Was Not Associated To Water Uptake Dynamicsmentioning

confidence: 96%

Section: Flavescensmentioning

confidence: 99%

Section: Effect Of Dry Storagementioning

confidence: 99%

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Differential incidence of the lemma on seed germination among different Paspalum dilatatum genotypes

2017

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“…This period is very close to that observed for natural dormancy breaking of ryegrass seeds and reported by Costa et al (2013). Research shows that, in freshly harvested seeds, the water ingress in tissues hinders the absorption of oxygen and that the storage of dry seeds for a certain time promotes the diffusion of oxygen into the interior, determining a reduction in the amount of germination inhibitors and favoring breaking seed dormancy (Duclos et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Methods for breaking seed dormancy of ryegrass during storage periods

Martins¹,

Radke²,

Monteiro³

et al. 2016

Afr. J. Agric. Res.

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The presence of dormant seeds makes it difficult to evaluate physiological quality and requires the use of appropriate methods in order to break seed dormancy. The objective of this study was to evaluate the effectiveness of different methods to break the dormancy of ryegrass seeds stored under environment conditions in different periods. Ryegrass seeds, BRS Ponteio cultivar, produced in two locations were used and evaluated after 60, 90, 120, 150 and 180 days of storage under environment conditions. Seeds were submitted to the following methods to break dormancy: sowing at 20 to 30°C without applying any method to break dormancy (control); pre-cooling (5°C) for 3 days + KNO 3 followed by sowing at 15 to 25°C; pre-drying (45°C) for 96 h followed by sowing at 20-30°C; immersing the seeds in sodium hypochlorite (NaClO) at 0.5% for 24 h, followed by drying at 45°C for 6 h and sowing at 15 to 25°C. At 60 days after harvest, the most effective method was immersion of seeds in a NaClO solution followed by drying at 45°C. From 90 days after harvest, all methods were equally effective to break seed dormancy, except pre-drying (45°C) for 96 h, which negatively affected the physiological quality of seeds. There is a difference in the effectiveness of the methods employed to break the dormancy of ryegrass seeds depending on the type of post-harvest storage.

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