Mechanism of the glumes in inhibiting seed germination of Leymus chinensis (Trin.) Tzvel. (Poaceae)

Y., H.; Liang, Zhengwei; Liu, M.; Wang, M. M.

doi:10.15258/sst.2010.38.3.13

Cited by 14 publications

(17 citation statements)

References 17 publications

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“…palea and lemma) were removed, with four species germinating greater than 70%. Although technically challenging to remove the covering structures without damaging the embryo, this approach can been adapted for the propagation of large numbers of Triodia , as in other Poaceae (Adkins et al ; Meissner ; Wells & Dixon ; Gallart et al ; Ma et al ; Farley et al ). It is most likely that the covering floret structures inhibit germination though restricting the growth of the embryo.…”

Section: Discussionmentioning

confidence: 99%

“…It is most likely that the covering floret structures inhibit germination though restricting the growth of the embryo. Artificial weakening of the floret structure using sulphuric acid has proven to increase germination in Microlaena stipoides by 25% (Stevens et al ) and in Leymus chinensis by greater than 40% (Ma et al ). Similar to the effect of sulphuric acid treatment, the use of a novel flash flaming approach, designed to remove appendages and hairs of florets, has recently shown promise for improving germination in seeds of T. wiseana (Guzzomi et al ).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Overcoming physiological dormancy in seeds of Triodia (Poaceae) to improve restoration in the arid zone

Erickson

Shackelford

Dixon

et al. 2016

Restoration Ecology

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Reinstating dominant Triodia grassland communities following disturbance has been a focus of arid land restoration practitioners for decades in Australia. Yet, seed quality and variable seed germination have seriously hindered the reestablishment potential of Triodia species to date. This study set out to examine diaspore quality, germination requirements, and seed dormancy in seven Triodia species to identify first, then resolve, germination impediments. Freshly collected florets from all species were cleaned to ensure that each floret contained a viable seed and then evaluated for their initial germination capacity. Very low germination from florets (<10%) indicated the presence of physiological seed dormancy (PD) in all species. However, germination was significantly improved (up to 57%) with the use of 0.67 m karrikinolide (KAR 1 ), and to a lesser degree with 289 m gibberellic acid (GA 3 ). When the covering floret structures (i.e. lemma and palea) were removed, germination increased up to 59%, which was further enhanced after exposure to GA 3 (up to 66%) and KAR 1 (up to 92%). Optimal germination temperatures varied from 20 to 35 ∘ C and were species specific. Dry after-ripening (DAR −30 ∘ C and 50% relative humidity [RH]) of florets and seeds promoted the progressive loss of PD over 12-24 months storage for most species. Germination, dormancy level, and response to incubation temperature differed amongst species, experimental units (florets and seeds), DAR treatments, and after exposure to germination stimulants (GA 3 and KAR 1 ). For use in restoration seeding programs, careful consideration of seed pre-treatments is necessary to improve germination in Triodia species. Implications for Practice• Many seed-based restoration programs fail to consider all aspects of seed quality, handling, and use. • Correctly processing and storing seeds under optimized conditions will maximize seed viability. Higher germination and establishment potential can then be achieved by correctly identifying the presence of dormancy mechanisms and applying specific pre-treatments prior to sowing. • Like many grasses, seeds of Triodia species are physiologically dormant. When seeds are removed from covering floret structures, dry after-ripened at 30 ∘ C and 50% RH for 12-24 months, and/or treated with karrikinolide or gibberellic acid, significant improvements in germination are achieved. • Implementing these key steps at larger scales will ensure that seeds are used more efficiently and plant establishment becomes much more predictable.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Overcoming physiological dormancy in seeds of Triodia (Poaceae) to improve restoration in the arid zone

Erickson

Shackelford

Dixon

et al. 2016

Restoration Ecology

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“…Under laboratory conditions, physical removal (Ma et al . ; Erickson et al . ) or chemical abrasion (Stevens et al .…”

Section: Introductionmentioning

confidence: 99%

“…In grasses, seed dormancy is often a combination of two separate mechanisms acting on the embryo: (i) mechanical restriction imposed by the floret and (ii) a physiological barrier that acts by limiting the growth capability of the embryo . Under laboratory conditions, physical removal (Ma et al 2010;Erickson et al 2016) or chemical abrasion (Stevens et al 2015) has proven successful in overcoming this mechanical restriction, while after-ripening under controlled humidity conditions have successfully replicated natural physiological dormancy alleviation . Cycling dormant seeds through a series of wetting and drying events has also been highly successful (Hoyle et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Increasing the germination envelope under water stress improves seedling emergence in two dominant grass species across different pulse rainfall events

Lewandrowski

Erickson

Dixon

et al. 2016

Journal of Applied Ecology

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Summary Demographic recruitment processes, such as seed germination and seedling emergence, are critical transitional phases to the re‐establishment of degraded plant populations, but often fail due to rainfall not supporting plant requirements. Using species from the widespread arid Australian perennial grass genus Triodia, we investigated the interactions of seeds in different dormancy states and their functional germination envelope in response to water stress after simulated pulse rainfall events. Seed dormancy was alleviated in Triodia species to varying degrees by wet/dry cycling or by removing floret structures from seeds. The seeds were then exposed to different rainfall frequency and quantity events mimicking the 25th, median, 75th and 95th percentile rainfall events found in natural habitats for the study species in the north‐west Australian arid zone. Under 95th percentile rainfall conditions recruitment was highest, but still limited to 35% germination and 10% emergence of cleaned seeds (i.e. the least dormant state evaluated). This was related to the functional germination envelope as indicated by more negative base water potential thresholds (Ψb50) for cleaned seeds (≥ −0·33 MPa) compared to intact florets (≥ −0·26 MPa). As a result, the maximum cumulative time where soil water potentials were optimal for germination (Ψsoil ≥ Ψb50) was 1·6–2·6 times longer for cleaned seeds in large frequent rainfall events when compared to intact florets. Furthermore, seed dormancy, that usually prolongs seed survival, was linked to a short‐term reduction in seed viability, which may further reduce recruitment rates. Synthesis and applications. Our findings indicate that large frequent rainfall events raised soil water potentials above critical thresholds for germination and are important for successful plant establishment. If recruitment bottlenecks are a result of seed dormancy and variable rainfall for arid grass species, then this study shows benefits for alleviating seed dormancy prior to seeding in restoration sites, as this increases the environmental envelope for germination.

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“…Improvement in germination performance of Rhodes grass seeds on husked seeds might be attributed to different factors such as enhanced access of the caryopsis to moisture, exclusion of empty husks from the germination test, and removal of physical barrier. Previous studies indicated that the main mechanisms of glumes were the mechanical resistance of glumes (Ma et al, 2010). Therefore, seed quality testing laboratories need to consider husk removal treatment before germination tests are conducted.…”

Section: Experiments Imentioning

confidence: 99%

Storage period, husking and seed treatment effects on germination of Rhodes grass (<i>Chloris gayana</i> L.) seeds

Kalsa¹,

Geleta²,

Geleti³

2016

Sci. Technol. Arts Res. J.

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Seed dormancy is among the major problems associated with pasture establishment from Rhodes grass. Two experiments were conducted with the aim to assess the effects of storage period (years), husking and seed treatment on germination rate of Rhodes grass seeds of two cultivars, Callide and Masaba, at Kulumsa and Debre Zeit Research Centers. The first experiment included two seed lots (harvested in years 2013 and 2014) and two husking treatments (husked and with husk) laid out in split plot design with four replications. The second experiment had three seed lots (harvested in 2012, 2013 and 2014), three chemical treatments (KNO3, Ethanol, and H2O) and untreated control for each lot in randomized complete block design with three replications. In the first experiment, germination rate ranged from 13.5% in freshly harvested seeds with husk to 85.5% in aged seeds without husk. Husking improved germination and this may be attributed to improved access of emb water, exclusion of empty husks and elimination of physical barriers to germination. In the second experiment, germination rate ranged from 3.3% in untreated fresh seeds to 21.1% in seeds harvested in 2012 and pre-treatment with KNO harvested seeds of Rhodes grass have very low germination rate in both experiments while husk removal and pre-soaking in KNO3 solution improved performance in new as well as older seed stocks. However, it is recommended that further stu with comprehensive information on the period required in months to achieve maximum possible germination rate; the interactive effects of husking, chemical treatment, and genotype; and the underlying mechanism of dormancy.

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Mechanism of the glumes in inhibiting seed germination of Leymus chinensis (Trin.) Tzvel. (Poaceae)

Cited by 14 publications

References 17 publications

Overcoming physiological dormancy in seeds of Triodia (Poaceae) to improve restoration in the arid zone

Overcoming physiological dormancy in seeds of Triodia (Poaceae) to improve restoration in the arid zone

Increasing the germination envelope under water stress improves seedling emergence in two dominant grass species across different pulse rainfall events

Storage period, husking and seed treatment effects on germination of Rhodes grass (<i>Chloris gayana</i> L.) seeds

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