Timing of seed germination in two alpine herbs on the southeastern Tibetan plateau: the role of seed dormancy and annual dormancy cycling in soil

2017 ◽  
Vol 421 (1-2) ◽  
pp. 465-476 ◽  
Author(s):  
Guoyan Wang ◽  
Carol C. Baskin ◽  
Jerry M. Baskin ◽  
Xuejun Yang ◽  
Guofang Liu ◽  
...  
Keyword(s):  
Seed Germination ◽  
Tibetan Plateau ◽  
Seed Dormancy ◽  
Southeastern Tibetan Plateau

scholarly journals Role of the Early Miocene Jinhe-Qinghe Thrust Belt in the building of the Southeastern Tibetan Plateau topography

2021 ◽  
Vol 811 ◽  
pp. 228871
Author(s):  
Chengyu Zhu ◽  
Guocan Wang ◽  
Philippe Hervé Leloup ◽  
Kai Cao ◽  
Gweltaz Mahéo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Early Miocene ◽  
Thrust Belt ◽  
Southeastern Tibetan Plateau

scholarly journals Role of the Early Miocene Jinhe-Qinghe Thrust Belt in the building of the Southeastern Tibetan Plateau topography

2020 ◽  
Author(s):  
Chengyu Zhu ◽  
Guo-Can Wang ◽  
Philippe Hervé Leloup ◽  
Kai Cao ◽  
Gweltaz Mahéo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Early Miocene ◽  
Thrust Belt ◽  
Southeastern Tibetan Plateau

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

2017 ◽  
Vol 39 (2) ◽  
pp. 133-141
Author(s):  
Nicolás Glison ◽  
Luis Viega ◽  
Pablo Speranza
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Water Uptake ◽  
Intraspecific Variability ◽  
Paspalum Dilatatum ◽  
Stand Establishment ◽  
External Covering

Abstract: 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.

Role of seed coat in regulation of seed dormancy in houndstongue (Cynoglossum officinale)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Elisa Stabell ◽  
Mahesh K. Upadhyaya ◽  
Brian E. Ellis
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Elevated Level ◽  
Quantitative Relationship ◽  
Total Phenolic ◽  
Cynoglossum Officinale ◽  
Saturated Water ◽  
Stimulation Of

To understand the role of the seed coat in regulation of houndstongue seed dormancy, the effects of manipulation of seed coat integrity on seed germination and O2uptake were studied. The results suggest that the seed coat of this weed regulates dormancy in part by interfering with the diffusion of O2to the embryo. Scanning electron microscopy showed a network of ridges on the seed coat surface that were partially dissolved following 1.5 min of sulphuric acid scarification. Mechanical scarification removed fragments of the seed coat surface. Both scarification treatments stimulated seed germination. Supply of an elevated level of O2also stimulated seed germination. O2uptake by seeds imbibed in O2-saturated water was 150% higher than that for seeds imbibed in air-saturated water. Although all treatments that stimulated seed germination also stimulated O2uptake, there was a lack of a consistent, quantitative relationship between increases in O2uptake and seed germination in various experiments. This suggests that limitation of O2availability to the embryo is not the only factor involved in regulation of houndstongue seed dormancy by the seed coat. Mechanical restriction of embryo expansion by the seed coat may also be important. Methanol-insoluble phenolics constituted < 1% of the total phenolic pool in the embryo. Their potential oxidation could not account for more than a small fraction of the previously reported massive stimulation of O2uptake by the embryo upon decoating. The present O2uptake and seed germination studies indicate that not all of the large increase in O2uptake following decoating is essential for houndstongue seed germination.

scholarly journals Heat shock and plant leachates regulate seed germination of the endangered carnivorous plant <i>Drosophyllum lusitanicum</i>

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Susana Gómez-González ◽  
Maria Paniw ◽  
Kamila Antunes ◽  
Fernando Ojeda
Keyword(s):  
Heat Shock ◽  
Seed Germination ◽  
Seed Dormancy ◽  
Fire Ecology ◽  
Germination Rate ◽  
Natural Populations ◽  
Seed Viability ◽  
Carnivorous Plant ◽  
In Fire

Abstract. In fire-prone ecosystems, many plant species have specialized mechanisms of seed dormancy that ensure a successful recruitment after fire. A well-documented mechanism is the germination stimulated by fire-related cues, such as heat shock and smoke. However, less is known about the role of inhibitory germination signals (e.g. allelopathy) in regulating post-fire recruitment. Plant leachates derived from the unburned vegetation can enforce dormancy by means of allelopathic compounds, acting as a signal of unfavourable (highly competitive) niche for germination in pyrophyte species. Here, we assessed the separate effects of heat shock and plant leachates on seed germination of Drosophyllum lusitanicum, an endangered carnivorous plant endemic to Mediterranean fire-prone heathlands. We performed a germination experiment in which seeds were subjected to three treatments: (1) 5 min at 100 ∘C, (2) watering with plant leachate, and (3) control. Germination rate and seed viability was determined after 63 days. Heat shock stimulated seed germination in D. lusitanicum while plant leachates had inhibitory germination effects without reducing seed viability. Thus, both positive and negative signals could be involved in its successful post-fire recruitment. Fire would break seed dormancy and stimulate seed germination of D. lusitanicum through high temperatures, but also by eliminating allelochemical compounds from the soil. These results help to understand the population dynamics patterns found for D. lusitanicum in natural populations, and highlight the role of fire in the ecology and conservation of this endangered species. Seed dormancy imposed by plant-derived leachates as an adaptive mechanism should be considered more in fire ecology theory.

Heat shock, smoke and darkness: partner cues in promoting seed germination in Epacris tasmanica (Epacridaceae)

2000 ◽  
Vol 48 (5) ◽  
pp. 603 ◽  
Author(s):  
Craig A. Gilmour ◽  
Ronald K. Crowden ◽  
Anthony Koutoulis
Keyword(s):  
Heat Shock ◽  
Seed Germination ◽  
Effective Treatment ◽  
Seed Dormancy ◽  
Inhibitory Effect ◽  
Dormancy Breaking ◽  
Seasonal Drought ◽  
Breaking Seed Dormancy ◽  
Tasmanian Endemic

The Epacridaceae is one of the families that dominate Australian heathlands, environments prone to disturbance events such as fire and seasonal drought. To investigate the role of fire-related cues in breaking seed-dormancy mechanisms in the Epacridaceae, the influences of heat shock, darkness, direct smoke and varying concentrations of aqueous smoke solutions (5, 10 and 100%) on seed germination of the Tasmanian endemic Epacris tasmanica were examined. A small fraction (5.3%) of non-dormant E. tasmanica seed could germinate in the absence of fire-related cues. The most effective treatment for promoting seed germination was direct smoke (74.67%); however, germination with direct smoke was delayed by about two weeks when compared to other significant treatments, suggesting an initial inhibitory effect. Significant interactions were recorded between all classes of treatments (heat shock, darkness and smoke solutions), with treatments acting sequentially and additively to promote germination. The most effective combinatory treatment tested was 5% smoked water (5%S) in conjunction with darkness (D) and heat-shock (H) treatments (5%SDH), which raised germination levels to 49%. In the absence of heat shock, darkness and various concentrations of smoked water had no significant effect on seed germination. The 5%SDH treatment promoted seed germination significantly also in two wet-heathland (E. lanuginosa (42.7%) and E. obtusifolia (64.7%)) and two dry-heathland Epacris species (the Tasmanian endemic E. apsleyensis (72.7%) and the rare mainland Australian E. purpurascens (75%)). The results of this study indicate that fire-related dormancy-breaking cues act synergistically in promoting seed germination in E. tasmanica and suggesting that their level of influence may reflect the ecology of Epacris species.

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