scholarly journals Comparative Germination Ecology of Two Endemic Rhaponticum Species (Asteraceae) in Different Climatic Zones of the Ligurian and Maritime Alps (Piedmont, Italy)

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 708
Author(s):  
Valentina Carasso ◽  
Marco Mucciarelli ◽  
Francesco Dovana ◽  
Jonas V Müller
Keyword(s):  
Seed Germination ◽  
Alpine Plants ◽  
General View ◽  
Maritime Alps ◽  
Closely Related Species ◽  
Climatic Zones ◽  
Plant Nursery ◽  
The Relationship ◽  
Germination Requirements ◽  
Germination Strategy

Comparative studies of seed germination of closely related taxa can help increase our understanding of the ecological limitations of cold-adapted plants and forecast how they might respond to global warming. No studies exist on the relationship between thermoclimatic belts that classify mountain life zones according to bioclimatic criteria and the germination strategy of alpine plants. The aim of this study was to assess this relationship using two closely related species growing in different thermotypes and to test whether their germination responses were related to the climate at natural sites. Fresh Rhaponticum bicknellii and R. scariosum seeds were cold stratified for 0, 30, 60 and 90 days and tested for germination at 10, 15 and 20 °C. At the same time, seed burial experiments were run in the field and in the plant nursery. A GLM analysis showed that the length of cold stratification affected significantly only the germination of R. bicknellii seeds, while increasing temperatures prompted germination in both species. We found that R. bicknellii adopts a drought-avoiding germination strategy, while R. scariosum germination is favoured by warm temperatures. Our findings support the general view that alpine plants do not share common germination requirements and that any conclusions should be interpreted from a biogeographical and bioclimatic perspective. Therefore, seed germination and seedling establishment of endemic alpine species can also be predicted by looking at the bioclimate of the species’ range.

scholarly journals TEMPERATURE - GERMINATION RESPONSES OF SUNFLOWER (Helianthus annuus L.) GENOTYPES / GERMINACION COMO REACCION A LA TEMPERATURA EN LOS GENOTIPOS DEL GIRASOL (Helianthus annuus L.) / GERMINATION - RÉACTION À LA TEMPÉRATURE DANS LES GÉNOTYPES DE TOURNESOL (Helianthus annuus L.)

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 97-104
Author(s):  
F.M. Khalifa ◽  
A.A. Schneiter ◽  
E.I. El Tayeb
Keyword(s):  
Seed Germination ◽  
Helianthus Annuus ◽  
Maximum Rate ◽  
Germination Rate ◽  
Thermal Time ◽  
Large Temperature ◽  
Climatic Zones ◽  
Helianthus Annuus L ◽  
Wide Range ◽  
Cardinal Temperature

SUMMARY Seed germination of six sunflower (Helianthus annuus L.) hybrids was investigated across a range of eleven constant temperatures between 5°C and 45°C. Large temperature differences in germination rate 1/t (d-1), cardinal temperature (°C) and thermal time θ (°cd) were observed among hybrids. Base temperatures (Tb) varied between 3.3°C and 6.7°C whereas maximum germination temperatures (Tm) varied between 41.7°C and 48.9°C. Final germination fraction was attained at 15°C - 25°C whereas the maximum rate of germination was attained at 30.4°C - 35.6°C. The maximum germination rate of hybrid USDA 894, the cultivar with the slowest germination rate, was only 50% of that of hybrid EX 47. The low Tb and high Tm of sunflower appear to be one of the factors which explain the successful adaptation of sunflower to a wide range of temperature. These findings are discussed in relation to the origin of the crop and its wide adaptations in diverse habitats and climatic zones.

scholarly journals Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Seed Viability ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Viability Test ◽  
Physiological Dormancy ◽  
Different Temperatures ◽  
Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

Inhibitory effect of rosemary essential oil, loaded in liposomes, on seed germination of Acacia saligna, an invasive species in Mediterranean ecosystems

Botany ◽  
2019 ◽  
Vol 97 (5) ◽  
pp. 283-291 ◽  
Author(s):  
Alfredo Maccioni ◽  
Andrea Santo ◽  
Danilo Falconieri ◽  
Alessandra Piras ◽  
Maria Manconi ◽  
...  
Keyword(s):  
Seed Germination ◽  
Essential Oil ◽  
Invasive Alien Species ◽  
Mediterranean Ecosystems ◽  
Inhibitory Effect ◽  
Acacia Saligna ◽  
Southwestern Australia ◽  
Rosmarinus Officinalis L ◽  
Mediterranean Plant ◽  
Germination Requirements

Acacia saligna (Labill.) Wendl. is native of southwestern Australia, but has been planted extensively in many areas of the world, including the Mediterranean region, becoming highly invasive especially in coastal habitats. The aim of this study was to test whether the indigenous Rosmarinus officinalis L. essential oil (EO), loaded in liposomes, can inhibit the seed germination of the invasive alien Acacia saligna. Variability in seed germination requirements and responses among populations were evaluated. Germination tests under light, at constant temperatures and three concentrations of rosemary EO were carried out. Among the examined factors, only the EO amount and temperature had a highly significant effect on seed germination. The lowest EO quantity did not show differences compared with the control, while the highest amount inhibited significantly seed germination of all populations at all the tested temperatures. No seed recovered the ability to germinate after the EO treatment with either of the two washing methods. Our results allowed us to identify the minimum amount of rosemary EO capable of inhibiting the seed germination of the invasive Acacia saligna. These results could be useful for the control of this invasive alien species, thus allowing the conservation of indigenous Mediterranean plant species and habitats.

scholarly journals The role of strigolactones in host specificity ofOrobancheandPhelipancheseed germination

2010 ◽  
Vol 21 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Mónica Fernández-Aparicio ◽  
Koichi Yoneyama ◽  
Diego Rubiales
Keyword(s):  
Seed Germination ◽  
Host Specificity ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Parasitic Plants ◽  
Parasitic Weed ◽  
Low Concentrations ◽  
Weedy Species ◽  
Germination Requirements

AbstractStrigolactones are apocarotenoids regulating shoot branching. They are also known to be exuded by plant roots at very low concentrations, stimulating hyphal branching of arbuscular mycorrhizal fungi and germination of root parasitic weed seeds. We show that strigolactones play a major role in host specificity ofOrobancheandPhelipanche(the broomrapes) seed germination. This observation confirms that host-derived germination stimulants are an important component determining the host specificity of these parasitic plants. Weedy broomrape species were less specialized in germination requirements than the non-weedy species except forO. cumanaandO. foetidavar.broteri. Similar results were obtained with the root exudates. Some species, such asP. aegyptiacaandO. minor, showed a broad spectrum of host specificity in terms of seed germination, which was stimulated by exudates from the majority of species tested, whereas others, such asO. cumana,O. hederaeandO. densiflora, were highly specific. Some species, such asO. minor,P. aegyptiacaandP. nana, were responsive to the three strigolactones studied, whereas others were induced by only one of them, or did not respond to them at all. The synthetic strigolactone analogue GR24, generally used as a standard for germination tests, was not effective on someOrobancheandPhelipanchespecies. Seeds of some species that did not respond to GR24 were induced to germinate in the presence of fabacyl acetate or strigol, confirming the role of strigolactones in host specificity.

Dormancy break and germination requirements in acorns of two bottomland Quercus species (Sect. Lobatae) of the eastern United States with references to ecology and phylogeny

2020 ◽  
Vol 30 (3) ◽  
pp. 199-205
Author(s):  
Tracy S. Hawkins
Keyword(s):  
United States ◽  
Cold Stratification ◽  
Eastern United States ◽  
Closely Related Species ◽  
Temperature Regimes ◽  
Quercus Species ◽  
Physiological Dormancy ◽  
Alternating Temperature ◽  
Incubation Temperatures ◽  
Germination Requirements

AbstractQuercus species are ecologically and economically important components of deciduous forests of the eastern United States. However, knowledge pertinent to a thorough understanding of acorn germination dynamics for these species is lacking. The objectives of this research were to determine dormancy break and germination requirements for acorns of two eastern United States bottomland species, Quercus nigra and Quercus phellos (Section Lobatae), and to present results within ecological and phylogenetic contexts. Three replicates of 50 acorns of each species received 0 (control), 6, 12 or 18 weeks of cold stratification, followed by incubation in alternating temperature regimes of 15/6, 20/10, 25/15 and 30/20°C. Eighteen weeks of cold stratification were not sufficient for dormancy break in Q. nigra acorns. Cumulative germination percentages at 4 weeks of incubation were ≥77%, but only in incubation temperatures of 25/15 and 30/20°C. Dormancy break in Q. phellos acorns was achieved with 18 weeks of cold stratification, and cumulative germination percentages were ≥87% at 4 weeks of incubation in all test temperature regimes. Gibberellic acid solutions were not an effective substitute for cold stratification in either species. Phylogenetically, Q. nigra and Q. phellos are closely related species and, ecologically, both grow in the same habitat. Acorns of both species possess deep physiological dormancy (PD), but dormancy break and germination requirements differ in acorns of these two Quercus species.

scholarly journals Myxospermous seed-mucilage quantity correlates with environmental gradients indicative of water-deficit stress: Plantago species as a model

2019 ◽  
Vol 446 (1-2) ◽  
pp. 343-356 ◽  
Author(s):  
António Teixeira ◽  
Pietro Iannetta ◽  
Kirsty Binnie ◽  
Tracy A. Valentine ◽  
Peter Toorop
Keyword(s):  
Seed Germination ◽  
Water Deficit ◽  
Stress Responses ◽  
Environmental Gradients ◽  
Seedling Survival ◽  
Water Deficit Stress ◽  
Arid Environments ◽  
Seedling Mortality ◽  
The Relationship ◽  
Seed Mucilage

Abstract Aims Myxospermous seed mucilage is multifunctional and is often found in seeds (or achenes) of species occupying arid environments where the trait may influence seed-dispersal and -germination of seeds. The seed mucilage may also enhance soil-water retention, −hydraulic conductivity and -stability. However, the relationship between seed mucilage quantity, seed germination and seedling traits across environmental gradients which determine water-deficit stress has not yet been ascertained. Methods Therefore, we characterised and tested the relationship between seed mucilage quantity, water-deficit stress responses of seeds and seedlings of 36 accessions of four different Plantago species (P. albicans L., P. coronopus L., P. lagopus L. and P. anceolata L.). These were gathered from six regions across Europe, which presented environmental gradients (of rainfall and temperature), and varying soil qualities. Results Seed mucilage was significantly greater in seeds of accessions experiencing: highest summer temperatures; lowest summer precipitation; soils of the same warm dry regions which had greater capacity to retain water within narrow pore spaces. Under water-deficit stress, seeds with most mucilage exhibited a lower base water potential for germination, suffered least seedling mortality and exhibited the most successful seedling development. Conclusions The findings indicate that seed mucilage quantity appeared as an ‘adaptive’ trait and there is a relationship between seed-mucilage quantity, seed germination plus seedling survival and development under environmental conditions of highest water-deficit stress.

The relationship between invasive alien species and main climatic zones

2010 ◽  
Vol 19 (9) ◽  
pp. 2485-2500 ◽  
Author(s):  
Juan Shi ◽  
You-Qing Luo ◽  
Fan Zhou ◽  
Ping He
Keyword(s):  
Alien Species ◽  
Invasive Alien Species ◽  
Climatic Zones ◽  
The Relationship
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