Thermal thresholds for seed germination in Mediterranean species are higher in mountain compared with lowland areas

2018 ◽  
Vol 29 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Rosangela Picciau ◽  
Hugh W. Pritchard ◽  
Efisio Mattana ◽  
Gianluigi Bacchetta
Keyword(s):  
Seed Germination ◽  
Sea Level ◽  
Dormancy Breaking ◽  
Mediterranean Species ◽  
Thermal Thresholds ◽  
Data Loggers ◽  
Soil Temperatures ◽  
Germination Timing ◽  
Positive Effect ◽  
Neutral Effect

AbstractEach taxon is characterized by a temperature range over which seed germination is possible and this may vary in space and time in relation to climate and ecological conditions. We used thermal modelling to test the hypothesis that thermal thresholds for seed germination can predict germination timing of Mediterranean species along an altitudinal and environmental gradient. Seeds of 18 species were collected in Sardinia from sea level to 1810 m above sea level, and germination tests were carried out at a range of constant (5 to 25°C) and alternating (25/10°C) temperatures. Different dormancy-breaking treatments [gibberellic acid (GA3), cold (C) and warm (W) stratifications and dry after ripening (DAR)] were applied. The annual pattern of soil temperatures was recorded using 24 data-loggers buried close to the study species. The logged soil temperatures distinguished ‘Mediterranean lowland’ from ‘Mediterranean mountain’ species. Although germination was >50% in untreated seeds of most species, GA3 had a positive effect in all species. C either inhibited or had a neutral effect on germination, W did not enhanced seed germination, while DAR had a positive effect only in species from coastal environments. The thermal time constant (S) for 50% germination ranged from 22 to 357°Cd (degree days) above base temperatures (Tb) of –9 to 9°C, depending on species and treatments. Mediterranean lowland species had lower Tb values compared with upland species. This study revealed significant differences in germination thresholds of Mediterranean lowland and mountain species in relation to Tb and S that probably have an impact on germination timing in the field and niche competitiveness.

scholarly journals Effects of different treatments on seed dormancy breaking and germination in Acer cappadocicum Gleditsch var. cappadocicum

2020 ◽  
Vol 144 (3-4) ◽  
pp. 159-166
Author(s):  
Hanife Erdogan Genç ◽  
Ali Ömer Üçler
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Percentage ◽  
Growth Chamber ◽  
Dormancy Breaking ◽  
Seed Collection ◽  
Physiological Dormancy ◽  
Germination Value ◽  
Positive Effect ◽  
Collection Time

This study was carried out to determine effects of different pretreatment on seed germination and to overcome dormancy in Acer cappadocicum seeds. The seeds were collected in 2008 three times with aproximately 15-days intervals. In order to overcome dormancy, several germination treatments were applied. The treatments were (1) different seed collection time, (2)soaking in water, (3) cold-moist stratification and (4) GA<sub>3</sub> (gibberellic acid) application. The treated seeds were germinated in growing chamber at 5 <sup>0</sup>C and in greenhouse conditions. This research showed that seeds of Acer cappadocicum exhibit physiological dormancy and require stratification period to overcome seed dormancy. The highest germination percentage in the growing chamber subjected to GA<sub>3</sub> process after eight weeks of stratification treatment was 62 % for Acer cappadocicum seeds. The highest germination percentage in greenhouse was obtained with cold stratification after eight weeks (95 %). It was found out that GA<sub>3</sub> treatment had a significant effect on germination in growth chamber + 5 <sup>0</sup>C but GA<sub>3</sub> treatment didn’t have a significant effect on germination in greenhouse conditions. GA<sub>3</sub> treatment and soaking of unstratified seeds in water for 48 hr didn’t have any positive effect on germination value in greenhouse conditions. Although growth chamber and green house results both indicated that seed collection time did not seem to play a role as statistically on seed germination, Duncan’s test showed that the third seed collection time was in a different group.

Dormancy-breaking Studies on Echinacea angustifolia

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 456f-457 ◽  
Author(s):  
Ali O. Sari ◽  
Mario R. Morales ◽  
James E. Simon
Keyword(s):  
Native Americans ◽  
Seed Germination ◽  
Tap Water ◽  
The United States ◽  
Market Demand ◽  
Dormancy Breaking ◽  
Echinacea Angustifolia ◽  
Native Populations ◽  
Percent Germination ◽  
Dry Heating

Echinacea is a medicinal plant native to North America. It was used extensively by native Americans in the treatment of their ailments. It is presently one of the most popular medicinal plants in the United States. Its popularity has created a large market demand for the roots and foliage of the plant. The gathering of echinacea from the wild is leading to the reduction of native populations and the destruction of its genetic diversity. Cultivation of medicinal echinaceas is hindered by a low seed germination. Dormancy breaking studies were done on freshly harvested seeds of Echinacea angustifolia. Seed lots were placed under light at a constant temperature of 25 °C and at alternate temperatures of 25/15 °C for 14/10 h, respectively. Germination was more rapid and uniform and percent germination higher at 25 °C than at 25/15 °C. Seed tap-water soaking, dry heating, and sharp heating alteration did not increase germination. The application of 1.0 mM ethephon (2-chloroethylphosphoric acid) increased seed germination to 94% at 25 °C and 86% at 25/15 °C. Untreated seeds gave 65% germination at 25 °C and 11% at 25/15 °C. The application of 2500 mg·L–1 and 3500 mg·L–1 of GA to dry seeds and 2500 mg·L–1 to seeds that have been soaked under tap water and then dried increased germination to 82%, 83%, and 83% at 25 °C and 64%, 78%, and 64% at 25/15 °C, respectively.

scholarly journals Effect of dry heat treatment along with some dormancy breaking chemicals on oil palm seed germination

2017 ◽  
Vol 112 ◽  
pp. 489-493
Author(s):  
K.M. Tabi ◽  
G.F. Ngando Ebongue ◽  
G.N. Ntsomboh ◽  
E. Youmbi
Keyword(s):  
Heat Treatment ◽  
Seed Germination ◽  
Oil Palm ◽  
Dormancy Breaking ◽  
Dry Heat ◽  
Dry Heat Treatment

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.

scholarly journals Seed Germination in Cistus ladanifer: Heat Shock, Physical Dormancy, Soil Temperatures and Significance to Natural Regeneration

Plants ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 63 ◽  
Author(s):  
Luís Silva Dias ◽  
Isabel Pires Pereira ◽  
Alexandra Soveral Dias
Keyword(s):  
Heat Shock ◽  
Seed Germination ◽  
Natural Regeneration ◽  
Heat Load ◽  
Fire Effects ◽  
Ground Vegetation ◽  
Cistus Ladanifer ◽  
Physical Dormancy ◽  
Soil Temperatures ◽  
Heat Loads

Seeds of Cistus ladanifer experience bursts of germination following fires. The effects of heat shock from 10 °C to 150 °C on seed germination were investigated by final germination plus the number of days required for germination to start and finish, and symmetry of cumulative germination. The occurrence of physical dormancy in C. ladanifer seeds was investigated by a variety of methods, including imbibition, scanning electron microscopy (SEM) and light microscopy, and use of dyes. The significance of responses of C. ladanifer seeds to fires was investigated essentially by abstracting existing literature and by using fire effects models and simulations. Parameters of germination were variously affected by heat treatments—positively in the range 80–100 °C, negatively above 130 °C. Non-dormancy was consistently found in about 30% of seeds but no evidence was obtained to support the existence of physical dormancy in the dormant fraction of C. ladanifer seeds. Two complementary processes seem to be in place in seeds response to fire. A direct fire-driven increase in germination of virtually all seeds in response to the appropriate heat load produced by fire or, in the absence of such heat loads, the germination of the non-dormant fraction provided that above-ground vegetation burns.

SEED GERMINATION TIMING PATTERNS IN INTERMOUNTAINPENSTEMON(SCROPHULARIACEAE)

1995 ◽  
Vol 82 (3) ◽  
pp. 377-389 ◽  
Author(s):  
S. E. Meyer ◽  
S. G. Kitchen ◽  
S. L. Carlson
Keyword(s):  
Seed Germination ◽  
Germination Timing

scholarly journals Impact of Ag Nanoparticles on Seed Germination and Seedling Growth of Green Beans in Normal and Chill Temperatures

Agriculture ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 312 ◽  
Author(s):  
Roman Prażak ◽  
Agata Święciło ◽  
Anna Krzepiłko ◽  
Sławomir Michałek ◽  
Marta Arczewska
Keyword(s):  
Seed Germination ◽  
Rhizobium Leguminosarum ◽  
Net Photosynthesis ◽  
Antimicrobial Effect ◽  
Dry Weight ◽  
Short Term ◽  
Green Beans ◽  
Low Concentrations ◽  
Microbial Preparation ◽  
Positive Effect

The study analysed the effect of silver nanoparticles (AgNPs) on seed germination, field emergence and the physiological parameters of seedlings of two bean cultivars, ‘Bali’ and ‘Delfina’, under normal and chill temperatures. AgNPs solutions (0.25, 1.25 and 2.5 mg dm−3) were applied together with the microbial preparation Nitragina (containing Rhizobium leguminosarum bv. phaseoli) on seeds as a short-term pre-sowing treatment. Low concentrations of AgNPs (0.25, 1.25 mg dm−3) had an immediate beneficial effect, resulting in fast and uniform germination in laboratory and field conditions, as well as a positive effect in the later stages of seedling development, manifested as an increase in the average seedling height, fresh and dry weight and net photosynthesis. Particularly, favourable effects were noted in suboptimal temperature conditions, suggesting that AgNPs activate plant mechanisms of tolerance to environmental stress. The highest concentration tested of AgNPs was not particularly effective for the plants but had a strong antimicrobial effect, which was beneficial in period of seed germination, but at the later stage of plant development was unfavourable probably due to disruption of symbiosis between the bean seedlings and rhizobia.

scholarly journals Fungicidal seed treatment on germination and seedling vigour of lentil var. BINA Masur-3

2017 ◽  
Vol 3 (1) ◽  
pp. 140-144
Author(s):  
A Rokib ◽  
MS Monjil
Keyword(s):  
Seed Germination ◽  
Root Length ◽  
Seed Treatment ◽  
Shoot Length ◽  
Seedling Vigour ◽  
Green House ◽  
Seed Pathology ◽  
Vigour Index ◽  
Positive Effect ◽  
Improve Seed Germination

Effectiveness of six fungicides viz., Provax-200 (Carboxin+Thiram), Bavistin DF (Carbendazim), Dithane M-45 (Mancozeb), Secure (Mancozeb+Fenamidone), Antracol (propineb) and Daconil (Chlorothalonil) were evaluated to improve seed germination and seedling vigour of lentil variety BINA Masur-3. The experiment was conducted in the Green House of Seed Pathology Centre, Bangladesh Agricultural University, Mymensingh. Positive effect of seed treatment with fungicides on seed germination and seedling vigour of lentil was recorded. At 20 DAS, increased seed germination over control was observed in treated seeds with Deconil (10.40%) and Antracol (10.00%) followed by Dithane M-45 (7.20%). Seeds treated with Deconil and Dithane M-45 produced seedlings with higher shoot length, root length and seedling vigour. At 20 DAS, higher percent increased vigour index over control was found in Dithane M-45 (24.64%) and Deconil (22.44%), respectively.Asian J. Med. Biol. Res. March 2017, 3(1): 140-144

Dormancy and cardinal temperatures for germination in seed from nine quinoa genotypes cultivated in Chile

2020 ◽  
Vol 18 (3) ◽  
pp. 143-148
Author(s):  
C. Ayala ◽  
F. Fuentes ◽  
S. Contreras
Keyword(s):  
Seed Germination ◽  
South America ◽  
Sea Level ◽  
Optimum Temperature ◽  
Maximum Percentage ◽  
Significant Difference ◽  
Physiological Dormancy ◽  
Breeding Programmes ◽  
Sprouting Resistance ◽  
Cardinal Temperatures

AbstractIn Chile, two quinoa ecotypes are grown: salares, also present in the highlands of Bolivia, and coastal, in central and southern areas of the country, at sea level. Genotypes from the coastal ecotype have characteristics that differentiate them from the most popular quinoa genotypes grown in the Andean Region of South America. The objectives of this study were: (1) to determine the cardinal temperatures for seed germination in quinoa genotypes from coastal and salares ecotypes cultivated in Chile, and (2) to study the presence of physiological dormancy (PD) in these genotypes. Seed germination from nine quinoa genotypes, two from salares and seven from coastal ecotypes, was evaluated in a gradient of temperatures between 11 and 42°C. Germination was also evaluated at 20°C at 0, 7 and 15 months from harvest. Results showed that seed from the nine genotypes germinated at their maximum percentage between 11 and 35°C. However, their faster germination occurred between 25 and 35°C. There was a significant difference between optimum temperature for germination between genotypes from coastal (28°C) and salares (30°C). An increase in germination rates after 7 months of storage suggested the presence of a non-deep PD in seeds from coastal ecotype, which may be useful to improve pre-harvest sprouting resistance in quinoa breeding programmes.

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