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.

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.

scholarly journals Practical Methods for Breaking Seed Dormancy in a Wild Ornamental Tulip Species Tulipa thianschanica Regel

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1765
Author(s):  
Wei Zhang ◽  
Lian-Wei Qu ◽  
Jun Zhao ◽  
Li Xue ◽  
Han-Ping Dai ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Combined Treatment ◽  
Individual Treatment ◽  
Cold Stratification ◽  
Slight Effect ◽  
Sowing Depth ◽  
Physiological Dormancy ◽  
Commercial Breeding ◽  
Breaking Seed Dormancy

The innate physiological dormancy of Tulipa thianschanica seeds ensures its survival and regeneration in the natural environment. However, the low percentage of germination restricts the establishment of its population and commercial breeding. To develop effective ways to break dormancy and improve germination, some important factors of seed germination of T. thianschanica were tested, including temperature, gibberellin (GA3) and/or kinetin (KT), cold stratification and sowing depth. The percentage of germination was as high as 80.7% at a constant temperature of 4 °C, followed by 55.6% at a fluctuating temperature of 4/16 °C, and almost no seeds germinated at 16 °C, 20 °C and 16/20 °C. Treatment with exogenous GA3 significantly improved the germination of seeds, but KT had a slight effect on the germination of T. thianschanica seeds. The combined treatment of GA3 and KT was more effective at enhancing seed germination than any individual treatment, and the optimal hormone concentration for the germination of T. thianschanica seeds was 100 mg/L GA3 + 10 mg/L KT. In addition, it took at least 20 days of cold stratification to break the seed dormancy of T. thianschanica. The emergence of T. thianschanica seedlings was the highest with 82.4% at a sowing depth of 1.5 cm, and it decreased significantly at a depth of >3.0 cm. This study provides information on methods to break dormancy and promote the germination of T. thianschanica seeds.

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 Factors Affecting Seed Dormancy and Germination of Greater Bur-Parsley (Turgenia latifolia)

2018 ◽  
Vol 36 ◽  
Author(s):  
M. REZVANI ◽  
S.A. SADATIAN ◽  
H. NIKKHAHKOUCHAKSARAEI
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Seedling Emergence ◽  
Potassium Nitrate ◽  
Germination Percentage ◽  
Dormancy Breaking ◽  
Planting Depth ◽  
Factors Affecting ◽  
Drought And Salt Stresses

ABSTRACT: Our knowledge about seed dormancy breaking and environmental factors affecting seed germination of greater bur-parsley (Turgenia latifolia) is restricted. This study has addressed some seed dormancy breaking techniques, including different concentrations of gibberellic acid (GA3) and potassium nitrate (KNO3), leaching duration, physical scarification as well as some environmental factors effective on seed germination such as salt and drought stresses, pH and seed planting depth. Seed germination was promoted with lower concentrations of KNO3 (0.01 to 0.02 g L-1), while higher concentrations reduced germination percentage. Seed dormancy was declined by low concentrations of GA3 up to 100 ppm. Seeds of greater bur-parsley germinated in a range of pH from 3 to 7. With enhancement of drought and salt stresses, seed germination decreased. Also, there was no seed germination in a high level of stresses. Seedling emergence reduced as planting depth increased. Use of GA3, KNO3, leaching and physical scarification had a positive effect on seed dormancy breaking of greater bur-parsley. The information from the study increases our knowledge about seed dormancy breaking techniques, response of germination to drought and salt stresses and also determination of distribution regions of greater bur-parsley in the future.

Effects of Chemical Treatments on Seed Germination of Zoysia (Zoysia japonica Steud.)

2013 ◽  
Vol 850-851 ◽  
pp. 1295-1302
Author(s):  
Li Li Qian ◽  
Shan Wang ◽  
Kai Ye ◽  
Cheng Fang
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Treatment Time ◽  
Warm Season ◽  
Dormancy Breaking ◽  
Zoysia Japonica ◽  
Chemical Treatments ◽  
Chemical Agents ◽  
The Right

Zoysia (Zoysia japonica Steud.) is a warm-season turf grass, which possess seed coat-imposed dormancy that hampers germination. The objective of the present study was to determine the most effective methods in breaking the seed dormancy of zoysia. This experiment was used to find the right concentration and treatment time. KOH, NaOH, C3H6O, and H2SO4solutions are the four kinds of chemical agents used which were evaluated and sixty four treatments were conducted. The results indicated that all chemical agents investigated can successfully remove glumes and promote seed germination of zoysia under certain concentrations and treatment times. The best method for seed dormancy breaking in zoysia was 20% KOH solution for 30 min.

scholarly journals Physiology of Breaking Seed Dormancy and Increasing Seed Germination in Senna alata (L) Roxb Seeds in Nigeria

2020 ◽  
Vol 15 (1) ◽  
pp. 1-6
Author(s):  
Vincent Ishola Esa ◽  
Taiwo Ayanniyin Ayanbamiji ◽  
Ayobami Daniel Abo
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Breaking Seed Dormancy ◽  
Senna Alata

scholarly journals Methods of breaking seed dormancy for ornamental passion fruit species

2017 ◽  
Vol 23 (1) ◽  
pp. 72 ◽  
Author(s):  
Thalita Neves Marostega ◽  
Petterson Baptista Da Luz ◽  
Armando Reis Tavares ◽  
Leonarda Grillo Neves ◽  
Severino De Paiva Sobrinho
Keyword(s):  
Experimental Design ◽  
Seed Germination ◽  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Potassium Nitrate ◽  
Plant Production ◽  
Commercial Plant ◽  
Fruit Species ◽  
Breaking Seed Dormancy ◽  
And Control

The Passiflora L. genus covers a diversity of wild species with ornamental potential, especially due to the intrinsic beauty of its exotic flowers, flowering more than once a year and the lush foliage. However, Passiflora seeds present dormancy complicating seed germination and the establishment of commercial plant production with species with high ornamental potential. This study was conducted to determine the best pre-germination treatments to overcome seed dormancy for Passiflora quadrangularis, P. nitida, P. foetida, P. eichleriana, P. alata, P. cincinnata, P. mucronata, P. micropetala, P. suberosa, P. morifolia and P. tenuifila. The experimental design was completely randomized, with five treatments and four replicates, with 25 seeds per plot. Pre-germination treatments were: seeds soaked in 1,000 mg L- 1 GA3 (gibberellic acid) for 6 hours, seeds soaked in 0.2 % KNO3 (potassium nitrate) for 24 hours, seeds soaked in 1 % KNO3 for 24 hours, partial seedcoat scarification with sandpaper number 120 and control (seeds untreated). Percentage of germination, germination velocity index and radicle length were evaluated for all species. The results showed that GA3 was effective to overcome seed dormancy in P. suberosa (86%), P. morifolia (68 %) and P. tenuifila (54%). KNO3 1% had significant effect on overcoming dormancy in seeds of P. eichleriana (66%) and scarification with sandpaper increased seed germination of P. micropetala (38%).

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