Mating system modulates degree of seed dormancy in Hypericum elodes L. (Hypericaceae)

2015 ◽  
Vol 25 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Angelino Carta ◽  
Gianni Bedini ◽  
Angela Giannotti ◽  
Laura Savio ◽  
Lorenzo Peruzzi
Keyword(s):  
Seed Germination ◽  
Mating System ◽  
Seed Dormancy ◽  
Evolutionary Dynamics ◽  
Mixed Mating ◽  
Primary Dormancy ◽  
Germination Response ◽  
Hand Pollination ◽  
Physiological Dormancy ◽  
Mixed Mating Strategy

AbstractKnowledge of processes responsible for seed dormancy can improve our understanding of the evolutionary dynamics of reproductive systems. We examined the influence of the breeding system on primary seed dormancy in Hypericum elodes, an Atlantic–European softwater pools specialist plant that exhibits a mixed mating strategy (the ability to both self- and cross-pollinate) to set seeds. Seeds were obtained through hand pollination treatments performed in a natural population during three consecutive years. Primary dormancy of seeds recovered from each pollination treatment was measured by analysing the seed germination response at dispersal and after various periods of cold stratification. While all collected seeds exhibited physiological dormancy, the degree of primary dormancy was associated with the pollination treatments. Weak and rapid loss of primary dormancy characterized seeds recovered from self-pollinated flowers, while stronger dormancy was found in seeds obtained from cross-pollination. The association between pollination treatments and primary dormancy indicated that the mating system should be considered as a source of variation for dormancy degree, proportional to self- and cross-pollinations (selfing rate) within populations of this species. These results suggest that by shedding seeds with various degrees of dormancy, plants may distribute their offspring across time by means of polymorphism in germination response. We conclude that seed germination alone is not an appropriate fitness measure for inbreeding depression estimates, unless dormancy is removed.

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 Applying seed germination studies in fire management for biodiversity conservation in south-eastern Australia

Web Ecology ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 47-54 ◽  
Author(s):  
T. D. Auld ◽  
M. K. J. Ooi
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Fire Regimes ◽  
Functional Trait ◽  
Strong Response ◽  
South Eastern ◽  
Germination Response ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Abstract. We examine the patterns of germination response to fire in the fire-prone flora of the Sydney basin, south-eastern Australia, using examples from several decades of research. The flora shows a strong response to fire-related germination cues. Most species show an interaction between heat and smoke, a number respond only to heat, whilst a few are likely to respond only to smoke. Many recruit in the first 12 months after fire and show no obvious seasonal patterns of recruitment, whilst several species have a strong seasonal germination requirement, even in this essentially aseasonal rainfall region. Key challenges remaining include designing future seed germination studies within the context of informing the germination response surface to smoke and heat interactions, and incorporation of the impact of varying soil moisture on seed germination post-fire, including its affect on resetting of seed dormancy. An understanding of the resilience of species to frequent fire also requires further work, to identify species and functional types most at risk. This work must ideally be integrated within the framework of the management of fire regimes that will change under a changing climate. We suggest that the functional classification of plant types in relation to fire could be enhanced by a consideration of both the type of germination response to fire (type of cues required) and the timing of the response (seasonally driven in response to seed dormancy characteristics, or independent of season). We provide a simplified version of such an addition to functional trait classification in relation to fire.

The great diversity in kinds of seed dormancy: a revision of the Nikolaeva–Baskin classification system for primary seed dormancy

2021 ◽  
pp. 1-29
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seed Dormancy ◽  
Seed Coat ◽  
Classification System ◽  
Primary Dormancy ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Whole Seed ◽  
Dust Seeds ◽  
Impermeable Seed Coat ◽  
Morphological Dormancy

Abstract This review provides a revised and expanded word-formula system of whole-seed primary dormancy classification that integrates the scheme of Nikolaeva with that of Baskin and Baskin. Notable changes include the following. (1) The number of named tiers (layers) in the classification hierarchy is increased from three to seven. (2) Formulae are provided for the known kinds of dormancy. (3) Seven subclasses of class morphological dormancy are designated: ‘dust seeds’ of mycoheterotrophs, holoparasites and autotrophs; diaspores of palms; and seeds with cryptogeal germination are new to the system. (4) Level non-deep physiological dormancy (PD) has been divided into two sublevels, each containing three types, and Type 6 is new to the system. (5) Subclass epicotyl PD with two levels, each with three types, has been added to class PD. (6) Level deep (regular) PD is divided into two types. (7) The simple and complex levels of class morphophysiological dormancy (MPD) have been expanded to 12 subclasses, 24 levels and 16 types. (8) Level non-deep simple epicotyl MPD with four types is added to the system. (9) Level deep simple regular epicotyl MPD is divided into four types. (10) Level deep simple double MPD is divided into two types. (11) Seeds with a water-impermeable seed coat in which the embryo-haustorium grows after germination (Canna) has been added to the class combinational dormancy. The hierarchical division of primary seed dormancy into many distinct categories highlights its great diversity and complexity at the whole-seed level, which can be expressed most accurately by dormancy formulae.

Rates of inbreeding in the androdioecious clam shrimp Eulimnadia texana

1999 ◽  
Vol 77 (9) ◽  
pp. 1402-1408 ◽  
Author(s):  
S C Weeks ◽  
N Zucker
Keyword(s):  
Mating System ◽  
Mating Systems ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Clam Shrimp ◽  
Inbreeding Rate ◽  
Male Frequency ◽  
Relationship Of ◽  
The Relationship ◽  
Mixed Mating Strategy

Populations of the clam shrimp Eulimnadia texana exhibit androdioecy, which is a mixed mating system composed of males and self-compatible hermaphrodites. It has been suggested that such mating systems are evolutionarily unstable, and yet most populations of E. texana appear to exhibit both outcrossing and selfing (a mixed mating strategy). Genetic and sex-ratio features of seven populations of these clam shrimp confirm that the majority of these populations show a mixture of inbreeding and outcrossing modes of reproduction. Additionally, we suggest that the relationship of inbreeding rate with male frequency indicates that mating is not random, as was suggested in a previous model of the mating system of E. texana.

Mechanisms of seed dormancy in an annual population of Zostera marina (eelgrass) from The Netherlands

1991 ◽  
Vol 69 (9) ◽  
pp. 1972-1976 ◽  
Author(s):  
Paul Garth Harrison
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Zostera Marina ◽  
Early Winter ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Annual Population ◽  
Effects Of Temperature ◽  
Viable Seeds

Mechanisms of dormancy of seeds from an annual population of the seagrass Zostera marina L. (eelgrass) in the SW Netherlands were investigated in the laboratory. Both physiological dormancy (a requirement for reduced salinity for germination) and physical dormancy (imposed by the seed coat) existed in recently shed seeds. Physiological seed dormancy was partly released in the seed bank by early winter, but physical dormancy lasted longer. By March seeds germinated quickly in the dark in full-strength seawater without artificial weakening of the seed coat. Viable seeds were released with coats that ranged from green (easily ruptured by the embryo) to brown (not easily ruptured); this variation may account for the occasional seedlings that appear during winter. No significant effects of temperature or light on germination were detected. A reexamination of the literature suggests that the observed variation in timing of germination in eelgrass populations may be a result of hitherto overlooked aspects of dormancy. Key words: eelgrass, seagrass, seed coat, seed dormancy, seed germination, Zostera marina.

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.

scholarly journals Promoting Germination in Ornamental Palm Seeds through Dormancy Alleviation

2009 ◽  
Vol 19 (4) ◽  
pp. 682-685 ◽  
Author(s):  
Hector E. Pérez
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Commercial Production ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Morphological Dormancy

Delayed and inconsistent seed germination often hampers commercial production of palms (Arecaceae). Such sporadic germination is commonly due to seed dormancy. Mature, freshly shed seeds of palms typically display a combination of underdeveloped embryos (morphological dormancy) and the inability of developing embryos to rupture covering structures (physiological dormancy). Fruit and seedcoats are capable of imbibing water. Therefore, dormancy due to water-impermeable fruit or seedcoats (physical dormancy) does not occur. Removal of embryo covering structures, such as the pericarp and operculum, followed by incubation under moist, warm (25–35 °C) conditions promotes rapid and complete germination. Complete burial in soil promotes germination of seeds in intact fruit of loulu palm (Pritchardia remota).

scholarly journals Seed-dormancy depth is partitioned more strongly among habitats than among species in tropical ephemerals

2018 ◽  
Vol 66 (3) ◽  
pp. 230 ◽  
Author(s):  
Adam T. Cross ◽  
Matthew D. Barrett ◽  
Shane R. Turner ◽  
Kingsley W. Dixon ◽  
David J. Merritt
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Soil Depth ◽  
Species Turnover ◽  
Sandy Soils ◽  
Fine Scale ◽  
Hydrological Conditions ◽  
Seed Biology ◽  
Germination Response ◽  
Habitat Variation

Seed biology in the annual herbaceous flora of ecologically stressful, seasonally wet habitats remains largely unexplored. Temporal and spatial species turnover among these habitats is often high, yet little is known about how fine-scale habitat variation drives intraspecific variability in seed dormancy depth and seed germination requirements. The present study characterised seed dormancy and investigated the germination biology of six closely related herbaceous annual species of Byblis from northern Australia. We assessed variation in the response of seeds of all species to temperature cues, as well as light and the naturally occurring germination stimulants karrikinolide (KAR1) and ethylene. We also examined intraspecific variation in germination response and seed-dormancy depth for three widely distributed species with overlapping distribution occurring in habitats with differing soil thermal and hydrological conditions. Seed germination in all six species was significantly increased by exposure to either KAR1 or ethylene, with this effect being amplified in two species (B. filifolia and B. rorida) following a period of warm, dry after-ripening. Seed-dormancy depth and the germination response of seeds to both KAR1 and ethylene were partitioned more strongly among habitats than among species. Populations on shallow (<20-cm soil depth) sandy soils produced less dormant seeds than did populations of the same species on deeper sandy soils (40+ cm) or on heavy cracking clays. The upper soil profile of shallow soil habitats was exposed to higher average temperatures, greater diurnal temperature fluctuation and greatly reduced moisture persistence compared with deeper soils. Fine-scale differences in the thermal and hydrological conditions of seasonally wet habitats appear to be strong drivers of dormancy depth in seeds of tropical Byblis. Widely distributed species exhibit high levels of plasticity in seed-dormancy depth and germination response among different habitats, with similar responses being observed for sympatric species. So as to fully understand species turnover in tropical ephemerals, future studies should examine phenotypic plasticity and the rate of local adaptation of seed traits in greater detail.

Dormancy breakage in Cercis chinensis seeds

2020 ◽  
Vol 100 (6) ◽  
pp. 666-673
Author(s):  
Yunpeng Gao ◽  
Mingwei Zhu ◽  
Qiuyue Ma ◽  
Shuxian Li
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Germination Percentage ◽  
Physical Dormancy ◽  
Optimal Method ◽  
Hard Seed ◽  
Positive Effects ◽  
Physiological Dormancy ◽  
Hard Seed Coat

The seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.

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