The canonical RdDM pathway mediates the control of seed germination timing under salinity

Plant performance is commonly temperature-dependent so that this performance could vary with climate warming. Seeds are among the most important propagules of plants, and seed traits strongly influence plant invasion success. Therefore, understanding seed traits under climate warming is useful for predicting invasion risks. To this end, we conducted a warming experiment with an infrared radiator and examined the effects of 5 years warming (approximately 2°C above ambient) on the seed quality and subsequent germination of Solidago canadensis from North America, where it is native (24 native populations), and from China, where it is invasive (29 invasive populations). Temperature regimes (i.e., ambient vs. warming) interacted with population sources (i.e., native vs. invasive) to significantly influence seed germination, but not thousand-seed mass. Warming significantly advanced the seed germination timing of native S. canadensis populations and increased their seed germination rate; warming did not influence the germination timing but decreased the germination rate of invasive S. canadensis populations. Across two temperature regimes combined, 24 native S. canadensis populations had smaller seeds, later germination timing, and lower germination rate than 29 invasive S. canadensis populations. These findings suggest that climate warming could facilitate the seed germination of native but not invasive populations. Our data also highlight that invasive populations might be more successful than native populations due to better seed quality and faster and higher seed germination.

Download Full-text

Patterns of amplified restriction fragment polymorphism in the germination of Festuca hallii seeds

Seed Science Research ◽

10.1017/s0960258510000188 ◽

2010 ◽

Vol 20 (3) ◽

pp. 153-161

Author(s):

Jie Qiu ◽

Yuguang Bai ◽

Yong-Bi Fu ◽

John F. Wilmshurst

Keyword(s):

Genetic Variation ◽

Seed Germination ◽

Genetic Differentiation ◽

Restriction Fragment ◽

Population Based ◽

Canadian Prairie ◽

Band Frequency ◽

Restriction Fragment Polymorphism ◽

Festuca Hallii ◽

Germination Timing

AbstractTiming of seed germination influences plant lifetime fitness and can affect the ability of plant populations to colonize and persist in changing environments. However, the genetic variation of the seed germination response remains poorly understood. The amplified restriction fragment polymorphism (AFLP) technique was applied to characterize the genetic variation of germinated seeds collected from three Festuca hallii populations in the Canadian prairie. Three subpopulations with early, intermediate and late germination were identified from each population, based on germination tests at 10, 15 and 20°C in controlled growth chambers. Three AFLP primer pairs were employed to screen a total of 540 assayed seedling samples and 188 polymorphic AFLP bands were scored for each sample. None of the assayed AFLP bands were significantly associated with seed germination, but marked differences in estimates of mean band frequency were observed for various groups of germinating seeds under different test temperatures. Partitioning of the total AFLP variation showed that 5.9% AFLP variation was present among seeds of the three populations, 0.3% among seeds of three germination subpopulations, and 0.5% among seeds grouped for germination temperature. Genetic differentiation was significant among 27 groups of seeds representing population, germination timing and test temperature. Subpopulations with early and intermediate germination shared similar genetic backgrounds and were genetically differentiated from the late germination subpopulation. These results indicate that seed genotypes respond slightly differently to environmental variation, resulting in significant but weak genetic differentiation in the germination of F. hallii seeds. Implications for plant establishment and fescue restoration are discussed.

Download Full-text

Modelling seed germination response to temperature inEucalyptusL'Her. (Myrtaceae) species in the context of global warming

Seed Science Research ◽

10.1017/s0960258517000010 ◽

2017 ◽

Vol 27 (2) ◽

pp. 99-109 ◽

Cited By ~ 7

Author(s):

Anne Cochrane

Keyword(s):

Life History ◽

Seed Germination ◽

Western Australia ◽

Thermal Tolerance ◽

Greenhouse Gas Emission ◽

Climate Scenario ◽

Wet Season ◽

Physiological Tolerance ◽

Species Vulnerability ◽

Germination Timing

AbstractSeed germination is vital for persistence of many plant species, and is linked to local environmental conditions. Small increases in temperature during this critical life history transition may threaten species by altering germination timing and success. Such changes in turn may influence population dynamics, community composition and the geographic distributions of species. In this investigation, a bi-directional temperature gradient plate was used to profile thermal constraints for germination in 26 common, threatened and geographically restrictedEucalyptusspecies (Myrtaceae) from southern Western Australia. These observed data were used to populate models to predict optimum germination responses (mean time to germination, germination timing and success) under current (1950–2000 averages) and future (2070 high greenhouse gas emission climate scenario) mean monthly minimum and maximum temperatures. Many species demonstrated wide physiological tolerance for high germination temperatures and an ability to germinate outside current and forecast future autumn–winter wet season temperatures, suggesting that climatic distribution is a poor proxy for thermal tolerance forEucalyptusseed germination. Germination for some species is predicted to decline under forecast conditions, but the majority will maintain or improve germination particularly during the cooler winter months of the year. Although thermal tolerance may benefit persistence of manyEucalyptusspecies in southern Western Australia as warming becomes more severe, large rainfall declines are also forecast which may prove more detrimental to plant survival. Nonetheless, this framework has the potential to identify seed resilience to heat stress in an early life history phase and hence species vulnerability to one characteristic of forecast environmental change.

Download Full-text

Fluctuating natural selection accounts for the evolution of diversification bet hedging

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2008.1920 ◽

2009 ◽

Vol 276 (1664) ◽

pp. 1987-1992 ◽

Cited By ~ 95

Author(s):

Andrew M. Simons

Keyword(s):

Seed Germination ◽

Time Scales ◽

Geometric Mean ◽

Empirical Support ◽

Natural Environments ◽

Bet Hedging ◽

Fluctuating Selection ◽

Quantitative Test ◽

Geometric Mean Fitness ◽

Germination Timing

Natural environments are characterized by unpredictability over all time scales. This stochasticity is expected on theoretical grounds to result in the evolution of ‘bet-hedging’ traits that maximize the long term, or geometric mean fitness even though such traits do not maximize fitness over shorter time scales. The geometric mean principle is thus central to our interpretation of optimality and adaptation; however, quantitative empirical support for bet hedging is lacking. Here, I report a quantitative test using the timing of seed germination—a model diversification bet-hedging trait—in Lobelia inflata under field conditions. In a phenotypic manipulation study, I find the magnitude of fluctuating selection acting on seed germination timing—across 70 intervals throughout five seasons—to be extreme: fitness functions for survival are complex and multimodal within seasons and significantly dissimilar among seasons. I confirm that the observed magnitude of fluctuating selection is sufficient to account for the degree of diversification behaviour characteristic of individuals of this species. The geometric mean principle has been known to economic theory for over two centuries; this study now provides a quantitative test of optimality of a bet-hedging trait in nature.

Download Full-text

THE EVOLUTIONARY ECOLOGY OF SEED GERMINATION OF ARABIDOPSIS THALIANA: VARIABLE NATURAL SELECTION ON GERMINATION TIMING

Evolution ◽

10.1554/04-418 ◽

2005 ◽

Vol 59 (4) ◽

pp. 758 ◽

Cited By ~ 21

Author(s):

Kathleen Donohue ◽

Lisa Dorn ◽

Converse Griffith ◽

EunSuk Kim ◽

Anna Aguilera ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Natural Selection ◽

Seed Germination ◽

Evolutionary Ecology ◽

Germination Timing

Download Full-text

Quantifying the oxygen sensitivity of seed germination using a population-based threshold model

Seed Science Research ◽

10.1017/s0960258507657389 ◽

2007 ◽

Vol 17 (1) ◽

pp. 33-43 ◽

Cited By ~ 23

Author(s):

Kent J. Bradford ◽

Daniel Côme ◽

Françoise Corbineau

Keyword(s):

Standard Deviation ◽

Seed Germination ◽

Time Constant ◽

Threshold Model ◽

Seed Priming ◽

Population Based ◽

Physiological Status ◽

Wide Range ◽

Time Courses ◽

Germination Timing

AbstractSeeds vary widely in the sensitivity of germination to oxygen (O2) partial pressure, depending upon the species, temperature, dormancy state and physiological status of the seeds. Most analyses of the O2 sensitivity of germination have focused on final germination percentages and estimated the O2 percentage in air that is required to reduce germination to a given percentage (usually 50%). In contrast, we have applied a population-based threshold model utilizing time courses of germination to quantify three parameters related to seed germination sensitivity to O2 availability: the median base (or threshold) O2 percentage, the standard deviation of O2 thresholds among seeds in the population, and an oxygen–time constant that relates O2 percentage to germination timing. The model fits germination responses accurately across a wide range of O2 concentrations. The response to O2 was logarithmic in all cases, with the O2 percentage required for 50% germination ranging from 21% to as low as 0.005%, depending upon the species, the temperature and the seed dormancy level. Modelling indicated that some seeds can adapt to low O2 percentages and shift their thresholds to lower values over time. Lower temperatures decreased the minimum O2 threshold, as did after-ripening. Seed priming generally reduced the oxygen–time constant and increased the standard deviation of germination responses, but had relatively little effect on the O2 sensitivity per se. The population-based threshold model can be used to quantify the O2 sensitivity of seed germination and to predict germination rates and percentages when O2 availability is limiting.

Download Full-text

The effect of soil inoculants on seed germination of native and invasive species

Botany ◽

10.1139/cjb-2016-0248 ◽

2017 ◽

Vol 95 (5) ◽

pp. 469-480 ◽

Cited By ~ 6

Author(s):

Bailey J. Balshor ◽

Matthew S. Garrambone ◽

Paige Austin ◽

Kathleen R. Balazs ◽

Claudia Weihe ◽

...

Keyword(s):

Invasive Species ◽

Seed Germination ◽

Native Species ◽

Seed Mass ◽

Complex Process ◽

Percent Germination ◽

Soil Inoculant ◽

Germination Timing ◽

Native Shrubs ◽

Different Response

Successful reintroduction of native species through ecological restoration requires understanding the complex process of seed germination. Soil microbes play an important role in promoting native establishment and are often added to restoration sites during seed sowing. We tested the role of soil- and lab-grown bacterial inoculants on germination timing and percent germination for 19 species of plants commonly found in coastal California. Each species exhibited a different response to the inoculant treatments, but overall time-to-germination was longer and percent germination was lower with the soil inoculant compared with the control or other treatments. The invasive species in our study had the highest percent germination of all species and germinated faster than all native shrubs. Germination timing was negatively correlated with percent germination and with seed mass. Our results suggest that lab-grown inoculant and chemical treatment are effective at increasing germination in some native species, whereas soil inoculant is not. Given differences in germination timing between native and invasive species, restoration practitioners could consider using herbicide to treat areas seeded with native shrubs immediately following germination of invasive species without harming most natives, although germination timing and herbicides need further study in relation to microbial effects on seed germination.

Download Full-text

Physiological and environmental control of seed germination timing in Mediterranean mountain populations of Gundelia tournefortii

Plant Growth Regulation ◽

10.1007/s10725-021-00717-5 ◽

2021 ◽

Author(s):

Efisio Mattana ◽

Pablo Gómez-Barreiro ◽

Nizar Youssef Hani ◽

Khaled Abulaila ◽

Tiziana Ulian

Keyword(s):

Seed Germination ◽

Environmental Control ◽

Seed Morphology ◽

East Mediterranean ◽

Control Seed ◽

High Germination ◽

Edible Species ◽

Mediterranean Mountains ◽

Puncture Force ◽

Germination Timing

AbstractFruit and seed morphology interact with embryo physiology and environmental conditions to control seed germination timing. This interaction plays a pivotal role in ecosystems with narrow windows for seedling establishment, such as the Mediterranean mountains. In this study, we investigated the germination responses of the secondary capitula (disseminules) of Gundelia tournefortii from East Mediterranean mountain populations. When incubated at 15 °C, intact capitula did not reach 20% of final germination, with or without the addition in the germination substrate of GA3 (250 mg L−1), while extracted fruits reached 50% of germination, which increased to ca. 70% when treated with GA3. Cold stratification enhanced final germination of the capitula at 15 °C to ca. 65%, although almost half of the initially sown capitula germinated during the second month of stratification at 5 °C. During the stratification at 5 °C, peak puncture force needed to pierce the basal part of the capitula decreased linearly and capitula started germinating after one month, which corresponded to a peak puncture force of 0.41–0.35 N. These findings highlight the presence of mechanical and hormonal components of physiological seed dormancy. The morphology of the disseminules controls seed germination timing, by interacting with cold winter temperatures and starting seed germination only in early winter. These findings not only provide new insights on the reproduction from seeds of this plant, but by highlighting high germination of cold-stratified intact capitula, can also support plant propagation programmes for this key wild edible species, very important for food security and the livelihoods of local communities in the East Mediterranean region.

Download Full-text