Phenotypic plasticity in seed germination relates differentially to overwintering and flowering temperatures

Abstract

Phenotypic plasticity in seed dormancy may allow plant species to cope with rapid environmental changes, such as climate warming. In controlled experimental settings, plasticity in dormancy has been found to relate to temperature during seed maturation, but this relationship has not been tested in field conditions. Here we analyse for the first time the variation in dormancy during five successive years in wild populations of the study species Centaurium somedanum, to determine how this variation is related to average temperatures during specific seasons of plant activity. We performed laboratory germination experiments to measure: (1) the degree of dormancy at dispersal; and (2) the sensitivity to dormancybreaking factors. We calculated average temperatures during four seasons of plant activity (overwintering, vegetative growth, flowering and seed maturation) for each year, and tested the relationship between these temperatures and patterns of dormancy variation, using Generalized Linear Models. Dormancy varied among sites and years, seeds being more dormant in colder years. For the degree of dormancy at dispersal, we found a positive relationship with flowering temperature and a significant effect of collection site. For the sensitivity to dormancy-breaking factors, we found no significant differences among sites, a positive relationship with flowering temperature and a negative relationship with overwintering temperature. Phenotypic plasticity in dormancy in C. somedanum is thus especially marked in the sensitivity to dormancybreaking factors. Temperatures during overwintering and flowering have differential effects on this plasticity, allowing the plant to detect the gradient of seasonality, a main ecological feature of its distribution.These results highlight the importance of taking into account more than average temperatures when assessing the response of plant phenotypic plasticity to climate change.

Predicted global warming scenarios impact on the mother plant to alter seed dormancy and germination behaviour inArabidopsis

“…Genetically identical cohorts of seeds can adapt to contrasting life cycles (Montesinos‐Navarro, Picó, & Tonsor, ), and both spring and autumn germination windows have been described in coastal, but not montane Spanish populations (Montesinos, Tonsor, Alonso‐Blanco, & Pico, ). In cold years, the impact of low temperature will result in increased dormancy (Fernández‐Pascual & Jiménez‐Alfaro, ) as shown in lab experiments (Chiang et al, ; Huang et al, ; Kendall et al, ; Kendall & Penfield, ). This behaviour supports the predictions of Springthorpe and Penfield () in the Col ecotype at different locations.…”

“…A recent study of phenotypic plasticity in seed dormancy highlights the importance of considering varying weather conditions rather than just constant average temperatures when assessing responses to global warming (Fernández‐Pascual & Jiménez‐Alfaro, ). In the present work, we investigate the extent of this phenotypic plasticity in Arabidopsis using a unique thermogradient polyethylene tunnel.…”

Seed dormancy and longevity variability of Hirschfeldia incana L. during storage

“…Therefore, seed germination is subject to strong selection pressure and, consequently, is likely to be highly sensitive to climatic changes (Walck et al ., 2011). A better understanding of variation of seed germination and viability within a population is important, as phenotypic plasticity might provide a buffer against climate change (Fernández-Pascual and Jiménez-Alfaro, 2014; Hudson et al ., 2015).…”

Plant-derived smoke and temperature effects on seed germination of five Helianthemum (Cistaceae)

“…The low germination of the banked seeds cannot be due to the conservation process, as the initial germination just after collection was even lower (Supplementary material 1). As these seeds were collected in a different site and year, the differences in germination could be due to local adaptation or phenotypic variation in physiological seed dormancy (Fernández-Pascual and Jiménez-Alfaro, 2014;Fernández-Pascual et al, 2013). In any case, it is interesting to note that the size of the smoke effect seemed to be larger in those populations that germinated less (Cangas and Ibias), supporting its potential role as a dormancy-breaking signal.…”