Understanding how plant species respond to extreme conditions is crucial for predicting their ecological resilience under climate change. Here, we aim to forecast the ecological resilience of the Mediterranean cliff species Brassica incana (Brassicaceae) by estimating population variation in germination response under novel extreme environmental conditions. We investigated the thermal germination responses in 14 populations of B. incana by exposing seeds to temperatures within and outside conditions experienced in their local environment. Then, we quantified among- and within-population variation in germination response to extreme temperatures, estimated genotype-by-environment interactions (G × E) and tested if population performance at extreme temperatures is explained by local climate. We found significant among-population differences in germination response, a different level of within-population variability, and different mechanisms underlying G × E patterns. Also, populations experiencing warmer temperatures in their local environment showed a better performance at both cold and hot extremes while populations experiencing colder temperatures showed a limited ability to germinate under extreme conditions. Our results suggest that populations experiencing warmer temperatures in their local environment have a higher potential to face future thermal extreme conditions and their role is thus crucial to promote species ecological resilience.

Mediterranean coastal cliffs are reservoirs of plant biodiversity, hosting vulnerable plant species particularly exposed to the risk of local extinction due to extreme abiotic conditions and climate changes. Therefore, studies aiming to understand the tolerance of cliff plant species to abiotic stresses are important to predict their long‐time persistence or to highlight inherent threats. We used an integrative approach including anatomical, physiological and phenotypic analyses on (a) seeds, (b) cotyledons of seedlings; and (c) young plants to assess whether the cliff species Brassica incana, can tolerate exposure to different seawater (SW: 25%, 50% and 100%) concentrations during the early stages of its life cycle. Seeds could germinate when exposed to up to 50% SW. Seeds did not germinate in 100% SW, but could resume germination after washing with freshwater. Seed germination rate also decreased with increasing SW concentration. Exposure to SW decreased stomatal size and stomatal index of cotyledons and caused long‐lasting and severe damage to the photochemical reactions of photosynthesis. Photochemistry was also sensitive to SW in young plants, but the effect was lower than in cotyledons. This may involve a remodulation of chloroplast dimensions and activation of cellular metabolism. However, photochemical reactions limited photosynthesis at100% SW even after recovery from SW exposure. Our data show that B. incana has strong tolerance to seawater and shows clear signs of halophytic adaptation. Whilst seeds and juvenile plants are able to withstand SW, the seedling stage appears to be more sensitive.

Cadmium (Cd) contamination is a severe problem in the environment and produces detrimental effects on crop productivity and quality. Characterization of crop performance at different Cd concentrations is crucial to identify pollution-safe cultivars with low translocation efficiency to aboveground organs to be used for food safety. Here, we estimated germination, survival, growth, photosynthetic pigments, Cd bioaccumulation, among-organs translocation, and ionic balance in six Solanum melongena L. (eggplant) cultivars from the central Mediterranean basin. On two cultivars, we also analyzed expression of genes involved in Cd uptake, i.e., heavy metal ATPases (HMAs) and metal tolerance proteins (MTPs). We found that Cd has a negative effect on all the investigated parameters but with relevant among-cultivar differences. Cd-treated plants showed a decrease in germination rate and survival. Photosynthetic pigments showed opposite trends, i.e., with increasing Cd contents, we observed a decrease in chlorophylls and an increase in carotenoids. The investigated cultivars showed high ability of sequestrating Cd in roots but a low translocation efficiency to the aboveground organs, suggesting a good potential for food safety. The response of plants to Cd was mediated by a different expression of the MTP and HMA gene families. Our study represents the first comprehensive investigation of Cd tolerance in eggplant varieties from the Mediterranean basin and highlights the importance of comparative studies to identify Cd-tolerant cultivars.

Seed traits underlying germination, by determining the environment experienced by plants throughout their lifetime, can play a key role in shaping plants’ adaptive strategies. However, the genomic bases of adaptation in seed traits and its link with local biotic and abiotic environments remain largely unexplored. Here, we used a pool-sequencing approach combining genome-wide association (GWA), genome-environment association (GEA) and a genome wide scan of a spatial genomic differentiation index (X^TX) to identify putative signatures of adaptation in seed traits and to climate and pollinator community across 14 populations of the wild plant species Brassica incana. We observed a complex genetic architecture potentially involved in seed trait adaptation, which varied depending on the seed trait function. Also, we identified several candidate genes simultaneously linked to signals of adaptation in seed traits and local abiotic or biotic conditions. These results expand our understanding on the adaptive value of seed traits, on its interaction with environmental conditions and on its potential for shaping the evolutionary trajectory of wild plant populations.

Background and aims: Local adaptation to edaphic conditions might produce edaphic specialization, possibly limiting the potential for persistence in novel environments. Therefore, evaluating how different populations can cope with novel edaphic environments is crucial to forecast species survival. Methods: We conducted a reciprocal transplant experiment in greenhouse conditions in five Dianthus rupicola populations. We characterized the edaphic environments and estimated, in twelve maternal seed families per population, germination performance, seedling survival and photosynthetic efficiency in home vs. foreign soils. These data were used to test for local adaptation to the edaphic environment and to estimate genotype-by-environment interactions (G $$\times$$ × E). Lastly, to estimate the additive genetic variance of each population, we quantified levels of genomic inbreeding. Results: In four populations, we found strong patterns of local adaptation in germination performance and seedling survival, but not in photosynthetic efficiency. Populations showed similar extents of genetic diversity. Also, four populations were characterized by a significant G $$\times$$ × E in plant performance verified by an increase in the expression of variance. However, the frequency of families being able to germinate in such environments was different among the populations. Conclusion: Our study shows that the edaphic environment can lead to strong natural selection in early plant life-cycle stages. However, maternal families that overcome the first critical phases show a wide tolerance to transplant soils. These families hidden within a population might have the potential to adapt to novel edaphic environments enhancing species survival in fragmented Mediterranean habitats.