Cadmium (Cd) is considered one of the most toxic heavy metals to living organisms, being very persistent in soil and non-biodegradable, thus posing a long-term hazard to plants and humans. In recent years, the application of different molecules at the seed level, known as chemical seed priming, has been studied as a method to improve stress tolerance in plants. In the present study, we tested the effect of hydro-priming and proline priming of lettuce (Lactuca sativa L.) seeds on germination, photosynthetic pigments, and metal metabolism under cadmium stress. Plants primed with proline showed better germination under cadmium stress (100% versus 84% for non-primed and hydro-primed seeds). Priming with 20 mM of proline increased the chlorophyll a and total chlorophyll contents by 40.8% and 18.6%, respectively, while these parameters decreased in other seedlings under Cd stress. Similarly, 20 mM of proline improved the uptake of Zn and Fe in roots under Cd stress. This indicates that 20 mM of proline treatments may be beneficial for maintaining a normal photosynthetic capacity and mineral uptake under Cd stress, but further metabolomics and transcriptomic data should reveal the exact mechanisms of action.

The increase in soil salinity has a negative effect on the growth and yield of plants. Mitigating the negative effects of soil salinity is therefore a difficult task and different methods are being used to overcome the negative effects of salt stress on crop plants. One of the often-used approaches is seed priming that can increase plants’ vigor and resilience. In this paper, we tested the effects of hydropriming, proline priming, and salicylic acid priming on the mitigation of the negative effects of salt stress on two bell pepper varieties (Capsicum annuum L.): Herkules and Kurtovska kapija. Sweet bell pepper seeds were primed following desiccation to achieve the original water content, and subsequently cultivated in salt-supplemented medium. The positive effects on vigor (in the form of increased germination and seedling establishment) as well as on level of tolerance for salt stress were recorded for both cultivars. The positive effects varied between the priming treatments and pepper cultivar used. The results of germination, seedling performance, photosynthetic pigments, and osmolytes were measured for seedlings grown from unprimed and primed seeds with under 0, 25, and 50 mM of NaCl. Both cultivars demonstrated greater germination when primed with proline and salicylic acid, while the Herkules cultivar demonstrated a higher tolerance to salt when proline was used as the priming agent. Priming with salicylic acid and proline in the seed improved germination and seedling performance, which could be related to the increase in proline content in the seedlings.

This study presents the first report on phenolic composition and bioactivity of ethanolic extracts of three plant species that grow in the western Balkan mountains and are used in traditional folk medicine: Valeriana montana, Salix retusa, and Campanula hercegovina. Phenolics were extracted from different aerial plant parts using 80% ethanol to assess the possibility of sustainable use of these plants as a source of bioactive compounds without disruption to the roots (for V. montana) or destruction of whole habitats (for S. retusa and C. hercegovina). The ethanolic extract of V. montana flower contained noticeable levels of apigenin and quercetin. The branches and bark of S. retusa were significantly rich in catechin, while rutin was the major phenolic found in the leaf extract of C. hercegovina. Furthermore, the flower extract of V. montana revealed the best antioxidant activity, which was comparable to 4-hydroxybenzoic acid and quercetin. Considering antimicrobial activity, the leaf extracts of V. montana and C. hercegovina demonstrated potent activity against all microbes tested, while the extracts of S. retusa were moderately effective. The presented results emphasize the potential of these plants as novel sources of bioactive compounds.

Seed biopriming is increasingly recognized as a strategy capable of inducing molecular memory that enhances plant performance under heavy-metal stress. Here, we investigated how biopriming Silene sendtneri seeds with Paraburkholderia phytofirmans PsJN establishes a transcriptional state that predisposes seedlings for improved cadmium (Cd) tolerance. RNA-seq profiling revealed that primed seeds exhibited differential gene expression prior to Cd exposure, with strong upregulation of detoxification enzymes, antioxidant machinery, metal transporters, photosynthetic stabilizers, and osmoprotectant biosynthetic genes. Enrichment of gene ontology categories related to metal ion detoxification, redox homeostasis, phenylpropanoid metabolism, and cell wall organization indicated that biopriming imprints a preparatory transcriptional signature resembling early stress responses. Upon Cd exposure, primed plants displayed enhanced physiological performance, including preserved integrity, elevated antioxidant activity, particularly peroxidases in roots, higher osmolyte accumulation, stabilized micronutrient levels, and substantially increased Cd uptake and sequestration. These coordinated responses demonstrate that biopriming induces a sustained molecular memory that accelerates and strengthens downstream defense activation. These findings demonstrate that PGPR-based biopriming establishes a stable transcriptomic memory in seeds that enhances cadmium tolerance, metal sequestration, and stress resilience, highlighting its potential for improving hyperaccumulator performance in phytoremediation and stress adaptation strategies.

This study evaluated the effects of different seed priming treatments on the ex situ propagation of the Balkan endemic species Silene sendtneri Boiss. Seeds were subjected to hydropriming, silicic acid, salicylic acid, proline and combined salicylic acid–proline treatments prior to in vitro cultivation. Following aseptic germination, seedlings were transferred to Murashige and Skoog medium supplemented with 1.0 mg L⁻¹ BA and 0.2 mg L⁻¹ IBA, and their shoot multiplication response, rooting, and acclimatization success were assessed. Seed priming significantly influenced subsequent propagation stages. Plantlets derived from seeds treated with 0.5 mM salicylic acid and 10 mM proline + 0.5 mM salicylic acid exhibited the highest multiplication rates, superior morphological quality, increased rooting frequency, and the greatest acclimatization success. Hydropriming and higher proline concentrations generally resulted in reduced propagation performance. The results indicate that seed priming can influence multiple stages of the ex situ propagation process and may represent a simple and practical addition to micropropagation protocols aimed at improving conservation-oriented plant production of endemic species.