Seeds

Nanopriming with metal nanoparticles (NPs) is a promising strategy for improving seedling quality in horticultural crops. This study evaluated the effects of hydropriming, ZnO, SiO₂, ZnO + SiO₂, a ZnMo nanofertilizer, and two commercial biostimulants (Osmoplant and Codasil) on the early development of Capsicum annuum L. seedlings. Morphological, physiological, and biochemical traits, including biomass, stem architecture, number of leaves, chlorophylls, carotenoids, SPAD index, and nitrate reductase (NR) activity, were measured under controlled conditions. The ZnO and ZnO + SiO₂ treatments promoted stronger root growth, higher pigment content, and higher NR activity. SiO₂ alone and ZnMo showed intermediate improvements, while Osmoplant and Codasil had more limited effects. Multivariate analyses provided complementary information: heat maps revealed correlations between traits, PCA differentiated treatment responses, and radar charts integrated performance profiles. Overall, the results provide promising evidence that seed nanopriming, particularly with ZnO and ZnO + SiO₂, improves seedling vigor and transplant potential in jalapeño peppers.

Chenopodium quinoa Willd. (quinoa) is a very promising crop due to its nutraceutical properties and strong tolerance to extreme conditions, including high UVB. However, the physiological mechanisms underlying its adaptation to high UVB are still unclear, especially during germination as its traditional sowing consists of either broadcasting or continuous stream distribution in furrows. We evaluated the response of germinating quinoa seeds to acute UVB radiation, looking at the mobilization of starch reserves as well as the utilization of starch and free sugars. Biometric and physiological traits were evaluated in control (0 W m⁻²) and UVB (3.4 W m⁻²)-exposed seeds during a 24 h treatment starting with seed imbibition. Quinoa exposed to UVB showed a delay in germination and strong reduction in root elongation. Although the negative effect of UVB on germination was fully recovered at 48 h of imbibition, that on root elongation was irreversible, especially with a longer exposure time. Further analysis showed low differences in the concentration of free sugars, except at 2 and 24 h of treatment. Furthermore, starch mobilization in UVB-treated seeds was strongly reduced compared to control. This was associated with the amylolytic activity analysis, which showed strong reductions in both α- and β-amylase activities during the whole treatment, indicating that UVB strongly reduced enzyme activation for the mobilization and use of starch reserves. Overall, these data suggest that quinoa seeds can regulate the expression of genes encoding enzymes involved in reserve mobilization, in order to resist to acute UVB radiation and maintain seed viability.

Aquatic plants may rely on seeds to promote population persistence after severe disturbances, such as droughts. We characterized the seed germination dynamics for three Potamogeton species following seed storage under dry versus submerged conditions. Overall germination levels were highest for P. lucens and, more specifically, were higher after submerged storage (70.4%) than dry storage (56.0%). Overall germination levels were lower for the two other species and displayed a different response to storage conditions; they were higher after dry storage (P. natans: 24.6%; P. pectinatus: 28.1%) than submerged storage (10.8 and 7.1%, respectively). Only P. natans would have likely made a large seed bank contribution as follows: 42.2% of its seeds remained ungerminated and viable after submerged storage, while this figure was 17.4% for seeds that had experienced dry storage. Our results suggest the species differ in their reproductive strategies. Sexual reproduction plays an important role in Potamogeton lucens, adding new individuals to plant populations every year; however, the low viability of the species’ ungerminated seeds suggest its seed bank contribution may be small, rendering it vulnerable to long periods of unfavourable environmental conditions. In contrast, P. natans would likely make a larger seed bank contribution, underscoring the role its seeds may play in population persistence across years. Potamogeton pectinatus may minimally rely on its seeds, which fits with its predominant use of vegetative reproduction in the field. While its seeds might contribute little to population persistence, they may nonetheless promote genetic variability among populations.