Seed is the dissemination unit of plants initiating an important stage in the life cycle of plants. Seed development, comprising two phases: embryogenesis and seed maturation, may define the quality of sown seed, especially under abiotic stress. In this review we have focused on the recent advances in the molecular mechanisms underlying these complex processes and how they are controlled by distinct environmental factors regulating ion homeostasis into the seed tissues. The role of transporters affecting seed embryogenesis and first stages of germination as imbibition and subsequent radicle protrusion and extension were revised from a molecular point of view. Seed formation depends on the loading of nutrients from the maternal seed coat to the filial endosperm, a process of which the efflux is not clear and where different ions and transporters are involved. The clear interrelation between soil nutrients, presence of heavy metals and the ion capacity of penetration through the seed are discussed in terms of ion effect during different germination stages. Results concerning seed priming techniques used in the improvement of seed vigor and radicle emergence are shown, where the use of nutrients as a novel way of osmopriming to alleviate abiotic stress effects and improve seedlings yield is discussed. Novel approaches to know the re-translocation from source leaves to developing seeds are considered, as an essential mechanism to understand the biofortification process of certain grains in order to cope with nutrient deficiencies, especially in arid and semiarid areas. Finally, the role of new genes involved in hormone-dependent processes, oxidative response and water uptake into the seeds during their development or germination, have been described as plant mechanisms to deal with abiotic stresses.

The present work aims to explore the potential to improve quality of purslane microgreens by combining water salinity and LED lighting during their cultivation. Purslane plants were grown in a growth chamber with light insulated compartments, under different lighting sources on a 16 h d⁻¹ photoperiod—fluorescent lamps (FL) and two LED treatments, including a red and blue (RB)) spectrum and a red, blue and far red (RB+IR) LED lights spectrum—while providing all of them a light intensity of 150 µmol m⁻² s⁻¹. Plants were exposed to two salinity treatments, by adding 0 or 80 mM NaCl. Biomass, cation and anions, total phenolics (TPC) and flavonoids content (TFC), total antioxidant capacity (TAC), total chlorophylls (Chl) and carotenoids content (Car) and fatty acids were determined. The results showed that yield was increased by 21% both in RB and RB+FR lights compared to FL and in salinity compared to non-salinity conditions. The nitrate content was reduced by 81% and 91% when microgreens were grown under RB and RB+FR, respectively, as compared to FL light, and by 9.5% under saline conditions as compared with non-salinity conditions. The lowest oxalate contents were obtained with the combinations of RB or RB+FR lighting and salinity. The content of Cl and Na in the leaves were also reduced when microgreens were grown under RB and RB+FR lights under saline conditions. Microgreens grown under RB light reached the highest TPC, while salinity reduced TFC, Chl and Car. Finally, the fatty acid content was not affected by light or salinity, but these factors slightly influenced their composition. It is concluded that the use of RB and RB+FR lights in saline conditions is of potential use in purslane microgreens production, since it improves the yield and quality of the product, reducing the content of anti-nutritional compounds.