The current work aimed to investigate the effect of seed priming with different agents (CaCl₂, KCl, and KNO₃) on germination and seedling establishment in seeds of the barley species of both Hordeum vulgare (L. Manel) and Hordeum maritimum germinated with three salt concentrations (0, 100, and 200 mM NaCl). The results showed that under unprimed conditions, salt stress significantly reduced the final germination rate, the mean daily germination, and the seedling length and dry weight. It led to a decrease in the essential nutrient content (iron, calcium, magnesium, and potassium) against an increase in sodium level in both of the barley species. Moreover, this environmental constraint provoked a membrane injury caused by a considerable increase in electrolyte leakage and the malondialdehyde content (MDA). Data analysis proved that seed priming with CaCl₂, KCl, and KNO₃ was an effective method for alleviating barley seed germination caused by salt stress to varying degrees. Different priming treatments clearly stimulated germination parameters and the essential nutrient concentration, in addition to increasing the seedling growth rate. The application of seed priming reduced the accumulation of sodium ions and mitigated the oxidative stress of seeds caused by salt. This mitigation was traduced by the maintenance of low levels of MDA and electrolyte leakage. We conclude that the priming agents can be classed into three ranges based on their efficacy on the different parameters analyzed; CaCl₂ was placed in the first range, followed closely by KNO₃, while the least effective was KCl, which placed in the third range.

The current investigation aims to underline the impact of salicylic acid or calcium chloride seed pre-treatments on mineral status and oxidative stress markers, namely levels of electrolyte leakage (EL) and lipid peroxidation levels, measured as thiobarbituric reactive substances (TBARS), and the activity of some antioxidant enzymes in roots and leaves of plants in two barley species grown under various salt treatments. Overall, our results revealed that salinity inhibits essential nutrient absorption such as iron, calcium, magnesium and potassium and stimulates the absorption of sodium. Also, this environmental constraint induced oxidative stress in plants in comparison with the control conditions. This state of oxidative stress is reflected by an increase in TBARS content as well as the stimulation of EL values. In addition, salinity induced disturbances in the activity of antioxidant enzymes, which were mainly dependent on the applied salt concentration and the species. In addition, Hordeum marinum maintained high antioxidant enzyme activity and low levels of oxidative stress parameters, which reinforces its salt-tolerant character. Importantly, salicylic acid or calcium chloride seed priming alleviated the mineral imbalance and the oxidative damage induced by salinity. Moreover, seed priming improves iron, calcium magnesium and potassium content and limitsthe accumulation of sodium. Also, both treatments not only decrease TBARS levels and limit EL, but they also stimulate the antioxidant enzyme activities in the leaves and roots of the stressed plants as compared with stressed plants grown from non-primed seeds. Interestingly, the beneficial effects of the mentioned treatments were more notable on Hordeum vulgare species.

Iron (Fe) deficiency causes great disturbances to plant growth, productivity and metabolism. This study investigated the effect of bicarbonate-induced Fe deficiency on Foeniculum vulgare (Mill) growth, nutrient uptake, the accumulation of secondary metabolites and the impact on bioactivities. When grown under indirect Fe deficiency conditions (⁺Fe ⁺Bic), the plants decreased their total mass, an effect that was clearly evident in shoots (−28%). Instead, roots were the main organ affected regarding variations in the phenolic profile and their respective functionalities. Hydromethanolic extracts from bicarbonate-treated roots had a remarkable increase in the levels of phenolic compounds, both of flavonoids (isoquercetin and isorhamnetin) and phenolic acids (gallic acid, chlorogenic acid, syringic acid, ferulic acid, caffeic acid and trans-cinnamic acid), when compared to equivalent extracts from control plants. In addition, they exhibited higher scavenging abilities of DPPH•, NO•, RO₂•, as well as inhibitory capacities towards the activity of lipoxygenase (LOX), xanthine oxidase (XO) and acetylcholinesterase (AChE). The overall results suggest that fennel species may modulate secondary metabolites metabolism to fight damages caused by iron deficiency.

Iron (Fe) is a vital nutrient for the development of many plants. Therefore, enhancing plant performance and production in relation to Fe deficiency is becoming a serious challenge. In this work, we intended to survey the effect of seed pretreatment with salicylic acid (SA) on oxidative status, phenolic composition, and related antioxidant activities in two varieties of Sulla carnosa (Sidi Khlif: SK and Kalbia: KA) treated with different Fe concentrations. In unprimed plants, the levels of phenolic compounds were very distinguishable among the two varieties, being superior in KA compared to SK. Interestingly, priming KA seeds with SA under control conditions or deficient conditions (D+SA treatment) caused a decreasing tendency in the contents of total phenolic compounds (TPC) and total flavonoids (TFC), whereas an opposite behavior was observed in SK. Moreover, an improvement of hydroxycinnamic and flavonoid groups, in addition to antioxidant activities (TAC, DPPH^●, β-carotene and FRAP), was markedly found in SK primed with SA. According to these findings, SA seed pretreatment had a beneficial effect on the metabolic performance of this species under different Fe supply, regardless of whether the intensity of improvement was related to Fe concentration applied, variety, as well as plant organ. The results suggest that SA can account for the effective modulation of the secondary metabolites metabolism in S. carnosa plants to deal with the detrimental impacts of Fe deficiency.

Improving forage crops performance under iron (Fe) deficiency conditions is challenging, thus besides genotypic screening new approaches are required. Among these new approaches, priming technique is eco-friendly, efficient and cost effective. The aim of this study was to evaluate the remedial effect of salicylic acid (SA 0.25 mM) seed priming on plant growth, ionic content, in addition to the photosynthetic capacity under different Fe concentration conditions in two Sulla carnosa cultivars ‘Sidi Khlif’ and ‘Kalbia’, with different tolerance to such constraint. Under unprimed conditions, Fe deficiency reduced shoot relative growth rate (RGR), Fe and potassium (K) contents along with chlorophyll concentration in both cultivars, compared to the control. Nevertheless, S. carnosa was able to maintain root RGR under these unfavorable conditions. Additionally, Fe deficiency affected differently the gas exchange parameters. Interestingly, priming seeds with SA improved growth performance, as well as Fe and K uptake of deficient S. carnosa plants via simulating the medium acidification. The changes above described in all physiological parameters were much less pronounced in ‘Sidi Khlif’ than in ‘Kalbia’. We conclude that SA seed priming had a positive effect on the physiological behavior of S. carnosa plants subjected to Fe deficiency. However, the degree of recover varied depending on the cultivar and the plant tissue. Mitigation of Fe deficiency by SA could be in part due to the aptitude to assure an enhanced plant growth and the adjustment of photosynthetic activity promoting more effective nutrient assimilation.

Salinity is among the main abiotic constraints limiting crop productivity worldwide. Salt tolerance can be improved by introducing adaptive traits from wild species and enhancing pre-existing salt-adaptive mechanisms through priming. This study evaluated the beneficial effect of salicylic acid (SA, 1.25 mM) and calcium chloride (CaCl₂, 5 mM) seed priming on plant growth under salinity in the domestic barley Hordeum vulgare (Hv) and the wild, salt-adapted Hordeum maritimum (Hm). Primed plants were grown under control, 100 and 200 mM sodium chloride (NaCl) for two weeks. Growth and hormone profiling were performed. Hv showed higher growth inhibition than Hm but was more responsive to stress alleviation by priming, particularly with SA, which increased biomass by up to 47% at 200 mM NaCl. The contrasting responses of both species reflected distinct hormonal strategies. The intrinsic salt tolerance of Hm appears linked to high constitutive levels of stress- and growth-related hormones. In Hv, growth recovery under salinity following priming was associated with hormonal reprogramming, involving reduced abscisic acid (ABA) accumulation and enhanced levels of growth-promoting hormones (indole-3-acetic acid (IAA), trans-zeatin (tZ), and isopentenyl adenine (iP)), especially in roots. Hormonal changes mediated by priming are analyzed in relation to adaptive growth responses and species’ ecological origins.