Promotion of Physiological and Biochemical Characteristics in Fe Deficienct-Stressed Salvia hispanica in Relation to Foliar-Spraying of Salicylic Acid

Salicylic acid (SA) is a plant growth regulator partake in multiple defense responses against plant constraints, including iron (Fe) deficiency. The intend of the current study was to inspect the effects of SA foliar spraying on growth activity, nutritional elements uptake, photosynthetic activity and antioxidant performance in Salvia hispanica cultivars grown in inert sand. Chia plants were subjected weekly either to distilled water or SA foliar spraying (1 mM SA) over a period of eight weeks. Under control condition, induced Fe deficiency treatment decreased shoot dry weight, total chlorophylls and mineral elements, whereas that of roots was not upsetted by such constraint. Moreover, it affected the photosynthetic and non-enzymatic actitivities by inhibiting net photosynthetic assimilation rate (An) (–13%), water use efficiency (WUE) (–19%) and intrinsic water use efficiency (IWUE) (–20%). Notably, in plants treated with salicylic acid, both An, gs, WUE and IWUE were substantially improved, reaching 127, 120, 121 and 118%, respectively, in versus control leaves. Interestingly, SA foliar application mitigated whole plant weight, shoot biomass, root length, photosynthetic pigments and gas exchange efficiency. As well, the highest polyphenolic and flavonoid contents were recorded in stressed sprayed roots with 1 mM SA, where they reached 1.52 and 0.62 mg/g dry weight calculated as gallic acid/catechin equivalent respectively. Likewise, they exhibited a potential antioxidant capacity, quenching DPPH radical, noteworthy ferric reducing power as well as potent anti-lipoxygenase (LOX)/ acetylcholinesterase (AChE) activities. Overall, foliar aspersion of SA can have a positive regulatory role in alleviating Fe deficiency in chia plants.