Antioxidant Enzymes and Germination Pattern: Upshot of High Salinity on Soluble Protein and Average Weight of Spinacia oleracea (Spinach) Seedlings

Spinach (Spinacia oleracea L.) is widely considered as a functional food mainly due to its various beneficial components including vitamins, minerals, phytochemicals, bioactive and antioxidant compounds that stimulate health beyond basic nutrition. The overwhelming agricultural crop at salinity conditions faced several abiotic and biotic stresses that unfortunately reduced the potential applicability of highly nutritious plants. Therefore, in this study the response of antioxidant enzymes were studied at different germination stages of the seedlings and results suggested that all antioxidant enzymes play a crucial role during oxidative stress. Spinach (Spinacia oleracea L.) seedlings had the potential to germinate remarkably well up to 800 mM NaCl concentration and the average weight of seedlings and soluble protein content was efficiently increased at high salinity. During oxidative stress, catalase, ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase, and glutathione reductase significantly showed tolerances to salinity stress conditions. Among them, Ascorbate Peroxidase presented significant activity even at 600 mM of NaCl in germination stage 1. The antioxidant defense mechanism of Spinacia oleracea is activated at the very early stage of germination which perhaps helps the plant to survive under harsh conditions thus maintaining the nutritional components of the plant.