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

Abstract

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.

Effects of Exogenous Melatonin on the Growth and Physiological Characteristics of Ginkgo biloba L. under Salinity Stress Conditions

“…Low (0.02 mmol•L −1 ) melatonin significantly increased Pro concentration under high (200 mmol•L −1 ) NaCl treatment, while low and medium (0.1 mmol•L −1 ) melatonin decreased Pro concentration under low (50 mmol•L −1 ) NaCl treatment, approximating control levels. This concentrationdependent pattern aligns with previous research on SP concentration by Bano [52], and on SS concentration and Pro concentration by Cheng [53] in camphor pine. This may be due to melatonin's role as a signaling molecule influencing the synthesis of SP and SS [54], which is affected by NaCl stress concentration.…”

The effect of salinity stress on the Phaseolus vulgaris L. plant

“…The total protein was higher at 50 and 150 mM NaCl and decreased at 200 mM NaCl (145.92,126.88,and 118.38 mg/g DW) respectively. This is in contrast to Bano et al (2021), who noticed an increase in the total protein under high saline conditions. However, the same results were documented in Kumar et al (2010) study, who noticed the rise of total protein content increased under saline stress, but this content decreased under high levels of salt, which agreed with our study.…”

“…Gadallah (1999) explains that the reason behind the increment of soluble proteins is the degradation of some structural proteins. Also, Bano et al (2021) reported that soluble protein levels declined under saline conditions, especially at 800 mM, which is similar to our result.…”