Effects of hydro- and bio-priming on some physiological and biochemical characteristics of quinoa (Chenopodium quinoa) seedlings under drought stress

Quinoa (Chenopodium quinoa Willd.) is a grain-like crop with a high-grown potential in Iran. Quinoa is a very nutritious plant because of its high nutritional value, therefore, compared to milk nutrition by the FAO. This study was conducted to evaluate quinoa seedlings' physiological and biochemical properties under the effects of priming and drought stress treatments. The experiment was factorial based on a completely randomized design in a greenhouse at the Agriculture Faculty of Shahed University, Tehran, Iran. Experimental factors included priming at two levels (hydro-priming and bio-priming) and drought stress at five levels (control (0), -0.5, -1, -1.5, and -2 MPa with polyethylene glycol). Analysis of variance showed that the effects of priming and drought stress were significant on most of the studied traits. The results showed a significant decrease in quinoa seedling indices (such as shoot and root dry weight) under high levels of drought stress. However, the application of bio-priming (growth-promoting bacteria) improved physiological indices, such as proline content and antioxidant enzyme activity. The interactions of priming and drought stress were significant on fructose, glucose, proline content. The highest seedling proline content was related to -2.0 MPa in bio-priming, and the lowest was to non-stress conditions in hydro- and bio-priming This study showed that the highest mean dry weight of shoots, protein content, enzymatic and non-enzymatic antioxidants was observed at the bio-priming level. The priming treatments (hydro and bio) leads to improvement characteristics such as root dry weight, proline content, superoxide dismutase activity, and anthocyanin content.