The concerned study aimed to evaluate the effects of various pre-sowing treatments on germination parameters and morphological, physiological, and biochemical traits of amaranth (Amaranthus hypochondriacus L.) under normal (25 °C±2 °C) and low (4 °C±2 °C) temperatures. The different treatments comprised H₂O (control), gibberellic acid (GA₃), hydrogen peroxide (H₂O₂), calcium chloride (CaCl₂), succinic acid (SuA), and salicylic acid (SA). The results showed GA₃ (300 mg/l), SuA (500 mg/l), H₂O₂ (50 mmol/l), SA (138 mg/l), and CaCl₂ (3000 mg/l) positively affected the amaranth seedlings’ germination and growth traits. GA₃, SuA, H₂O₂, and CaCl₂ had a better effect on amaranth seeds by enhancing the germination rate and seed energy and shortening the germination time. The treatments with SA, GA₃, SuA, H₂O₂, and CaCl₂ boost the total antioxidants, chlorophyll a and b, and carotenoid contents in the amaranth seedlings at room and low temperatures. H₂O₂ and CaCl₂ treatments further stimulated and increased the chlorophyll a and b contents, while GA₃ and H₂O₂ increased the carotenoid content in amaranth seedlings with chilling stress, revealing a positive anti-cold effect.

Keywords: Amaranth (A. hypochondriacus L.), pre-sowing treatments, low-temperature stress, plant growth stimulants, antioxidant system, photosynthetic pigments

Key findings: The results authenticated pre-sowing treatments with GA₃ (300 mg/l) and H₂O₂ (50 mmol/l) application considerably enhanced the carotenoid content in the amaranth seedlings under chilling stress conditions; they demonstrated a significant cold tolerance-enhancing effect.