Potassium nitrate seed priming enhances root system architecture and metabolic activity in tomato (Solanum lycopersicum L)

KNO₃, an inorganic salt, plays a crucial role in regulating growth, stress responses, and various physiological processes, including seed germination and root architecture. Previous research has established the role of KNO₃ in improving the seed quality, but the specific mechanism which contributes to the seed enhancement and nutrient acquisition remains uninvest gated. Priming with potassium nitrate (KNO₃) is a promising strategy to enhance seed quality and seedling performance under suboptimal conditions. The effects of KNO₃ priming on both seed metabolism and germination and early seed growth in tomato (Solanum lycopersicum) is investigated in this study. Seeds were seeded with four KNO₃-primed tomato in varying concentrations (0.1%, 0.5%, 1% and 1.5%) for 21 h. In this present study, 1% of KNO₃ is the most effective concentration, which significantly improves germination percentage, seedling dry weight, germination speed, and seed vigour indices compared to both control and hydroprimed seeds. Validation across three varieties of tomato further confirmed the effectiveness of 1.0% KNO₃ priming on seed quality. It regulates seed physiological activity by increasing total chlorophyll, total soluble protein, total soluble sugar, and proline levels, along with elevated antioxidant enzyme activities such as superoxide dismutase (SOD) in primed seedlings. It helps in reducing the deterioration of the membrane, indicated by a reduction in MDA content. Root scanning in three varieties showed further enhancement in root morphology, indicated by elevated levels of average diameter, total root volume, root length, total surface area, and nodule tips. The present study also focuses on emphasizing the benefit of seed quality and root architecture of tomato by using KNO₃ priming, and thereby serve as an efficient means to enhance both seedling establishment and seed performance.