Responses of Tobacco Plants After the Exogenous Application of L-Aspartic Acid

Abstract

The increasing use of chemicals in agricultural production and its environmental impacts have reached significant levels. One of the proposed solutions to this problem is the use of amino acids. L-aspartic acid (ASP) is an amino acid found in the composition of amino acid-based biostimulant products, playing a critical role in plant growth and stress management. No previous studies have reported ASP applications in tobacco. Therefore, this study investigated the effects of different application frequencies (once, twice, and thrice) and doses (control, 1, 5, 10, and 20 mM) of ASP on tobacco's agronomic parameters (leaf width, leaf length, plant height, yield, quality grade index) and chemical composition (reducing sugar, nicotine, ammonia). Our research findings demonstrated that foliar application of ASP could modify both the agronomic and chemical characteristics of tobacco. The highest values across all parameters were achieved with twice applications. The quality grade index (QGI), which was 48.3% in control conditions, increased to 55.6% under 1 mM ASP treatment. Reducing sugar and nicotine values ranked as follows according to dose variations: 10 mM < 20 mM < 5 mM < Control < 1 mM. The lowest chemical content was observed with thrice applications, showing decreases of 4.7%, 7.2%, and 5.1% compared to twice applications. Correlations indicating toxic effects emerged with high-frequency applications and elevated doses. Applications exceeding twice at 5 mM for yield and 1 mM for efficiency and chemical composition demonstrated adverse effects. Our results indicate the necessity for in-depth investigation of ASP application mechanisms under various stress conditions in plant production.