O derivado de aminoácido D-Ac106 favorece o crescimento de Lactuca sativa em cultivo hidropônico?

Abstract

The increasing global demand for food requires strategies that enhance agricultural productivity in a sustainable manner, without expanding cultivated areas. In this context, biostimulants and plant growth regulators may represent promising tools to improve crop performance, especially when used in conjunction with more efficient systems such as hydroponics. In previous studies, the compound D-Ac106, an acetylated thiohydantoin derived from an amino acid, demonstrated potential as a regulator of root growth in different species, motivating further studies aimed at its practical application. Thus, the objective of this work was to develop and evaluate new formulations containing D-Ac106, aiming at its solubilization in aqueous media and safe and efficient application in Lactuca sativa. Two new formulations were obtained, and two others previously described were also evaluated. In germination assays, none of the formulations were detrimental to seedlings growth. However, the treatment with the formulation containing D Ac106 dissolved in 0.065% or 0.1% ethyl lactate, resulted in a significant decrease in plants’ fresh mass, root length, and germination speed index. When compared to the control, D-Ac106 (≥ 2.5 mg/L) dissolved in ethanol, dimethyl sulfoxide, propylene glycol, and polyethylene glycol-400 promoted a significant increase in root length, reaching an increase of about 150% at 25 mg/L. Similar results were obtained with direct solubilization in water, with the positive effect restricted to highest concentrations, an indicative of lower bioavailability of D-Ac106 in excipient(s)-free solution. The increment in roots and shoot dry matter noted from hydroponics cultivation in the presence of D-Ac106 dissolved in polysorbate 20 plus diethylene glycol monoethyl ether was a result of the presence of excipients only. No changes in the evaluated parameters were noted when D-Ac106 (1 mg/L) was applied via the other formulations. The activity of the antioxidant enzymes catalase (CAT) and ascorbate peroxidase (APX) in seedlings grown in phenolic foam in the presence of 0.625 mg/L D-Ac106 aqueous solution was 33,5% lower than that of control seedlings, suggesting absence of oxidative stress. Overall, the results demonstrate that D-Ac106 is suitable for use in the tested formulations, although further studies are required to identify the proper concentrations to better exploit the biostimulant potential of D-Ac106.