S-abscisic Acid is a pure, naturally derived plant growth regulator capable of effectively enhancing drought resistance and lodging resistance in maize. Furthermore, it facilitates yield increases by regulating vegetative overgrowth, lowering ear placement, and improving grain quality.
Acting as a plant "stress-inducible factor," this substance rapidly activates ABA-dependent signaling pathways when maize encounters drought stress. This activation induces stomatal closure to reduce water transpiration while simultaneously promoting deeper root penetration and enhancing water uptake capacity. Studies indicate that treatment with a concentration of 2–3 mg·kg⁻¹ can significantly increase the plant height, root length, and catalase activity of maize seedlings, thereby strengthening their physiological foundation for drought resistance.
Regarding lodging resistance, the exogenous application of S-abscisic Acid inhibits excessive internode elongation in the stem, enhances vascular bundle development, and improves stem mechanical strength. Its mechanism of action involves regulating the balance between endogenous gibberellins and auxins, thereby achieving the desired "growth-regulating" (anti-overgrowth) effect. Additionally, S-abscisic Acid optimizes plant architecture by lowering the height of the ear placement; this shifts the plant's center of gravity downward, significantly reducing the risk of lodging during windy or rainy weather.
In terms of quality improvement and yield enhancement, S-abscisic Acid coordinates the balance between vegetative and reproductive growth, facilitating the translocation of photosynthetic products to the grain. This process leads to an increase in both the number of grains per ear and the thousand-grain weight. Field trials have demonstrated that the judicious application of S-abscisic Acid can boost maize yields by over 5%, while also improving grain plumpness and test weight, and reducing the incidence of mold.
Practical Application Recommendations:
Seed Dressing/Soaking: Soaking seeds in a 0.3–0.5 mg/L S-abscisic Acid solution for 6–12 hours can improve germination rates and enhance seedling-stage stress resistance.
Growth Regulation (Anti-overgrowth) at Seedling Stage:Foliar application of a 1–2 ppm solution during the 6–8 leaf stage can effectively inhibit internode elongation and lower the ear placement.
Critical Stress-Resistance Periods:Apply a 50–100 ppm solution via spraying during the jointing stage, or 3–5 days prior to anticipated drought or low-temperature conditions, to bolster the plant's overall stress resistance capabilities.
