Synergistic effects of basal media and plant growth regulators on the in vitro micropropagation of Asparagus racemosus

Abstract

Asparagus racemosus (Shatavari) is a high-value medicinal herb facing genetic depletion due to over-exploitation and climate-induced propagation challenges. This study established an optimized in vitro micropropagation protocol by evaluating the synergistic effects of two basal media, Murashige and Skoog (MS) and Woody Plant Medium (WPM), supplemented with varying concentrations (0–4 mg/L) of five plant growth regulators (NAA, IBA, IAA, KN, and BAP). One-way ANOVA confirmed that PGR type and concentration significantly influenced both shoot proliferation and elongation. Cytokinins, particularly kinetin (KN), outperformed auxins for shoot induction. The highest proliferation was achieved in WPM supplemented with 4 mg/L KN, yielding 3.80 ± 0.25 shoots per explant after 30 days. Long-term kinetics monitored over 90 days revealed that WPM supported consistent, aggressive growth, whereas MS medium exhibited irregular kinetics with a growth lag at 60 days. Conversely, MS medium supplemented with 1 mg/L IAA was most effective for elongation. A significant physiological trade-off was observed between shoot number and length. These findings demonstrate that while MS is suitable for specialized elongation, WPM provides a superior, stable environment for sustained, large-scale biomass production of A. racemosus.