Enhancing Micropropagation of Adenophora liliifolia: Insights from PGRs, Natural Extracts, and pH Optimization

Abstract

The endangered plant species Adenophora liliifolia faces threats to its survival in the wild, necessitating the development of effective micropropagation techniques for potential reintroduction efforts. This study demonstrates that Adenophora liliifolia effectively reproduces on MS synthetic medium with diverse plant growth regulators (PGR) and natural extracts, facilitating swift micropropagation for potential future reintroduction endeavors. It highlights the substantial impact of PGR composition and natural extracts on the growth and development of A. liliifolia. The ideal growth medium for A. liliifolia was determined to be ½ MS with specific treatments. Additionally, incorporating silver nitrate (AgNO3) at 5 mg L−1 into the medium led to enhanced root formation and shoot length, albeit excessive concentrations adversely affected root development. Varying concentrations of NAA significantly affected different plant growth parameters, with the 0.1 mg L−1 treatment yielding comparable plant height to the control. Moreover, 50 mL L−1 of coconut water bolstered root formation, while 200 mL L−1 increased shoot formation during in vitro propagation. However, elevated doses of coconut water (CW) impeded root development but stimulated shoot growth. Experiments measuring chlorophyll a + b and carotenoid content indicated higher concentrations in the control group than differing levels of applied coconut water. Optimizing pH levels from 6.8–7 to 7.8–8.0 notably enhanced plant height and root formation, with significant carotenoid accumulation observed at pH 6.8–7. Soil samples from A. liliifolia’s natural habitat exhibited a pH of 6.65. Ultimately, the refined in vitro propagation protocol effectively propagated A. liliifolia, representing a pioneering effort and setting the stage for future restoration initiatives and conservation endeavors.