Evaluating Paeonia emodi propagation protocols by seed and root cuttings and phytochemical analysis of the plants

Abstract

The present study aimed to develop conventional propagation protocols for Paeonia emodi, a threatened and high-value medicinal herb of the Himalayan region. Different experiments were conducted to evaluate the effects of various concentrations of plant growth regulators (PGRs) on seed germination and vegetative propagation (root cuttings) in nursery conditions. Leaves of well-developed plants were used to evaluate phytochemical content and antioxidant activity. Seed germination percentage reached a maximum (78.88 ± 1.25%) with gibberellic acid + abscisic acid treatment (GA3+ABA) at a concentration of 100 µM each. However, 100% sprouting was observed in roots treated with 500 mg L−1 indole-3-butyric acid (IBA). Seeds treated with GA3 (100 µM) induced a maximum plant height (11.98 ± 0.05 cm). Similarly, roots treated with IBA (500 mg L−1) resulted in 35.54 ± 0.84 cm plant height and maximum root diameter (25.18 ± 0.90 mm) in IBA (100 mg L−1) treated plants. Among differently treated plants, total phenolic content (100.95 ± 1.36 mg GAE/g dw) and 2, 2′-azinobis-3-ethylbenzothiazoline-6-sulfonate assay activity (25.24 ± 0.35 mg AAE/g dw) were higher in GA3+ABA (100 µM each) treated seed raised plants. However, vegetatively propagated plants treated with IBA 100 mg L−1 had the highest levels of total phenolics (110.42 ± 3.42 mg GAE/g dw) and 2, 2′-diphenyl-1-picrylhydrazyl assay activity (22.35 ± 0.48 mg AAE/g dw). The results of the study will help in the mass multiplication of the species for large-scale production.