In vitro tetraploid induction and plant regeneration of Pinellia ternata, a pearl-like herb

Abstract Pinellia ternata (Thunb.) is a widely used Chinese medicinal herb in many countries around the globe. However, asexual reproduction causes the germplasm of P. ternata to degrade, and there is little research on genetic breeding. This study aims to induce tetraploid ‘Pearl’ P. ternate plants using colchicine-treated leaves and tubers to obtain superior germplasm resources. The in vitro medium of autotetraploid plants was then optimized through orthogonal experiments, and the morphology, tissue, and cells of diploid and tetraploid plants were compared. The results indicated that the number of chromosomes in diploid plants was 2n = 2x = 66, while the tetraploid plants was 2n = 4x = 132 by somatic chromosome counting and flow cytometry analysis. The leaf was more suitable than the tuber for polyploid induction, and the maximum induction rate was 29.49% when leaves were treated with a 0.05% colchicine solution for 96 h. In MS medium supplemented with 0.1 mg L− 1 6-BA, 0.1 mg L− 1 NAA, and 1.0 mg L− 1 KT, tetraploid leaves could develop into plantlets with roots, and there was a 100% transplant survival rate. The tetraploid P. ternata had larger and denser leaves, thicker petioles, and larger stomata, but shorter plants than the diploid. Meanwhile, the number of tubers produced by tetraploid leaves grows. This study induced tetraploid in P. ternata and established a tetraploid artificial rapid propagation system for P. ternata, providing the theoretical foundation and experimental support for its genetic breeding and variety enhancement.