Fig. 1 Diagram of P. delenatii stem elongation and shoot regeneration via stem node culture, a1, a2 young ex vitro shoots with 1.5–2.0 cm length; b, c ex vitro elongated shoots under LED conditions after 4 months; d nodes separated from young elongation shoot; e1 stem nodes cultured in solid medium and e2 stem nodes cultured in liquid medium with cotton substrate for 1.5 months; f completely in vitro seedlings after 3 months; g1 elongated shoots in the darkness for 4 months; g2 elongated shoots were transferred to light for recovering chlorophyll content; h stem nodes were cut into orderly positions; i stem nodes development in greenhouse