Effects of Nutrients and Growth Regulators on Seed Germination and Development of Juvenile Rhizome Proliferation of Gastrodia elata In Vitro

Abstract

Two prevalent issues with Gastrodia elata growing in a natural wild environment are the necessary symbiotic seed germination with Mycena spp. and the long growing cycle of protocorms into mature rhizomes with Armillaria mellea. This study explored the most suitable nutrients to germinate seeds and the developmental stages and propagated protocorm/juvenile rhizomes (jrhs) through a tissue culture approach. Adding humic acid, mashed potato, peptone, and (indole-3-acetic acid) IAA to the 2 g/L Hyponex 7-6-19 basal medium accelerated seed germination into protocorms with an average length of 2 mm. The nutrients best for the in vitro propagation of jrhs consisted of 1 g/L Hyponex 7-6-19 and MS salts with 1/2 NH4NO3 and KNO3, 2 mg/L BA, 2 mg/L NAA, 2 g/L tryptone, 2 g/L glutamic acid, 1 g/L chitosan, 10 g/L apple puree, 20 g/L mashed potato, 100 mL/L coconut water, and 1.5 g/L A. mellea powder, at a pH level of 6. The maximum length and number of jrhs were 17.2 ± 0.8 mm and 76.6, respectively, in two subcultures. The in vitro propagation system started from seeds of G. elata can be employed as a potential method to propagate protocorm/jrhs for the cultivation of mature rhizomes from indoor or outdoor cultures.