Efficient ex vitro rooting, acclimatization, and cultivation of Curcuma longa L. from mycorrhizal fungi

Acclimatization is the most delicate stage of micropropagation, which makes it challenging to obtain new seedlings. The use of suitable substrates associated with arbuscular mycorrhizal fungi (AMFs) has been promising during this stage. The goal of this study was to investigate the influence of different AMFs and substrates on the acclimatization of Curcuma longa L. The C. longa seedlings were obtained from in vitro cultivation with a specific medium for 120 days. After this period, they were transplanted into plastic pots containing two substrate formulations. The first compound was soil and vermiculite (1:1 v/v), and the second was a commercial substrate for vegetables, containing vermicompost and vermiculite (1:1:1 v/v). The fungi used in the study were Rhizophagus clarus, Claroideoglomus etunicatum, and a mixture of the two fungi. A treatment with no fungi was used as the control. After 240 days, the growth and structural characteristics of the plant were measured, as well as nutrients and soil–quality parameters. The use of a substrate rich in organiac matter (substrate 2) associated with R. clarus and C. etunicatum promoted 100% survival of C. longa plants. In this condition, the plants were more vigorous. The root system increased in size and biomass, being robust with the presence of many roots. The soil indicators revealed that the fungi helped with the lower activity of the metabolic quotient and increased basal respiration, indicators that demonstrated the beneficial action of the fungi for the plants. In addition, changes in stomatal conformation and density probably allowed greater CO2 diffusion. © 2020, Korean Society of Crop Science (KSCS).