Ex situ conservation of Elaeocarpus angustifolius Blume via in vitro regeneration using DKW medium

Abstract

An accurate concentration of growth hormones in the medium is essential for successful tissue culture experiments in tree species. This study evaluated the efficacy of various plant growth regulators (PGRs) in Driver-Kuniyaki-Walnut (DKW) medium for callus induction and Elaeocarpus angustifolius Blume plant regeneration. Leaves from three-year-old sapling were inoculated onto DKW medium supplemented with 2-4D, NAA and Kin (0.5 mg L^-1 – 4 mg L^-1) for callus initiation. The optimal concentration for initiating callus was found to be 2 mg L^-1 of 2, 4-D. The DKW medium supplemented with 2 mg L^-1 Kinetin (Kin) showed the highest shoot regeneration frequency (91%) and an average of 21.2±1.93 shoots per explant and shoot length of 3.8±0.92cm. For rooting, a 1/2-strength DKW medium supplemented with indole-3-butyric acid (IBA) (2.5 mg L^-1) had maximum rooting frequency (83%) with an average of 3.2$\pm$0.42 cm roots per explant and root length of 2.82$\pm$1.02cm. A survival rate of 98% was achieved once in vitro regenerated plantlets were acclimated to field conditions. Three markers such as RAPD, ISSR, and SSR were used to confirm the genetic fidelity of the plantlets. The in vitro-raised clones were found to be true-to-type as all bands from the in vitro regenerated plants were monomorphic and identical to those of the in vivo plants.