Embryo culture is an efficient way to conserve a medicinally important endangered forest tree species Strychnos potatorum

Abstract

The present study reports a protocol for germination of Strychnos potatorum (ver. Tel. Chilla) using zygotic embryo culture as an embryo rescue method. A 100% germination rate was obtained by culturing the embryos on full-strength Murashige and Skoog’s medium (MS) containing 20 g/L sucrose in comparison to McCown and Lloyd’s Woody Plant Medium (WPM). Germination rates decreased when the sucrose concentration was lower or higher than 20 g·L⁻¹. WPM/MS medium containing glucose at levels 30, 20, 15 g·L⁻¹ showed a smaller percentage of germination and at quarter strength, WPM/MS medium with glucose did not respond. Multiple shoot formation was found at 1.0–2.0 mg/L BAP; 3.0 mg/L Kn; 2.0 mg/L TDZ on MS medium with 20 g·L⁻¹ sucrose. Germination rates improved when the embryos were placed upright (vertically) in the medium. The in vitro germinated seedlings were acclimatized in a walk-in-chamber and maintained in the green house with the survival rate of 65%–75%. These plants were transferred to the field and were found to be phenotypically normal, healthy and similar to donor plants. This protocol will be useful to overcome seed dormancy and for rapid multiplication and conservation of S. potatorum using zygotic embryo culture.

Keywords

endangered tree species / Strychnos potatorum / In vitro zygotic embryo culture / immobilization of zygotic embryos / embryo rescue