Auxin and nutritional stress coupled somatic embryogenesis in Oldenlandia umbellata L.

Abstract

Somatic embryos were induced from internodal segment derived callus of Oldenlandia umbellata L., in MS medium supplemented with different concentrations of 2,4-Dichlorophenoxy acetic acid (2,4-D). Initially calli were developed from internodes of microshoots inoculated in 2.5µM NAA supplemented medium. Then calli were transferred to 2,4-D added medium for somatic embryogenesis. Nutritional stress coupled with higher concentration of 2,4-D triggered somatic embryogenesis. Nutritional stress was induced by culturing callus in a fixed amount of medium for a period up to 20weeks without any external supply of nutrients. Addition of 2.5µM 2,4-D gave 100% embryogenesis within 16weeks of incubation. Callus mass bearing somatic embryos were transferred to germination medium facilitated production of in vitro plantlets. MS medium supplemented with 2.5µM benzyl adenine and 0.5µM α-naphthalene acetic acid produced 15.33 plants per culture within 4weeks of culture. Somatic embryo germinated plants were then hardened and transferred to green house.