Abiotic Stress Induces Morphological, Physiological, and Genetic Changes in Orthosiphon stamineus Benth. In Vitro Cultures

Abstract

Orthosiphon stamineus is a well-known medicinal herb that has long been used as a traditional treatment for a variety of ailments and disorders. In this study, in vitro grown O. stamineus plantlets were subjected to various stress factors to elucidate the effects of these stresses on the occurrence of somaclonal variation in this species. Murashige and Skoog (MS) media supplemented with 2.0 mg/L kinetin plus 0.5 mg/L IAA was identified as the optimum in vitro regeneration media (OM). The data analysis confirmed the clonal nature of the resulting plantlets. The plantlets were also exposed to various stress factors such as high salinity, abscisic acid (ABA), and high cytokinin concentrations, by subculturing the plantlets on OM added with various concentrations of NaCl, ABA, and high kinetin levels. Exposure to the various stress factors was observed to result in the occurrence of somaclonal variation in O. stamineus, where the incidence of hyperhydricity was found to be the most prominent. An ISSR analysis revealed 70.12% polymorphism among the variants. The results showed that the chlorophyll content and photosynthetic ability of plantlets were reduced when the abiotic stress levels increased.