In vitro propagation and cytogenetic stability of Tripleurospermum insularum (Asteraceae) - a critically endangered insular endemic species from Turkey

Tripleurospermum insularum (Asteraceae) is a critically endangered (CR) insular endemic species in Turkey and is facing high risk of extinction. Here, a rapid and efficient in vitro propagation protocol using nodal segments obtained from seedling shoots cultured on Murashige and Skoog (MS) basal medium supplemented with different plant growth regulators (PRGs) was developed to conserve T. insularum. Besides, the cytogenetic fidelity of propagated plants was tested with DNA ploidy level using flow cytometry (FCM) as well as chromosome counting. The highest shoot number and length of shoot per explant were achieved in MS medium containing 4.6 mu M zeatin (ZEA) and 0.5 mu M indole-3-acetic acid (IAA). No variation in DNA ploidy level (2x) and somatic chromosome number (2n = 18) of all propagated plants were observed. In vitro rooting of shoots was achieved at 100% efficiency in the medium supplemented with 2.9 mu M IAA. The rooted plantlets were transferred ex vitro with 74% survival. This is the first report of a successfully developed micropropagation protocol for ex situ conservation of T. insularum.