In vitro seed germination and seedling propagation in Campanula spp

Abstract

The present research investigated in vitro seed germination and seedling multiplication methods to preserve and introduce new naturalized valuable Campanula species to the floriculture markets. Populations of Campanula barbata L., Campanula latifolia L., Campanula rapunculoides L., Campanula spicata L., and Campanula trachelium L. from various sites in northern Italy were considered in this study. Seeds were sown on half-strength Murashige and Skoog (MS) basal medium with 1-naphthaleneacetic acid (NAA), 6-benzyladenine (BAP) and kinetin, added or withheld, after which final germination percentage (FGP), mean germination time and time of 50% germination (T 50) indices were measured. C. rapunculoides showed the highest FGP after 2 weeks in both the presence (53%) and absence (56%) of plant growth regulators. Among the other species, no statistical differences were detected in the presence of growth regulators, except for C. barbata, in which FGP was nearly 0%. In the absence of phytohormones, seed germination in C. spicata was statistically higher (34%), compared to C. barbata (0%), and both C. latifolia and C. trachelium (about 19%). After 4 months, the seedlings were transferred to full-strength MS basal medium with or without NAA and BAP. In all Campanula species tested, the best shoot-forming and rooting response was observed on substrates that contained plant growth regulators.