In vitro seed germination and seedling propagation in Campanula spp.

The present research investigated in vitro seed germination and seedling multiplication methods to preserve and introduce new naturalized valuable Campanula species into the floriculture markets. Populations of Campanula barbata L., Campanula latifolia L., Campanula rapunculoides L., Campanula spicata L., and Campanula trachelium L. from various Northern Italy sites were considered. Seeds were sown on a half-strength Murashige & Skoog (MS) basal medium with 1-naphthaleneacetic acid (NAA), 6-benzyladenine (BA), and kinetin, added or withheld. Final Germination Percentage (FGP), Mean Germination Time (MTG), and Time of 50% Germination (T50) indices were estimated. C. rapunculoides demonstrated the highest FGP after two weeks in both the presence (53%) and absence (56%) of plant growth regulators. Among the other species, no statistical differences were detected in presence of growth regulators, excepting for C. barbata, in which FGP was nearly 0%. In absence of phytohormones C. spicata was statistically favoured (34%), compared to C. barbata (0%), and both C. latifolia and C. trachelium (about 19%). After four months, the seedlings were transferred to full-strength MS basal medium with NAA and BA, added or withheld. The best shooting and rooting were observed on substrates with plant growth regulators, in all the Campanula species.