In vitro induction of polyploidy in Cercis glabra Pamp

This study systematically compared the effects of several different in vitro treatment methods and explant types on the induction of polyploidy in Cercis glabra Pamp. Analysis of nuclear DNA content using flow cytometry indicated that treating either apical or lateral buds of in vitro shoot cultures with an aqueous solution of 150 μM oryzalin for 12–96 h produced tetraploid plants irrespective of the type of bud treated. In contrast, shoots cultured on solidified media containing oryzalin failed to produce polyploid nuclei suggesting limited uptake and/or transport of oryzalin in shoot cultures. Using aqueous treatments of oryzalin and shoot cultures, polyploid C. glabra plants were successfully produced, rooted, and established in the greenhouse. Although an increase in the frequency of polyploid nuclei was detected in callus cultures grown on media containing orzyalin, these treatments significantly reduced callus growth and viability. Results from this study indicate that aqueous treatment of in vitro grown shoot cultures may provide an efficient and simple method for the generation of polyploid plants.

► Tetraploid plants of Cercis glabra were produced by treating in vitro shoots with oryzalin.
► Treatment of either apical or lateral buds with aqueous solutions of oryzalin was both effective at producing tetraploid nuclei.
► The duration of oryzalin treatment was not critical, as tetraploid nuclei were derived from buds treated from 12 to 96 h.
► Treatment of shoots in solidified medium, or treatment of callus, was not effective methods to produce tetraploid plants.