Reproduction and invasiveness in St. John’s wort

Reproduction and invasiveness in St. John’s wort

Reproduction and invas­ive­ness in St. John’s wort

The rel­at­ive abil­ity of dif­fer­ent plant taxa to invade new biogeo­graphic regions suc­cess­fully is depend­ent upon a num­ber of bio­lo­gical and phys­ical factors, one of which is the repro­duct­ive sys­tem, which dir­ectly influ­ences pop­u­la­tion struc­ture, gene flow and evol­u­tion­ary poten­tial. Considering seed form­a­tion, plants can repro­duce through sex (self­ing and out­cross­ing) or apo­mixis (asexual repro­duc­tion through seed.

St. John’s wort (Hypericum per­foratum) is such an invas­ive spe­cies which is indi­gen­ous to cent­ral and east­ern Europe; it is self-compatible and can repro­duce through sex or apo­mixis. H. per­foratum has suc­cess­fully invaded North America since the first record of intro­duc­tion in Lancaster, Pennsylvania in 1793. Its high gen­o­typic plas­ti­city in con­junc­tion with vari­able levels of fac­ultat­ive apo­mixis are hypo­thes­ized to have con­trib­uted to its rapid spread through­out the con­tin­ent. For example, in an ana­lysis of mul­tiple phen­o­typic traits, Maron et al. (2004) demon­strated that the intro­duc­tion of H. per­foratum into North America was accom­pan­ied by rapid cli­matic adaptation.

Using an ana­lysis of a col­lec­tion of European nat­ive and North American invas­ive acces­sions, a recent paper in Molins Annals of Botany exam­ines biogeo­graphic dif­fer­en­ti­ation in both nat­ural and intro­duced pop­u­la­tions, and test whether vari­ation in apo­mixis traits is cor­rel­ated with the propensity for H. per­foratum to invade novel environments.


Molins, M.P., Corral, J.M., Aliyu, O.M., Koch, M.A., Betzin, A., Maron, J.L., & Sharbel, T.F. (2014) Biogeographic vari­ation in genetic vari­ab­il­ity, apo­mixis expres­sion and ploidy of St. John’s wort (Hypericum per­foratum) across its nat­ive and intro­duced range. Annals of Botany, 113 (3): 417–427 doi: 10.1093/aob/mct268.
St. John’s wort (Hypericum per­foratum) is becom­ing an import­ant model plant sys­tem for invest­ig­a­tions into eco­logy, repro­duct­ive bio­logy and phar­ma­co­logy. This study invest­ig­ates biogeo­graphic vari­ation for pop­u­la­tion genetic struc­ture and repro­duc­tion in its ances­tral (European) and intro­duced (North America) ranges. Over 2000 indi­vidu­als from 43 loc­al­it­ies were ana­lysed for ploidy, microsatel­lite vari­ation (19 loci) and repro­duc­tion (flow cyto­met­ric seed screen). Most indi­vidu­als were tet­raploid (93 %), while lower fre­quen­cies of hexaploid (6 %), dip­loid (<1 %) and trip­loid (<1 %) indi­vidu­als were also iden­ti­fied. The pres­ence of pure and mixed pop­u­la­tions rep­res­ent­ing all three genetic clusters in North America demon­strates that H. per­foratum was intro­duced mul­tiple times onto the con­tin­ent, fol­lowed by gene flow between the dif­fer­ent gene pools. Taken together, the data presen­ted here sug­gest that plas­ti­city in repro­duc­tion has no influ­ence on the invas­ive poten­tial of H. per­foratum.


AJ Cann. ORCID 0000-0002-9014-3720

Alan Cann is a Senior Lecturer in the School of Biological Sciences at the University of Leicester and Internet Consulting Editor for AoB.