Variation in the content of hypericins in four generations of seed progeny of Hypericum perforatum somaclones.

The content of hypericins in in vitro regenerated Hypericum perforatum plants (R (0)) and four generations of their seed progeny (R (1)-R (4)) was compared. The mean content of hypericins in field-grown plants over the period 1992-2002 gradually increased under selection, and in the R (4) generation it was almost seven-times higher than that in the R (0) somaclones. Significant difference between hypericin content in diploids and tetraploids was detected in R (0), R (1) and R (3) generations. Hypericin content in four diploid and tetraploid lineages originated from a single somaclone was genotype dependent. To eliminate the influence of environmental conditions during different growing seasons, we used seeds of selected R (0)-R (3) plants to derive R'(1) to R'(4) generations cultivated during the same years. In this case no statistically significant difference in hypericin content was found between the R'(1)-R'(4) generations. Apomictically and sexually derived plants were distinguished by PCR using variable numbers of tandem repeats (VNTR) primers. The content of hypericins in apomictically derived progenies was compared.

Reproduction pathway analysis of several Hypericum perforatum L. somaclonal families.

Flow cytometry seed screen of mature seeds originating from several in vitro regenerated Hypericum perforatum L. somaclones and their seed progenies were used to screen the ways of reproduction of 4 subsequent generations of several somaclonal families and to search for the relation between the ploidy and prevalent mode of reproduction. The prevalent reproduction pathway of diploid plants was sexual reproduction. Seed samples of plants with higher ploidy levels showed an extensive variation in the mode of reproduction: BII and BIII hybrid formation and/or aposporous pseudogamy including parthenogenetic development of a reduced embryo sac.