Variations in ploidy, chloroplast DNA (matK and rbcL), and 18S rDNA in the medicinal plant Pinellia ternata Breit., naturally occurring in Japan, were investigated. Microscopic examination revealed variations in chromosome number, with counts of 78 (2n = 6x), 91 (2n = 7x), and 104 (2n = 8x), suggesting that the ploidy level of the plant in Japan ranges from 6x to 9x, as confirmed by flow cytometric analysis. The ploidy levels did not exhibit a discernible correlation with the geographical distribution of accessions in Japan, except for the exclusive presence of 9x plants in Okinawa Prefecture. The ploidy levels also did not correlate with the corm growth and the effective ingredient content in the corm. Furthermore, chloroplast DNA analyses revealed the existence of two distinct groups among the Japanese accessions. These genetic variations did not demonstrate any apparent association with the geographical distribution of the plant. In contrast, polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) analysis of 18S rDNA sequences showed no discernible variations within the studied P. ternata population.
EGUCHI et al. (Thu,) studied this question.