Karyotypic Studies of Commelina benghalensis variety benghalensis and C. forskalaei (Commelinaceae) from Nigeria

抄録

The study investigated the mitotic chromosomes of two variants of C. benghalensis var. benghalensis and C. forskalaei from Nigeria using classical cytogenetic techniques. The two variants of C. benghalensis var. benghalensis have the same diploid chromosome number of 2n=22 and the same karyotype formula of (8 m+10 sm+4 st) chromosomes. The two variants of C. forskalaei have the same diploid chromosome number of 2n=30 and the same karyotype formula of (14 m+6 sm+10 st) chromosomes. Terminal satellites were observed on the short arms of sub-terminal chromosome pair number 13 of C. forskalaei cf₁ and the short arms of sub-terminal chromosome pair number 7 of C. forskalaei cf₂. No satellites were observed in the chromosomes of the two variants of C. benghalensis. The chromosomes of the two variants of C. benghalensis var. benghalensis are mainly medium sized (1.00–1.43 µm) while the chromosomes of C. forskalaei are mainly small sized (0.47–0.97 µm). Results indicate interspecific variation in chromosome numbers and forms in the two Commelina species investigated.