Karyological Studies on Some Species of Lobelia

抄録

1) In the present study, seven species of Lobelia were dealt with karyologically. They were found to constitute a polyploid series, 2x-4x-6x, with 7 as the basic number; L. inftata, L. dresidensis and L. syphilitica are diploid species, L. sessilifolia a tetraploid species, L. Erinus and L. Richardsonii hexaploid species, and L. triquetra contains both diploid and hexaploid individuals.
2) The comparison of idiograms between three diploid species, L. inflata, L. syphilitica and L. dresidensis reveals certain marked differences in the size and structure of their components (cf. Figs. 8a-c).
3) From a study an the chromosome arrangement at MI of PMCs in L. sessilifolia, it was found that the Bonfiguration with 4 bivalents lying inside and the other 10 lying outside was prevalent, as the floating magnet theory of chromosome arrangement demands.
4) In the somatic division of L. sessilifolia, a unique behavior of the nucleolus was detected. The nucleolus divides at an early stage into two, one of which parts is connected wich the distal end of one definite chromosome, the double-constricted one, while the other part is entirely free from any chromosome. No connection was observable between the satellite-chromosomes and the nucleolus in either the somatic and meiotic divisions.