Cyto-genetical Investigations on Lindenbergia indica (Linn.) Kuntze and Mazus japonicus (Thunb.) Kuntze

抄録

In the present investigation, the chromosome numbers for Lindenbergia indica (n=15 and 2n=30) and Mazus japonicus (n=20 and 2n=40) have been reported. The karyotype analysis revealed the presence of 4 and 8 satellited chromosomes respectively in their somatic complements. The two taxa under consideration show marked difference between them as regard the morphology of somatic chromosomes. On the basis of length, these chromosomes fall under 2 broad classes in both taxa but in L. indica they are either short or very short (9 morphological types) while in M. japonicus they are either long or medium-sized (12 morphological types).
In general, the meiotic cycle is normal except showing a few cases of minor anomalies. In addition, multivalent formation takes place in M. japonicus. Secondary association of bivalents could be encountered in both taxa. In L. indica, as in some other genera under the family, the maximum association is in four groups indicating the basic number for the family. The presence of some extra-nuclear bodies in the pollen mother cells could be noted. These take bright stain with crystal violet but are Feulgen-negative.
The karyotypes of four species worked out by the present authors, have been analysed. Moreover, the range of size variation in somatic chromosomes within the family have been compared and taxa possessing chromosome numbers in multiples of 5 (gametic) or 10 (somatic) have been enlisted. The phylogenetic significances of the presence of diverse nature of karyotypes, participation of unequal bivalents in units of secondary association and also the occurrence of both consistent and inconsistent numbers of chromosomes in members of the family have been discussed.