Simple Chromocenter Type Research Articles

Karyomorphological studies on halophytic plants. I. Some taxa of Chenopodium.

1. Karyomorphological studies were carried out in halophytic and nonhalophytic Chenopodium.2. Halophytic C. glaucum was dipolid with n=9, 2n=18; semi-halophytic C. acuminatum var. japonicum was tetraploid with n=18, 2n=36, non-halophytic C. album was hexaploid with n=27, 2n=54, C. album var. centrorubrum hexaploid with 2n=54, and C. ambrosioides var. pubescens n=16, 2n=32.3. The five taxa were found to have similar karyomorphological features categorized into the same ‘simple chromocenter type’ at resting stage, proximal and gradient heterochromatic type at prophase, and homogeneous type in size and symmetric type in arm-ratio at metaphase.4. Morphological features of chromosomes were found to be correlated to the phylogenetic interrelationships in taxa, while no particular feature was found in relation to halophytic habit, except for polyploidy.5. It was proposed that the morphological features of the chromosomes appear not as the product of adaptive reaction to the environmental conditions but as the product of phylogenetic reaction.

Karyomorphological Studies in Some Parasitic Species of the Scrophulariaceae, I

A karyomorphological comparison of four genera of the tribe Buchnereae and two genera of the tribe Euphrasieae, root parasites of the subfamily Rhinanthoideae of the Scrophulariaceae, is presented along with 12 new chromosome counts. The interphase nuclei are of the simple chromocenter type. Macranthera and Aureolaria have more subtelocentric chromosomes than those of the other genera studied, which indicates higher asymmetric variation in their karyotypes. In all the karyotypes decrease in size from the longest to the shortest chromosomes is gradual. All the species studied show karyotypic heteromorphology and heteromorphic homologous chromosomes.