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- Title
Male meiosis, morphometric analysis and distribution pattern of 2x and 4x cytotypes of Ranunculus hirtellus Royle, 1834 (Ranunculaceae) from the cold regions of northwest Himalayas (India).
- Authors
Kumar, Puneet; Singhal, Vijay Kumar
- Abstract
In this study, we examined the chromosome number, detailed male meiosis, microsporogenesis, pollen fertility and morphological features and distribution of 2x and 4x cytotypes of Ranunculus hirtellus Royle, 1834. The majority of the populations scored now from cold regions of the northwest Himalayas showed tetraploid (n=16) meiotic chromosome count and one of the populations studied from the Manimahesh hills existed at diploid level (n=8). The individuals of diploid cytotype exhibited perfectly normal meiotic course resulting in 100% pollen fertility and pollen grains of uniform sizes. On the other hand, the plants of the tetraploid cytotype from all the populations in spite of showing normal bivalent formation and equal distribution to the opposite poles at anaphases showed various meiotic abnormalities. The most prominent among these meiotic abnormalities was the cytomixis which involved inter PMC (pollen mother cell) chromatin material transfer at different stages of meiosis-I. The phenomenon of cytomixis induced various meiotic abnormalities which include chromatin stickiness, pycnotic chromatin, laggards and chromatin bridges, out of plate bivalents at metaphase-I, disoriented chromatin material at anaphase/ telophase and micronuclei. Consequently, these populations exhibited varying percentages of pollen sterility (24 - 77 %) and pollen grains of heterogeneous sizes. Analysis of various morphometric features including the stomata in 2x and 4x cytotypes showed that increase in ploidy level in the species is correlated with gigantism of vegetative and floral characters and the two cytotypes can be distinguished from each other on the basis of morphological characters. The distribution patterns of the 2x and 4x cytotypes now detected and 2x, 3x, 4x cytotypes detected earlier by workers from other regions of the Indian Himalayas have also been discussed.
- Subjects
HIMALAYA Mountains; CHROMOSOMES; STOMATA; RANUNCULACEAE; POLLEN
- Publication
Comparative Cytogenetics, 2011, Vol 5, Issue 3, p143
- ISSN
1993-0771
- Publication type
Article
- DOI
10.3897/CompCytogen.v5i3.1359