Cytological studies of Angiosperms (174 species) from District Kangra, Himachal Pradesh (India).

摘要

During the present study, 360 populations of 174 species belonging to 82 genera and 23 families of dicots have been cytologically worked out from different localities of District Kangra (Himachal Pradesh) between 550 and 3,800 m altitude. As many as 10 species including Berberis ceratophylla (2n=28), Caltha alba (2n=32), Corydalis meifolia (2n=16), C. thyrsiflora (2n=16), Impatiens reidii (2n=14), Indigofera hamiltonii (2n=16), Potentilla thomsonii (2n=14), Sedum trifidum (2n=36), Stellaria semivestita (2n=26) and Viola canescens (2n=12) have been cytologically worked out for the first time at world level. New intraspecific diploid cytotypes have been recorded in 11 species while new intraspecific tetraploid cytotypes are noticed in 15 species. B-chromosomes have also been reported in 3 species viz. Anemone obtusiloba, Clematis grata and Ranunculus diffusus for the first time at world level. The species of the area are active state of evolution, depicting heterogeneity in chromosome numbers involving polyploidy (48 species, 28.18%) as well as irregular meiotic behavior. The meiotic abnormalities have been witnessed in 69 species (39.65%) showing different types of irregularities such as cytomixis, interbivalant connections, unoriented bivalents, chromatin stickiness, chromosomal laggards and bridges as well as abnormal microsprogenesis. All these meiotic abnormalities lead to reduced pollen fertility and formation of variable sized pollen grains in most of these species.