干旱区生态环境知识资源中心

Present work pertains to the cytological investigations performed in Ranunculus laetus for the first time from Indian cold deserts and adjoining high hills of North-west Himalayas which covers Chamba, Kinnaur, Kullu and Lahaul-Spiti districts of Himachal Pradesh. We here also report for the first time the presence of 1 B-chromosome in two accessions studied from Dalhousie hills. Twelve accessions scored presently from these regions uniformly shared the same meiotic chromosome number, n=14 and existed at tetraploid level (based on x=7). Of these, eight accessions showed abnormalities during male meiosis, such as pollen mother cells (PMCs) involved in chromatin transfer at different stages of meiosis, chromosome stickiness, pycnotic chromatin material, out of plate bivalents at metaphase-I, nonsynchronous disjunction of some bivalents, and laggards at anaphases/telophases. Consequent to these meiotic irregularities, microsporogenesis in meiocytes is abnormal characterized by the presence of dyads, polyads, and micronuclei and included micronuclei in sporads. These irregularities during meiotic course resulted into varying percentage of pollen sterility (9-31%) and pollen grains of heterogeneous sizes. The remaining four accessions showed regular meiotic course, normal microsporogenesis and nearly cent percent pollen fertility (97.90-100%).