Meiotic Studies in Some Members of Caesalpiniaceae R. Br. from the Western Himalayas (India)

Abstract

SummaryThe present paper deals with meiotic studies on 31 populations covering nine species belonging to three genera of the family Caesalpiniaceae from different geographical areas of the Western Himalayas. Variable chromosome number reports for Cassia demidiata (2n=32) and C. mimosoides var. wallichiana (2n=32) world-wide and Caesalpinia decapetala (2n=22) in India have been added to the previous reports of these species. The course of meiosis varies from normal to abnormal in different populations of three species: Caesalpinia decapetala, Cassia fistula, and C. occidentalis. Meiotic abnormalities are in the form of cytomixis, chromosomal stickiness, and formation of laggards and bridges, all resulting in abnormal microsporogenesis. Heterogenously sized fertile pollen grains and reduced reproductive potentialities have invariably been observed in all the meiotically abnormal populations.

Variations of morphology, ecology and chromosomes ofAconitum heterophyllumWall., an endangered Alpine medicinal plant in Himalayas

“…Cytomixis and chromatin stickiness result from genetic factors (Fadaei et al 2010) or environmental factors (Nirmala and Rao 1996) as well as genetic-environmental interaction (Baptista-Giacomelli et al 2000). Cytomixis or occurrence of multipolar cells and meiotic irregularities in anaphase segregation of chromosomes seems to be responsible for the formation of large-sized pollen grains and low pollen fertility in these meiotically abnormal populations, as has been reported earlier in several angiosperms (Rani et al 2011). Hypo-and hyperploid PMC formation is attributed to cytomixis (Fadaei et al 2010;Jeelani et al 2012;Kumar et al 2013;Rani et al 2013), which, especially when accompanied by other meiotic abnormalities, leads to anomalous microsporogenesis resulting in the formation of variablesized pollen grains (Nirmala and Rao 1996).…”

“…Aconitum L. contains 300 species globally (cf. Rani et al 2011). Of these, 181 species/197 cytotypes have been determined, with chromosome numbers of 2n = 16-64, including 42.54% polyploids species (Rani et al 2011).…”

“…Rani et al 2011). Of these, 181 species/197 cytotypes have been determined, with chromosome numbers of 2n = 16-64, including 42.54% polyploids species (Rani et al 2011). Of 27 taxonomically known species from India, chromosome numbers are known in 12; 50% have a polyploid nature; and x = 8 is be the base number for the genus (Rani et al 2011).…”

“…A number of studies of this species have been performed including chemical characterization (Jabeen et al 2011), cultivation (Nautiyal et al 2006;Srivastava et al 2011), molecular profiling, conservation and sustainable utilization (Nautiyal and Nautiyal 2004;Seethapathy et al 2013), reproductive biology , ecology (Bhat et al 2014) and cytology (Siddique, Beigh, et al 1998;Rani et al 2011).…”