Manjit Inder Singh Saggoo

Male meiosis and behaviour of sex chromosomes in different populations of Rumex acetosa L. from the Western Himalayas, India

Detailed meiotic analysis in 28 North West Himalayan populations of dioecious plant Rumex acetosa L. was carried out. The species is generally discussed as an important plant having sex chromosomes. Male meiosis in all the studied populations clearly showed the formation of six bivalents and one trivalent during diakinesis and metaphase-I. The sex chromosomes in male plants exhibit a chain of trivalent (Y1–X–Y2). In addition, among the presently investigated populations ring-shaped trivalents were also observed for the first time in the species. Varied frequency of abnormal segregation of sex trivalent was also observed leading to XY:Y segregation instead of normal X:Y1Y2 segregation. A majority of the populations exhibit normal meiosis. Plants of six populations show meiotic abnormalities like cytomixis, laggards, bridges, chromatin stickiness, etc., leading to reduced pollen fertility. Translocation between an autosome and sex chromosomes was also observed in some of the populations. 0–1B chromosomes were noticed in one population. This is the first ever meiotic analysis of the species from India.

Cytology in few medicinally important wild taxa from high altitude regions of North-West Himalaya of Himachal Pradesh (India)

The aim of the present study was to explore the cytological knowledge in few medicinally important wild flowering plants inhabiting high altitude regions of northwest Himalaya. Meiotic studies were performed in 14 populations of five species, namely, Euphrasia himalayica Wettst. (2n=22), Lancea tibetica Hook. f. & Thomson (2n=18), Phlomis bracteosa Royle ex Benth. (2n=44), Picrorhiza kurrooa Royle ex Benth. (2n=34) and Thymus linearis Benth. (2n=26) growing in Lahaul-Spiti and Chamba districts of Himachal Pradesh. Phlomis bracteosa, is a tetraploid while other species are at diploid level. The report of 2n=18 for Lancea tibetica is the first ever chromosome number record for the genus on world-wide basis while diploid chromosome count for E. himalayica and tetraploid count for P. bracteosa are new to science. For rest of the species previous reports have been confirmed.

Cytomorphological investigations in Oxyria digyna Hill. from the Kashmir Himalaya, India

In the present paper, detailed cytomorphological investigations in Oxyria digyna Hill. from Kashmir Himalaya—India have been reported for the first time. All the 14 investigated populations of O. digyna are diploid based on x = 7. Out of these in two populations 0–2B chromosomes have been recorded for the first time while 6 populations differed significantly in their meiotic characteristics. Meiotic abnormalities during male meiosis observed include inter PMC chromatin transfer (cytomixis). Non-synchronous disjunction of some bivalents, laggards and bridges at anaphases and telophases. Consequent to these meiotic anomalies, microsporogenesis in meiocytes is abnormal resulting in to dyads, triads and polyads with or without micronuclei. The overall effect is seen in reduced pollen fertility. Unreduced pollen grains were observed in some populations, which differed significantly in their size compared to the normal (reduced) pollen grains. It is observed that a smaller frequency of pollen grains differed morphologically in Aharbal and Yosmarg populations. The remaining eight populations showed regular meiotic course, normal microsporogenesis and high percentage of pollen fertility (95.09–99.09 %).