Cytological investigations of some polypetalous plants from District Sirmaur of Himachal Pradesh in the Western Himalayas, India

Abstract

As a part of our programme to explore and evaluate genetic diversity of flowering plants of Western Himalayas, at present 180 species of Polypetalae have been cytologically worked out for the first time from District Sirmaur of Himachal Pradesh in the Western Himalayas. New/ varied chromosome numbers are recorded for 37 species (39 cytotypes) belonging to 25 genera of 15 families of polypetalous plants. The taxa being cytologically worked out for the first time on worldwide basis include eight species as Caltha alba (2n=32), Corydalis ramosa (2n=16), Geum elatum (2n=28), Heracleum canescens (2n=22), Pleurospermum brunonis (2n=22), Rhodiola wallichiana (2n=28), Saxifraga parnassifolia (2n=16), and Stellaria semivestita (2n=26). New intraspecific cytoypes have been recorded at present against previously known cytotypes of some soecies on worldwide basis in case of 15 species as, Cassia mimosoides var. wallichiana (2n=32), Duchesnea indica (2n = 28), Geum roylei (2n=28), Impatiens bicornuta (2n=14), I. laxiflora (2n=14, 16), Nasturtium officinale (2n=16), Pimpinella acuminata (2n=18), Potentilla atrosanguinea (2n=28), P. gerardiana (2n=28), Sibbaldia cuneata (2n=28), Sibbaldia micropetala (2n=14, 28), Sida cordifolia (2n=16), Saxifraga diversifolia (2n=16), Stellaria monosperma (2n=26) and Stellaria media (2n=26), Likewise, ten species have been cytologically worked out for the first time from India as: Berberis vulgaris (2n=28), Bergenia ciliata (2n=34), Chaerophyllum aromaticum (2n=22), Epilobium palustre (2n=36), Geranium ocellatum (2n=36), Potentilla argyrophylla (2n=56), Saxifraga brunonis (2n=16), Saxifraga sibirica (2n=16), Sedum multicaule (2n=28), and Thalictrum minus (2n=14). Moreover for 4 species, varied cytotypes are being reported on India basis as: Potentilla kleiniana (2n=14), Sida cordata (2n=16) Silene vulgaris (2n=48), and Trifolium repens (2n=16). Sirmaur is the southeastern district of Himachal Pradesh forming distinct phyto-geographical pocket of Western Himalayas and lies between latitude 30°22'30" and 31°01'20" north and longitude 77°01'12"and 77°49'40" east, occupying an area of 2,826 km 2 with altitudinal ranges from 400-3,630 m. In this area subclass Polypetalae is represented by 59 families, 194 genera and 334 species including cultivated ones (Kaur and Sharma 2004). Since the area of investigation i.e. district Sirmaur (H.P.) is new to study, all the species have been cytologically worked out for the first time from this part. A perusual of literature shows total absence of cytological picture of this vast diverse flora except for single report by (Bala et al. 2010) on Erigeron karvinskianus, (2n=36) of the family Asteraceae of Gamopetalae. To study the genetic diversity at intra-and interspecific levels and to further enrich the chromosomal database of angiospermic species from India, the present meiotic studies based programme of polypetalous plants has been carried out around the whole year covering maximum localities of this part of the Western Himalayas. Though 180 species of polypetalae have been cytologically studied by us from this region, the present paper deals with the meiotic studies on 37 species with new /varied chromosome counts.