Karyotypic studies on certain members of Cyperaceae from Punjab, north west India.

Abstract

The members of Cyperaceae, referred to as sedges, are common in the Punjab as nearly 36 species are known from the state flora (Nair 1978) and 25 species are recorded from Patiala itself (Sharma and Bir 1978). Inspite of a large amount of work on the cytology of sedges both in India and elsewhere, studies on the mitotic chromosomes are few and practically no work has been done on the members of north Indian plains. Therefore, the present work on karyotypes of 10 species belonging to four genera was taken up not much with the idea of recording the chromosome numbers but with the objective of bringing out the variability, if any, amongst individuals of different populations. Materials and methodsCertain sedges offer a distinctive advantage in that in the young pollen, mitosis can be studied with a fairly good ease and the presence of a single set of chromo somes makes the analysis of karyotypes easy. For pollen mitosis, not earlier ob served in sedges, young spikes were fixed in 1:3 mixture of glacial acetic acid and ethyl alcohol for 24 hours. Acetocarmine squashes of young pollen were made and slides made permanent in euparol following usual procedures. Camera lucida drawings of mitotic chromosomes were made at a constant magnification for all the species so as to note the comparable chromosome sizes. Following Stebbins (1971), chromosomes were marked with respect to the position of centromere (V-meta centric, L-submetacentric and J-acrocentric). Idiograms were drawn at constant magnification with primary constrictions represented by 2mm gap and secondary constriction by 1mm gap. Chromosome gradient index (GI)I and chromosome symmetry index (SI)2 are calculated according to Pritchard (1967). In GI and SI values, an arbitrary value of 50 is taken as a threshold between symmetrical and asymmetrical karyotypes, species scoring values above this figure have symmetrical karyotypes while those with lower values indicate the asymmetrical condition. Vouchers are preserved in PUN.1 GI is affected by size of chromosomes.More the difference in smallest and largest chromo some, less will be the value of GI and karyotype will be asymmetrical. 2 If in a taxon short and long arms of chromosomes are equal or almost equal (i.e. chromo some are meta or submetacentric), SI value will be high and karyotype is symmetrical and if the differences in short and long arms of chromosomes are greater, the position will be reverse.

Chromosome Number Reports in Six Species of <i>Cyperus</i> Linn. from North India

“…It is a tetraploid cytotype based on x=10. Previously, the species showed chromosomal diversity with four cytotypes, n=36, 40, 42 and 44 (Bir et al 1988, Cheema et al 1993a and n= 40 (Rath and Patnaik 1975) in the studies on North Indian sedges from our laboratory.…”

“…From Southern India, Tejavathi and Nijalingappa (1990) observed mitosis of nineteen species of sedges and Subramanian (1988) worked out 18 species under six genera of Cyperaceae. Bir et al (1988Bir et al ( , 1990Bir et al ( , 1992Bir et al ( , 1996, Bir and Cheema (1994), Cheema et al (1992Cheema et al ( , 1993a, Cheema and Bir (1996), reported meiotic chromosome counts for 125 taxa under 44 species from NW India. Further Cheema et al (2017) reported meiosis in 10 species of Cyperaceae and Cheema et al (2018) worked on C. tenuispica from North India and recorded new chromosome number (2n=14).…”

Cytogenetics, genome size and anther anatomy inBulbostylis(Cyperaceae)

“…flavescens Roseng. (Q 3952), and then placed together in a Petri dish (96 mm) with 0.5 ml nuclear extraction buffer from (1972,1975), mehra and sachdeva (1975) 5 ii Kral (1971), rath and Patnaik (1975, 1978, Bir et al (1986Bir et al ( , 1988Bir et al ( , 1990Bir et al ( , 1992 Kral (1971) the kit Partec CyStain PI Absolute P (05-5022). Samples were ground with a razor blade.…”

Chromosome Numbers and Basic Chromosome Numbers in Monocotyledonous Genera of the Western Himalayas (India)

“…Cytologists have examined grasses from different parts of India: eastern (Sharma and Sharma, 1961;Sharma and Chatterjee, 1967;Sanyal and Sharma, 1972a,b;Mehra and Sachdeva, 1975;Mehra, 1982), northeastern (Mehra and Chaudhary, 1981;Kalia and Mehra, 1986;Christopher and Jacob, 1990), central (Koul and Paliwal, 1964;Gill et al, 1980), southern (Venkateswarlu and Pantulu, 1970;Christopher and Abraham, 1971;Christopher et al, 1987;Nijalingappa and Bai, 1990;Rao et al, 1993;Nair et al, 1999;Kameshwari and Muniyamma, 2001) and northern (Mehra and Kohli, 1966;Sharma and Kaur, 1980;Sharma and Kumar, 1985;Bir et al, 1987;Gupta et al, 2008;Gupta and Gupta, 2008). For northwest India -Punjab along with part of Haryana covered in the last decade - Bir et al (1986Bir et al ( , 1990, Cheema and Bir (1995), Gupta and Gupta (2008), Gupta et al (2008), Gupta (2009) and Kaur andGupta (2008-2009) have made significant studies of members of the Cyperaceae and Poaceae families. For the Western Himalayas a large number of cytological reports are available for monocots from Kashmir (Mehra and Remanandan, 1973;Mehra and Sharma, 1977;Mehra and Pandita, 1984;Pandita and Mehra, 1984;Pandita, 1986;Gohil and Koul, 1988;Koul and Gohil, 1989, 1991.…”