Pleione 7(1): 219 - 227. 2013. ISSN: 0973-9467 © East Himalayan Society for Spermatophyte Taxonomy Karyomorphological observations on some taxa of Asteraceae of Nepal 1 2 1 Pushpa Karna (Mallick) , Laxmi Manandhar and Buddha Laxmi Vaidya 1Tri-Chandra Multiple Campus, Ghantaghar, Kathmandu, Nepal 2Central Department of Botany, Kirtipur, Nepal [Received revised 15.06.2013; Accepted 20.06.2013] Abstract Chromosome number and karyomorphology of ten taxa of Asteraceae viz. Ageratum conyzoides Linnaeus, Anaphalis triplinervis (Sims) C.B. Clarke var. triplinervis, Aster peduncularis subsp. nepalensis Grierson, Bidens pilosa var. minor (Blume) Sherff, Crassocephalum crepidioides (Bentham) S. Moore, Eupatorium adenophorum Sprengel, Sonchus asper (Linnaeus) Hill, Spilanthes calva de Candolle, Tagetes patula Linnaeus, Rhynchospermum verticillatum Reinwwart collected from different parts of Nepal were observed. Chromosome numbers in somatic cells were recorded to be 2n = 20 in Ageratum conyzoides, Anaphalis triplinervis var. triplinervis; 2n = 40 in Aster peduncularis subsp. nepalensis; 2n = 24 in Tagetes patula; 2n = 36 in Bidens pilosa var. minor and Spilanthes calva; 2n = 40 in Crassocephalum crepidioides; 2n = 50 in Eupatorium adenophorum; 2n = 18 in Sonchus asper and Rhynchospermum verticillatum. Chromosome number and karyomorphology for Aster peduncularis subsp. nepalensis studied in this research are new report. Chromosome counts of Anaphalis triplinervis var. triplinervis, Eupatorium adenophorum, in the present investigation new numbers of chromosomes have been reported. Chromosome counts of Crassocephalum crepidioides, Rhynchospermum verticillatum and Tagetes patula tally with previous reports. The chromosome number and karyotype of the taxa in the present study except 3 taxa viz. A. conyzoides, C. crepidioides and S. asper are new record for Nepal. Key words: Asteraceae, Chromosome number, karyotypes INTRODUCTION Asteraceae is one of the largest families of flowering plants which comprise ca.1500 genera and 23000 species worldwide (Judd et al. 1999). In Nepal 111 genera and 417 species are reported from different regions (Press et al 2000; Ohashi 1975; Hara & Williams 1979). They are mostly from temperate to tropical regions. Cytological studies of different taxa of Asteraceae appear to be less known. However, karyomorphological studies of several species of Asteraceae have been done by several previous workers including Joshi (1988) and Malla et al (1981). Economically, the plants under present study come under one of the most important families of flowering plants having medicinal, aesthetic, and ornamental values. 220 Karyomorphological observations on some taxa of Asteraceae Leaf juice of Ageratum conyzoides, Bidens pilosa, and Eupatorium adenophorum is applied externally on cuts and wounds to check bleeding (FRBG 21, 2003). Plant paste of Spilanthes calva is applied on snake bite, root paste of Crassocephalum crepidioides is applied on cuts and wounds (DPR 28, 2007). Flower paste of Anaphalis triplinervis is used as an antiseptic application in wounds for both human and cattle (Bhattarai 1989; Pohl 1990). Plant paste of Sonchus asper is applied to wounds and boils (FRBG 21, 2003). Rhynchospermum verticillatum is used as ornamental plants. Roots and seeds of Tagetes patula are purgative, flowers are of great religious value and are used in worshiping ((DPR 28, 2007). MATERIAL AND METHODS Ten genera of Asteraceae were collected from different parts of the Nepal. Voucher specimens and reference slides are deposited in Central Department of Botany, Tribhuvan University, Kathmandu, Nepal. Mitotic study was made from the healthy root tips. Roots were excised at 11 to 12 A.M. and were pretreated in 0.002 mol. 8-hydroxyquinoline for 3 hours. The pretreated root tips were fixed in glacial acetic acid and ethanol in 1:3 ratios. Fixed root tips were stained in 2 % aceto-orcein and squashed with 45 % acetic acid. For karyotype analysis, method of classifying chromosomes suggested by Leven et al. (1964 – 1965) was followed. Photomicrographs of desired plates were taken; camera lucida drawings and ideograms for each taxon was done. RESULTS AND DISCUSSIONS Photomicrographs of desired plates (PLATE - I: Fig. 1a-10a), Camera Lucida drawings (PLATE - II: Fig. 1b-10b) and Ideograms (PLATE - III: Fig. 1c-10c) for each taxon are given below. Cytological observations are summarized in Table 1. Ageratum conyzoids Linnaeus [2n = 20; Voucher No. 101] The karyotype consists of 4 different types of chromosomes with centromere at median point, median region, sub-median region and sub terminal region. The chromosome length ranged from 0.2 to 1.3 µm with mean length 1.4 µm and absolute length 14 µm. TF % is 38.5. Karyotype formula is M6+m4+sm8+st2. Anaphalis triplinervis (Sims) C.B. Clarke var. triplinervis [2n = 20; Voucher No. 102] The karyotype consists of 3 different types of chromosomes with centromere at median point, median region, and sub terminal region. The chromosome length ranged from 0.2 to 1.3 µm with mean length 1.3 µm and absolute length 13.1µm. TF % is 40.4. Karyotype formula is M8+m10+st2. Aster peduncularis subsp. nepalensis Grirson [2n = 40; Voucher No. 103] The karyotype consists of 3 different types of chromosomes with centromere at median point, median region, and sub median region. The chromosome length ranged from 0.2 to 1.3 µm with mean length 1.1 µm and absolute length 23.6µm. TF % is 41.5. Karyotype formula is M18+m2+sm18. Bidens pilosa Linnaeus var. minor (Blume) Sherff [2n = 36; Voucher No. 104] The karyotype consists of 4 different types of chromosome with centromere at median point, median region, sub median region and sub terminal region. The chromosome length Pushpa Karna (Mallick) et al 221 ranged from 0.2 to 1.3 µm with mean length 1.0 µm and absolute length 19.2 µm. TF % is 38.5. Karyotype formula is M16+m2+sm16+st2. Crassocephalum crepidioides (Bentham) S. Moore [2n = 40; Voucher No. 105] The karyotype consists of 3 different types of chromosomes with centromere at median point, median region and sub median region. The chromosome length ranged from 0.2 to 1.7 µm with mean length 1.0 µm and absolute length 20.6 µm. TF % is 42.2. Karyotype formula is M22+m2+sm16. Eupatorium adenophorum Sprengel [2n = 50; Voucher No. 106] The karyotype consists of 4 different types of chromosome with centromere at median point, median region, sub median region and sub terminal region. The chromosome length ranged from 0.1 to 0.8 µm with mean length 0.7 µm and absolute length 18.4 µm. TF % is 34.7. Karyotype formula is M4+m12+sm30+st4. Rhynchospermum verticillatum Reinwardt [2n = 18; Voucher No. 138] The karyotype consists of 3 different types of chromosomes with centromere at median point, median region and sub median region. The chromosome length ranged from 0.2 to 0.5 µm with mean length 0.5 µm and absolute length 5.1 µm. TF % is 39.2. Karyotype formula is M4+ m8+Sm6. Sonchus asper (Linnaeus) Hill [2n = 18; Voucher No. 107] The karyotype consists of 3 different types of chromosomes with centromere at median point, median region, and sub median region. The chromosome length ranged from 0.41 to 2.1 µm with mean length 1.9 µm and absolute length 17.3 µm. TF % is 40.1. Karyotype formula is M6+m6+s6. Spilanthes calva de Candolle [2n = 36; Voucher No. 108] The karyotype consists of 4 different types of chromosomes with centromere at median point, median region, sub median region and sub terminal region. The chromosome length ranged from 0.2 to 1.3 µm with mean length 0.9 µm and absolute length 16.9 µm. TF % was 39.0. Karyotype formula is M14+m2+sm18+st2. Tagetes patula Linnaeus [2n = 24; Voucher No. 109] The karyotype consists of 4 different types of chromosomes with centromere at median point, median region, sub median region and sub terminal region. The chromosome length ranged from 0.4 to 1.7 µm with mean length 1.7µm and absolute length 21.2 µm. TF % was 40. 5. Karyotype formula is M8+m8+sm6+st2. Previous cytological works of Mehra & Remanandan (1975), Gaonkar & Torne (1991) showed two different haploid numbers (n = 10, 20) in Ageratum conyzoides. Maharjan (1977) reported n = 20 and Nirmala & Rao (1981) reported 2n = 20 in this taxon. Present study with 2n = 20 in this taxon tallies with the result of Nirmala & Rao (1981). According to the results of Morton (1993) and Dey (1979), the diploid number is 2n = 40 in this plants . However, Husaini & Iwo (1990) confirmed the number n = 18. Ageratum conyzoides have been found in three cytotypes. Haploid chromosome number n = 18 may be aneuploid situation. The cytological observation by Love & Love (1982) was with the haploid number n = 14 in Anaphalis triplinervis var. triplinervis. However in the present study, the diploid number is 2n = 20 for this species. In Aster peduncularis subsp. nepalensis, the diploid number 2n = 40 is observed this perhaps a new record for this taxon. 222 Karyomorphological observations on some taxa of Asteraceae Table 1. Karyomorphology of ten different members of Asteraceae. Name of the plants Chrom. Range of Mean Absolute Karyotype TF% Fig Number chrom. length length formula no. (2n) Length (µm) (µm) (µm) Ageratum conyzoides 20 0.2-1.3 1.4 14 M6+m4+sm8+st2 38.5 1a, 1b,1c Anaphalis triplinervis 20 0.2-1.3 1.3 13.1 M8+m10+st2 40.4 2a, var. triplinervis 2b,2c Aster peduncularis 40 0.2-1.3 1.1 23.6 M18+m4+sm18 41.5 3a, subsp. nepalensis 3b,3c Bidens pilos var. minor 36 0.2-1.3 1.0 19.2 M16+m2+sm16+st2 38.5 4a, 4b,4c Crassocephalum 40 0.2-1.7 1.0 20.6 M22+m2+sm16 42.2 5a, crepidioides 5b,5c Eupatorium 50 0.1-0.8 0.7 18.4 M4+m12+sm30+st4 34.7 6a, adenophorum 6b,6c Sonchus asper 18 0.41to 1.9 17.3 M6+m6+s6.