Cytological Observations on Some W. Himalayan Monocots Ll
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Cytologia 41: 5-22, 1976 Cytological Observations on some W. Himalayan Monocots ll. Smilacaceae, Liliaceae and Trilliaceae P. N. Mehra and S. K. Sachdeva Department of Botany, Panjab University, Chandigarh, India Received May 16, 1974 Hutchinson (1959) segregated most of the woody non-xerophytic members from the former family Liliaceae and placed them into several distinct families like Smila caceae, Ruscaceae and Philesiaceae and also raised the tribe Parideae of Krause (1930) to the family level designated as Trilliaceae. The family Liliaceae (sensu Hutchinson) now consists of 250 genera and 3,700 species, while the family Smilaca ceae includes 4 genera and 375 species (Willis 1966). The family Trilliaceae is the smallest of the three being comprised of 4 genera and 53 species (Willis l.c.). A perusal of the literature reveals that cytological data on Smilacaceae are rather meagre, but the families Liliaceae and Trilliaceae have been fairly well studied as they provide ideal material for such investigations. Although a number of reports on the cytology of Indian members have appeared, several W. Himalayan taxa are still unexplored. In order to fill this gap the present study was undertaken. This communication presents cytological data on 17 taxa of this region. Materials and methods The materials were collected from nature in the W. Himalayas. Voucher specimens have been deposited in the Herbarium of the Department of Botany, Panjab University, Chandigarh. For meiotic studies flower buds were fixed in 1:3 acetic alcohol with an addition of a little chloroform for a period of about 24 hours and then transferred to 95% alcohol. Squashes were made in 2% aceto carmine. For mitotic studies young root-tips were pretreated with 0.003M solution of 8-hydroxyquinoline for 3-4hours. The root-tips were rinsed in water, fixed in 1:3 acetic alcohol and macerated in 9:2 mixture of 2% lacmoid solution in 45 acetic acid and N.HCI. Squashes were made in 2% aceto-lacmoid solution. Graph paper ruled in 1mm squares was used for drawing idiograms. The primary con striction was represented by 2mm gap and the secondary constriction by 1mm gap. In determining the chromosome morphology Battaglia's (1955) terminology was employed. The terms median, submedian, subterminal and terminal chromo somes have been used for describing their morphology. Unless otherwise stated, the photomicrographs were made at a uniform magnification of •~1500. Ex planatory diagrams have been given wherever found necessary. Photomicrographs have been taken on Printon R Agfa films. The prints were made using different grades of Agfa glossy paper. 6 P. N. Mehra and S. K. Sachdeva Cytologia 41 Results Table 1 lists the species, their chromosome numbers and the specific localities from where they were collected. The details are as follows: Table 1. 1976 Cytological Observations on some W. Himalayan Monocots II 7 Table I (cont'd) * Species investigated for the first time . t New chromosome number report (New Cytotypes) . Literature cited in Table 1 according to Darlington and Wylie (1955), Cave et al. (1956-1968), Love and Love (1961), Fedorov (1969) and Taxon (1969-1973). Smilacaceae Smilax L. Seven species of the genus are met with in the W. Himalayas (Hooker 1894). Three species have presently been worked out. S. aspera L. is well represented in the Simla hills between 1,500-2,100m. Its roots are valued as substitute for Indian sarsaparilla. PMCs revealed the haploid chromosome number to be n=16 (Fig. 1). Meiosis was normal. The present count conforms to the report of Carvalho (1948). S. elegans Wall. occurs in the Kumaon hills at an altitude of 1,800-2,100m. Its chromosome number, as determined from PMCs, was found to be n=16 (Fig. 2). The course of meiosis was perfectly normal. The species has been studied for the first time. S. parvifolia Wall. is common in the Simla and Kumaon hills at 1,500-2,100m. PMCs revealed 16 bivalents at M-I (Fig. 3). Meiosis was regular. This is the first report for the species. A study of the literature reveals that only fragmentary reports on some of the species of the genus exist. Mention may be made of the work of Lindsay (1930), Nakajima (1933, 1937), Jensen (1937), Lewis et al. (1962) and Larsen (1966). The genus is polybasic with x=13, 14, 15 and 16 (Darlington and Wylie 1955). All the species investigated to date are diploids with the sole exception of S. china which is a tetraploid with 2n=60 (Sato 1942). Liliaceae 8 P. N. Mehra and S. K. Sachdeva Cytologia 41 Asparagus L. Five species occur in the W. Himalayas of which three have been presently studied. A. curillus Ham. is met with in the Kumaon hills at 900-1,500m. Ten bivalents were discernible at M-I (Fig. 4). Meiosis was normal. The present finding con Figs. 1-6. 1, Smilax aspera, n=16 at early M-I . 2, S. elegans, n=16 at early M-I (arrows in dicate univalents). 3, S. parvifolia , n=16 at M-I. 4, Asparagus curillus, n=10 at M-I f . 5, A. ilicinus, n=10 at M-I. 6, Smilacina purpurea , 2n=36 in root-tip mitosis. All •~1500 . 1976 Cytological Observations on some W. Himalayan Monocots II 9 firms the report of Malik and Tandon (1959). A. filicinus Ham. was collected from the Kashmir hills at 1,500-2,100m. At M-I ten bivalents were observed (Fig. 5). Meiosis was found to be regular. The present report is in conformity with the findings of Larsen (1963). A. racemosus Willd. occurs commonly in the Nainital and Kashmir hills at an altitude of 900-1,500m. Meiotic chromosome number in the species was found to be n=10 (Fig. 7). The course of meiosis was normal. This report is in agree Figs. 6a-9. 6a, explanatory diagram to Fig. 6. 7, Asparagus racemosus, n=10 at M-I. •~2500. 8-9. Eremurus himalaicus. 8, A-1 showing seven chromosomes at each pole. 9, pollen mitosis showing n=7. Both •~1500. ment with the findings of Sharma and Bhattacharyya (1957). Thombre (1959) and Raju (1960), however, observed 2n=30 and 2n=40 respectively, obviously indicat ing the existence of cytological races in this species. Smilacina Desf. Only one species of this genus, S. purpurea occurs in the W. Himalayas. 10 P. N. Mehra and S. K. Sachdeva Cytologia 41 S. purpurea Wall, occurs commonly in the Simla and Kumaon hills between 2,700-3,300m. Root-tip mitoses gave a mitotic count of 2n=36 chromosomes (Figs. 6, 6a). The karyotype consisted of ten pairs of large and eight pairs of small chromosomes (Fig. 19). Of the large chromosomes, two pairs possessed median primary constriction, three pairs submedian and five pairs subterminal primary constriction. One chromosome pair had two secondary constrictions, one situated subterminally and the other submedianly in the long arm. Of the eight pairs of small chromosomes, three were median, three submedian and two subterminal. Chromosome size ranged from 10ƒÊ to 3ƒÊ. Mehra and Pathania (1960) earlier reported n=18 in this species. The base number for the genus is x=9 (Darlington and Wylie 1955) and the species, therefore, is at tetraploid level. Majority of the species of this genus investigated to date are also tetraploids. However, Kwano (1966) observed tetraploid, octaploid and 16 ploid races in a single species S. racemosa. Photomicrographs of S. japonica var. robusta and S. yezoensis given by Hara and Kurosawa (1963) and that of S. formo sana by Chuang et al. (1963) showed the basic karyotypes to consist of ten pairs of large and eight pairs of small chromosomes, thus agreeing exactly with the Himala yan species. Eremurus Bieb. E. himalaicus Baker is widespread on dry rocks of Kashmir hills at 2,100 3,000m. It is a highly ornamental horticultural plant with white flowers . The chromosome number was determined from PMCs and pollen mitoses . PMCs revealed n=7. At A-I 7:7 distribution of chromosomes was observed (Fig. 8). Meiosis was normal. Pollen mitoses too showed n=7 (Fig. 9) . The karyotype consisted of five large and two small chromosomes (Fig . 20). All the five large chromosomes possessed subterminal primary constriction . Of the two small chromosomes, one possessed median and the other submedian centromere. None of the chromosomes showed secondary constriction . Chromosome size ranged from 9ƒÊ to 4ƒÊ. The present report is in agreement with the findings of Burstrom (1929) and Oksala and Therman (1958). Sato (1942) described the karyotype of E . robustus (2n=14) in which he observed five pairs of large chromosomes with subterminal primary constriction and two pairs of short chromosomes also with subterminal primary constriction, thus suggesting a highly advanced type of karyotype in the species. The presently worked out species is diploid , x=7 being the base number for the genus. Polyploidy does not seem to have played any role in the evolution of species within the genus, as all the species hitherto investigated are diploids . Lilium L. Six species of this genus occur in the W . Himalayas (Hooker 1894). Two species have presently been worked out . L. cordifolium Thunb. occurs in the interior ranges of the Kumaon hills between 1,800-3,000m. The chromosome number was determined only from root -tip mitoses which showed 2n=24 (Fig. 10) . The karyotype is asymmetrical with a very gradual transition from long to short chromosomes except for two chromo somes (Fig. 21). The two largest pairs had submedian primary constriction and one of these possessed a secondary constriction in the short arm . All the remaining 1976 Cytological Observations on some W. Himalayan Monocots II 11 ten pairs were with subterminal primary constriction and of these, two pairs had a subterminal secondary constriction in the long arm.