Cytology of Some W. Himalayan Ranunculaceae P. N. Mehra and P
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Cytologia 37: 281-296, 1972 Cytology of Some W. Himalayan Ranunculaceae P. N. Mehra and P. Remanandan Departmentof Botany,Panjab University, Chandigarh-14,India ReceivedSeptember 24, 1970 Introduction Ranunculaceae is a moderately large family, chiefly of the temperate regions of the Northern Hemisphere with 35 genera and about 1,500 species. In India it is represented by 115 species belonging to 19 genera (Hooker 1882), a majority of which are distributed in the alpine and sub-alpine belts of the Himalayas. The family is of considerable importance because of its relatively primitive position in the hier archy of flowering plants and inclusion in it of a number of important ornamental and medicinal plants. On these scores the family deserves a greater attention on the part of cytogeneticists than it has so far received. The previous work on the family is rather scattered. The more important contributions in the field are those of Langlet (1927, 32, 36), Stebbins (1938), Gregory (1941), Zhukova (1961) and recently of Kurita (1959, 61, 62, 66, 67) who has studied the karyotypes of a number of taxa. Members of the family growing in India have hitherto attracted little atten tion. Barring a few reports of chromosome numbers by Sobti and Singh (1961) on Ranunculus sps. and Mehra and Sobti (1955) on Indian aconites no work of any significance has so far been attempted. The present paper gives a cytological account of 23 taxa met with in the Western Himalayas, based mostly on meiotic studies. Material and method The material for the present investigation was collected from the wild sources in Kashmir, Simla and Kumaon hills within an altitude range of 100-5,000m. The plants were identified in the field with the help of local floras and confirmed by comparing them at the Central National Herbarium, Calcutta. The voucher speci mens have been deposited in the Herbarium of the department of Botany, Panjab University, Changigarh-14. Cytological studies were made mainly from the pollen mother cells at meiosis. Flower buds were fixed in carnoy's fluid. Acetocarmine technique was employed for staining the chromosomes. In order to detect the existence of intraspecific cytological races, same species was screened from a wide range of localities. All the photomicrographs were taken at a magnification of •~1,510 and the camera lucida drawings made at a uniform magnification of •~1,375. 282 P. N. Mehra and P. Remanandan Cytologia 37 Observations Table 1 summarises the data in respect of the taxa worked out and the specific localities from where they were collected. Species marked * are investigated for the first time, whereas those marked t represent new cytological races. Short notes in respect of each species are mentioned in the text below. 1. Anemone vitifolia Ham. It is a robust perennial herb with beautiful white flowers in decompound cymes, very much similar to the garden A. japonica. It is a good potential orna mental plant worth introduction. Diakinesis revealed 7 large bivalents which were of the rod, ring, or X type (Fig. 1). Their behaviour during meiosis was regular. However, nonsynchronous disjunction and laggards were observed in some cells and these later organised themselves into micronuclei (Fig. 2). The pollen fertility was 98 percent. This is a new report for the species. 2. A. obtusiloba Don. This beautiful perennial medicinal herb grows extensively on the open hill tops in the temperate and alpine Himalayas at an altitude of 2,400-2,500m. Hooker (1882) states that it is a variable species in respect of the size, hairiness and colour of flowers. He distinguishes a form which is quite glabrous with very many golden sepals as var. glabra. The typical species in which the leaves and peduncles are densely covered with silky hairs was collected from Simila Hills. It revealed the 2n number to be 26 from the root tip squashes. The chromosomes are fairly large in size and mostly metacentric. The karyotype is symmetric (Fig. 6). The var. glabra was collected from Gulmarg and other alpine regions in Ka shmir. At metaphase I, it showed 7 large sized bivalents. The meiosis was found to undergo a normal course. However, precocious disjunction of one or two bivalents was a common feature at anaphase I (Fig. 3). Occasionally laggards were observed which failed to be included into the telophase nuclei resulting in the formation of micronuclei (Fig. 5) of different sizes. The pollen fertility was 90 percent. Sobti and Singh (1961) reported the gametic number n=8 under the name of A. obtusiloba from Kashimir. Possibly it is the same taxon as the one studied presently under the name var. glabra. If this surmise is correct, then there is some error in the report made by these authors. In conclusion it may, however, be stated that the two taxa, A. obtusiloba pro per and the var. glabra are sufficiently distinct morphologically. Now it turns out that they are distinct cytologically too. In our opinion there is every justification in raising this variety to a specific rank. 3. A. rivularis Buch.-Ham. It is a perennial herb found throughout India, especially in meadows above an altitude of 1,500m. The species revealed 8 large sized bivalents at diakinesis (Fig. 7). Three bivalents showed two interstitial chiasmata each, two were with a single interstitial chiasma and of these one was associated with the nucleolus (Fig. 1972 Cytology of Some W. Himalayan Ranunculaceae 283 Table 1 284 P. N. Mehra and P. Remanandan Cytologia 37 Table 1 (Contd.) * Species investigated for the first time . •õ Cytotypes investigated for the first time. 7). The course of meiosis was regular. Late disjunction of one of the bivalents was observed in a few cells. The pollen fertility was found to be 95 percent. The species is worked out for the first time. 4. Thalictrum reniforme Wall. The species is common in the woods at an altitude of 2,400-3,000m in the Naini tal Hills. The finding of n=7 (Fig. 8) is a new report for the species. Chromo somes are rather small in size. The behaviour of them at the first and second meiotic divisions was normal resulting in about 97 percent pollen stainability. 5. T. foliolosum DC. It is a common perennial herb of the temperate Himalayas. Being of medicinal value it is much sought for its rhizome. At diakinesis 7 bivalents were discernible. This confirms the earlier report by Langlet (1927) for the species. Meiosis was normal and pollen fertility 97 percent. 6. Clematis montana Ham. It is a gracious woody climber rambling over shrubs and with rich clusters of strikingly beautiful white flowers. It is common on open hill sides ascending to 3,600m. The species is widely cultivated as an ornamental. It is poisonous and its root is of medicinal value. The finding of n=8 from the pollen mother cells confirms the previous report of Meurman and Therman (1939). At diakinesis 8 medium sized bivalents were Figs. 1 and 2. Anemone vitifolia, n=7. 1, M-I showing chiasmata formation. 2, abnormal cell showing micronucleus formed from lagging chromosomes at A-I. Figs. 3-5. A. obtusiloba var. glabra n=7. 3, M-I displaying precocious separation of one pair (arrow). 4, M-II, 7:7 chromosomes at each pole. 5, abnormal cell showing organisation of laggards into micronuclei at A-I. Fig. 6. A. obtusiloba, 2n=26, root tip mitosis. All figs. •~1,510. 1972 Cytology of Same W. Himalayan Ranunculaceae 285 286 P. N. Mehra and P. Remanandan Cytologia 37 Figs. 7-15. 7, Anemone rivularis, n=8, diakinesis displaying the distribution of chiasmata and a nucleolar bivalent at arrow. •~1,510. 8, Thalictrum reniforme, n=7, diakinesis, •~1,375. 9, Adonis chrysocyathus, n=16, A-I showing 16:16 separation, •~1,375. 10 and 11, Ranunculus hir tellus, n=8. 10, diakinesis displaying chiasmata distribution and two nucleolar bivalents, •~1,510. 11, abnormal cell with a micronucleus, •~1,510. 12, R. diffusus, n=16, diakinesis, •~1,375. 13, R. laetus, n=16, diakinesis, •~1,375. 14, R. laetus, n=14, diakinesis, •~1,510. 15, R. ar vensis, n=16, M-II, •~1,375. 1972 Cytology of Some W. Himalayan Ranunculaceae 287 clearly observed. Their arrangement at the equatorial plane was regular at meta phase I. Further stages of meiosis were normal and the pollen fertility was found to be 98 percent. 7. Adonis chrysocyathus Hook. f. and Thomas . This perennial herb of the alpine belt is dreaded by shepherds in Kashmir who believe it to cause frequent deaths among sheep and goats. It grows at an elevation of 3,000-3,900m. Because of its large golden yellow flowers and luxur ious fern-like leaves it would be a good potential ornamental worthy of cultivation . The species is a tetraploid on the base number x=8. At anaphase I 16:16 distribution was observed. However, 5 pairs of rather longish chromosomes dis junct later than the rest (Fig. 9). The course of meiosis was normal and 93 percent of the pollen was fertile. This is a new report for the species. 8. Ranunculus hirtellus Royle. It is a common perennial herb of the sub-alpine Western Himalayas which grows at an altitude of 800-3,000m. At diakinesis 8 bivalents and a nucleolus were seen (Fig. 10). Four of these were ring-bivalents held together by two terminal chiasmata, two bivalents possessed a single terminal chiasma and the remaining two had a single interstitial chiasma each. One of the rings was associated with the nucleolus. Meiosis was found to undergo a mildly disturbed course. Anaphase I was regular with 8:8 distribution.