CHROMOSOME NUMBERS IN INDIAN MEDICINAL PLANTS

Transcription

1 CHROMOSOME NUMBERS IN INDIAN MEDICINAL PLANTS BY R. SUNDARA RAGHAVAN (Central Botanical Laboratory, Botanical Survey of India) Received February 27, 1957 (Communicated by Dr. E. K. Janaki Ammal) THE Flora of India more than that of any other country in the world, abounds in plants which are of medicinal value to both man and beast. These plants have been collected and utilized from very ancient times and our present knowledge is based on the intelligent observation and inquiry of our ancestors. Minute morphological differences in plants like the presence or absence of hair and the thickness of leaves or the size of flowers, have been the means of differentiating species. It is only on the correct identification of the plant that the authencity and utility of the drug depends, and today with the advance of Botany it is possible to identify plants with the use of a modern Herbarium. However, it has often been shown that the medicinal properties of a plant are dependent on the habitat of the plant. Studies of medicinal plants from different habitats becomes important especially when we propose to grow drug plants on a large scale as in the case of Rauvolfia or Emblica. The active principles of a plant vary not only with the different seasons and with the different environments the plant is grown but they also depend on the "ploidy" of the plant. It often occurs that the same species of a genus may have different polyploid varieties. Such polyploids owing to the duplication of genes may also be richer in medicinal and other properties. The content of vitamin C in triploid apples and tetraploid tomatoes is markedly higher than in the diploid. Thus, there is a direct correlation between polyploidy and vitamin content. In the same way the ephedrine content of the various polyploid species of Ephedra is on the whole higher than that of the diploid (Janaki Ammal, unpublished). The study of genetic variation in medicinal plants becomes important before selecting the right variety to cultivate, and a knowledge of the chromosome numbers of medicinal plants is of primary importance. In this paper the chromosome numbers of some of the genera and species of medicinal plants which are being cultivated in the Central Botanical 294

2 Chromosome Numbers in Indian Medicinal Plants 295 %,,.. i.) ~. ~r r aa" \ 4 28O0 5~ / 1800 '"<'o,# -, ) J l J 4*.).t! I Sf f ~ r % /,9 ~. j.",. ;'.-,',t' %,. t%1t. f,.,,. I ~r(f IO B3 J " TI~XT-FIOS

3 296 R. SUNDARA RAGI-IAVAN Laboratory are given and variation in chromosome numbers have been noted wherever they have been observed by others. The observations of the plants have been made mainly from root tips. These were fied in chrome-acetic-formalin, sectioned at 12 t~ and stained in crystal violet. Where the plants flowered, pollen mother cells have also been studied. The buds were fied in acetic alcohol and squashed in acetocarmine. Camera lucida drawings were made and the appropriate magnification is given at the end of the drawings. Of the twenty plants eamined, the chromosome numbers of nine plants have been reported for the first time and these have been marked with * Five plants marked ** show numbers different from previous observations. In the remaining si plants the chromosome numbers are the same as reported by previous workers (vide Chromosome Atlas of Flowering Plants, by Darlington and Wylie, 1955). The present study has revealed the presence of polyploidy for the first time in Emblica officinalis and in the genus Rauvolfia. In Emblica officinalis a high polyploid (7) has been discovered in a Lucknow variety. Perry (1943) has reported the number of the diploid as 2n = 28. In the three species of Rauvolfia studied there is an interesting grade of polyploidy indicating the basic number of the genus as = 11. Both Calotropis procera and C. gigantea have indicating the basic number of the genus as It is interesting to note that Hemidesmus indicus also has a basic number of = 11. Thus = 11 is the most common basic number for the family Asclepiadacece. In Aegle marmelos the diploid (2n ) form which was not known before has now been found in the wild from the Vindhyas as well as in plants grown in Lucknow. Ghimpu (1929) has reported the diploid number of Cissus quadrangularis as ca 45 but present observations have shown 2n = 24 chromosomes in the Indian form. It is probable that the plant eamined by Ghimpu might be a tetraploid one. The diploid number of 2n = 18 reported for Curculigo orchioides (2n = 18) in the present paper agrees with the findings of Sheriff (1946). Sato (1938) has reported 2n-----ca 50 for the same species. Polyploidy may account for the difference in number. In Cuscuta reflea Finn (1937) has reported 2n -~ 28 ( = 7) but observations in the Lucknow plant has revealed n = 16 only. Thus a new basic number ( = 8) is found occurring in the same species. It is interesting to note that the North American Cuscutas are reported to have a basic number of =15(7+8).

4 Chromosome Numbers in Indian Medicinal Plants 297 The following is the list of chromosome numbers of medicinal plants studied :-- Family and Name Vernacular Name Present Observation MORINGACEAE Moringa pterygosperma Lam. Sainga 2n = 28 POLYGONACEtE Rume dentatus L... n = 20 EUPHORBIACEJE *Phyllanthus niruri L. * * Emblica officinalis Gaertn. Jangli amali 2n = 26 Amla, amlika 2n = 98 CA ESALPINACE.,E Bauhinia purpurea L. Koiral, Karalli 2n = 28 AMPELIDACE.,E * * Cissus quadrangularis L. RUTACEiE * * Aegle marmelos Corr. * Toddalia asiatica Lamk. Murraya k~enigii Spreng. Murraya eotica L. Hasjora 2n = 24 B~el 2n Dahan, Kanj 2n = 72 Katnim 2n = 18 Marchula 2n = t8 APOCYNACEtE * Rauvolfia serpentina Benth. *R. densiflora Benth. *R. canescens L. ASCLEPIADACE~ *Calotropis procera R. Br. *C. gigantea R. Br. *Hemidesmus indicus R. Br. COMPOSIT/E Xanthium strumarium L. CONVOLVULACE/EE ** Cuscuta reflea Rob. ACANTHACE,E *Andrographis paniculata Nees. HYPOXIDACEIE ** Curculigo orchioides Gr, ertn Sarpagandha Ak, Madar Ak, Akra Anantmul Chhotagokhru Akasbela Kalomegh, Kiriat Kalimusli, Muslikand n=ll 2n=44 2n = 66 n= 18 n = 16 n = 25 2n = 18

5 298 R. SUNDARA RAGHAVAN SUMMARY The paper deals with the chromosome numbers in some of the Indian medicinal plants Of the twenty plants studied, the chromosome numbers of nine plants are reported for the first time. Five plants had numbers different from previous observations. REFERENCES Finn, W. Ghimpu, V. C. R. Janaki Ammal, E. K. Perry, B. A. Sate, D. Sheriff, A.. J. Inst. Bet. Acad. ScL Ukr., 1937, 12, Congr. Int. Agric. Bucarest, Chromosome Atlas of Cultivated, Plants, 1945 (Darlington and Janaki Ammal, 1945).. Amer. J. Bet., 1943, 30, Cytologia, 1938, 9, Curr. Sci., 1946, 15, 354. EXPLANATION OF TEXT-FIGURES TEXT-FI6s Fig. 1. Somatic metaphase of Phyllanthas niruri showing 2n = 26 chromosomes. Magnification, 2,800. Fig. 2. Somatic metaphase of Cissus quadrangularis showing 2n = 24 chromosomes. Magnification, 2,800. Fig. 3. Somatic metaphase of Aegle marmelos showing 2n = 18 chromosomes. Magnification, 2,800. Fig. 4. Somatic metaphase of Toddalia asiatica showing 2n = 72 chromosomes. Magnification, 2,800. Fig. 5. Metaphase II of Rauvolfia serpentina showing I1 chromosomes. Magnification, 1,800. Fig. 6. Somatic metaphaso of Rauvolfia serpentina showing 2n= 22 chromosomes. Magnification, 2,800. Fig. 7. Somatic metaphase of Rauvolfia densiflora showing 2n chromosomes. Magnification, 2,800. Fig. 8. Somatic metaphase of Rauvolfia canescens showing 2n = 66 chromosomes. Magnification, 2,800. Fig. 9. Somatic metaphase of Calotropis procera showing chromosomes. Magnification, 2,800. Fig. 10. Somatic metaphase of Calotropis gigantea showing chromosomes. Magnification, 2,800. Fig. 11. Somatic metaphase of Hemidesmus indicus showing chromosomes. Magnification, 2,800. Fig. 12. Diakinesis of Cuscuta re.flea showing 16 bivalents. Magnification, 700.