Cytotogia 50: 1-8, 1985

Cytological Studies in Some Members of

V. K. Singhal, B. S. Gill and S. S. Bir

Department of Botany, Punjabi University, Patiala-147 002,

Accepted April 18, 1983

Malpighiaceae, a tropical family of trees and climbing are represented by 60 genera and 800 (Airy Shaw 1973). Cytological information about the family is rather scanty. So far only 28 species are worked out including 17 species from India. The members exhibit a great amount of chromosomal diversi ty involving inter and intraspecific polyploidy as well as aneuploidy. Obviously, further investigations on the family members are desirable and presently six species (8 taxa) are investigated from North and Central India.

Material and methods

For meiotic studies appropriate sized flower buds obtained from the wild as well as cultivated members were fixed in Carnoy's fluid. Anthers were squashed in 1 % acetocarmine and slides were made permanent in euparal. fertility was estimated with 1:1 glycerol-acetocarmine mixture.

Observations

Information on the chromosome numbers, ploidy levels, pollen fertility, source of material and previous reports of the presently investigated species are presented in Table 1. Only in case of crassifolia (n=12), glabra (n=20) and periplocaefolium (n=10) the meiosis is normal while the rest of the taxa show certain abnormalities details of which are given below:

1. Banisteria laevifolia A. Juss. Individuals from the Botanic Gardens revealed the presence of 2n=20. In addition to the presence of B-chromosomes, meiotic irregularities like univalents, laggards, etc., are noticed in some PMCs. Analysis of chromosomal associations at diakinesis and MI reveals that 67.0% of the PMCs have perfect 10 bivalent (Fig. 1) formation and 10:10 chromosome distribution. The average frequency per PMC for bivalent works to 9.6 (Table 2). In the rest of the PMCs, 2-6 univalents are present (Fig. 2). Laggards which are frequently present at A-I/T-I (Fig. 3) and A-II/T-II seem to have been derived from the univalents, average frequency of which is 0.8 per PMC. Consequential to these abnormalities pollen fertility reduces to 53%. About 35% PMCs are found to have up to 2 B-chromosomes (Figs. 4, 5). 2 V. K. Singhal, B. S. Gill and S. S. Bir Cytologia 50 1985 Cytological Studies in Some Members of Malpighiaceae 3

Figs. 1-9. 1-5. Banisteria laevifolia. 1, MI with 10 bivalents. 2, MI showing 2n=20=8II+ 4I. 3, laggard at AI. 4, diakinesis showing 10II+1B. 5, MI with 9II+2I+1B. 6-9. benghalensis. 6, MI with 2n=56=6III+15II+8I. 7, AI with irregular distribution and 1 B chromosome. 8, laggards at TI. 9, MI with 2n=60=3IV+4III+16II+4I. 4 V. K. Singhal, B. S. Gill and S. S. Bir Cytologia 50

2. (Linn.) Kurz Two chromosomal races, 2n=56 and 60, are detected presently. The cytotype with 2n=56 is detected from Northern India whereas 2n=60 is from the Central Indian forests. All the cultivated (Patiala) are with 2n=56 and without accessory chromosomes whereas the wild plants studied from the Debra Dun forests having the same chromosome number (2n=56) possess one accessory chromosome. In the cytotype with 2n=60 a variable number (1-4) of B-chromosomes are seen.

Table 2. Data on chromosomal associations and B-chromosomes in Banisteria laevifolia

Table 3. Data on chromosomal associations in the cytotypes of Hiptage benghalensis

All the three taxa which are otherwise morphologically indistinguishable and have the same flowering period (March-April) show abnormal meiosis and some pollen sterility. Data pertaining to chromosomal associations in these cytotypes are sum marised in Table 3.

Figs. 10-17. 10-11, Hiptage benghalensis. 10, mixed AI with 60 chromosomes and 4 B-chromo somes. 11, lagging chromosomes at Al. 12-17, Stigmaphyllon ciliatum. 12, MI with 10 bivalents. 13, MI with 2n=20=2IV+2II+8I. 14, MI with 2n=20=2III+3II+8I. 15, MI with 2n=20=6II+8I. 16, laggards at TI. 17, laggards at TII. 1985 Cytological Studies in Some Members of Malpighiaceae 5 6 V. K. Singhal, B. S. Gill and S. S. Bir Cytologia 50

3. Stigmaphyllon ciliatum (Lam.) A. Juss. The chromosome number 2n=20, in this cultivated species, is worked out from meiosis which is highly abnormal due to the presence of multiple associations, univalents, laggards and partial failure of cytokinesis. Analysis of 85 PMCs at diakinesis and M-I reveals that 10 bivalents (Fig. 12) are constituted in 47.1% of the PMCs, whereas multiple associations of 3-6 chromosomes (Figs. 13, 14) in 11.1% of the PMCs. Univalents which vary from 2-20 (Fig. 15) are present in 51.7% of the PMCs. Average for various associations per PMC works to 0.01VI+ 0.05IV+0.l3III+8.l4II+3.07I (Table 4). Incidence of laggards at A-I/T-I (Fig. 16) and A-II/T-II (Fig. 17) is fairly high, leading to the complete or partial failure of cytokinesis and formation of monads and dyads. Consequently, pollen grains of variable sizes are produced of which as many as 41% are sterile.

Discussion

The present report of B-chromosomes for Banisteria laevifolia and Hiptage benghalensis is a new record for the family Malpighiaceae. Banisteria laevifolia was so far known to be tetraploid with 2n=40 (Pal 1964).

Table 4. Data on chromosomal associations in Stigmaphyllon ciliatum

The present count of 2n=20 not only adds a new diploid cytotype but also establishes the existence of intraspecific polyploidy for the species. is another ornamental species exhibiting intraspecific polyploidy (2x, 4x). The tetraploid cy totype (2n=40) is quite well represented in the Indian taxa (Pal 1964, Pandey and Pal 1980, Sarkar et al. 1980), whereas the diploid (2n=20) is counted both from India and elsewhere (Bawa 1973, Pandey and Pal 1980). Hiptage benghalensis is quite variable cytologically as is apparent from the ex istence of cytotypes with 2n=42 (Roy and Mishra 1962), 2n=56 (Roy and Mishra 1962, the present studies) and 2n=58 (Pal 1964, Devar 1981, Devar and Boraiah 1981). The present record of 2n=60 is a new report for the species and is the highest number so far recorded in the family Malpighiaceae. It is not possible to comment upon the level of ploidy in these cytotypes as no other species is known chromosomally. However, role of aneuploidy and polyploidy is quite apparent. Multivalent formation in the presently studied cytotypes (2n=56, 60) indicates that some chromosomes of the different genomes of these polyploids are partially or completely homologous. In , the chromosome numbers 2n=20 (Nanda 1962) and 1985 Cytological Studies in Some Members of Malpighiaceae 7

2n=28 (Rao 1954) have been recorded from the plants cultivated at F. R.I., Dehra Dun. The current finding from the same source, however, shows the number to be n=12 which has also been counted from elsewhere (Fouet 1966, Bawa 1973). As such x=12 seems to be the base number for the Byrsonima. Presence of univalents in the diploid species, Banisteria laevifolia (2n=20) and Stigmaphyllon ciliatum (2n=20) might be attributed to the partial nonhomology in some of the chromosomes. But the existence of multiple associations of up to six chromosomes involving only 3.3% of the chromosomes along with the high incidence of univalents (51.7% PMCs) in S. ciliatum might be due to the hybrid nature of the taxon as has been suggested by Stebbins (1971). Of the different base numbers existent in the family (x=6, 9, 10, 11, 12, 17, 19, 21), x=10 is more frequent being represented in six of the cytologically known 13 genera. Intraspecific polyploidy represented in four species is also based on x=10. The next common base number is x=6 and show polyploid series. It is thus clear that base numbers x=6 and 10 are common to the cytologically known species.

Summary

Cytological studies have been carried out on six species of the family Malpighi aceae. The count of 2n=20 for Banisteria laevifolia adds a new diploid cytotype and establishes intraspecific polyploidy for the species. A new cytotype of 2n=60 has been recorded for Hiptage benghalensis which establishes the highest number for the family. The record of B-chromosomes for the two species, B. laevifolia and H. benghalensis are also the first counts for the family. Presence of univalents in diploid species, B. laevifolia and Stigmaphyllon ciliatum is due to the partial nonhomology in some of the chromosomes. Multiple associ ations along with the high frequency of univalents in S. ciliatum might be due to the hybrid nature of the taxon. All the three cytotypes of H. benghalensis are poly ploids showing abnormal meiosis and reduced pollen fertility.

Acknowledgements

Authors wish to express their sincere thanks to University Grants Commission, New Delhi for financial help under a project Grant No. 017 BIO/SCS./76.

References

Airy Shaw, H. K. 1973. Willis: A Dictionary of Flowering Plants and Ferns. Cambridge Univ. Press, Cambridge. Bawa, K. S. 1973. Chromosome numbers of tree species of a lowland tropical community. J. Arnold Arbor. 54: 422-434. Darlington, C. D. and Wylie, A. P. 1955. Chromosome Atlas of Flowering Plants. George Allen & Unwin Ltd., London. Devar, K. V. 1981. In IOPB Chromosome number reports LXXI. Taxon 30: 508-519. - and Boraiah, G. 1981. A note on the karyomorphology of Hiptage benghalensis (L.) Kurz. 8 V. K. Singhal, B. S. Gill and S. S. Bir Cytologia 50

Curr. Sci. 50: 904-905. Fouet, M. 1966. Contribution a l'etude cyto-taxonomique des Malpighiacees. Adansonia 6: 457-505. Nanda, P. C. 1962. Chromosome numbers of some trees and shrubs. J. Indian Bot. Soc. 41: 271-277. Pal, M. 1964. Chromosome numbers in some Indian Angiosperms. 1. Proc. Indian Acad. Sci. 60B: 347-350. Pandey, R. M. and Pal, M. 1980. In IOPB Chromosome number reports LXVIII. Taxon 29: 533-547. Rao, H. S. 1954. Chromosome numbers in forest plants. Ind. For. 80: 551-552. Roy, R. P. and Mishra, N. C. 1962. Cytological studies in Malpighiaceae. Proc. Indian Sci. Congr. Assoc. Part III. 49: 335. Sarkar, A. K., Datta, N. and Chatterjee, U. 1980. In IOPB Chromosome number reports LXVII . Taxon 29: 347-367. Stebbins, G. L. 1971. Chromosomal Evolution in Higher Plants. Edward Arnold Ltd ., London.