Cytologia 47: 109-116, 1982 Cytotaxonomy of Malvaceae III. Meiotic studies of Hibiscus, Abelmoschus , Azanza, Thespesia, Malachra, Urena and Pavonia Aparna Dasgupta and R. P. Bhatt1 Department of Pharmacy , S. V. Govt. Polytechnic., Bhopal, India Received January 22, 1980 Family Malvaceae includes many familier plants of cultivation notably cotton . Cytological work on economically important plants of this family has received greater attention, though work has also been done on a few wild species by some workers like Youngman (1927), Davie (1933), Skovsted (1935, 1941), Bates (1967), Bates and Blanchard (1970), Hazra and Sharma (1971), Kachecheba (1972), Bhatt and Dasgupta (1976). However, detailed meiotic study has not been done on many genera and species of the family which is necessary to know the type of ploidy and the basic numbers of chromosomes from which the evolution might have progressed . The present investigation includes 15 species belonging to the tribe Hibisceae and Ureneae of the family Malvaceae. The species of the tribe Ureneae are simple polyploids of seven (Skovsted 1935) which has also been noticed in the present work. However, different chromosome numbers have been reported in the tribe Hibisceae. This vast range of chromosome numbers in the tribe especially necessiated the study of chromosome numbers and the ploidy level. This investigation also aimed at understanding the basic chromosome numbers from which the evolution is supposed to have progressed and the evaluation of systematic position of different taxa as understood at present. Out of 15 species studied meiotic study has been done for the first time in Hibis cus vitifolius, H. hirtus, H. panduraeformis, H. caesius, Abelmoschus manihot, Malachra capitata and Pavonia zeylanica. Materials and methods Mature seeds for the cytological investigations were collected or obtained from different localities in Gujarat, Madhya Pradesh, Uttar Pradesh and Karnataka (Table 1). The seeds of all the populations were grown in the Botanical garden of M. S. University, Baroda for selecting suitable buds for meiotic studies. Difficulty was encountered in studying meiotic divisions which were obtained from both fresh and fixed flower buds. The fixed materials showed the best results in most of the cases. The flower buds were fixed in modified Carnoy's fluid (6:3:1) for at least 24 hours to clear the cytoplasm. In Thespesia populnea and Azanza lampas only the anther mass was fixed in the fixative after several washes in the same to get good preparations. Before smearing in 2% aceto-carmine, the anthers 1 Department of Botany , Faculty of Science, M. S. University, Baroda, India. 110 Aparna Dasgupta and R. P. Bhatt Cytologia 47 were transferred in 45% acetic-acid for at least 1 hour. The slides were made perma nent following Celariar's (1956) butyl-alcohol schedule and mounted in euparal. Drawings were made at table-level on steindorff research microscope using E. Leitz-Wetzlar camera lucida apparatus at 15•~120 (apochromat) magnification. Table 1. Observations Tribe-Hibisceae Genus-Hibiscus Linn. 1. H. sabdariffa Linn. Meiosis is regular in all collections showing 36 bivalents at metaphase I (Fig. 1). This is in confirmation with the earlier works of Skovsted (1935), Menzel and Wilson (1963). 2. H. cannabinus Linn. Meiosis is normal, showing 18 bivalents at diakinesis and metaphase I (Fig . 2). This confirms the reports by Skovsted (1935); Menzel and Wilson (1963) . In dia kinesis two bivalents near the nucleolus reveal the presence of 1 satellited and 1 secondarily constricted chromosomes in the somatic complement , reported by authors (1976). 3. H. vitifolius Linn. As far could be ascertained from the available literature , this is the first report of meiotic study of the species. The meiotic behaviour of chromosomes is found to be regular in a majority of PMCs showing 17 distinct bivalents at diakinesis and metaphase I (Figs. 7 and 6). However , a few abnormalities like secondary associa tion of bivalents at metaphase I (Figs . 32), irregular distribution of chromosomes at anaphase I (Fig. 34), laggards at anaphase I and laggard at telophase I (Fig . 33) were noticed. Tetrads of linear as well as isobilateral types have been recorded . 1982 Cytotaxonomy of Malvaceae III 111 Figs. 1-15. Meiotic stages. 1, metaphase I. H. sabdariffa. 2, diakinesis. H. cannabinus. 3, dia kinesis. H. caesius. 4, diakinesis. H. hirtus. 5, metaphase I. Azanza lampas. 6, metaphase I. H. vitifolius. 7, diakinesis. H. vitifolius. 8, diakinesis. H. panduraeformis. 9, metaphase I. H. trionum. 10, metaphase I. Malachra capitata. 11, metaphase I. Pavonia zeylanica. 12, metaphase I. Abel moschus manihot. 13, diakinesis. H. ovalifolius. 14, diakinesis. Urena lobata wiht 2 nucleolus and 2B chromosomes (•¨). 15, metaphase I. Pavonia patens. 112 Aparna Dasgupta and R. P. Bhatt Cytologia 47 4. H. trionum Linn. Meiotic study shows the presence of 28 bivalents at metaphase I (Fig. 9). The present observation of n=28 confirms the earlier observation of Skovsted (1935), but differs from Rao's (1941) report of n=14. 5. H. hirtus Linn. No report on meiotic study is available in the literature. Meiosis is normal showing 32 bivalents at diakinesis and metaphase I (Fig. 4). 6. H. ovalifolius (Forsk.) Vahl Earlier workers like Skovsted (1941); Gill and Abubakar (1975) have reported n=32 for the species. In the present work 16 bivalents at diakinesis (Fig. 13) were observed with regular meiotic division. However, noncongressional bivalent (Fig. 18), grouping (5 groups) of bivalents (Fig. 16) at metaphae I; irregular distribution at anaphase I (Fig. 19) laggard at telophase I (Fig. 17) were noticed in few PMCs. 7. H. panduraeformis Burm. Regular meiotic division showing 12 distinct bivalents (Fig. 8) at diakinesis and metaphase I confirms the report by the authors (1976). The secondary associa tion of bivalents showing 6 groups (l(5)+2(2)+3(l)-Fig. 29) at metaphase I, grouping of chromosomes at metaphase II (Fig. 28) and nonsynchronization at anaphase II (Fig. 30) are some of the abnormalities recorded in few PMSs during meiotic study of different populations. 8. H. caesius Garcke No earlier record of the cytological work for the species is mentioned in the available literature. The meiosis is regular showing 18 bivalents at diakinesis and metaphase I (Fig. 3). Genus-Abelmoschus Medik. 9. A. manihot (Linn.) Medik. Meiosis is regular showing 65 bivalents at metaphase I (Fig. 12). No record of meiotic study is mentioned in the available literature . Genus-Azanza Alef. 10. A. lampas (Cav.) Alef. The meiotic behaviour is regular in all the populations . In contrast to Young man's (1931) and Rao's (1967) reports of n=13 , the present observation is n=14 at metaphase I (Fig. 5) and anaphase I. Genus: Thespesia Soland ex. Corr. 11. T. populnea (Linn.) Soland ex. Corr . Earlier reports are n=13 by Youngman (1931); n=12 by Hazra and Sharma (1971). In contrast to these findings the present observation is n=14 for the species. Figs. 16-34. Meiotic stages. 16-19: H . ovalifolius. 16, metaphase I showing 5 groups of biva lents. 17, telophase I showing laggards (•ª) . 18, metaphase I showing non-congressional bivalent (•ª). 19, anaphase I showing irregular distribution . 20-25: Thespesia populnea . 20, metaphase I (Sid e view) showing interlocking of 2 bivalents (•ª) . 21, metaphase I showing non-congressional bivalents (•ª). 22, metaphase I showing non-congressional bivalent (•ª) . 23, metaphase I (Side 1982 Cytotaxonomy of Malvaceae III 113 view) showing 14 bivalents. 24, anaphase I normal. 25, metaphase I (Polar view) showing group ing of some bivalents. 26, metaphase I Urena lobata showing 7 groups of bivalents. 27-30: H. pan duraeformis. 27, metaphase II, normal. 28, metaphase II showing grouping of some chromosomes. 29, metaphase I showing secondary association of bivalents in 6 groups. 30, anaphase II showing non-synchronized division. 31, metaphase I Pavonia patens showing 2 groups of bivalents. 32 34: H. vitifolius. 32, metaphase I showing 6 groups of bivalents. 33, telophase I showing laggard (•ª). 34, anaphase I showing irregular distribution. 114 Aparna Dasgupta and R. P. Bhatt Cytologia 47 Meiosis is fairly regular showing 14 bivalents at metaphase I and anaphase I (Figs. 23 and 24). Abnormalities like non-congressional (Figs. 21 and 22) interlocking (Fig. 20) and tendency towards association of bivalents (Fig. 25) are observed in few PMCs. Tribe-Ureneae Genus-Malachra Linn. 12. M. capitata Linn. Meiotic study for the species is done for the first time. PMCs show 28 bivalents at metaphase I (Fig. 10) and regular distribution at anaphase I. Genus-Urena Linn. 13. U. lobata Linn. The present report of n=14 is in line with the previous report by Hazra and Sharma (1971). In addition to normal bivalents (n=14), two darkly stained bodies were observed at diakinesis (Fig. 14). This confirms the report of the same by Hazra and Sharma (1971). The meiosis is fairly regular in the majority of the populations studies. However, grouping of bivalents at metaphase I (2(3)+3(4)+ 2(1)=7 groups) is noticed in a few PMCs (Fig. 26). Genus-Paivonia Cav. 14. P. zevlanica Cav. It is apparent from the available literature that the species has remained un explored cytologically. Number of PMCs examined in two populations, show normal behaviour of chromosomes with n=28 at metaphase I (Fig. 11). However, non-congressional bivalent was observed in metaphase I. 15. P. patens (Andr.) Chiov. The meiotic study shows the presence of 14 bivalents at metaphase I (Fig. 15) which confirms the earlier report of n=14 by Bates (1967). Except for occasional grouping of bivalents at metaphase I (Fig. 31) meiosis is normal. Discussion The meiosis is regular in most of the taxa analysed. However, a few irregulari ties like laggards in anaphase and telophase I and II, irregular distribution at anaphase I and non-congressional bivalents, secondary association of bivalents at metaphase I are noticed in a few species.