jopat 12 2007 31 -38 Journal Of Phvtomedicine And Therapeutics The pollen morphology of Nigerian Bignoniaceae juss. G.E. Ugbabe1, A.E. Avodele', J.I .Okogun and U.S Inyang1 National Institute for Pharmaceutical Research and Development P. M. B. 21 Gorki Abuja. Nigeria. Department o f Botany and Microbiology- University o f Ibadan Ibadan Nigeria. E-mail: bavodelefevahoo.com The Pollen grains of eleven species of the Bignoniaceae represented in Nigeria have been studied by the light Microscope. The pollen grains are mostly circular or elliptic. The circular ones include those of Crescentia cujete Linn. Markhamia tomentosa (Benth.) K.Schum., Newbouldia la'evis Seem.. OroxyUum indicum Vent., Spatliodea campanulata P.Beauv., Stereospermum acuminatissimum K.Schum., Stereospermum kunthianum Cham., and Tabebuici rosea (Berthol)DC./ while the Elliptic ones are: Kigali a africana (Lam) Benth.. Markhamia litlea (Benth.) K.Schum. and Tecoma stans (Linn ) H.B & K. and the shape/class range from prolate, sub-prolate to prolate spheroidal. The Prolate ones are Kigelia africana, Markhamia tomentosa, and Tecoma stans; the Subpralate types includes those of Crescentia cujete, Markhamia lutea, OroxyUum indicum. Spathodea campanulata and Stereospermum acuminatissimum; while the Prolate-Spheroidal types are those of Stereospermum kunthianum and Tabebuia rosea. They are either tefra- colporate or tri-colporate. The pollen of Crescentia cujete is Tetra-Colporaie while tiic others are Tri-colporate (Tri-colporate = Pollen grains with three ectocolpi;). The different pollen types are useful in the identification of the Nigerian Bignoniaceae. Keywords. Pollen grains. Morphology, Bignoniaceae, Nigeria. Introduction Bignoniaceae Juss. is a family of shrubs or lianas and rarely herbs and is made up of about 100 genera and 800 species (12). The family is distributed in the Tropics and forms an important part of the vegetation (10), while a few of the species are found in the temperate and sub-tropical regions. Hutchinson and Dalziel (4) recorded five genera in Nigeria. These are Kigelia africana (Lam.) Bent, Markhamia lutea (Benth.) K. Schurn., Markhamia tomentosa (Benth.) K, Schum, Newbouldia laevis Seem. Spathodea campanulata P.Beauv. Stereospermum acuminatissimum K. Schum., and Stereospermum kunthianum Cham. Beside these are also introduced species such as Crecsentia cuiete Linn, Tabebuia rosea (Berthol.) D.C, Tecoma stans (Linn.) H.B&K and Oroxylum indicum Vent in the country. * Corresponding Author Abstract |3 1 | UNIV ERSIT Y O F IB ADAN L IB RARY Ulgbabe, GiB. etui jopat 12 2007 31 -38 Flbwers of the Bignoniaceae are bisexual, zygomorphic, hypogynous with bract&andlbractioles present. Placentation is axial. Seeds are exalbuminous, usually flattened! with membranous wings although with few exceptions. The flowers are belHs'rtapedl Members of this family are grown mostly for ornamental and medicinal punposesdn N igeria. There are several reasons why pollen identification is important: firstly, most pollbnigrains are very distinctive, easily recognizable and identifiable to the family, genus^or even species rank. Thus very specific information can be obtained about tliie'plhnttthat serve as adult host and foraging plants. Secondly, pollen is composed off sponopollinin. Sporopollinin is very durable and does not easily decay. Therefore, pollen remains as a durable natural marker in insects. Thirdly, from the identification of pollen, the geographical origin of the plant from which the pollen came canioftenibe determined. This is especially important when there is temporal andlgeographical variation in the distribution of the identified plant. Pbllen architecture has great significance in the taxonomy of angiosperms. and interpreting inter-relationship among them (6); The first successful attempt at using characters' ini the classification of plants was made by Lindley, (7). Since then, Endthman (2, 3.)., Patel and Datta (7), Sowunmi (11) and several others have worked! on; the: morphology of the pollen grains of different regions and have emphasized itsphylogenetic significance. The' aimi of this study is to obtain characters of the pollen grains of the family Bignoniaceae im Nigeria which may contribute to the understanding of the taxonomy of the family and the identification and delimitation of the taxa. i’ idterialsand methods Pbllbmsamples were obtained from fresh and herbarium specimens (the herbarium specimenfrwere obtained fromForestry Herbarium Ibadan (FHI) and University of Ibadhm Herbarium (U1H). The sample areas are: Crescentia cujete from U.I Bbtanicallgarden (FHI 106915), Kigelia africana from Akoko-Oba (FHI 106899); MarMamiw liitea from Abeokuta (FHI 40321); Markhamia tomentosa from University Ibadan, Ibadan (UIH 19117); Newbouldia laevis from University of Ibadam (iFMfl 106905); Oruxyllum indicum from U.I (UIH 19114); Spathodea campunulata: from U.I (FHI 1106900);. Stereospermum acuminatissimum from (Dlbhomejji Forest Reserve (FHI 1106904) Stereospermum kunthianum from Nigeria.fFHII 19737); Tabebuia rosea from U.I (FHI 1106901); Tecoma stuns from National Institute for Pharmaceutical Research and Development NIPRD (FHI 1106902)1 These were acetolysed by treatment with acetic acid anhydride and concentrated! tri-Oxonitrate V acid using Erdthman's method (3). The acetolysed pollemgrainswere mounted in glycerin jelly. In each case, measurements of widest equatorialldiameter (E) and polar axis (P) of eleven pollen grains were taken. Mean, |3 2 | UNIV ERSIT Y O F IB ADAN L IB RARY Ugbabe, G.E. et al jopat 12 2007 31 - 38 range and standard error were calculated for all quantitative variables based on eleven measurements chosen randomly. Photomicrographs of the prepared slides were taken with NIKON X 35 DX camera mounted on a N1KON-AFX-DX microscope. Results The pollen grain characters of the Bignoniaceae in Nigeria are shown on Table 1 and the photomicrographs on Plates 1-II1 (1-11). The pollen grains of the species studied are mostly circular or elliptic. They range from prolate, sub-prolate to prolate spheroidal (Table 1) and are tetra-colporate or tri-colporate. The prolate types are found in Kigelia africana, Markhamia tomentosa, Newbouldia laevis and Tecoma stems. Subprolate types occur in Crescendo cujete, Markhamia lutea, Oroxylum indicum Spathodea campanulata and Stereospennum acuminatissimum. Prolate- spheroidal was recorded in Stereospennum kunthianum and Tabebuia rosea. Most of the pollen grains are tri-colporate grains with 3 colpi and 3 furrows. The mean exine thickness ranges from 0.8pm in Tabebuia rosea to 1.7pm in Markhamia tomentosa. The lowest equatorial diameter of 16.8pm was recorded in Markhamia tomentosa and the highest of 48.8pm was recorded in Oroxylum indicum. Polar axis, ranges from 20.8pm in Spathodea campanulata to 76.8 pm in Oroxylum indicum. The equatorial axis has the lowest mean record of 23.6pm in’Spathodea campanulata and Tecoma stans and the highest of 46.0pm in Oroxylum indicum. The lowest P/E% of 90.0.pm was recorded in Spathodea campanulata and the highest of 184.0pm was recorded in Oroxylum indicum. The lowest mean P/E% of 106 was recorded in Stereospennum kunthianum and the highest of 149.2 pm in Spathodea campanulata. The size of the pollen grains show variation from species to species as shown in Table l.The shape of the pollen grains in the taxa show more uniformity: while those of Kigelia africana, Markhamia lutea and Tecoma stans are mainly elliptic, the rest are circular. C. cujete: Plate 1, Table 1. Mean diameter of: 28.4±4.8pm; shape: subprolate; size: media/rather small; pollen: circular. K. africana: Plate 2 and Table 1. Mean diameter: 28.4±2.5pm; shape: prolate, size: media/medium .Pollen: elliptic M. lutea: Plate 3, Table 1.Mean diameter: 24.8 ± 4.4pm, shape: subprolate size: media/rather small. Pollen: elliptic. M. tomentosa: Plate 4, Tablel.Mean diameter: 25.6 ± 3.6pm shape: prolate, size: media/medium. Pollen: circular. N. laevis: Plate5, Table 1 .Mean diameter: 28.4 ± 3.0pm shape: prolate; size: rather media/medium. Pollen: circular. Oroxylum indicum: Plate 6, Tablel: Mean diameter 46.0 ± 8.4pm shape: UNIV ERSIT Y O F IB ADAN L IB RARY Table 1: Pollen grain Characters of the Family Bignoniaceae in Nigeria SI N o G e n u s /s p e c ie s A M B S h a p e T y p e E x in e th ip k n e s s P o la r A x is (P ) E q u a to r ia l A x is (E ) P /E % 1 Crescentia cujete C irc u la r S u b p ro la te T e tra - C o lp o ra te 1.2(16+0.3)2.4 22.4(32.0+4.1)36.0 18.4(28.4+4.8)33.6 105(113+14.1)148 2 Klgelia africana E llip t ic P ro la te T r i- c o lp o ra te 1.2(1 .5+0.2 )16 34.4(38+2.6)42.4 24.8(28.4+2.5)32 123(135.21+17)171 3I Markhamia lutea E llip t ic S u b p ro ia te T r i-c o lp o ra te 1 6 (1 6 + 0 )1 6 24(32.8+5.2)42.4 19.2(24.8+4.4)32 97(132.3+25)176 ' 4 Markhamia tomentosa C ie c u la r P ro la te T r i- c o lp o ra te 1 2 (1 7 + 0 .4 )2 .4 26.4(34+3.6)39.2 16.8(25.6+3.6)31.2 106(132.8+22) 186 5 Newbouldia iaevis C irc u la r P ro la te T r i-c o lp o ra te 1 2 (1 5 + 0 .2 )1 6 38.4(41.6+2.2)46.4 24.8(28.4+3)30.4 124(146.5+12)162 6 Oroxylum irtdicum C irc u la r S u b p ro la te T r i-c o lp o ra te 0.2(11.5+0.1)1.6 47.2(56.8+0.8)76.8 34.4(46+8.4)48.8 94(123.5+26)184 7 Spalhodea campanulata C irc u la r S u b p ro la te T r i-c o lp o ra te 0.8(14+0.5)2.4 20.8(35.2+5.2)38.4 19.2(23.6+3.8)30.4 90(149.2+15)149 s8 Stereospermum acuminatissimum C irc u la r S u b p ro la te T r i- c o lp o ra te 0 .8 (1 5 + 0 .2 )1 6 23.2(30.8+3.6)35.2 19.2(27.2+4.4)32.8 100(113.2+19)150 9 Stereospermum kunthianum C irc u la r P ro la te S p h e ro id a l T r i- c o lp o ra te 1 2 (1 4 + 0 .4 )1 6 24(30.4+4)37.6 23.2(28.8+3.7)36 100(106+5)116 1 ° Tabebuia rosea ■ C irc u la r P ro la te S p h e ro id a l T r i- c o lp o ra te 0.8(0.8+0J0.8 30(30+3.4)36 25.6(27.6+1.6)31.2 97(108.7+11)132 11 Tecoma starts E llip t ic P ro la te T r i- c o lp o ra te 0 .8 (1 0 + 0 .2 )1 2 24(33.2+3.5)36.8 17.6(23.6+4.4)30.4 111(140.7+22)183 Minimum (Mean + Standard error) Maximum. All measurement in Microns. AMB=Ambient. U gbabe, G .E. et al jopat 12 2007 31-38 UNIV ERSIT Y O F IB ADAN L IB RARY Ugbabc, G.E. cl al jopat 112 2007 %51 -.08 Plate I 1: Crescentiia cujete. Pollen type: Tetra-colporate 2: Kigelia africana. Pollen type: Tri-colporate 3: Markhamia lutea. Pollen type: Tri-colporate 4: Markhamia tomentosa. Pollen type: Tri-colporate Plate II 5: Newbouldia laevis. Pollen type: Tricolporate 6: Oroxyllum indicum. Pollen type: Tri-colporate 7: Spathodea campanulata. Pollen type: Tri-colporate 8: Stereospermum acuminatissimum. Pollen type: Tri-colporate |3 5 | UNIV ERSIT Y O F IB ADAN L IB RARY Ugbabe. G.E. el al jopat 12 2007 31 -38 Plate III 9: Stereospermum kunthianum Pollen type: Tri-colporate 10: Tabebuia rosea. Pollen type: Tricolporate 11: Tecoma starts. Pollen type: Tri-colporate subprolate, size: magna/rather large, pollen: Circular. Spathodea campanulata: Plate 7, Tablel.Mean diameter: 23.6 ± 3.8pm, shape: subprolate; size: .minuta/small. Pollen: Circular. Stereospermum acuminatissimum: Plate 8, Tablel: Mean diameter 27. 2 ± 4.4pm, shape: subprolate, size: media/medium. Pollen: circular. S. Kunthianum: Plate 9, Tablel Mean diameter: 28.8 ± 3.7pm, shape: prolate spheroidal, size: media/medium. Pollen: circular. Tabebuia rosea: Plate 10, Tablel. Mean diameter 27.6 ± 1.6pm, shape: prolate spheroidal, size: media/medium. Pollen: circular. Tecoma stans: Plate 11, Tablel Mean diameter 23.6 ± 4.4pm, shape: prolate, size: minuta/small. Pollen: elliptic. Discussion The size of the pollen grains show variations from species to species. The shapes of the pollen grains show more uniformity-they are either prolate, sub- prolate or prolate spheroidal. While K. africana, M. tomentosa, N. laevis and T. stans are the prolate type those of C. cujete, M. lutea O. indicum, S. campanulata and S. acuminatissimum are of the sub-prolate type and those of S: kunthianum and T. stans are of the prolate spheroidal type. They are either cirgular or elliptic, while those of Kigelia africana, Markhamia lutea and Tecoma stans are mainly elliptic, the rest are circular. The pollen types in the Bignoniaceae studied here are Tri-colporate and Tetra-colporate. C. cujete has tetra-colporate Pollen while the rest are Tri-colporate. This shows that the position of C. cujete in this family should be reconsidered. And 36 UNIV ERSIT Y O F IB ADAN L IB RARY Ugbabe. G.E. et al jopat 13 200'31 -38 moreover C. cujete has simple leaves while the other members of the family in this study have compound leaves. Erdthman (3) classified pollen grains into groups according to sizes e.g. perminuta (diameter less than 10pm). minuta (diameter 10-25pm). media (diameter 25- 50pm), magna (diameter 50-I00pm). permagna (diameter 100-200 pm), giganta (diameter greater than 200pm): while Hydes and Adams (5) on the other hand, classified pollen grain size into less than 10pm (very small), IO-25pm (small), 25- 30pm (rather small), 30 40 pm (medium) 40 50pm (rather large), 50 100pm (large) greater than 100 pm (very large). So based on these two groupings, and from the measurements of Polar and Equatorial axis, the pollen grains of Crescentia cujete, Kigelia africana, Markhamia lutea, M. tomentosa, Newbouldia laevis, Stereospermum acuminatissimum, S. kunthianum and Tabebuia rosea belong to the group media/medium, those of Spathodea campanulata and Tecoma stans belong to the group minuta/rather small while that of Oroxyllum indicum belongs to the group magna/rather large. While the type of pollen grain and the AMB are useful characters in the taxonomy of the Bignoniaceae, characters like shape/class and exine thickness have little or no significance in the taxonomy of the members of this family. Acknowledgement We would like to acknowledge the following people, Dr. (Mrs.) Y. Kunle, Dr. (Mrs.) Chidime, Mrs. G. Ajoku. Mr. J. Akinloye, Mr. & Mrs. C. Mpama, Mrs. J. Ibrahim, Mall. M. Muazzam, Mr. A. Jegede, A. Usman and all M.P.R & T.M Dept. N.I.P.R.D Abuja who have contributed in one way or the other to make this work a success. References 1. Darlington, C. D. and Wylie, A. P (1956). Chromosome Atlas o f Flowering Plants. Hefner Publishing Co. New YorkP. 318 320 2. Erdthman, G. (1943): An Introduction to Pollen Analysis. Chronica Botanica Co. Waltham, Mass, U. S. A. 3. Erdthman G. (1952). Pollen Morphology and Plant Taxonomy. Chronica Botanica Co. Waltham, Mass U. S. A. P. 6-10. 4. Hutchinson. J. and Dalziel, J. M (1954). Flora o f West Tropical African. Vol. II. Part 1. Crown Agents for Oversea Government and Administrations London P. 383 388. 5. Hydes, H. A and Adams, K. F. (1958). Atlas o f Airborne Pollen Grains. London MacmillanandCo.Ltd.P.105-109. •' 6. Olubukola, A. and Illoh, H. C. (1996). Pollen Grain Morphology o f Some Species o f Hibiscus. Nigerian Journal of Botany 9:9-14. 7. Patel, G. I. and Datta, R. M. (1958). Pollen Grain Studies in Various Types of Corchorus O litorius L. C. coprulans L. and some other species o f Corchorus. Grana Palynologica 1:18 24. 37 ‘ UNIV ERSIT Y O F IB ADAN L IB RARY Ugbabe, G.E. et al jopat 12 2007 31 - 38 8. Peter Hoen, (1999). Glossary of Pollen and Spore Terminology (Revised and 2"'1 edition). Parts 1-5.. 9. Prasat, S. S. (1963). Pollen Grain Morphology o f Certain Malvaceae. Journal of Indian Botanical Society. 42:463. 10. Shnshina,G. (1989). Savanna Plants. An Illustrated Guide. MacmillanP. 157- 158 11. Sowunmi, M. A. (1973). Pollen Grains o f Nigerian Plants. Grana\3:145 186. 12. Watson, L. and Dallwitze, M. J. (1992). The families ofFlowering Plants. Description, Illustration, Identification and Information Retrieval Version P. 1-13 1381 UNIV ERSIT Y O F IB ADAN L IB RARY