The JapaneseSocietyJapanese Society for Plant Systematics ISSN 1346-7565 Acta Phytotax, Geobot, 63 (3): 155-157 (2013) SHORT COMMUNICATION ANewChromosome Number forBonnetiaceae (Malpighiales) KAZUO OGINuMAIAND HIROSHI ToBE2T* 'Department oj'Environmental Sciences, fuculty qfHuman Lij2r andEnvironmental Science. 2Department U}iiversityofKbchi,Kochi,.1opan; ofBotarulGraduateSchooiofScience, "[email protected],lp)oto-u.ac,ip dyoto UViiversi4}L lvoto 606-8502, Jopan. (Ziuthorfor correspondencel The farnily Bonnetiaceae, comprising 35 species in three genera, is one ofthe nine rnalpighialean fami- lies which are unknown or poorLy known with respect to chromosome numbers, Here we report the first exact chromosome count for the family based on Ploiarium alternijZ)lium, using somatic cells from young leaves. The chromosome number of 2n = 22 indicates the base number of the genus to be x = 11. = Comparisons with other Malpighiales suggest that x 11 has occurred as a homoplasy several times within the orden Key words: Bonnetiaeeae, chromosorne number, Malpighiales, Ptoiarium The Malpighiales are one ofthe largest orders from trees growing in Pasir Paniang, Singapore in angiosperms, consisting of about 16,OOO spe- (voucher: Qginuma & Lum s.n. in 2010, KYO). cies in 40 families distributed worldwide, mainly The methods of pretreatment, fixation, and stain- in the tropics and subtropics, In a preyious paper ing for chromosome observations fo11owed (Oginuma & [Ibbe 2010) we reported the first Oginuma et aL (1992). Three to five cells were ex- chrornosome counts for four families of Malpi- amined to determine the chromosome numbers. ghiales; Irvingiaceae, Ixonanthaceae, Lacistama- The terminology of chromosome morphology taceae, and Peraceae. Chromosome numbers still based on the centromere position fo11ows Levan remain unknown or are poorly understood in the et al. (1964). For comparison with other Malpi- nine fo11owing families: Bonnetiaceae, Centro- ghiales, besides our previous report (Oginuma & rlbbe placaceae, Ctenolophonaceae, Euphroniaceae, 2010), we examined all published data on Goupiaceae, Lophopyxidaceae, Malesherbiace- malpighialean families using Chromosome Num- ae, Medusagynaceae, and Quiinaceae. In this pa- bers ofFlowering Plants by Fedorev (1974), serial per we report a chromosome count of 2n = 22 for publications titled Index to Plant Chremosome Ploiarium alternij2)lium (Vahl) Melchior ofBon- Numbers (IPCN) (Ornduff 1967-1968, Moore netlaceae, 1973-1977), and IPCN Chromosome Reports in Bonnetiaceae are a small family of shrubs, Tropicos (Missouri Botanical Garden) (http:" comprising 35 species in two South American www.tropicos.orglProject!IPCN). genera (Arclp,taea Martius [two species] and The somatic chromosome number of Ploiari- Bonnetia Martius [30 species]) and one Southeast um alternijblium was 2n = 22. The chromosomes Asian genus (Ploiarium Korthals [two or three at metaphase gradually yaried in length from species]) (Stevens 2001 onwards), The only previ- about O.5 to 1.0 ptm. Of the 22 chromosomes, ous chromosome count fbr Bonnetiaceae report- most had a median, submedian or subterminal ed n = ca. 150 for Bonnetia cubensis (Britton)centromere, although the centromeric position of R.A. Howard (Lepper i982). several chromosomes was unclear. Satellites SomaticchromosomesofPloiariumalternij2)-were not observed (Fig. IA, B), The chromosome lium were examined using young leaves collected number 2n = 22 from R alternij2)lium indicates NII-Electronic Library Service The JapaneseSocietyJapanese Society for Plant Systematics 156 Acta Phytotax. Geobot Vol. 63 that the generic chromosome base number is x = stituting genera of Podostemaceae, The chromo- 11. Investigations of the chromosomes ofa repre- some number x = 1l, as in Ploiarium, is unknown sentative species ofArclrytaea and Bonnetia are or rare in these families. It has been found in at needed to confirm whetherx = 11 is restricted to least a few unrelated families, i.e., Chrysobalana- the Southeast Asian Ploiarium, ceae,Euphorbiaceae,Lacistemataceae,Rarnesia- The overall phylogenetic relationships within ceae, and Salicaceae. These findings suggest that the Malpighiales are not clearly resolved yet, Re- x = 1 1 has occurred several times as a homoplasy cent molecular analyses, hewever, show that in the Malpighiales, although the original base Bonnetiaceae are sister to Clusiaceae, and that a chromosome number fbr the order is still unceF clade of Bonnetiaceae and Clusiaceae is sister to taln. a strongly supported clade consisting of Calo- References phyllaceae, Hypericaceae, and Podostemaceae (Wurdack & Davis 2009; Ruhfe1 et al. 2011; Xi et ai. 2012; see also Soltis et aL 2011). In Clusiaceae Fedorov, A.A. 1974. Chromosome numbers of flowering plants. Otto Koeltz, Koeningstein, (14 genera 595 species), however, diverse chro- Lepper, L. 1982. Beitrtige zur Chromosomen-Dokumen- mosome numbers are recorded from 11 species in tation cubanischer Pflanzensippen 4. Revista Jard, three == generaClusia(2n 56,58,60),Garcinia(n Bot, Nac, Univ, Habana 3: 71-102, = 24, 26, 33; 2n = 48, 72, 80), and AJbrysca (n - 7). Levan, A., K. Fredga & A.A. Sandberg. 1964. Nornencla- Here- Only two of the 11 species in the three genera tureforcentromeric positionofchromesomes. ditas 52: 201-220. have the same chromosome number, n = 24 and Moore, RJ. 1973-1977. Index to plant chromosome num- 2n == 48 in Garcinia, Further investigations of bers. Vdlurnes for 1967-1971 and 1972 published in more species ofthese and other are needed genera 1973 and 1974, respectively. Oosthoek's Uitgesvers- to understand chromosome features ofthe family. maatsschappij B. V. Utrecht; yolume for 1973-74 pub- lished in 1977, Bohn, Scheltema and Holkema, Utre- With regard to related families, chromosome cht,Oginuma, numbers are known fbr two (n = 16; 2n = 42) of K. G, Ibara-Manriques & H, [Ibbe, 1992, the 13 constituting genera of Calophyllaceae, Chremosomes of Tiixtta plittieri (Asteraceae; Heli- from four == 8, 9, 10, 11; 2n = 16, 18, 40) genera (n antheae). Acta Phytotax. Geobot. 43: 135-137. of the nine constituting genera of Hypericaceae, Oginuma, K. & H. Tbbe. 2010. First chromosome counts - for four families of Malpighiales. Acta Phytotax. and seven (2n 20, 26 30, 34, 40) ofthe 48 con- , t s･ ny. .de B h.it e S e"e e' pt '.ny.:t F{a 1.Somatic chromosomes at metaphase in Ploiarium alternijloiium (2n= 22), A: micrograph. B: drawing ofmicrograph in A Scale bar equals 2 "m, NII-Electronic Library Service The JapaneseSocietyJapanese Society forforPlant Plant Systematics Apri1 2013 OG]NuMA & ToBE-Chromosome Number for Bonnetiaceae IS7 Geobot.61:49-54. & P.S. Soltis, 2011. Angiosperm phylogeny: 17 genes, Ornduff; R. 1967-1968. tndex to plantchromosorne num- 640 taxa. Amen J. Bot. 98: 704-730. bers. Vblumes for 1965 and 1966 published in l967 Stevens, P.F. 2001 onwards. Angiosperm Phylogeny Web- and 1968, respectively. The International Bureau for site, ver. 8. http:"www.mobot.orgfMOBOTIresearchf Plant Taxonomy and Nomenclature, Utrecht. APwebl [accessed October 24, 2012]. Ruhfe1, B.R., V. Bittrich, C.P. Bove, M.H,G, Gustafsson, Wurdack, K.J. & C.C. Davis. 2009. Malpighiales phylo- C,T. Philbrick, R. Rutishauser, Z, Xi & C.C. Davis. genetics: gaining ground on one of the most recalci- 201l. Phylogeny ofthe clusioid clade (Malphigiaies): tfant clades in the angiosperm tree of life, Amer, J. evidence from the plastid and mitochondrial ge- Bot. 96: 15Sl-1570. nomes. Amer, J. Bot. 98: 306-325. Xi, Z. B.R. Ruhfe1, H. Schaefer, A,M. Amorim, M, Sug- Soltis, D.E., S.A. Smith, N. Cellinese, K,J. Wu rdack, D.C. umaran, K.J. Wurdack, P.K. Endress, M,L, Mat- r[lank, S,F, Brockington, N.F. Refulio-Rodriguez, J.B. thews, P,F, Stevens, S,Mathews & C,C, Davis, 2012, Walker, M.J. Moore, B.S. Carlsward, C.D. Bell, M. Phylogenomics and a posteriori data partitiening re- Latvis, S. Crawley, C, Black, D, Diouf,Z. Xi, C,A. solve the Cretaceous angiosperm radiation Malpighi- Rushworth, M.A, Gitzendanner, K.J. Sytsma, Y=L. ales. Proc. Natl. Acad, Sci. U,S.A, (early edition, ac- Qiu, K,W. Hilu, C.C. Davis, M.J. Sanderson, R.S. cessed October 24, 201 2), Beaman, R.G. Olmstead, W.S. Judcl, M.J. Donoghue Received October 3i, 20f2; accepted ?Vbvember 26, 20J2 NII-Electronic Library Service.