Karyomorphology of Caesalpinia Species (Caesalpinioideae: Fabaceae) from Caatinga and Mata Atlantica Biomes of Brazil

Abstract

Out of 140 Caesalpinia s.l. species, only 20 species have the chromosome numbers presently known, and nine species have the karyomorphological studies available. We determine the karyotype and the chromosome morphometry in five Caesalpinia s.l. spp., and we describe the heterochromatin pattern in four of them. The diploid chromosome number of 24 was reported for the first time in Caesalpinia calycina, Caesalpinia microphylla and Caesalpinia pluviosa var. peltophoroides, and confirmed in Caesalpinia ferrea var. leiostachya and Caesalpinia pulcherrima. Different karyotype formulae were obtained for each of these five species. The chromosome asymmetry index varied from 34.94 % in C. pluviosa to 39.45 % in C. ferrea. The average chromosome length among the five species differed significantly (P<0.010). The heterochromatin blocks were evidenced by C-banding in both terminal and proximal regions of the Caesalpinia spp. chromosomes. This study represents a contribution toward an increased knowledge on cytogenetics and evolution of this genus.

Karyomorphology and karyotype asymmetry in the South American Caesalpinia species (Leguminosae and Caesalpinioideae)

“…The original cytogenetic data of five Brazilian endemic tree species were obtained as a complement to our previous karyomorphological studies (Rodrigues et al, 2012). Samples of each species were collected at different localities of Bahia State: C. bracteosa in Oliveira dos Brejinhos (13°36'07.6''S, 41°46'33.8''W), C. echinata in Ilhéus (14°47ꞌ20ꞌꞌS, 39°2ꞌ56ꞌꞌW) and Feira de Santana (12°16'01''S, 38°58'1''W), C. laxiflora and C. pyramidalis in Bom Jesus da Lapa (13°19'0.9''S, 43°20'14.8''W).…”

“…From this data, we calculated the ratio between chromosome arms (r = LA / SA), total chromosome length (TCL = SA + LA + SAT), the relative length of each chromosome, the average chromosome length (χ = ΣTCL / number of chromosomes), the haploid lot length (HLL), the AI for TF% (Huziwara, 1962), and the AI for A 1 of Romero Zarco (1986). The karyotypic formula was established, and the satellites were classified according to the pattern used before (Rodrigues et al, 2012). The karyograms and ideograms were obtained with the help of the Adobe Photoshop CS4.0 program.…”

“…Apical samples of roots were used to prepare the slides as described before (Rodrigues et al, 2012).…”

“…Only five Brazilian Caesalpinia s.l. species have their karyomorphological data published (Rodrigues et al, 2012). Of the Caesalpinia s.l.…”

“…s.l., comprises approximately 140 species with morphological characteristics that are very similar to each other (Lewis, 1998;Gasson et al, 2009). Caesalpinioideae has great interspecific and intraspecific variability in the number of chromosomes, and many species have diploid or an unknown chromosome number (Beltrão and Guerra, 1990;Jena et al, 2004;Biondo et al, 2005, Rodrigues et al, 2012. Taxonomic studies support the hypothesis that Caesalpinioideae is a non-natural group comprising paraphyletic tribes (Tucker and Douglas, 1994;Käss and Wink, 1996;Doyle et al, 1997Doyle et al, , 2000Herendeen, 2000;Bruneau et al, 2001;Kajita et al, 2001).…”