Chromosomes of four species of Commelina (Commelinaceae)

Abstract

Chromosome numbers, meiotic behaviour and karyotypes in 27 populations belonging to four species of Commelina L. from north-east Argentina and Paraguay have been studied. The basic number of chromosomes in all accessions is x = 15. For C. platyphylla Klotzsch ex Seub. (2 n = 2 x = 30) the chromosome number is reported for the first time.A new ploidy level (2 n = 6 x = 90) is presented for South American accessions of C. diffusa Burm. f. Commelina erecta L. and C. obliqua Vahl are tetraploids (2 n = 4 x = 60). Chromosomes behave regularly at meiosis and pair as bivalents in diploid and polyploid accessions. Chiasma frequency and distribution is reported for each species. The karyotype descriptions of C. platyphylla (18m + 12sm), C. obliqua (30m + 26sm + 4st) and hexaploid C. diffusa (38m + 44sm + 8st) are reported here for the first time. The data suggest an allopolyploid condition for tetraploids of C. erecta and C. obliqua.

Cytogenetic analyses as clarifying tools for taxonomy of the genus Callisia Loefl. (Commelinaceae)

“…The differences between the chromosome arms are moderate in C. monandra while in C. repens tends to be from moderate to high. Some moderate degrees of karyotype asymmetry and gradual differences in chromosome sizes were also shown in Commelina species, another member of the Commelinaceae family (Grabiele et al 2005).…”

“…Meiotic studies were carried out in young floral buds without fixation, or fixed in absolute ethanol : glacial acetic acid (3 : 1) for at least 12 h at 4 ºC and then stored in 70% ethanol (Grabiele et al 2005). Bivalent and chiasma frequencies were estimated by analysis of 30 pollen mother cells (PMCs) at diakinesis or metaphase I for each species.…”

IAPT chromosome data 28

“…Previously, this species was known to have chromosome number of n = 10 ( Kamble, 1997), 2n = 20 (Sastry, 1981) Previously, this species was known to have chromosome number of n = 9 (Khoshoo & Mukherjee, 1970) from India and 2n = 18 from outside India (Hanson & al., 2001). Previously, this species was reported to have 2n = 44 by Renugadevi & Sampathkumar (1983 Previously, the species was reported with n = 15 (Alam & Sharma, 1984;Patwary & al., 1987;Umoh & al., 1991), 2n = 18 (Zheng & al., 1989), 2n = 28 (Palomino & al., 1990), 2n = 30 (Cristobal de Hinojo & al., 1998), n = 45 (Grabiele, 2005) and 2n = 72 (Faden & Suda, 1980). For this species, it was previously reported 2n = 28 from West Africa (Morton 1967) and 2n = 30 from United States by Faden (1993).…”

Comparative pollination role of stamens and breeding system in three species of Commelina (Commelinaceae) in Ile-Ife, Nigeria

“…gigas. Nearly half of all Commelina species are polyploid, and members of the genus are known to show irregular multiples of the basic number of chromosomes (Grabiele et al 2005). Although polyploidy occurs in C. diffusa, most variants of the species (70%) are diploid (Grabiele et al 2005).…”

“…Nearly half of all Commelina species are polyploid, and members of the genus are known to show irregular multiples of the basic number of chromosomes (Grabiele et al 2005). Although polyploidy occurs in C. diffusa, most variants of the species (70%) are diploid (Grabiele et al 2005). However, the subspecies of C. diffusa investigated here have been reported to have a diploid chromosome number of 2n = 30 (Umoh et al 1991a), whereas C. erecta variants are predominantly polyploid (Grabiele et al 2005), and the two C. erecta variants investigated here have been reported to be tetraploid-2n = 4x = 60 (Umoh et al 1991b).…”