A Karyotype Comparison Between Two Closely Related Species of Acrostichum

Anatomical, Histochemical and Cytogenetic Features of <i>Doryopteris triphylla</i> (Pteridaceae)

“…The comparison of the karyotype estimated for D. triphylla with the few karyotypes described for other fern genera shows some similarities. The karyotype formula of D. triphylla exhibits metacentric and submetacentric chromosomes, a characteristic shared with others species of Acrostichum [21], Lycopodium [22] and Woodwardia [23]. Likewise, D. triphylla is diploid and shows a karyogram whose chromosome length (1.59 µm to 4.38 µm) is very similar to that observed in diploid species of Polypodium (2.2 µm to 4.5 µm) [24].…”

“…Moreover, although D. triphylla and the Acrostichum species analyzed by Marcon et al (2003) [21] are diploid, with 2n = 60, and similar in terms of chromosome morphology, chromosome length of Acrostichum (approximately 5.0 µm to 8.0 µm) is almost twice that observed in D. triphylla, which is reflected in its haploid chromosome complement, of nearly 100 µm in D. triphylla and 192 µm in Acrostichum.…”

“…However, chromosome length of D. triphylla and Polypodium is similar, but in Polypodium, most of the chromosomes are telocentric and the remaining chromosomes of the complement are acrocentric. Murray (1985) [24] and Marcon et al (2003) [21] did not mention metacentric or submetacentric chromosomes for that genus.…”

“…Karyotype analyses were performed for other ferns, such as some species of Acrostichum L., Lycopodium L. and Woodwardia Sm. [21] [22] [23], and of Polypodium L. [24]. The aims of this study were to characterize the anatomical traits of Doryopteris triphylla associated with its xeromorphic condition, analyze the chemical compounds secreted by the glandular trichomes, determine the sporophytic chromosome number, and estimate the corresponding karyotype.…”

Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

“…However, not all 5S and 45S rDNA sites in Maxillaria and in other genera generate CMA + bands, probably because the sites were too small to be detected with CMA (Zoldos et al, 1999;Marcon et al, 2003;. Schmid and Guttenbach (1988) obtained positive mithramycin A staining of vertebrate nucleolus organizer region (NOR) in various species except humans, the authors attributing this exception to the low repeat number (40-46 repeats per locus) of human NORs.…”