Claudio Palma-Rojas

CHROMOSOME NUMBERS OF CHILEAN PTERIDOPHYTES: FIRST CONTRIBUTION

Mitotic chromosome counts in Chilean pteridophytes confirm the diploidy described for Equisetum L. (2n = 216) and Blechnum L. (2n = 66), as well as the tetraploidy of Asplenium L. (2n = 144). Megalastrum spectabile (Kaulf.) A.R.Sm. et R.C.Moran is diploid (2n = 82), while in metaphases of Polystichum subintegerrimum (Hook. et Arn.) R.A.Rodr. chromosome numbers from ca. 311 to 328 were counted. Tetraploidy was also described in Adiantum chilense Kaulf. (2n = 116)

Non-destructive method to study the internal anatomy of the Chilean scallop Argopecten purpuratus.

ABSTRACT Scallop aquaculture has a 20-y-old history in Coquimbo, Chile. At the beginning develop and introduce on industrial level the culture techniques was the main goal, but in recent years research to improve the broodstock quality has been introduced. Development of non destructive procedures to determine gonadal ripeness were necessary. The use of magnetic resonance imaging proved to be an interesting tool to view the internal anatomy of the Chilean scallop Argopecten purpuratus (Lamarck 1819) without any harmful side effect. A central groove located in the middle of the adductor muscle, became visible using MRI, and could possibly be related to the haemolymphatic circulation system.

Karyological studies in Chilean species of Bomarea and Leontochir (Alstroemeriaceae)

Abstract Species from two genera belonging to the Alstroemeriaceae, Bomarea and Leontochir, were cytogenetically studied and compared to determine their detailed karyotypic composition. Bomarea is a polytypic genus represented by 100 species, with a distribution range from Mexico and Antilles (24°N) to Argentina (29°S) and Chile (17–40°S). In contrast Leontochir is a monotypic genus, endemic to the coastal area of the Atacama Desert in Chile (28°S). Bomarea salsilla, B. involucrosa, and Leontochir ovallei have a karyotype 2n = 18 with similar chromosome morphology. These data confirm the close relationship between both genera, suggested by earlier studies.

Karyological study in fifteen Leucocoryne taxa (Alliaceae)

The karyotype of fifteen Leucocoryne taxa was studied, assessing characteristics such as chromosome morphology and size, secondary constriction location, and asymmetry level. Two groups of Leucocoryne taxa were described based on chromosome number (2n = 10 and 2n = 18) and karyotype asymmetry. The haploid karyotype formula for the group 2n = 10 was 3m + 2st (or 2t), whereas for the group 2n = 18 was 7m + 2st (or 2t). Such results corroborate the karyotype descriptions previously carried out for some taxa of the genus. Leucocoryne taxa showed a high resemblance in chromosome morphology, but inter-specific differences were found in mean chromosome size. These data and previous studies based on gross chromosome morphology support Crosa’s hypothesis, which suggests that the cytotype 2n = 10 is diploid and perhaps ancestral, whereas that the cytotype 2n = 18 is tetraploid but with an additional chromosome fusion being probably a derived status.

Nuclear DNA content in Galaxias maculatus (Teleostei: Osmeriformes: Galaxiidae)

The nuclear DNA content (2C value) was determined in the commercial fish Galaxias maculatus (Galaxiidae) was determined by microdensitometry of erythrocyte n...

Comparación del cariotipo de Eucalyptus globulus y Eucalyptus cladocalyx (Myrtaceae)

A B S T R A C T Mitotic metaphase plates were analyzed in Eucalyptus globulus Labill. and Eucalyptus cladocalyx F. Muell. The chromosomes were observed by squashing root tips, pre-treated with 8Hydroxyquinoline and stained with the Feulgen reaction. Both, E. globulus and E. cladocalyx had a karyotype of 2n = 22, with 1A symmetry level, and chromosome sizes varying between 0.68 and 2.03 ∝m. Mean chromosome size differed significantly between E. cladocalyx (1.42 ∝m) and E. globulus (1.02 ∝m) (P < 0.01). The greater chromosomal size of E. globulus suggests a greater amount of DNA, probably originated by structural alterations. This evolutionary pattern of karyotype morphology might be associated, as well, with a high level of conservation in chromosome morphology.

Chromosome number of two Chilean species of Nothofagus (Nothofagaceae)

Se documenta un numero cromosomico 2n = 26 (x = 13) para Nothofagus dombeyi (Mirb.) Oerst. y N. glauca (Phil.) Krasser, el cual es similar al descrito previamente para otras especies del genero. Se incrementan a 13 las especies de Nothofagus con numero cromosomico conocido, existiendo dos numeros basicos (x = 13, 14).

Nuclear DNA content in Chilean species of Phycella and Rhodolirium (Amaryllidaceae)

RESUMEN Las determinaciones de ADN nuclear realizadas muestran que el valor 2C para Rhodolirium montanum Phil. (2n=2x=16) es de 17,39 pg y de 15,16 pg para Phycella ignea (Lindl.) Lindl. (2n=2x=16). Sin embargo, el tetraploide Phycella scarlatina Ravenna (2n = 4x = 32) tiene un valor de ADN 2C de 30,63 pg , el cual es concordante con su nivel de ploidia.

Karyotype study in Luzuriaga radicans (Liliales: Luzuriagaceae)

The karyotype of Luzuriaga radicans R. & P. was quantitatively studied, assessing characters such as chromosome morphology and size, satellite location, asymmetry level and bimodality. L. radicans has an asymmetric and bimodal karyotype 2n = 20 with three metacentric pairs, followed by six submetacentric and one subtelocentric chromosome pair. One satellite was observed in the short arm of chromosome pair 6. The total haploid set length was 48.7 μm and the mean chromosome size was 4.87 ± 2.35 μm. Comparing L. radicans with other two species of the genus a high resemblance among their karyotypes was found.

Nuclear DNA content in two Sphaeriidae species from Southern Chile (Bivalvia: Veneroida)

ABSTRACT The family Sphaeriidae is a group of cosmopolitan freshwater clams that inhabit temporary and permanent fluvial and lacustrine environments around the world. In Chile, Sphaeriidae is represented by 11 species belonging to the genera Musculium, Pisidium and Sphaerium. In this study, the nuclear DNA content (or 2C-value) of Musculium argentinum (d’Orbigny, 1835) and Pisidium llanquihuense Ituarte, 1999 was estimated for the first time. Musculium argentinum showed a 2C-value of 3.7 ± 0.38 pg, whereas P. llanquihuense showed a 2C-value of 3.57 ± 0.36 pg. These 2C-values are within the range previously reported for Sphaeriidae (2.35–5.7 pg), which includes diploids and polyploids, amounting to 13 of the species examined around the world. Of the cytological data available for the family, the nuclear DNA content can have a unifying role in understanding the magnitude of the chromosome polymorphisms within this polyploid complex.