Conventional Chromosome Staining Research Articles

Comparative Cytogenetics of Lace Bugs (Tingidae, Heteroptera): New Data and a Brief Overview.

Simple SummaryTingidae, or lace bugs, is a family of herbivorous true bugs, with approximately 2600 identified species in 318 genera classified in two or sometimes three subfamilies, among which the largest subfamily Tinginae comprises about 2500 species. Here, an account is given of the karyotypes of 16 lace bug species studied using conventional chromosomal techniques and FISH with two repetitive DNA probes, 18S rDNA and (TTAGG)n. We also summarize and analyze all information accumulated to date on karyotypes of lace bugs. In general, such information is available for 60 species and 22 genera of Tinginae. We show that lace bugs are characterized by: (1) very conservative karyotypes, with six pairs of autosomes in a haploid set; (2) either an XY or X(0) sex chromosome system; (3) a conventional sequence of sex chromosome divisions in male meiosis; (4) absence of the (TTAGG)n mechanism for maintaining telomere integrity; (5) four discrete patterns of 18S rDNA chromosomal localization. We conclude that the search for chromosomal landmarks is of paramount importance for the characterization of the lace bug cytogenetics in more detail.The lace bug family Tingidae comprises more than 2600 described species in 318 genera that are classified into the subfamilies Tinginae (about 2500 species and 300 genera), Cantacaderinae, and Vianadinae. We provide data on karyotypes of 16 species belonging to 10 genera of the tribes Tingini and Acalyptaini (Tinginae) studied using conventional chromosome staining and FISH. The species of Tingini possess 2n = 12A + XY, whereas those of Acalyptaini have 2n = 12A + X(0). FISH for 18S rDNA revealed hybridization signals on one of the medium-sized bivalents in species of both tribes. FISH with a telomeric probe TTAGG produced no signals in any species. In addition, we provide a list of all data obtained to date on Tingidae karyotypes, which includes 60 species from 22 genera of Tinginae. The subfamily is highly conservative in relation to the number and size of autosomes, whereas it shows diversity in the number and chromosomal distribution of the rDNA arrays, which may be located either on a pair of autosomes (the predominant and supposedly ancestral pattern), on one or both sex chromosomes, or on an autosome pair and the X. The absence of the “insect” telomeric sequence TTAGG in all species implies that Tinginae have some other, yet unknown, telomere organization.

Karyotypic diversity within the genus Makalata(Echimyidae: Echimyinae) of Brazilian Amazon: Chromosomal evidence for multiple species.

The genus Makalata is a taxonomically complex group of rodents on which few cytogenetic studies have been performed. Most of the published karyotypes were described based only on conventional chromosome staining. Here, we studied the karyotypes of Makalata from two Brazilian Amazonian states, Amapá and Pará, by Giemsa-staining, G- and C-banding, AgNO3-staining and FISH with 18S rDNA and telomeric sequences probes. We observed 2n = 66/FN = 124 in the Pará state population in Makalata sp; and 2n = 72/FN = 128 in the Amapá state population in M. didelphoides. Multiple chromosome rearrangements may have given rise to these karyotypes, which differ significantly from each other and from those reported in the literature. The chromosomal differences among the described Makalata karyotypes can act as a barrier to gene flow; since they are also associated with geographic barriers (e.g., rivers) and numerous molecular differences, they could be seen as evidence for reproductive isolation of populations from genus Makalata. Our data suggest that the genus is chromosomally diverse and the karyotypes may belong to different species. These karyotypes may prove useful as taxonomic markers for these rodents.

Comparative cytogenetics of the ground frogs Eupsophus emiliopugini Formas, 1989 and E. vertebralis Grandison, 1961 (Alsodidae) with comments on their inter- and intraspecific chromosome differentiation.

South American frogs of the genus Eupsophus Fitzinger, 1843 comprise 10 species. Two of them, Eupsophus vertebralis Grandison, 1961 and E. emiliopugini Formas, 1989 belong to the Eupsophus vertebralis group, exhibiting 2n = 28. Fundamental number differences between these species have been described using conventional chromosome staining of few specimens from only two localities. Here, classical techniques (Giemsa, C-banding, CMA3/DAPI banding, and Ag-NOR staining), and fluorescence in situ hybridization (FISH, with telomeric and 28S ribosomal probes), were applied on individuals of both species collected from 15 localities. We corroborate differences in fundamental numbers (FN) between E. vertebralis and E. emiliopugini through Giemsa staining and C-banding (FN = 54 and 56, respectively). No interstitial fluorescent signals, but clearly stained telomeric regions were detected by FISH using telomeric probe over spreads from both species. FISH with 28S rDNA probes and Ag-NOR staining confirmed the active nucleolus organizer regions signal on pair 5 for both species. Nevertheless, one E. emiliopugini individual from the Puyehue locality exhibited 28S ribosomal signals on pairs 4 and 5. Interestingly, only one chromosome of each pair showed Ag-NOR positive signals, showing a nucleolar dominance pattern. Chromosomal rearrangements, rRNA gene dosage control, mobile NORs elements, and/or species hybridization process could be involved in this interpopulation chromosomal variation.

A karyotype comparison between two species of bordered plant bugs (Hemiptera, Heteroptera, Largidae) by conventional chromosome staining, C-banding and rDNA-FISH.

A cytogenetic characterization, including heterochromatin content, and the analysis of the location of rDNA genes, was performed in Largus fasciatus Blanchard, 1843 and L. rufipennis Laporte, 1832. Mitotic and meiotic analyses revealed the same diploid chromosome number 2n = 12 + X0/XX (male/female). Heterochromatin content, very scarce in both species, revealed C-blocks at both ends of autosomes and X chromosome. The most remarkable cytological feature observed between both species was the different chromosome position of the NORs. This analysis allowed us to use the NORs as a cytological marker because two clusters of rDNA genes are located at one end of one pair of autosomes in L. fasciatus, whereas a single rDNA cluster is located at one terminal region of the X chromosome in L. rufipennis. Taking into account our results and previous data obtained in other heteropteran species, the conventional staining, chromosome bandings, and rDNA-FISH provide important chromosome markers for cytotaxonomy, karyotype evolution, and chromosome structure and organization studies.

Detection of Inter-chromosomal Stable Aberrations by Multiple Fluorescence In Situ Hybridization (mFISH) and Spectral Karyotyping (SKY) in Irradiated Mice.

Ionizing radiation (IR) induces numerous stable and unstable chromosomal aberrations. Unstable aberrations, where chromosome morphology is substantially compromised, can easily be identified by conventional chromosome staining techniques. However, detection of stable aberrations, which involve exchange or translocation of genetic materials without considerable modification in the chromosome morphology, requires sophisticated chromosome painting techniques that rely on in situ hybridization of fluorescently labeled DNA probes, a chromosome painting technique popularly known as fluorescence in situ hybridization (FISH). FISH probes can be specific for whole chromosome/s or precise sub-region on chromosome/s. The method not only allows visualization of stable aberrations, but it can also allow detection of the chromosome/s or specific DNA sequence/s involved in a particular aberration formation. A variety of chromosome painting techniques are available in cytogenetics; here two highly sensitive methods, multiple fluorescence in situ hybridization (mFISH) and spectral karyotyping (SKY), are discussed to identify inter-chromosomal stable aberrations that form in the bone marrow cells of mice after exposure to total body irradiation. Although both techniques rely on fluorescent labeled DNA probes, the method of detection and the process of image acquisition of the fluorescent signals are different. These two techniques have been used in various research areas, such as radiation biology, cancer cytogenetics, retrospective radiation biodosimetry, clinical cytogenetics, evolutionary cytogenetics, and comparative cytogenetics.

Detection of cross-sex chimerism in the common marmoset monkey (Callithrix jacchus) in interphase cells using fluorescence in situ hybridisation probes specific for the marmoset X and Y chromosomes.

Chimerism associated with placental sharing in marmosets has been traditionally analysed using conventional chromosome staining on metaphase spreads or polymerase chain reaction. However, the former technique requires the presence of proliferating cells, whereas the latter may be associated with possible blood cell contamination. Therefore, we aimed to develop a single-cell analysis technique for sexing marmoset cells. We applied fluorescent in situ hybridisation (FISH) to cell nuclei using differentially labelled X and Y chromosome-specific probes. Herein we present the validation of this method in metaphase cells from a marmoset lymphoblastoid cell line, as well as application of the method for evaluation of cross-sex chimerism in interphase blood lymphocytes and haematopoietic bone marrow cells from marmosets of same- and mixed-sex litters. The results show conclusively that haematopoietic cells of bone marrow and leucocytes from blood are cross-sex chimeric when the litter is mixed sex. In addition, single samples of liver and spleen cell suspensions from one individual were tested. Cross-sex chimerism was observed in the spleen but not in liver cells. We conclude that FISH is the method of choice to identify cross-sex chimerism, especially when combined with morphological identification of nuclei of different cell types, which will allow a targeted tissue-specific analysis.

Variability of 18rDNA loci in four lace bug species (Hemiptera, Tingidae) with the same chromosome number

Male karyotypes of Elasmotropis testacea (Herrich-Schaeffer, 1835), Tingis cardui (Linnaeus, 1758), Tingis crispata (Herrich-Schaeffer, 1838), and Agramma femorale Thomson, 1871 (Heteroptera, Cimicomorpha, Tingidae) were analyzed using conventional chromosome staining and FISH with 18S rDNA and (TTAGG)n telomeric probes. The FISH technique was applied for the first time in the Tingidae. In spite of the fact that all species showed the same chromosome number (2n = 12 + XY), they have significant differences in the number and position of rDNA loci. FISH with the classical insect (TTAGG)n probe produced no signals on chromosomes suggesting telomeres in lace bugs to be of some other molecular composition. Tingidae share absence of the (TTAGG)n telomeric sequence with all so far studied taxa of the advanced true bug infraorders Cimicomorpha and Pentatomomorpha.

Genotoxicity evaluation of environmental pollutants using analysis of nucleolar alterations.

Nucleolar alterations resulting from the action of either chemical or physical agents can serve as important genotoxicity biomarkers. In this study, the efficiency of AgNOR banding technique to identify the presence of nucleoli in micronucleus and assess nucleolar alterations in aberrant cells of Allium cepa was evaluated. Seeds of this plant were exposed to both water samples from a river that receives untreated urban effluent and to the trifluralin herbicide (0.84mg/L concentration), both analyzed in two different seasons (summer and winter seasons). Samples induced significant frequencies of chromosomal and nuclear aberrations and micronuclei, as observed in cells submitted to conventional chromosomal staining. The herbicide caused a significant increase in the number of nucleoli and micronuclei, interpreted as due to the elimination of excessive nucleolar material resulting from polyploidization. The use of the AgNOR technique enabled the identification of both the presence of the nucleolus in some micronuclei and the nucleolar organizer region (NOR) behavior of aberrant cells. The NOR-banding technique showed to be an efficient tool for studying the genotoxic effects caused by a xenobiotics and a complex environmental sample.

Molecular-cytogenetic analysis of Aegilops triuncialis and identification of its chromosomes in the background of wheat.

BackgroundSpecies belonging to the genus Aegilops L. are an important source of genetic material for expanding genetic variability of wheat. Ae. triuncialis is an allotetraploid in this genus which was originated from hybridization of Ae. umbellulata and Ae. markgrafii (Greuter) Hammer. Although the Ae. triuncialis karyotype was thoroughly examined by conventional chromosome staining and Giemsa C-banding, it is still poorly characterized using FISH markers. The objective of this study was to test the fluorescence in situ hybridization (FISH) patterns of Ae. triuncialis (2n = 4x = 28, CtCtUtUt) chromosomes using different repetitive sequences and to compare the produced patterns to the chromosomes of its diploid ancestors, with the aim of establishing a generalized Ae. triuncialis idiogram and detection of Aegilops chromosomes in the background of wheat.ResultsThe probes pSc119.2-1, pTa535-1, pAs1-1, (CTT)10 and the 45S rDNA clone from wheat (pTa71) were hybridized to chromosomes of Ae. triuncialis and compared with its diploid progenitors (Ae. umbellulata Zhuk., 2n = 2x = 14, UU and Ae. markgrafii (Greuter) Hammer, 2n = 2x = 14, CC) and Ae. cylindrica Host. (2n = 4x = 28, DcDcCcCc), another tetraploid species containing the C-genome. Ae. cylindrica was further analyzed by genomic in situ hybridization (GISH) using C genome probe in order to identify any possible translocation.ConclusionsIn general, FISH patterns of the Ut- and Ct-genome chromosomes of Ae. triuncialis were similar to those of U- and C-genome chromosomes of the diploid progenitor species Ae. umbellulata and Ae. markgrafii respectively, although some differences were observed. Two major 45S rDNA loci were revealed in the short arm of chromosomes A and C, of the Ct genome which correspond to homoeologous groups 1 and 5 respectively. Minor 45S rDNA loci were mapped on the short arm of chromosomes 1Ut and 5Ut. GISH analysis revealed three different non-reciprocal homologous or heterologous translocations between Cc and Dc chromosomes in all studied accessions of Ae. cylindrica.Electronic supplementary materialThe online version of this article (doi:10.1186/s13039-014-0091-6) contains supplementary material, which is available to authorized users.

First karyotype data on the family Myerslopiidae (Hemiptera, Auchenorrhyncha, Cicadomorpha).

In the first cytogenetic study of the recently proposed family Myerslopiidae the male karyotype of Mapuchea chilensis (Nielson, 1996) was analyzed using conventional chromosome staining, AgNOR- and C-bandings, and fluorescence in situ hybridization (FISH) with 18S rDNA and (TTAGG)n telomeric probes. A karyotype of 2n = 16 + XY, NOR on a medium-sized pair of autosomes, subterminal location of C-heterochromatin, and presence of (TTAGG)n telomeric sequence were determined. Additionally, the male internal reproductive system was studied.

Dynamics of chromosomal evolution in the genus Hypsiboas (Anura: Hylidae).

Hylidae is one of the most species-rich families of anurans, and 40% of representatives in this group occur in Brazil. In spite of such remarkable diversity, little is known about this family and its taxonomical and systematic features. Most hylids have 2n = 24, even though most of the cytogenetic data are mainly obtained based on the conventional chromosomal staining and are available for only 16% of Hypsiboas species, a genus accounting for about 10% of the hylid diversity. In this study, cytogenetic data of distinct species and populations of Hypsiboas were analyzed, and the evolutionary dynamics of chromosomal macro- and microstructure of these amphibians were discussed. Contrary to the conservativeness of 2n = 24, this genus is characterized by a high variation of chromosomal morphology with as much as 8 karyotype patterns. Differences in the number and location of nucleolus organizer regions and C-bands allowed the identification of geographical variants within nominal species and cytotaxonomical chromosomal markers. Comparative analyses revealed a strong phylogeographic relationship between chromosomal patterns in this group.

The chromosome banding pattern in two cytotypes (2n = 36 and 38) of blind mole rats from Turkey (Mammalia: Spalaxidae)

Two cytotypes (2n = 36 and 38) of blind mole rats, Nannospalax xanthodon (Nordmann, 1840), from the Aydın and Manisa provinces in Turkey were investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis were carried out. From the cytogenetic point of view, the particular phylogenetic position of these populations is supported by their low diploid numbers only, and the Cbanding pattern and the NORs distribution seem generally similar to populations with higher chromosome numbers. Several autosomal pairs with centromeric dark Cbands were observed in the 2n=36 cytotype. One autosomal pair possessed an interstitial dark C-band on the short arm; another pair possessed an interstitial dark Cband on the long arm. Whole C-heterochromatic short arms were observed in three subtelocentric autosomal pairs in the 2n=38 cytotype. Most of the other autosomal pairs possessed centromeric dark C-bands. Distinct dark C-bands were observed also in the presumed X chromosomes of both the cytotypes. The Ag-NOR regions were found on three autosomal pairs of both the cytotypes. These sites were located in telomeric areas of the short arms of two subtelocentric and one submetacentric pair.

The banded karyotype of the 2n = 58 chromosomal race of mole rats from Erzincan, Turkey

Abstract. In this study, the 2n = 58 chromosomal race of blind mole rats, Nannospalax xanthodon, from the Erzincan province in Turkey was investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis were carried out in the specimens studied. The karyotype included three small or medium-sized meta/submetacentric pairs and twenty-five acrocentric pairs of autosomes of gradually diminishing size (NFa = 62). C-heterochromatin regions were found in centromeric and pericentromeric areas or in short arms of some bi-armed autosomal pairs and in pericentromeric areas of a few acrocentric autosomes. The X chromosome had a centromeric C-positive band and the short arm of the Y chromosome appeared to be C-positively stained. The NORs were localized in distal heterochromatin areas of the short arms of two pairs of biarmed and one pair of acrocentric autosomes. Within the 58 chromosome populations reported from Turkey, two groups can be recognized differing by the presence or absence of a larg...

C- and NOR stained karyotypes of mole rat, Nannospalax xanthodon (2n = 54) from Kırıkkale, Turkey

In the present study, the 2n = 54 chromosomal race of blind mole rats, Nannospalax xanthodon superspecies, from Kırıkkale Province in Turkey was investigated. Conventional chromosome staining, Ag-NOR (Nucleolus Organizer Region) staining, and C-banding analysis were carried out on specimens of mole rats. The karyotype including 3 metacentric pairs (nos. 1-3), 3 submetacentric pairs (nos. 4-6), 3 subtelocentric pairs (nos. 7-9), and 17 acrocentric pairs (nos. 10-26) of autosomes (NFa = 70). C-heterochromatin regions were found in the centromeric and pericentromeric region and the short arms of some bi-armed autosomal pairs, and C-heterochromatin was localized in pericentromeric areas of a few acrocentric autosomes. The X chromosome has a centromeric C-positive band and the Y chromosome appeared to be uniformly and C-negatively stained. In all of the specimens studied the NORs were localized in distal heterochromatin areas of the short arms of 4 pairs (nos. 4, 5, 8, 9) of biarmed autosomes.

Evaluation of radiographic and genetic aspects of hereditary subluxation of the radial head in Bouviers des Flandres

To study radiographic and genetic aspects of hereditary radial head subluxation in Bouviers des Flandres. 26 related Bouviers des Flandres affected with bilateral subluxation of the radial head, 10 unaffected related dogs, and 29 unrelated Bouviers des Flandres with diagnoses of nonskeletal diseases. All dogs were radiographically studied, and their DNA was analyzed with a genome-wide screen of 1,536 single nucleotide polymorphisms. In addition, karyotyping was performed in an unaffected dam and its affected offspring. Both forelimbs of affected dogs were disproportionately short with caudolateral subluxation or luxation of the radial head. Angulation of the radial axis at the mid-diaphysis ranged from 9.3 degrees to 30.3 degrees (mean +/- SD, 14.9 +/- 6.1 degrees ), with an estimated age of onset from 0 to 4 months. Poorly defined medial coronoid processes and osteoarthritis of the elbow joint, cranial bowing of the olecranon, and disturbed growth in length of the ulna with sharply demarcated spurs were noticed on radiographs of affected dogs. Genealogical analysis indicated that most affected dogs were closely related, but the mode of inheritance was not clear. The DNA analysis found that 205 single nucleotide polymorphisms were monomorphic in the affected dogs. Conventional chromosome staining revealed no numerical chromosomal aberration. Congenital radial head luxation and subluxation in the studied Bouviers des Flandres were characterized by angulation of the radial axis leading to caudolateral subluxation of the radial head and insufficient growth of the distal portion of the ulna together with cranial bowing of the olecranon.

Variation in C-heterochromatin and NOR distribution among chromosomal races of mole rats (Spalacidae) from Central Anatolia, Turkey

In this study, the 2n=40, 58, 60 chromosome races of mole rats of the Nannospalax nehringi superspecies from the Konya province in Turkey were investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis was carried out on 25 specimens of mole rats from 13 localities. The description of conventional karyotypes revealed the detailed pattern of geographic distribution of individual races of mole rats in Central Anatolia. The C-positive regions were localized in centromeric areas, and/or in short arms of submetacentric and subtelocentric autosomes. In the 2n=40 race, C-heterochromatin regions were found in whole short arms of four biarmed autosomal pairs whereas C-heterochromatin was localized in pericentromeric areas of biarmed and acrocentric autosomes in the karyotypes of the other races. Autosomal pairs heteromorphic possibly due to deletion/addition of heterochromatin and euchromatin material in short arms were recorded in some populations of both the 2n=58 and 60 chromosome races. The distribution of nucleolar organizer regions (NORs) was described for the first time in the 2n=40 and 58 races. The NORs were localized in four pairs of biarmed autosomes in all the studied chromosomal races in distal heterochromatic and euchromatic areas of the short arms. The results demonstrate the considerable extent of variation in C-heterochromatin and NORs distribution in karyotypes of mole rats from Anatolia.

Different chromatin fractions of tomato ( Solanum lycopersicum L.) and related species

Conventional chromosome staining has suggested that more than 75% of the tomato chromosomes are constituted by heterochromatin. In order to determine whether more deeply stained proximal regions are classic heterochromatin, the distributions of C-bands and chromomycin A 3 (CMA) bands, and the prophase condensation patterns, were analysed in tomato. In this and most other species of the tomato clade, the 5S and 45S rDNA sites were also localised. In tomato, CMA banding was similar to C-banding. After conventional staining, all species displayed large condensed heteropycnotic regions that did not correspond to C-bands or CMA bands. Analyses of the CMA banded karyotypes revealed a low heterochromatin content. Around 12–17% of the chromatin of tomato was CMA + and 1/4 to 1/5 of this heterochromatin corresponded to 45S rDNA. In other species, the CMA + heterochromatin showed extensive variation (8–35%), but was never near the values found in the literature for tomato. These data suggest the existence of three principal fractions of chromatin in tomato and related species: the late condensed euchromatin corresponding to the terminal regions of the chromosomes, the precocious condensed euchromatin that occupies the major part of the chromosomes and the constitutive heterochromatin that represents those regions revealed by C-bands.

A chromosomal study on a Lebanese spittlebug Philaenus arslani (Hemiptera: Auchenorrhyncha: Aphrophoridae)

The meadow spittlebug genus Philaenus (Auchenorrhyncha: Aphrophoridae) is known to display marked colour polymor- phism. This study presents the results of a karyotype analysis of P. arslani from Lebanon using conventional chromosome staining, C-banding, fluorescent banding using base-specific fluorochromes (CMA3 and DAPI) and AgNOR-staining. This species has 2n = 18 + neo-XY, and differs from P. spumarius both in the number of chromosomes and sex chromosome system. During meiosis, the neo-XY bivalent is clearly heteromorphic being the largest in the complement. Furthermore, sex chromosomes show marked differ- ences in C-banding pattern. The NOR-bearing chromosomes are the first and one of the middle-sized pairs of autosomes. NORs are G-C rich. Furthermore, some blocks of constitutive heterochromatin on the sex chromosomes are also G-C rich. All other C-bands are DAPI or DAPI/ CMA3 positive, thus containing A-T rich DNA. The significant difference in the karyotype of P. arslani and P. spumarius indicates chromosomal transformations during the evolution of the genus Philaenus.

Cytogenetic analysis of four species of Pseudis (Anura, Hylidae), with the description of ZZ/ZW sex chromosomes in P. tocantins

Pseudis paradoxa paradoxa, P. p. platensis, P. bolbodactyla, P. fusca and P. tocantins were analyzed cytogenetically by conventional chromosomal staining, C-banding, silver staining and fluorescent in situ hybridization with an rDNA probe. Pseudis tocantins chromosomes were also stained with distamycin A/DAPI. All of the species had a diploid number of 2n = 24 chromosomes and the nucleolar organizer region (NOR) was located on pair 7. However, the karyotypes could be differentiated based on the morphology of chromosomal pairs 2 and 8, the region that the NORs occupied on the long arms of the homologous of pair 7, and the pattern of heterochromatin distribution. The subspecies P. p. paradoxa and P. p. platensis had identical karyotypes. Heteromorphism in NOR size was seen in P. p. paradoxa, P. p. platensis, P. bolbodactyla and P. fusca. Heteromorphic sex chromosomes (ZZ/ZW) were identified in P. tocantins. The W chromosome was subtelocentric and larger than the metacentric Z chromosomes. The differences observed in the C-banding pattern and in the position of the NOR on the sex chromosomes suggested that inversions and heterochromatinization were responsible for the morphological differentiation of these chromosomes.

Cytogenetic studies of four South American species of Paullinia L. (Sapindaceae)

Fil: Urdampilleta, Juan Domingo. Universidade Estadual de Londrina; Brasil. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto Multidisciplinario de Biologia Vegetal. Universidad Nacional de Cordoba. Facultad de Ciencias Exactas Fisicas y Naturales. Instituto Multidisciplinario de Biologia Vegetal; Argentina