Itayguara Costa | Universidade Federal do Ceará (original) (raw)

Uploads

Papers by Itayguara Costa

South African Journal of Botany

ABSTRACT The rock outcrop complexes in South-Eastern Brazil are mainly part of the Espinhaço (cam... more ABSTRACT The rock outcrop complexes in South-Eastern Brazil are mainly part of the Espinhaço (campos rupestres) and Mantiqueira Range (campos de altitude), belong to Brazilian Cerrado and Atlantic Tropical Rain Forest biomes. The high elevation formations, the relicts, are characterized by poor soils and daily extreme temperatures, occurring above 900 and 1500mts of altitude, respectivately, and possess a peculiar flora with high levels of endemism. Myrtaceae has widespread distribution at all Brazilian vegetation formations and present a high taxonomic complexity with hybrid species. The chromosome number for this family showed high frequency of 2n = 22 (x = 11), with the occurrence of polyploidy in several species, including the polyploid cytotypes. We carried out chromosome counts for ca. 80 species of Brazilian Myrtaceae in several genera, aiming to determine if occurrence of polyploidy would be associated with the distribution of some species in these environments. We found eight pairs of cytotypes and four different ploidy levels (2x, 3x, 4x and 6x) distributed in three genera. The greatest ploidy levels (3x and 4x) were found in some species of Eugenia and Myrcia occurring in campos rupestres against the diploid relatives in the Cerrado vegetation. Similar situation to Psidium, where 6x populations occurs at highest altitude of Mantiqueira Range while 4x is distributed in other Atlantic Tropical Rain Forest localities with lower altitudes, next to the sea level. Higher ploidy levels were also observed by others authors in species of others families, as Bromeliaceae, Velloziaceae, Orchidaceae and Xyridaceae, occurring in these rock outcrop mountains. In the future, studies will be conduced to explain the origin of polyploid cytotypes in these differential environments.

ABSTRACT With ca. 100 species, Psidium (Myrtaceae) is an important component of Neotropical flora... more ABSTRACT With ca. 100 species, Psidium (Myrtaceae) is an important component of Neotropical flora and widespread in the Brazilian Cerrado and Tropical Atlantic Rain Forest. This is a high taxonomic complex genus and some natural hybridization cases are related. Recent phylogenetic approach pointed Psidium as a monophyletic taxa, whereas with a reduced taxa sampling, being the delimitation of some species unclear. To help assist taxonomic delimitation and understanding of their species, in this work we applied different frameworks: (1) phylogenetic analysis based on molecular data, (2) chromosomal and (3) genome size studies in an evolutionary context. The phylogenetic analysis used Parsimony and Bayesian Inference of 26 species (24% of the genera diversity) and for DNA regions (ITS, ETS, psbA-trnH, ndhF). To determine the sister group we sampled some species of genera morphologically related to Psidium (Acca, Accara, Campomanesia, Mosiera, Myrrhinium, Pimenta and Ugni). The sampling comprised native species collected in the Amazonia, Brazilian Cerrado, Caatinga and Tropical Atlantic Rain Forest biomes. Psidium was confirmed to be monophyletic and its sister group is Myrrhinium. The cladogram indicates three principal clades, showing a clear biogeographical pattern. The species endemic to the Cerrado vegetation appear in two separate clades, each with good statistical support: one emerges as sister group to a clade comprising species from Caatinga and Tropical Atlantic Rain Forest, while the other cerrado clade is sister to Amazonian species. Some internal clades presented low resolution has a clade that includes the P. grandifolium complex, where recent works establish several unclear taxa as varieties and recognized as a very difficult taxonomic delimitation. The chromosomal approach includes 25 species in the majority taxa sampled in the phylogenetic analysis: Acca (1), Accara (1), Campomanesia (9), Myrrhinium (1), Mosiera (1), Pimenta (1) and Psidium (11). All species presents small chromosomes (<2µm) and the diploid chromosome number 2n=2x=22 occurred in these genera, exception for Psidium, where this number was observed in only two species (P. guajava and P. guineense). Polyploidy was observed in 82% of species of Psidium with a big variation on the ploidy levels (2n=22, 44, 55, 66, 88). For P. cattleianum were found tetra (2n=4x=44) and hexaploid (2n=6x=66) cytotypes, where 6x populations occurs at highest altitude than 4x that is distributed in other Atlantic Tropical Rain Forest localities with lower altitudes, next to the sea level. The distribution and number of rDNA 45S sites suggest a hybrid origin of hexaploid. The genome size (2C-value) was determined by flow cytometry for 10 species of Psidium. The intra-specific variation of 2C-value was 9-fold, in a positive correlation with ploidy level. This approach reinforces the indications of an allopolyploid origin of 6x cytotypes of P. cattleianum. Future studies will to increase the sampling of molecular and chromosomal data would help to clarify the species relationships and more detailed biogeographical patterns from Psidium, and to explain the origins of polyploidy in these differential environments.

TAXON, 2021

The shortage of reliable primary taxonomic data limits the description of biological taxa and the... more The shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the num...

Journal of Zoological Systematics and Evolutionary Research, 2021

Applied Vegetation Science, 2020

QuestionWe aimed to analyze how the topography, temperature and rainfall influence the floristic ... more QuestionWe aimed to analyze how the topography, temperature and rainfall influence the floristic distribution in three different topographic areas and their surrounding vegetation. We addressed three main questions: (i) How is the distribution of species among the topographic areas? (ii) Which abiotic variable is driving this distribution? and (iii) What is the difference among the mountain forests and between mountain forests and the Caatinga vegetation?LocationThe Maranguape mountain forest were divided into three topographic categories: windward (600–800 m, WMA), leeward (600–800 m, LMA) and top (above 800 m, TMA). We also considered another six areas of mountain forests and four Caatinga areas in Ceará State.MethodsWe calculated different structural parameters and the floristic diversity of each category. A Principal Correspondence Analysis was performed to analyze the indirect ordination of forest sites by species abundance. A Canonical Correspondence Analysis was conducted to ...

Molecular Phylogenetics and Evolution, 2017

Journal of Arid Environments, 2016

Review of Palaeobotany and Palynology, 2016

Revista de Biología Tropical, 2015

La estructura, dinámica y densidad de poblaciones de plantas en diferentes ecosistemas son contro... more La estructura, dinámica y densidad de poblaciones de plantas en diferentes ecosistemas son controladas por estacionalidad climática. La lluvia de semillas contribuye tanto al establecimiento y mantenimiento de los bosques, así como a la recuperación de áreas alteradas cerca de los fragmentos de bosque. El objetivo de este estudio es evaluar la tasa de deposición de diferentes semillas de especies endémicas y exóticas de árboles tanto al borde y como al interior del bosque. El área de estudio es un fragmento de bosque de 4 hectáreas ubicado en el campus de la Universidad Federal de Ceará. Para medir la lluvia de semillas, 80 recolectores fueron suspendidos a 20 cm del suelo. Las muestras fueron recolectadas mensualmente durante un año (Junio 2009-Mayo 2010), el material fue analizado en el laboratorio y las diásporas (frutos y semillas) fueron cuantificadas e identificadas taxonómicamente. Encontramos 23 383 semillas pertenecientes a 38 familias y 89 especies, con una densidad de 1 1...

ABSTRACT The main rock outcrops in SE Brazil occur at 900-2500 m.a.s.l. in the ranges of Espinhaç... more ABSTRACT The main rock outcrops in SE Brazil occur at 900-2500 m.a.s.l. in the ranges of Espinhaço and Mantiqueira as relicts of grassland/shrubland scattered in the threatened Brazilian Cerrado and Atlantic Tropical rainforest biomes. Experiencing poor soils and daily extreme temperatures, they have a peculiar flora with high level of endemism, among which Myrtaceae, Orchidaceae and Sapindaceae are important components. These families are widespread in Neotropical forests and all Brazilian biomes, besides having high taxonomic complexity with hybrid species. We carried out chromosome counts for 80 species of Myrtaceae, 17 Sapindaceae and 12 Orchidaceae. We found 16 pairs of cytotypes and five different ploidy levels (2x, 3x, 4x, 6x and 8x) distributed in six genera: Eugenia (6), Myrcia (1) and Psidium (1) – Myrtaceae; Hoffmannseggella (5) – Orchidaceae and Paullinia (2) and Urvillea (1) – Sapindaceae. The greatest ploidy levels in Myrtaceae and Orchidaceae were found in high altitudes of Espinhaço and Mantiqueira ranges, whereas Sapindaceae species have the highest ploidy levels in lower altitudes in the Tropical Atlantic rainforest. Bromeliaceae, Velloziaceae and Xyridaceae also have highly poliploid species in these two contrasting environments, and investigations aiming to explain the origin of polyploid cytotypes in these contrasting environments are necessary.

Theoretical and Experimental Plant Physiology, 2014