South-central Brazil Research Articles

Foraging Behaviour of Wild Bees at Hot Pepper Flowers (Capsicum annuum) and its Possible Influence on Cross Pollination

Native bees are effective pollinators of hot pepper plants, Capsicum annuum. In four gardens in south-central Brazil (Patos de Minas and Brası́lia) flowers of three cultivars received visits from 16 species of bees in eight genera: Hylaeus(Colletidae), Dialictus, Halictus, Augochlora,Augochloropsis and Ceratalictus(Halictidae), Exomalopsis andBombus (Apidae). No other insects were observed to visit the flowers. Some species of bee occurred in more than one garden. Individual bees gathered a full pollen load from 18 to 47 flowers and visited one to eight plants on a single foraging trip. In 76 shifts between plants, the bees made nine switches between cultivars. It is suggested that small native species of bees pollinate the flowers effectively and that their small foraging areas are important in keeping the cultivars of both hot and sweet peppers genetically distinct where several cultivars are grown close together.

Evolution of HLA-class I compared to HLA-class II polymorphism in Terena, a South-American Indian tribe

We have studied the HLA alleles of 60 unrelated healthy Terena and 10 Terena families. They are members of an isolated Brazilian tribe located in Mato Grosso do Sul (South Central Brazil). Six novel alleles were found in this population: HLA-A∗0219 (gf = 0.02), A∗0222 (gf = 0.15), HLA-B∗ 3520 (gf = 0.01), B∗3521 (gf = 0.03), B∗3912 (gf = 0.03) and B∗4803 (gf = 0.16). Five of the six novel alleles differ from their putative progenitors by amino acid replacements in residues that contribute to the pockets of the peptide-binding site. Many of the variants defined by molecular methods were not identified correctly by serological typing. We calculated heterozygosity values ( H) for HLA-A, -B, -C, DRB1, DQB1 and DPB1. The highest values were observed at the HLA-B locus, followed by HLA-A, -DRB1 and DQB1. Residue positions 9, 24, 45, 62, 67, 95, 114, 116, 156, and 163 of HLA class I showed heterozygosity values greater than 0.50. Nine of them contribute to the peptide-binding specificity pockets and one to the T cell receptor binding site. If HLA antigens are useful for defense against pathogenic agents, heterozygosity would offer an advantage by allowing binding of a larger repertoire of peptides to the class I molecules. Individuals that are heterozygous at these positions would probably have a wider repertoire of peptide presentation to T cells. The observed results including the presence of novel alleles in the class I HLA loci suggest a functionally significant, more rapid evolution of class I compared to class II loci in this South American isolated population.

Late Holocene Phytolith and Carbon-Isotope Record from a Latosol at Salitre, South-Central Brazil

The reliability of paleovegetation records inferred from soil phytolith assemblages and SOM (soil organic matter) carbon isotope analysis was examined in light of previous pollen and charcoal reconstructions. The sampled latosol is located in south-central Brazil (Salitre), at a boundary between forest and cerrado. The derived mean age of phytoliths and SOM at each level is the result of a balance between continuous translocation and selective dissolution. It increases with depth in a regular, quantifiable fashion that allows paleoenvironmental interpretation. Phytoliths and SOM tracers first record a savanna phase, associated with the last Holocene long dry period occurring between ca. 5500 and 4500 yr B.P. Two periods of tree community development followed, between ca. 4000 and 3000 and after ca. 970 yr. B.P., leading to the present cerrado/forest association. The dry spell interrupted this trend about 970 ± 60 yr B.P. The second development of woody elements was contemporaneous with an increase in anthropogenic fires. Therefore, climate was more important than fires and human activities in constraining the growth of vegetation during the last nine centuries at Salitre. More generally, despite pedogenic processes, soil phytoliths and δ13C values of the SOM may be accurate tracers of vegetation changes.

Développement et qualité de vie dans le Brésil contemporain : l'exemple de trois agglomérations urbaines

Abstract Many general studies are mistaken in their view of Brazil, when they consider the quality of life in the contemporary world : apparently, they only know Sâo Paulo and Amazonia. Actually, almost 80 % of Brazil's present population (which reaches 155 million inhabitants) live in the country's seven largest cities. The quality of life in Brazil is discussed here on the base of three examples; two of them - Sâo Paulo and Curitiba - belong to the « rich » area of South Central Brazil. The third one, the axis Ilheus-Itabuna - has been taken in the « poor » North- East. Indeed, unequality prevails in megapolis which are too big, but one must never overlook how diverse is Brazil and how multiple solutions have been found.

Recent discoveries of Proterozoic microfossils in south-central Brazil

Twenty-two Precambrian microfossiliferous localities, seven newly reported here, are known from the São Francisco Block and associated Brasília fold belt of south-central Brazil, reported from outcrop and drill core samples of Mesoand Neoproterozoic cherts, carbonates, and siliciclastics of the ∼1170 to ∼950 Ma old Paranoá Group and the ∼950 to ∼700 Ma old São Francisco Supergroup (composed of the Jequitaí Formation and the overlying Bambuí Group). Representatives of nearly 30 genera of Proterozoic microfossils, chiefly cyanobacteria and subsidiary acritarchs, have been reported from these strata, preserved mostly within carbonaceous black chert in flat-laminated and high-relief stromatolites, and represent a wide spectrum of environments evidently ranging from nearshore lagoonal to supratidal, intertidal, subtidal, and offshore marine settings. Contrary to previously held views, the microfossils are generally more abundant and better preserved in the older unit (Paranoá Group) than in the younger one (São Francisco Supergroup). Nevertheless, among the newly reported assemblages, one from the lower part of the Bambuí Group stands out as probably the best preserved and most diverse microbiota known from any Precambrian unit of South America. Although paleobiologic studies of the Brazilian Proterozoic are still in a formative stage, recent discoveries are highly promising, such as the detection in the work presented here of possible differences: (1) between the microfossil sizes in stromatolites of the Paranoá and Bambuí Groups; (2) in the abundance and size of acritarchs with respect to lithology and facies; and (3) in the microfossil assemblages preserved in morphologically distinct stromatolites.

Paleobiology de uma nova microflürula silicificada do Grupo Bambuí (Proterozoico Superior) da região de Unaí, MG

A moderately well-preserved and abundant assemblage of coccoidal, bacilliform, and filamentous organic-walled microfossils is here described from black chert colleted near the top of a 30 m-thick exposure of predominantly microbially laminated dolostone from the lower part of the Upper Proterozoic Bambui Group, 12,5 km NW of Unai, Minas Gerais, south-central Brazil. Of the 11 morphotypes described in this study, small colonies of coccoidal cells (3 species of Myxococcoides; Glenobotrydion aenigmatis Schopf; Form A) are most abundant, followed by tubular filaments (Siphonophyous sp.; 2 species of Eomycetopsis), and, finally, rare, solitary, large (20-40 µm) coccoidal forms (Form B; Form C) and a single colony of bacilliform cells (Eosynechococcus moorei Hofmann). The assemblage is dominated by apparently planktonic, small-celled (rarely exceeding 13 µm), colonial coccoidal forms, although filamentous forms may have played a significant role in the local benthos, as suggested by faintly preserved, palimpsestic (or ghost) filamentous fabrics and by the presence of poorly preserved tubes of Siphonophycus up to 32 µm in diameter. A single, large pair of thickwalled coccoidal cells (Form B) is here interpreted as a possible acritarch of as yet undetermined biostratigraphic value. The generally small, simple microfossils of this assemblage are similar to elements of the five other known Bambui assemblages and apparently rather typical of many other Late Proterozoic microfloras.

Revision of Viguiera sect. Maculatae (Asteraceae: Heliantheae)

Revision of Viguiera sect. Maculatae (formerly series Maculatae) results in recognition of 14 taxa, including 13 species and one subspecies. Of these, V. guerrerana, V. mirandae, V. sharpii, V. splendens, and V. eriophora subsp. poblana are newly described. All taxa are endemic to Mexico; distribution maps and illustrations are presented for each. Cladistic analysis, based on morphological characters, was used to explore possible phyletic relationships among taxa, and led to the division of the section into two series. Series Adenophyllae is characterized by subcylindric or campanulate heads and oblong pales; series Maculatae has campanulate to hemispheric heads and ovate pales. Chromosome numbers determined for ten of the taxa are uniformly n = 17, suggesting that, for the section, this is the base number and that polyploidy does not occur. Viguiera Kunth comprises approximately 180 species distributed from the western United States to central Argentina, with major concen- trations of species occurring in the central An- des, in south-central Brazil, and in south-central Mexico. The genus occurs primarily in season- ally dry, arid, elevated areas with some of its members extending into tropical lowlands. The genus includes herbaceous annuals and peren- nials as well as shrubs and small trees. Viguiera was established by Kunth (1820) based on the Cuban Viguiera helianthoides Kunth (later synonymized under Viguiera dentata (Cav.) Sprengel). The generic name honors French physician L. G. A. Viguier. According to Kunth, the genus is distinguishable from Helianthus L. by its receptacle, involucre, and pappus. Later authors (Cassini 1821; Gardner 1848; Bentham 1873) relied more heavily on the nature of the pappus of Viguiera (persistent with two awns and several squamellae in between) to separate it from Helianthus (pappus of deciduous awns with few or no squamellae). The species discussed in this paper were placed by Blake (1918) in subg. Viguiera (Cal- anticaria S. F. Blake) of sect. Viguiera (sect. Chlor- acra S. F. Blake) series Maculatae. More than half of the Mexican species of Viguiera are classified within this section. Blake (1918) relied heavily on morphological features of the phyllaries, which in sect. Viguiera are ovate-oblong, and indurated at the base with a narrow herbaceous apex. He distinguished series Brevifoliae, Den- tatae, Grammatoglossae, Maculatae, and Pinnati- lobatae by differences in the proportion and shape of the herbaceous and indurated parts of the phyllary. Blake also mentioned several oth- er distinguishing features such as habit, pappus, and head size, which supplemented the phyl- lary differences he observed. Seven species were included by Blake (1918) in series Maculatae: V. adenophylla, V. eriophora, V. maculata, V. oaxacana, V. quinqueradiata, V. sphaerocephala, and V. tra- chyphylla. According to Blake (1918), these species shared a perennial habit; scabrous, ovate leaves; oblong or oblong-lanceolate phyllaries with an indurated and vittate pale-margined base and a triangular herbaceous apex; and in- volucres arranged in 2-3 series. Since Blake's treatment, three new species be- lieved to be closely related to series Maculatae have been discovered. Miranda (1943) suggest- ed that V. insignis be placed in series Maculatae, probably based on the shrubby or tree-like hab- it of the species, although the pappus and num- ber of series of phyllaries (six to seven) present in this species do not conform to the series. Another species with apparent affinities to se- ries Maculatae but not conforming to its features is V. puruana, which has achenes with well-de- veloped awns but highly reduced squamellae. However, this species appears to be closely re- lated to two species of series Maculatae, V. oaxa- cana and V. sphaerocephala, with which it shares similar pale and phyllary structures. The third species, V. neocronquistii, conforms to the basic characters of the series. The present account is based on field work combined with laboratory and herbarium stud- ies of morphology, chemistry, and chromosome numbers. These studies suggest that the group is sufficiently distinctive to warrant sectional

Microfossils associated with silicified Stratifera undata Komar 1966 from the late Proterozoic Bambuí Group, south-central Brazil

Abstract Small, partly silicified, laterally linked stromatolites exhibiting a high degree of inheritance in the shape of successively stacked laminae from the lower Bambui Group (late Proterozoic), near Unai, Minas Gerais, south-central Brazil, are here described and classified as Stratifera undata Komar 1966. Rare, moderately preserved microfossils and stratiform concentrations of poorly preserved probable microfossils consist essentially of coccoidal forms, there being no convincing evidence of filamentous forms. If, in fact, coccoidal micro-organisms were the overwhelmingly dominant mat-formers, this represents an unusual situation among silicified microflorules from morphologically distinct Precambrian stromatolites yet is quite similar to that observed in another form of Stratifera ( S. biwabikensis from the Gunflint Iron-Formation), which, like the Unai stromatolites, also formed under permanently submerged conditions. S. undata is now known in Brazil from similar upper Proterozoic settings in two very widely separated localities, which suggests its potential use in regional stratigraphic correlation. As a result of this study, we recommend that greater attention be paid to the ‘simpler’ stromatolite morphologies, especially when micro fossiliferous, since such forms commonly comprise the basal portions of biostratigraphically significant stromatolites and may share a common microstructure with these same, more complex forms. Inasmuch as microstructure is generally acknowledged as the stromatolite property most closely controlled by biological factors, study of silicified microflorules within simpler forms may permit inferences regarding not only the microbial communities responsible for more complex stromatolites having the same microstructure but also possible biological reasons for the succession of distinct stromatolite assemblages observed in upper Precambrian rocks.

Revision of Chresta and Pycnocephalum (Compositae: Vernonieae)

Chresta and Pycnocephalum are syncephalous herbs that are restricted to the Central Plateau of Brazil. Chresta is adapted to the arid conditions of cerrado, grassy campo, and campo rupestre. The plants are characterized by tomentose to glabrate, strongly coriaceous leaves, corymbs of glom- erules or single, terminal glomerules (formed by the concrescence of several subglomerules), 20 to more than 200 heads per glomerule, typically 3 florets per head, and corollas 5-11 mm tall with a tube to lobe length ratio of 1-2. In contrast, Pycnocephalum is adapted to wet areas at high elevations within these arid regions and is distinguished by typically glabrate, membranaceous leaves, solitary glomerules (not formed by concrescence) or compound corymbs of 6-10 glomerules, 5-25 heads per glomerule, 4-12 florets per head, and corollas 8-21 mm tall with a tube to lobe length ratio of 2-4.5. Two new combinations are made: Pycnocephalum angustifolium and P. pinnatifidum. Chresta Vell. and Pycnocephalum DC. (Com- positae: Vernonieae) comprise, respectively, four and three species of syncephalous peren- nial herbs that are restricted to the arid Central Plateau of Brazil. Chresta is adapted to the arid conditions of shrubby cerrado, grassy campo, and campo rupestre (sensu Eiten 1978, 1982, 1983) at elevations of 500-2400 m within the vast mo- saic of savanna covering south-central Brazil. In contrast, Pycnocephalum is restricted to wet grassy campo or the margins of rivers or streams at elevations of 800-1200 m within these arid regions. Although some taxa are often limited to specific habitats, both genera are abundant within their respective ecological preserves. It has been widely accepted that Pleistocene climate fluctuations produced a repeated alter- nation of semi-arid and humid conditions in South America. During semi-arid phases, wide- spread areas of xerophytic caatinga (Eiten and Goodland 1979; Bucher 1982) and degraded cerrado (Vanzolini 1973) created more favorable conditions for long-distance dispersal from the Andes (Van der Hammen 1974). Currently, these climatic fluctuations have produced nu- merous well-documented plant and animal re- fugia peripheral to the Amazon Basin (Vuilleu- mier 1971; Vanzolini 1973; Van der Hammen 1974; Prance 1977; Pires and Prance 1977; Simpson and Haffer 1978; Mori et al. 1981; Prance 1982). The Veadeiros refuge in Goias and the Serra do Mar refuge in southeastern Brazil were formed during the Quaternary pe- riod, were repeatedly colonized during the Pleistocene, and are among the oldest refugia in Brazil. Five out of the seven species in Chres- ta and Pycnocephalum are found within the Veadeiros refuge. Of the remaining two taxa, C. pycnocephala appears to be a Minas Gerais variant of C. exsucca, and modern collections of P. pinnatifidum are unknown. Thus, it is possible that Veadeiros has served as the center of dis- persal and diversification for Chresta and Pyc- nocephalum.

Amazon Basin: A System in Equilibrium

Despite the very active deforestation of the last decade, the Amazon Basin is still primarily covered with trees and is a system in equilibrium. The Andes form a barrier at the western end of the basin and, coupled with the prevailing easterly winds, ensure an almost unique precipitation and water-recycling regime. On average 50 percent of the precipitation is recycled, and in some areas even more. The soils are poor. Most of the nitrogen and phosphorus is found in the soil, and the remaining nutrient elements are found in the standing biomass. There is some nutrient recycling and little loss from the intact ecosystem, and the small input of nutrients from precipitation maintains a small positive nutrient balance. Continued large-scale deforestation is likely to lead to increased erosion and water runoff with initial flooding in the lower Amazon, together with reduced evapotranspiration and ultimately reduced precipitation. Reduced precipitation in the Amazon could increase the tendency toward continentality and adversely affect climate and the present agriculture in south-central Brazil.

Gravel deposits survey in south central Brazil

The largest hydroelectric development of Brazil, with 37 hydroelectric power plants, is located on the Parana river basin, in the south central region of the country.

An analysis of the effects of frosts on the principal coffee areas of Brazil

Frost damage on coffee plantations in south-central Brazil is not a frequent occurrence. However, when this area is affected by a severe frost — as happened in August of 1975 — the consequences for the agricultural economy of south-central Brazil and the socio-economic condition of the rural labourers are serious. In this paper the meteorological characteristics of a frost condition are outlined and their physiological effects upon coffee bushes are stated. A differentiation is made as to the timely occurrence of frosts and their effects on crops. If the frost hits during harvest time (April through June) the beans may be burned and a qualitative loss may ensure. If the frost occurs after the harvest, only the coffee bushes are affected and they may have recovered by the following agricultural year. The most devastating frosts are those that occur late in winter (August-September) because they kill the buds and the flowers so that next year's harvest will be lost. Coffee in south-central Brazil is usually grown on plantations of 10 to 100 ha, and 100 to 1000 ha. There has been a trend to expand the coffee growing area into Mato Grosso-Rondonia, while in the state of Parana, where frosts are more severe but the soils are better, coffee growing in large estates has intensified. Moreover, the introduction of new methods of planting and mechanization of the agricultural work have brought about an intensification of coffee production. Analysis of the improvements in cultivating pratices and of agricultural mechanization that these two processes have caused a drastic reduction in the demand for agricultural labourers. Added to this, the possibilities of rural employment have also been adversely affected by the trend among many coffee growers to introduce other crops into their estates in order to minimize their losses due to frost.

Revision of Vernonia Series Flexuosae (Compositae: Vernonieae)

SeriesFlexuosae consists of eight closely related species. The taxa are collectively unique in their morphology and share similar flavonoid compounds. They range from south-central Brazil southwest into Bolivia, Paraguay, Uruguay and Argentina. The eight species are keyed, described and mapped and synonymies are provided.

First report of well-preserved precambrian microfossils in Brazil (Paraopeba formation, Bambuí Group, near Brasilia)

Thin sections of black chert from two 'localities at the base of the upper Precambrian Paraopeba Formation (Bambui Group) near Brasilia in south-central Brazil contain abundant microfossils. Although supposed Precambrian rnicrofossils have been recorded previously from Precambrian rocks (summarized in FAIRCHILD DARDENNE, in prep.), the following preliminary study marks the first time that well-preserved, morphologically diverse rnicrofossils have been reported from indisputably Precambrian rocks in Brazil. These rnicrofossils occur in silicified, branched, columnar stromatolites from 3040 km north of Unai, Minas Gerais, about 100 km to the northwest in silicified, flat-Iaminated dolostone 30 km west-southwest of Sao Gabriel, Goias. Solitary colonial forms predominate at both localities, with the Sao Gabriel assemblege being the better preserved, more diverse, more abundant assemblage. These discoveries are important because (1) They provide a standard of comparison for past future rnicrofossil fmds in the Brazilian Precambrian; (2) They may further elucidate the relationships between biological content columnar stromatolite morphology, thereby facilitating insight into the possible reasons for the apparent of stromatolites; (3) Together with stromatolite data (see FAIRCHILD DARDENNE, in prep.), they may help us to better date and correlate the Bambu! Group make better paleoenvironrnental paleogeographical interpretations of these strata. On a broader scale, the Unai Sao Gabriel rnicrofloras represent additional valuable evidence for deciphering the early evolution of the algae for testing Precambrian biostratigraphic schemes (see SCHOPF, 1977).

Spore Morphology of Anemia Subgenus Coptophyllum

Anemia Swartz is a genus of leptosporangiate ferns consisting of approximately 90 species. The genus inhabits tropical and semitropical latitudes in Africa, India, and the Americas, with two species reaching the United States. Anemia generally is divided into three subgenera: Coptophyllum, Anemiorrhiza, and Anemia. The present study deals with a scanning electron microscopic examination of spores of six species of subg. Coptophyllum, four of which are endemic to the Planalto region of south-central Brazil. Subgenus Coptophyllum has been monographed by Mickel (1962), who noted spore morphology as viewed with a light microscope. Previous studies of Anemia spores also include the work of Erdtman (1957). The spores of Anemia are unique among ferns in their tetrahedral shape and surface pattern of conspicuous ridges separated by striae. Protuberances or ridge extensions occur where the ridges join the trilete scar. The present study was undertaken in an attempt to discover morphological details not visible in light microscopy that might be of taxonomic value. While I was the field assistant to Dr. William R. Anderson on the 1973 New York Botanical Garden Expedition to the Planalto region of south-central Brazil, I collected spore samples of various Anemia species. All were air-dried. Spore samples of six species, 18 specimens altogether, belonging to subg. Coptophyllum were mounted on aluminum studs with double-adhesive tape and coated with a thin (200-400A) layer of gold-palladium. The samples were then examined at 15 kv and photographed using the JEOL JSM-U3 Scanning Electron Microscope (SEM) of the Electron Microscopy Center, Texas A & M University. To best facilitate comparisons, proximal, distal, and ornamentation micrographs were included for all species examined. Measures and magnifications are based upon those indicated by the instrument. Although absolute accuracy in magnification is rare in the SEM, relative measures between the spores can be assumed to be correct. In the following listing, collections cited with an asterisk are illustrated in this paper. The specimens examined, all of which were from Brazil, are: A. elegans (Gardn.) Presl.-Goias: Alto do Paraiso, Anderson, Hill, et al. 6670; Serra dos Cristais, Anderson, Hill, et al. 8186; Serra Dourada, Anderson, Hill, et al. 9982; Serra dos Pireneus, Anderson, Hill, et al. 10295.* Matto Grosso: Barra dos Gargas, Anderson, Hill, et al. 9823. A ferruginea H.B.K.--Goias: Alto do Paraiso, Anderson, Hill, et al. 6794; Serra dos Pireneus, Anderson, Hill, et al. 10344. Minas Gerais: Serro do Espinhago, Anderson, Hill, et al. 8415, 8767.* Matto Grosso: Barra dos Gargas, Anderson, Hill, et al. 9904. A. glareosa Gardn.-Goias: Alto do Paraiso, Anderson, Hill, et al. 6655; Serra Dourada, Anderson, Hill, et al. 9983.*

Industrialisation, Agricultural Specialisation, and Frontier Settlement in South-Central Brazil, 1940-70

The field work for this study was undertaken during my tenure as Ford Foundation Visiting Professor at the Institute for Economic Research, University of São Paulo, Brazil. I want to thank William H. Nicholls for making available to me some of his unpublished materials. Milton Campanario and Abby Rashid helped assemble and organise the raw data.

New Endemic Species of Harpalyce (Leguminosae: Brongniartieae) from South-Central Brazil with a Key to the Brazilian Species

Harpalyce parvifolia andH. robusta, endemic species from the Serra do EspinhaCo, State of Minas Gerais, and Chapada dos Veadeiros, State of Goias, respectively, are described and included in a new key to the Brazilian members of the genus.

Changes in the Agriculture of South Central Brazil

Changes in the Agriculture of South Central Brazil