RESUMO
SUMMARY: In 2004, Xiphopenaeus kroyeri, one of major species in commercial fisheries in Brazil was included in the list of brazilian overfished species and, in 2006, two cryptic species were identified in the Atlantic Ocean by molecular approaches: Xiphopenaeus sp. I and II. In 2019, Carvalho-Batista et al. described both Xiphopenaeus sp. I and Xiphopenaeus sp. II and these species were named X. kroyeri and X. dincao, respectively. This study aimed at performing morphometric analysis in order to identify potential fishing stocks of X. kroyeri sensu strictum along Brazilian coast. The results obtained separate Caravelas, Atafona and Balneário Camboriú from all the other populations studied and showed three groups: Ubatuba, Nova Almeida; Ubatuba, Cananéia; Ubatuba, Santos. These results indicate that the maritime limits practiced in closed seasons along Brazil are embracing the detected morphometric stock boundaries observed for Xiphopenaeus kroyeris.s.
RESUMEN: En 2004, Xiphopenaeus kroyeri, una de las principales especies de la pesca comercial en Brasil, fue incluida en la lista de especies brasileñas sobre explotadas y, en 2006, se identificaron dos especies crípticas en el Océano Atlántico mediante enfoques moleculares: Xiphopenaeus sp. I y II. En 2019, Carvalho-Batista et al. describieron tanto Xiphopenaeus sp. I y Xiphopenaeus sp. II y a estas especies denominaron X. kroyeri y X. dincao, respectivamente. Este estudio tuvo como objetivo realizar un análisis morfométrico con el fin de identificar posibles poblaciones de pesca de X. kroyeri sensu strictum a lo largo de la costa brasileña. Los resultados obtenidos en Caravelas, Atafona y Balneário Camboriú se separaron de todas las demás poblaciones estudiadas y mostraron tres grupos: Ubatuba, Nova Almeida; Ubatuba, Cananéia; Ubatuba, Santos. Estos resultados indican que los límites marítimos practicados en temporadas de veda a lo largo de Brasil están abarcando los límites de stock morfométricos observados para Xiphopenaeus kroyeris.s.
Assuntos
Animais , Penaeidae/anatomia & histologia , Grupos de População Animal , BrasilRESUMO
OBJECTIVES: To determine (i) whether peridomestic Attalea phalerata palms in fragmented human-occupied areas of the Alto Beni, Bolivia, are infested by triatomines; (ii) the specific status of triatomines captured in the area; and (iii) the rate of natural Trypanosoma cruzi infection among those triatomines. METHODS: One hundred and twenty-five live-bait traps were used to sample 47 A. phalerata palms in three Alto Beni localities. Active search for vectors was also performed in 10 chicken coops and three rice storage units. Only Rhodnius specimens were found. As nymphs of closely related Rhodnius species are morphologically undistinguishable, and because of controversy in the literature regarding which Rhodnius species occur in Bolivia, collected insects were identified through molecular taxonomy. Phylogenetic analyses of DNA sequences obtained for a fragment of the mitochondrial cytochrome b gene and for the nuclear ITS-2 ribosomal region were used as molecular markers. Natural infection rates were determined using a pair of primers that PCR-amplify a 330-bp fragment of the parasite's kDNA. RESULTS: Twelve nymphs were captured in five A. phalerata palms (from two of the three localities studied), and an adult was collected from a chicken coop in Iniqua (and morphologically identified as Rhodnius stali). All nymphs (as well as the adult) were molecularly identified as R. stali based on the two molecular markers used. A single nymph was found to be infected with T. cruzi. CONCLUSIONS: Attalea phalerata palms represent an important sylvatic ecotope occupied by R. stali in the Alto Beni region of Bolivia, where there are signs of T. cruzi transmission to humans, despite the preliminary indication of low level of natural infection of the vectors.
Assuntos
Cycas/parasitologia , Insetos Vetores/classificação , Rhodnius/classificação , Animais , Bolívia , Citocromos b/genética , DNA Ribossômico/genética , Insetos Vetores/genética , Insetos Vetores/parasitologia , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Rhodnius/genética , Rhodnius/parasitologia , Análise de Sequência de DNA , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Triatoma infestans, now eliminated from most of South America by control campaigns, has been and still is the main Chagas disease vector due to its ability to colonize rural dwellings. The traditional hypothesis put forth to explain T. infestans adaptation to the synanthropic environment rests on the domestication of wild guinea pigs, one of its natural hosts, by Andean tribes about 5000 BC. Here we present two new hypotheses, based on organized human social activities. The first involves maize production, storage and distribution during the Inca period. Maize granaries could host wild rodent populations that would attract sylvatic T. infestans that were later dispersed during maize distribution. The second hypothesis is associated with the contemporary Urkupiña Virgin festival, near Cochabamba, where thousands of pilgrims gather for rituals in an area that is part of a sylvatic T. infestans focus, thus favoring the contact with the insects and leading to their passive dispersal.
Assuntos
Doença de Chagas/transmissão , Insetos Vetores/crescimento & desenvolvimento , Triatoma/crescimento & desenvolvimento , Agricultura , Animais , Bolívia/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/parasitologia , Doenças Transmissíveis Emergentes/transmissão , Férias e Feriados , Humanos , Insetos Vetores/parasitologia , Triatoma/parasitologia , Zea maysRESUMO
The haematophagous insects of the subfamily Triatominae (Hemiptera-Reduviidae) have great epidemiological importance as vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Mepraia was originally described as a monotypic genus comprised of Mepraia spinolai, distributed along coastal areas of northern Chile (from Region I to the Metropolitan Region). Recently, some M. spinolai populations have been ranked as a new species named Mepraia gajardoi. Several populations along the distribution range of the genus were sampled, and genetic differentiation was studied based upon the analysis of three molecular markers: cytogenetics (karyotype and chromosome behaviour during meiosis using the C-banding technique), mitochondrial DNA (a cytochrome oxidase I gene fragment), and nuclear ribosomal DNA (intergenic region including the two internal transcribed spacers ITS-1 and ITS-2 and the 5.8S rRNA gene). The data here presented indicate that populations within the Mepraia genus (excluding Region II specimens) can be divided into two separate lineages. One lineage is comprised of specimens from the northernmost Region I and represents M. gajardoi. The other includes samples from the southern III, IV and the Metropolitan Regions, and represents M. spinolai. Region II individuals deserve particular attention as their relationship to the two identified lineages is not clear-cut. While they appear to belong to M. spinolai based on cytogenetics and rDNA markers, COI results indicate a closer relationship to M. gajardoi. This disagreement can be due to mitochondrial DNA introgression or the retention of ancestral polymorphisms.
Assuntos
DNA Intergênico/genética , Insetos Vetores/genética , Triatominae/genética , Animais , Sequência de Bases , Doença de Chagas , Chile , Citogenética , Feminino , Geografia , Gônadas/química , Masculino , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Alinhamento de SequênciaRESUMO
To make reliable interpretations about evolutionary relationships between Trypanosoma rangeli lineages and their insect vectors (triatomine bugs of the genus Rhodnius) and, thus, about the determinant factors of lineage segregation within T. rangeli, we compared phylogenies of parasite isolates and vector species. Sixty-one T. rangeli isolates from invertebrate and vertebrate hosts were initially evaluated in terms of polymorphism of the spliced-leader gene (SL). Further analysis based on SL and SSUrRNA sequences from 33 selected isolates, representative of the overall phylogenetic diversity and geographical range of T. rangeli, supported four phylogenetic lineages within this species. By comparing the phylogeny of Rhodnius species with that inferred for T. rangeli isolates and through analysis of the geographical range of the isolates, we showed that there is a very significant overlap in the distribution of Rhodnius species and T. rangeli lineages. Congruence between phylogeographical analysis of both T. rangeli lineages and complexes of Rhodnius species are consistent with the hypothesis of a long coexistence of parasites and their vectors, with lineage divergence associated with sympatric species of Rhodnius apparently without association with particular vertebrate hosts. Separation of T. rangeli isolates from vectors of distinct complexes living in sympatry favours the absence of gene flow between the lineages and suggests evolution of T. rangeli lineages in independent transmission cycles, probably associated to specific Rhodnius spp. ecotopes. A polymerase chain reaction assay based on SL intergenic sequences was developed for simultaneous identification and lineage genotyping of T. rangeli in epidemiological surveys.
Assuntos
Hemípteros/parasitologia , Filogenia , Trypanosoma/classificação , Tripanossomíase/transmissão , Animais , Sequência de Bases , DNA de Protozoário/genética , Cães/parasitologia , Geografia , Humanos , Dados de Sequência Molecular , Gambás/parasitologia , Saimiri/parasitologia , Trypanosoma/genética , Trypanosoma/isolamento & purificaçãoRESUMO
Rhodnius prolixus is one of the most important primary vectors of human Chagas disease in Latin America. Its morphology is, however, identical to that of the members of the Rhodnius robustus cryptic species complex, which includes secondary vectors. The correct identification of these taxa with differential vector competence is, therefore, of great epidemiological relevance. We used the alignment of 26 mitochondrial cytochrome b haplotypes (663 bp) to select for PCR-amplifiable species-specific regions. We designed one forward primer on a region conserved across all haplotypes, and three reverse primers that anneal to species-specific regions and amplify fragments of different lengths for R. prolixus (285 bp) and for members of the two major R. robustus lineages: group I (349 bp) and groups II-IV (239 bp). These fragments were easily identifiable on regular 1.5% agarose gels. This multiplex PCR assay was successfully tested on 81 specimens from six Latin American countries, and used to determine the phylogeographic boundaries for each species. It is a simple, objective, and cost-effective assay. Its PCR-based nature makes it applicable to any insect developmental stage, as well as to dried specimens, and insect remains. It should be particularly useful in areas where representatives of these Rhodnius species occur in sympatry.
Assuntos
Doença de Chagas/transmissão , Insetos Vetores/genética , Reação em Cadeia da Polimerase/métodos , Rhodnius/genética , Animais , Sequência de Bases , Doença de Chagas/epidemiologia , Citocromos b/genética , Primers do DNA/genética , DNA Mitocondrial/genética , Haplótipos/genética , Humanos , Mitocôndrias/genética , Alinhamento de Sequência/métodos , América do Sul/epidemiologia , Especificidade da EspécieRESUMO
Anopheles halophylus Silva-do-Nascimento & Lourenço-de-Oliveira was recently described using morphological and biological variants in specimens previously identified as Anopheles triannulatus (Neiva & Pinto). Because these two species occur in sympatry in central Brazil, we used allozymes to determine the extent of gene flow to confirm that they are different species. Of 11 allozyme loci analyzed, one (Mpi) was found to be diagnostic for An. halophylus and An. triannulatus, confirming their specific status. This locus revealed a second sibling species within An. triannulatus sensu lato. An. halophylus and the new undescribed species were confirmed using random amplified polymorphic DNA markers that showed moderate genetic divergence among these three sympatric and closely related taxa (D = 0.145-0.428). Moreover, this marker indicates that An. halophylus and the new species are more closely related to each other than either is to An. triannulatus.
Assuntos
Anopheles/classificação , Anopheles/genética , Alelos , Animais , Anopheles/anatomia & histologia , Brasil , Enzimas/genética , Frequência do Gene , Genótipo , Técnica de Amplificação ao Acaso de DNA Polimórfico , Especificidade da EspécieRESUMO
Genetic relationships among 10 species of bugs belonging to the tribe Rhodniini (Hemiptera: Reduviidae), including some important vectors of Chagas disease, were inferred from allozyme analysis of 12 enzyme loci (out of 21 enzyme systems examined), using agarose gel electrophoresis. These species formed two clusters: one comprising Rhodnius brethesi, R. ecuadoriensis, R. pallescens and R. pictipes; the other with Psammolestes tertius, Rhodnius domesticus and the Rhodnius prolixus group comprising R. nasutus, R. neglectus, R. prolixus and R. robustus. The resulting tree was [((R. ecuadoriensis, R. pallescens) R. brethesi) R. pictipes], [R. domesticus (P. tertius [(R. nasutus, R. neglectus) (R. prolixus, R. robustus)])]. Rhodnius nasutus and R. neglectus differed by only one locus, whereas no diagnostic loci were detected between R. prolixus and R. robustus (22 loci were analysed for these four species), despite considerable DNA sequence divergence between species in each of these pairs. Allozymes of the R. prolixus group showed greater similarity with Psammolestes tertius than with other Rhodnius spp., indicating that Rhodnius is paraphyletic and might include Psammolestes.
Assuntos
Doença de Chagas/transmissão , Isoenzimas/genética , Rhodnius/classificação , Rhodnius/enzimologia , Triatominae/classificação , Triatominae/enzimologia , Animais , Eletroforese em Gel de Ágar/veterinária , Insetos Vetores/classificação , Insetos Vetores/enzimologia , Insetos Vetores/genética , Isoenzimas/análise , Filogenia , Rhodnius/genética , Especificidade da Espécie , Triatominae/genéticaRESUMO
Studies were performed on five Brazilian populations of Lutzomyia longipalpis: Salvaterra (PA), São José do Ribamar (MA), Canindé (CE), Natal (RN) and Gruta da Lapinha, Lagoa Santa (MG). No morphological differences were observed that could distinguish between these populations. Homogeneity tests showed that the allopatric populations display a certain heterogeneity and that the sympatric populations, with different patterns of spots, are homogeneous. The Student-Newman-Keuls test, represented by Euler-Venn diagrams, showed a disjunction between the populations from the north/northeast and the one from Gruta da Lapinha. Genetic distances between the four populations (excluding the Canindé population) were within the range of intrapopulational differences. The Gruta da Lapinha population displayed a heterozygotic deficiency that could be a consequence of high levels of inbreeding due to cryptic habits of living in a small cave. These results do not favor the hypothesis of a L. longipalpis species complex in Brazil, and the species should be considered high polymorphic.
Assuntos
Psychodidae/anatomia & histologia , Animais , Brasil , Feminino , Frequência do Gene , Variação Genética , Masculino , Psychodidae/classificação , Psychodidae/genéticaRESUMO
Kissing bugs or triatomines (Reduviidae: Triatominae) are vectors of the Chagas' disease agent Trypanosoma cruzi. There is a current need for more sensitive tools for use in discrimination of different bug populations and species, thus allowing a better understanding of these insects as it relates to disease transmission and control. In a preliminary analysis of the mitochondrial large subunit ribosomal RNA (mtlsurRNA) and cytochrome B (mtCytB) genes, we used DNA sequencing to study species identification and phylogeny. In both examined gene regions, about 46% of nucleotide positions exhibited polymorphism. The examined region of mtCytB appears to have evolved more rapidly than the examined region of mtlsurRNA. Phylogenetic analysis of both gene fragments in the examined species produced similar results that were generally consistent with the accepted taxonomy of the subfamily. The two major tribes, Rhodniini and Triatomini, were supported, along with additional clades that corresponded to accepted species complexes within the Rhodnius and Triatoma genera. The one chief exception was that Psammolestes coreodes sorted into the Rhodnius prolixus-robustus-neglectus clade, with bootsrap values of 99% and 81%, respectively, for the mtlsurRNA and mtCytB fragments. All of the individual species examined could be distinguished at both genetic loci.
Assuntos
Doença de Chagas/transmissão , DNA Mitocondrial/química , Insetos Vetores/classificação , Triatominae/classificação , Animais , Sequência de Bases , Grupo dos Citocromos b/química , Grupo dos Citocromos b/genética , Primers do DNA/química , Insetos Vetores/química , Insetos Vetores/genética , Dados de Sequência Molecular , América do Norte , Filogenia , Reação em Cadeia da Polimerase/veterinária , RNA Ribossômico/química , RNA Ribossômico/genética , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , América do Sul , Triatominae/química , Triatominae/genéticaRESUMO
DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was used to infer the genetic structure of nine geographical Triatoma infestans populations and their phylogenetic relationship with T. melanosoma and T. brasiliensis. T. infestans and T. melanosoma were compared by morphometry, allozyme and cytogenetic analyses, as well as subjected to reciprocal crosses, in order to clarify the taxonomic status of the latter. No differences were found to distinguish the two species and the crosses between them yielded progeny. T. infestans populations presented four haplotypes that could be separated in two clusters: one formed by the samples from Bolivia (Andes and Chaco) and the other formed by samples from Argentina and Brazil. Silvatic and domestic T. infestans populations from Bolivia (Andes) were genetically identical.
Assuntos
DNA Mitocondrial/química , DNA de Protozoário/química , Variação Genética , Triatoma/genética , Animais , Argentina , Sequência de Bases , Bolívia , Brasil , Grupo dos Citocromos b/genética , DNA Mitocondrial/genética , DNA de Protozoário/genética , Feminino , Masculino , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da Espécie , Triatoma/citologiaRESUMO
An eletrophoretic analysis of three species of the subgenus Dendromyia (Wyeomyia luteoventralis, Wy. ypsipola and Wy. testei) and three species belonging to different groups in the genus Wyeomyia (Wy. negrensis, Wy. mystes and Wy. confusa) was performed. Eight enzyme loci were analyzed. High values of genetic identify were detected among the species of the subgenus Dendromyia: Wy. luteoventralis, Wy. ypsipola and Wy. testei (mean value 0.63). On the other hand low values of genetic identify were observed among Wy. negrensis, Wy. mystes and Wy. confusa (mean value 0.23), suggesting that they belong, at least, to distinct subgenera within the Genus Wyeomyia. The UPGMA phenogram revealed the grouping of the Dendromyia species, while the others clustered at lower identity levels.
Assuntos
Culicidae/genética , Animais , Culicidae/classificação , Variação GenéticaRESUMO
A greenhouse experiment was carried out with Brachiaria brizantha (Hochst ex A.Rich) Stapf. cv. Marandu to study the effects of potassium rates in dry matter yield, plant tillering, potassium concentration and distribution in sampled parts of shoots. Ground quartz was used as substrate in pots. Eight potassium rates (0; 9.75; 39; 78; 156; 234; 312 and 468 mg K L-1) were used and the experiment was set in a randomized complete block design, with four replications. Plants were first harvested 38 days after transplanting the seedlings to the pots and the second harvest 33 days after the first one. In each harvest, plant tops were separated into: non-expanded leaves, laminae of the two newly expanded leaves, laminae of the other expanded leaves and culms plus sheaths. After the second harvest, roots were collected. Forage yield, plant tillering and potassium concentration in each sampled part were increased with potassium rates in the substrate. Maximum forage yield was reached at potassium rates of 365 and 399 mg L-1 and the highest tiller number ocurred at rates of 312 and 468 mg L-1. A second-order model fitted to the potassium concentration in the non-expanded leaves picked up in the two harvests and also in the other sampled parts in the first harvest. For the expanded (newly or other) leaves or culms and sheaths in the second harvest, the data for potassium concentration fitted to a first-order model. The amount of potassium in the culms and sheaths exceeded that of any other part sampled in the shoot of this forage. The use of young leaf blades for potassium diagnosis in this forage is recommended. Critical potassium levels in this plant tissue were between 22 and 29 g kg-1.
O experimento foi conduzido em casa-de-vegetação, envolvendo a forrageira Brachiaria brizantha (Hochst ex A.Rich.) Stapf. cv. Marandu, com o objetivo de avaliar o efeito de doses de potássio na produção de matéria seca, perfilhamento, concentração e distribuição relativa de potássio nas partes da planta. Utilizou-se sílica como substrato. Foram utilizadas oito doses de potássio (0; 9,75; 39; 78; 156; 234; 312 e 468 mg K L-1) em um delineamento experimental em blocos completos ao acaso, com quatro repetições. As plantas foram colhidas 38 dias após o transplante, no primeiro corte e 33 dias após este, no segundo corte, sendo separadas em folhas não-expandidas, lâminas de folhas novas, lâminas de folhas velhas e colmos mais bainhas. Por ocasião do segundo corte foram também coletadas as raízes. Os resultados mostraram efeitos positivos das doses de potássio na produção de matéria seca da parte aérea e das raízes, no número de perfilhos e na concentração de potássio em cada parte amostrada da forrageira. Os valores máximos de produção de matéria seca foram atingidos com doses de potássio entre 365 e 399 mg K L-1, enquanto o maior número de perfilhos nas plantas foi obtido com as doses de 312 e 468 mg K L-1. A concentração de potássio aumentou de forma quadrática nas folhas não-expandidas do crescimento de ambos os cortes, enquanto nas demais partes amostradas obedeceu a um modelo do segundo grau no primeiro corte, sendo linear no segundo corte, em função das doses de potássio. A quantidade de potássio foi mais elevada nos colmos mais bainhas do que em quaisquer das outras partes amostradas nessa forrageira. Para diagnose nutricional de potássio nessa espécie recomenda-se o uso de lâminas de folhas novas, nas quais os níveis críticos de potássio ficaram entre 22 e 29 g kg-1.
RESUMO
A greenhouse experiment was carried out with Brachiaria brizantha (Hochst ex A.Rich) Stapf. cv. Marandu to study the effects of potassium rates in dry matter yield, plant tillering, potassium concentration and distribution in sampled parts of shoots. Ground quartz was used as substrate in pots. Eight potassium rates (0; 9.75; 39; 78; 156; 234; 312 and 468 mg K L-1) were used and the experiment was set in a randomized complete block design, with four replications. Plants were first harvested 38 days after transplanting the seedlings to the pots and the second harvest 33 days after the first one. In each harvest, plant tops were separated into: non-expanded leaves, laminae of the two newly expanded leaves, laminae of the other expanded leaves and culms plus sheaths. After the second harvest, roots were collected. Forage yield, plant tillering and potassium concentration in each sampled part were increased with potassium rates in the substrate. Maximum forage yield was reached at potassium rates of 365 and 399 mg L-1 and the highest tiller number ocurred at rates of 312 and 468 mg L-1. A second-order model fitted to the potassium concentration in the non-expanded leaves picked up in the two harvests and also in the other sampled parts in the first harvest. For the expanded (newly or other) leaves or culms and sheaths in the second harvest, the data for potassium concentration fitted to a first-order model. The amount of potassium in the culms and sheaths exceeded that of any other part sampled in the shoot of this forage. The use of young leaf blades for potassium diagnosis in this forage is recommended. Critical potassium levels in this plant tissue were between 22 and 29 g kg-1.
O experimento foi conduzido em casa-de-vegetação, envolvendo a forrageira Brachiaria brizantha (Hochst ex A.Rich.) Stapf. cv. Marandu, com o objetivo de avaliar o efeito de doses de potássio na produção de matéria seca, perfilhamento, concentração e distribuição relativa de potássio nas partes da planta. Utilizou-se sílica como substrato. Foram utilizadas oito doses de potássio (0; 9,75; 39; 78; 156; 234; 312 e 468 mg K L-1) em um delineamento experimental em blocos completos ao acaso, com quatro repetições. As plantas foram colhidas 38 dias após o transplante, no primeiro corte e 33 dias após este, no segundo corte, sendo separadas em folhas não-expandidas, lâminas de folhas novas, lâminas de folhas velhas e colmos mais bainhas. Por ocasião do segundo corte foram também coletadas as raízes. Os resultados mostraram efeitos positivos das doses de potássio na produção de matéria seca da parte aérea e das raízes, no número de perfilhos e na concentração de potássio em cada parte amostrada da forrageira. Os valores máximos de produção de matéria seca foram atingidos com doses de potássio entre 365 e 399 mg K L-1, enquanto o maior número de perfilhos nas plantas foi obtido com as doses de 312 e 468 mg K L-1. A concentração de potássio aumentou de forma quadrática nas folhas não-expandidas do crescimento de ambos os cortes, enquanto nas demais partes amostradas obedeceu a um modelo do segundo grau no primeiro corte, sendo linear no segundo corte, em função das doses de potássio. A quantidade de potássio foi mais elevada nos colmos mais bainhas do que em quaisquer das outras partes amostradas nessa forrageira. Para diagnose nutricional de potássio nessa espécie recomenda-se o uso de lâminas de folhas novas, nas quais os níveis críticos de potássio ficaram entre 22 e 29 g kg-1.
RESUMO
In a greenhouse experiment Brachiaria brizantha Stapf, cv. Marandu was grown in a nutrient solution. The treatments were a complete nutrient solution, nutrient solutions with the omissions of each macronutrient (N, P, K, Ca, Mg and S) and a control (with the omission of all macronutrients). Plants were harvested 50 days after transplanting. Dry matter yield, tiller number and plant height were recorded, and nutrient concentrations in shoot and root were determined. Omissions of N and P were the most limiting for plant growth, whereas K and Ca did not affect grass growth and tillering. Mg and S omissions resulted in significant decreases in the plant parameters. Great decreases in plant nutrient concentrations were verified in the treatments with nutrient omissions in solution. Visual symptoms of deficiencies were observed for each nutrient omission treatment, with those of N and P being the first and that of Ca being the latest shown by the plants. Studies on forms and sources of nutrients for nutrient solution to be used with this grass are suggested.
Em experimento de casa de vegetação, cultivou-se Brachiaria brizantha Stapf. cv. Marandu em solução nutritiva, tendo como tratamentos a solução completa, as omissões individuais de N, P, K, Ca, Mg, S e a testemunha (com omissão dos macronutrientes). Fez-se o acompanhamento da manifestação dos sintomas visuais de deficiência e, 50 dias após o transplante, avaliou-se a produção de matéria seca (MS), número de perfilhos (NP), a altura das plantas (H), bem como a composição mineral da parte aérea e das raízes. As omissões de N e P limitaram o crescimento, ao passo que a omissão de K não afetou a produção de MS e NP. A omissão de Ca não trouxe, para o período considerado, restrições na produção de MS, NP e H. Nas omissões de Mg e S as plantas tiveram fraco desempenho, superando apenas os tratamentos onde foram omitidos o N e o P. A composição mineral da parte aérea só apresentou diferenças acentuadas nos teores para os nutrientes omitidos. Sintomas visuais de deficiência foram observados para todas as omissões, sendo os primeiros manifestados através da omissão do N e do P e os últimos, através da omissão do Ca. São sugeridos estudos para melhor definição do balanço entre formas e fontes de nutrientes para a solução nutritiva quando utilizada no cultivo de plantas de Brachiaria brizantha cv. Marandu.
RESUMO
In a greenhouse experiment Brachiaria brizantha Stapf, cv. Marandu was grown in a nutrient solution. The treatments were a complete nutrient solution, nutrient solutions with the omissions of each macronutrient (N, P, K, Ca, Mg and S) and a control (with the omission of all macronutrients). Plants were harvested 50 days after transplanting. Dry matter yield, tiller number and plant height were recorded, and nutrient concentrations in shoot and root were determined. Omissions of N and P were the most limiting for plant growth, whereas K and Ca did not affect grass growth and tillering. Mg and S omissions resulted in significant decreases in the plant parameters. Great decreases in plant nutrient concentrations were verified in the treatments with nutrient omissions in solution. Visual symptoms of deficiencies were observed for each nutrient omission treatment, with those of N and P being the first and that of Ca being the latest shown by the plants. Studies on forms and sources of nutrients for nutrient solution to be used with this grass are suggested.
Em experimento de casa de vegetação, cultivou-se Brachiaria brizantha Stapf. cv. Marandu em solução nutritiva, tendo como tratamentos a solução completa, as omissões individuais de N, P, K, Ca, Mg, S e a testemunha (com omissão dos macronutrientes). Fez-se o acompanhamento da manifestação dos sintomas visuais de deficiência e, 50 dias após o transplante, avaliou-se a produção de matéria seca (MS), número de perfilhos (NP), a altura das plantas (H), bem como a composição mineral da parte aérea e das raízes. As omissões de N e P limitaram o crescimento, ao passo que a omissão de K não afetou a produção de MS e NP. A omissão de Ca não trouxe, para o período considerado, restrições na produção de MS, NP e H. Nas omissões de Mg e S as plantas tiveram fraco desempenho, superando apenas os tratamentos onde foram omitidos o N e o P. A composição mineral da parte aérea só apresentou diferenças acentuadas nos teores para os nutrientes omitidos. Sintomas visuais de deficiência foram observados para todas as omissões, sendo os primeiros manifestados através da omissão do N e do P e os últimos, através da omissão do Ca. São sugeridos estudos para melhor definição do balanço entre formas e fontes de nutrientes para a solução nutritiva quando utilizada no cultivo de plantas de Brachiaria brizantha cv. Marandu.
RESUMO
An orchard of guava (Psidium guayava L.) located in Aliança, SP, Brazil, had its fruits picked up at 15 to 90 days of age, in 15-day intervals. The soil was an Ultisol and the three varieties studied were: Okawa n° 2, Pedro Sato and Kumagai. The fruits were dried, weighed, grounded and analysed for all the macronutrients and for the micronutrients B, Cu, Fe, Mn and Zn. The highest fruit weights were obtained at 60 days of age for the Pedro Sato and Kumagai varieties, whereas the same happened at 75 days for the Okawa n° 2 variety. Fruits harvested from Pedro Sato and Kumagai plants removed more nutrients than those from Okawa n° 2 plants. The three varieties removed macronutrients in the following increasing order: Mg, Ca, P, S, N and K. Among the micronutrients, B, Zn and Fe had the highest amounts removed by fruits, whereas Cu had the lowest.
Em um pomar de goiabeira implantado em um solo Podzolizado de Lins e Marília variação Lins, situado no Município de Aliança, SP, foram coletados frutos desde os 15 dias até os 90 dias de idade, com intervalos de 15 dias, nas variedades de mesa Okawa n° 2, Pedro Sato e Kumagai. O frutos foram secados, pesados e analisados para todos os macronutrientes e para os micronutrientes B, Cu, Fe, Mn e Zn. As variedades Pedro Sato e Kumagai tiveram peso máximo dos frutos aos 60 dias e exportaram maiores quantidades dos nutrientes que a variedade Okawa n° 2, que teve peso máximo dos frutos aos 75 dias. Nas três variedades a exportação dos macronutrientes por planta e por unidade de área obedeceu a seguinte ordem crescente: Mg, Ca, P, S, N e K. Entre os micronutrientes o B, o Zn e o Fe foram os mais exportados, o Mn foi intermediário e o Cu foi o de menor exportação.
RESUMO
An orchard of guava (Psidium guayava L.) located in Aliança, SP, Brazil, had its fruits picked up at 15 to 90 days of age, in 15-day intervals. The soil was an Ultisol and the three varieties studied were: Okawa n° 2, Pedro Sato and Kumagai. The fruits were dried, weighed, grounded and analysed for all the macronutrients and for the micronutrients B, Cu, Fe, Mn and Zn. The highest fruit weights were obtained at 60 days of age for the Pedro Sato and Kumagai varieties, whereas the same happened at 75 days for the Okawa n° 2 variety. Fruits harvested from Pedro Sato and Kumagai plants removed more nutrients than those from Okawa n° 2 plants. The three varieties removed macronutrients in the following increasing order: Mg, Ca, P, S, N and K. Among the micronutrients, B, Zn and Fe had the highest amounts removed by fruits, whereas Cu had the lowest.
Em um pomar de goiabeira implantado em um solo Podzolizado de Lins e Marília variação Lins, situado no Município de Aliança, SP, foram coletados frutos desde os 15 dias até os 90 dias de idade, com intervalos de 15 dias, nas variedades de mesa Okawa n° 2, Pedro Sato e Kumagai. O frutos foram secados, pesados e analisados para todos os macronutrientes e para os micronutrientes B, Cu, Fe, Mn e Zn. As variedades Pedro Sato e Kumagai tiveram peso máximo dos frutos aos 60 dias e exportaram maiores quantidades dos nutrientes que a variedade Okawa n° 2, que teve peso máximo dos frutos aos 75 dias. Nas três variedades a exportação dos macronutrientes por planta e por unidade de área obedeceu a seguinte ordem crescente: Mg, Ca, P, S, N e K. Entre os micronutrientes o B, o Zn e o Fe foram os mais exportados, o Mn foi intermediário e o Cu foi o de menor exportação.