PRODUÇÃO DE MUDAS DE VIDEIRA 'RUBI' PELO MÉTODO DE ENXERTIA DE MESA em ESTACAS HERBÁCEAS DOS PORTA-ENXERTOS IAC 313 'TROPICAL' E IAC 766 'CAMPINAS'

Com o objetivo de estudar o método de enxertia de mesa em estacas herbáceas para a obtenção de mudas de videira, experimentos foram desenvolvidos em câmara de nebulização, localizada no ripado do Departamento de Produção Vegetal da Faculdade de Ciências Agrárias e Veterinárias da UNESP, no período de novembro de 1997 a dezembro de 1999. Foram utilizadas estacas herbáceas dos porta-enxertos IAC 313 'Tropical' e IAC 766 'Campinas' e borbulhas e garfos da cultivar Rubi. Foram testados os métodos de enxertia de garfagem em fenda cheia e de borbulhia em placa, em estacas herbáceas sem raízes e enraizadas, o tipo de proteção do enxerto, o tamanho das estacas e o recipiente de enraizamento. Foram avaliados o enraizamento e o pegamento de enxertos. O método de enxertia de mesa com garfagem e com proteção do enxerto com saco plástico apresentou maior pegamento de enxerto aos 30 (45,25%) e 60 dias (66,20%) após a enxertia. O tamanho da estaca não afetou o pegamento dos enxertos. Contudo, em todos os experimentos, o índice de sobrevivência dos enxertos foi muito baixo ou nulo. Estacas sem enxertia proporcionaram maior porcentagem de enraizamento (65,62%) em relação às estacas enxertadas. O método de enxertia de mesa em estacas herbáceas dos porta-enxertos IAC 313 'Tropical' e IAC 766 'Campinas' não foi eficiente para a formação de mudas de videira.

Caracterização e identificação das cultivares de pessegueiro Tropical e Douradão através de marcadores RAPD

Foi realizada a caracterização genética das cultivares de pêssego Tropical e Douradão pelo método RAPD, em comparação com 'Dourado-1', 'Tutu', 'Maravilha', 'Rubro-sol', 'Flordaprince', 'Aurora-1' e 'Talismã' do Banco Ativo de Germoplasma de Frutas de Caroço do IAC, mantido no Núcleo de Agronomia de Capão Bonito, utilizando DNA extraído de folhas jovens. Foram obtidos 31 marcadores genéticos a partir dos primers altamente polimórficos OPAD10, OPAE04, OPAE07, OPAE09, OPAE11, OPAJ04 e OPAJ06, selecionados de 96 primers avaliados. Os marcadores RAPD utilizados indicaram eficientemente o grau de parentesco entre cultivares, exceto em cultivares originadas de polinização livre. Verificou-se que, mesmo entre as cultivares irmãs como 'Tutu' e 'Talismã', encontrou-se certa distância genética (0,29), mostrando que por RAPD é possível caracterizar-se germoplasma aparentado. 'Tropical' e 'Douradão' foram bem caracterizados em relação aos parentais e demais cultivares, com as distâncias genéticas variando de 0,26 a 0,89.

Avanços na fruticultura tropical no Brasil

Os principais aspectos que marcaram a evolução técnica das culturas do abacaxizeiro, mamoeiro e maracujazeiro no Brasil foram discutidos. em abacaxizeiro, tem-se constatado uma inovação no sistema de comercialização da cv. Smooth Cayenne, que consiste no uso de caixas de papelão ondulado para o mercado interno, cujo objetivo é propiciar uma garantia de sabor inserida em uma marca. O recente lançamento de cultivares resistentes à fusariose, pela Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) (Imperial e Vitória) e IAC (Fantástico), traz novas perspectivas de produtividade. em maracujazeiro, a maior contribuição aos pomares foi dada pelo melhoramento genético, inicialmente voltado apenas para ampliação da produtividade da cultura. No início dos anos 2000, o lançamento das primeiras cultivares de maracujá - mais produtivas e com qualidade de fruta diferenciada para os dois segmentos de mercado (frutas frescas e agroindústria), transformou o cenário produtivo brasileiro. Com a criação de um sistema organizado de produção e comercialização de sementes e mudas selecionadas, ampliou-se significativamente a qualidade dos pomares. Atualmente, a disponibilidade de novas cultivares tolerantes à virose (VEFM) e cultivares regionais passou a representar um diferencial para a cultura. em mamoeiro, destaca-se a ocorrência do Mosaico do Mamoeiro (Monte Alto-SP, 1967), que determinou a migração da cultura pelo Estado e sua expulsão para outros estados, até sua fixação na Bahia e no Espírito Santo, os maiores produtores nacionais. Comparam-se as técnicas utilizadas nos diferentes períodos de produção, antes e depois do surgimento do mosaico, que permitiram ao Brasil lançar-se no mercado externo, tornando-se o maior exportador mundial de mamão, com lavouras produtivas e frutos de ótima qualidade. Nesta evolução, soma-se a contribuição do melhoramento genético, que disponibilizou sementes de alta qualidade, com reflexos nas práticas culturais e de propagação. São apresentadas de colheita e de pós-colheita diferenciadas que resultaram em melhorias no padrão de qualidade das frutas exportadas para o mercado europeu e norte-americano.

Chlorophyll fluorescence of tropical tree species in a semi-deciduous forest gap

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Temporal dynamics of two species of Chaetophoraceae (Chlorophyta) in tropical streams of São Paulo State, Southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sucessão da comunidade de algas perifíticas em reservatório oligotrófico tropical (São Paulo, Brasil): comparação entre período seco e chuvoso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaporative cooling and cutaneous surface temperature of Holstein cows in tropical conditions

Foram estudados os efeitos da temperatura cutânea (Ts) sobre a taxa de termólise por evaporação cutânea (Es) de vacas Holandesas cronicamente expostas ao sol, considerando a pigmentação do pelame. Dezesseis vacas puras de origem foram medidas quanto à evaporação e à temperatura cutâneas às 13 h, após 6 horas de exposição ao sol, no mesmo local (flanco, pescoço e glúteo) e considerando separadamente as malhas negras e as brancas. A evaporação cutânea foi medida por meio de cápsula ventilada. Nas áreas negras a taxa de sudação (138,9 ± 8,5 g.m-2.h-1), a taxa de termólise por evaporação cutânea (93,3 ± 5,7 W.m-2) e a temperatura da superfície cutânea (33,1 ± 0,2°C) foram maiores que nas áreas brancas (109,5 ± 9,7 g.m-2.h-1, 73,6 ± 6,5 W.m-2 e 32,6 ± 0,2°C, respectivamente). Há uma relação exponencial entre evaporação e temperatura cutâneas, que pode ser representada pela equação Es = 31,5+3,67 exp{(Ts-27,9)/2,19115}, com coeficiente de determinação r²=0,68. A taxa de termólise por evaporação cutânea permanece quase constante (cerca de 48 W.m-2) até que a temperatura cutânea atinge aproximadamente 31°C.

Carbon dioxide emission related to chemical properties of a tropical bare soil

In this work the relationship between CO2 emissions and the soil properties of a tropical Brazilian bare soil was investigated. Carbon dioxide emissions were measured on three different days at different soil temperature and the soil moisture conditions, and the soil properties were investigated at the same points that emissions were measured. The soil CO2 emissions were correlated to carbon content, cation exchange capacity and free iron content at the 65 points studied in an area of 100 x 100 m located in southern Brazil. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Atrazine interaction with tropical humic substances by Enzyme Linked Immunosorbent Assay

Enzyme-Linked Immunosorbent Assay (ELISA) has been evaluated by analyzing rich-humic water samples from tropical rivers. The samples were spiked with atrazine at ppb level Different pHs (4 to 9) and humic concentrations (2.5 to 40 mg L-1) were investigated. The assay performance showed a strong dependence on the pH values and amount of humic matter at low atrazine concentration. From all the conditions studied the low pH (pH 4) and high humic substances concentrations (40 mg L-1) showed the greatest influence. The IC50 value to control sample (no humic) diminished from 0.28 nmol L-1 to 0.64 nmol L-1 to humic acid solution. This effect is specially noted for the humic acid fractions, since fulvic acid fractions showed no significant change on the immunoassay results. Additionally, it has been demonstrated that at basic pH the matrix effect produced by the natural Brazilian water sample containing humic substances even at 40 mg L-1 disappears. Therefore, the ELISA method used to determine atrazine, can be employed to determine this pesticide in water samples containing humic substances without prior preparation.

Variations in tree community composition and structure in a fragment of tropical semideciduous forest in southeastern Brazil related to different human disturbance histories

In an area of tropical seasonal semideciduous forest, the soil characteristics, floristic composition, physiognomic structure, and the distribution of three regeneration and three dispersal guilds were studied for four stands within the forest that had documented histories of varying degrees of human disturbance. The aim was to study forest regeneration in areas of preserved forest and secondary forest, with parts of both types of forest experiencing either 'intensive' or 'occasional' cattle trampling. The study was carried out in the Sebastiao Aleixo da Silva Ecological Station, Bauru, São Paulo State, Brazil. Two stands were called 'secondary' because they corresponded to forest tracts that were felled and occupied by crops and pastures in the past and then abandoned to forest regeneration ca. 40 years before this study. The other two stands, called 'preserved', corresponded to areas of the fragment where the forest has been maintained with only minor human impacts. The arboreal component of the tree community (diameter at breast height or dbh greater than or equal to 5 cm) was sampled in 20 plots of 40 m x 40 m, and the subarboreal component (diameter at the base of the stem or dbs < 5 cm and height greater than or equal to 0.5 m) in subplots of 40 m x 2 m. Physiognomic features, such as canopy height and density of climbing plants, were registered all over a 5 m x 5 m gridline laid on the sample plots. Soil bulk samples were collected for chemical and textural analyses. Most detected differences contrasted the secondary to the preserved forest stands. The soils of the secondary stands showed higher proportions of sand and lower levels of mineral nutrients and organic matter than those of the preserved stands, probably due to higher losses by leaching and erosion. Compared to the secondary stands, the preserved ones had higher proportions of tall trees, higher mean canopy height, lower species diversity, higher abundance of autochorous and shade-tolerant climax species, and lower abundance of pioneer and light-demanding climax species. Despite the high proportion of species shared by the preserved and secondary stands (108 out of 139), they differed consistently in terms of density of the most abundant species. on the other hand, the secondary and preserved stands held similar values for tree density and basal area, suggesting that 40 years were enough to restore these features. Effects of cattle trampling on the vegetation were detected for the frequency of trees of anemochorous and zoochorous species, which were higher in the stands under occasional and intensive cattle trampling, respectively. The density of thin climbers was lower in the stands with intensive trampling. (C) 2004 Elsevier B.V. All rights reserved.

LONGITUDINAL DISTRIBUTION OF MACROALGAE IN 2 TROPICAL LOTIC ECOSYSTEMS FROM SOUTHEASTERN BRAZIL

Macroalgal species richness and diversity were analysed along a longitudinal profile in small and large scales during Spring, Fall and Winter, respectively in a small stream and a mid size river in the northwest region of São Paulo State, southeastern Brazil (20 degrees 23'-20 degrees 49'S, 49 degrees 26'-51 degrees 19'W). Longitudinal variation in species richness and diversity in small scale was strongly associated with incident light. Microhabitat distribution (from data taken by quadrat technique) revealed no significant correlations. Principal coordinates analysis (PCO) indicated no consistent groupings among sampling sites in distinct seasons (Spring, Fall and Winter). Longitudinal analysis in large scale revealed different patterns in the two seasons sampled (Spring and Winter), whereas species diversity presented a consistent tl end: high upstream, low in mid reaches and higher downstream. It was associated with type of substratum in Spring, rocky substrata presenting the highest values for species richness and diversity. Weak correlations were observed in Winter. Microhabitat distribution showed significant correlations between species abundance and the following variables: positive for rocky substrata and current velocity and negative for sandyclayish substratum and macrophyte-dominated substratum. PCO delineated only one consistent grouping formed by the two headwater sites. Small scale macroalgal distribution corroborated the longitudinal pattern predicted by the River Continuum Concept, whereas the large scale approach showed a distribution more associated with substratum type than to light availability. These results showed an opposite trend in relation to the expected distributional pattern. Longitudinal distribution in macroalgal community structure has yet to be better documented, particularly for tropical streams and no generalization is possible at this stage.

Attraction of ambrosia beetles (Coleoptera : Scolytidae) to different tropical pine species in Brazil

Ambrosia beetles are the predominant Scolytidae in Brazil. Little is known about the attractiveness of exotic conifer tree volatiles to native scolytids. Objectives were to compare the attractiveness of logs with and without bark of Pinus oocarpa Schiede, P. caribaea variety bahamensis Barrett & Golfari, P, car. variety caribaea Barrett & Golfari and P. car. variety hondurensis Barrett & Golfari over time to native scolytids in different pine stands, to compare the relative attractiveness of logs relative to ethanol traps, to determine how long it takes for logs to become attractive to ambrosia beetles and when attraction peaks occur, and to determine if volatiles released by live standing trees would mask volatiles released by logs of the same species. In young stands, Hypothenemus was the predominant insect genus, whereas in older stands Xyleborus predominated. Debarked logs trapped more beetles than logs with bark. Pine log species attractiveness was not influenced by volatiles present in the stand. Beetles were divided into the following 3 groups, based on response to log volatiles and ethanol: (1) species attracted to ethanol and not responding to pine terpenes Ambrosiodmus hagedorni (Iglesia), A. retusus (Eichhoff), X. spinulosus Blandford, Corthylus schaufussi Schiede, Cryptocarenus heveae (Hagedorn), H. obscurus (F.), (2) species attracted to ethanol but responding to pine terpenes Xyleborinus gracilis (Eichhoff), X. affinis Eichhoff, H. eruditus Westwood, Premnobius cavipennis Eichhoff, and (3) species more attracted to pine terpenes and less responsive to ethanol, A. obliquus (Le Conte), X. ferrugineus F,, X. catulus Blandford. Pinus car. ;variety bahamensis was the least attractive pine, P. oocarpa the most attractive. The attraction peak varied according to the season; logs were not attractive to beetles 10 wk after cutting.