Jurandi Gonçalves de Oliveira

Portable chlorophyll meter for the quantification of photosynthetic pigments, nitrogen and the possible use for assessment of the photochemical process in Carica papaya L.

Os metodos utilizados para a extracao de clorofila em materiais vegetais sao destrutivas e baseiam-se em metodos que utilizam solventes orgânicos. Este trabalho propoe a quantificacao nao-destrutiva dos teores de clorofila e nitrogenio por meio do SPAD-502. Ainda, foi possivel estabelecer uma relacao entre a fluorescencia e os valores obtidos pelo SPAD-502. Tal metodologia podera proporcionar uma substancial economia de tempo, espaco e recursos contribuindo na melhoria das interpretacoes dos processos fotossinteticos. Para tanto, foram utilizadas folhas de mamoeiros (grupos Solo e Formosa) de diferentes estadios de desenvolvimento, coletadas de plantas com 15 meses de idade, cultivadas em plantio comercial no municipio de Sao Francisco de Itabapoana/RJ. Foram estabelecidas correlacoes entre os teores de clorofila e carotenoides extraidos em DMSO, os teores de nitrogenio, a fluorescencia da clorofila a (Ff, Fmax, Fn/Fmax, qN, qP, NPQ) e as leituras pelo SPAD 502 em folhas da especie em estudo, dos grupos Solo e Formosa. Os resultados mostraram que enquanto a variavel qP e a relacao Fn/Fmax foram crescentes, ate leituras do SPAD-502 proximas a 40, as variaveis qN e NPQ se mostraram decrescentes. Foi verificado que a variavel Fmax apresentou uma correlacao linear, direta, em relacao aos valores do SPAD-502, enquanto que a variavel Ff nao apresentou nenhuma correlacao com os valores do SPAD-502. De acordo com os resultados apresentados, concluiu-se que o determinador portatil de clorofila podera ser utilizado na quantificacao dos pigmentos fotossinteticos (clorofilas e carotenoides) e podera indiretamente auxiliar nas interpretacoes avancadas do processo fotoquimico da fotossintese em plantas da especie Carica papaya L.

Accumulation of SALT protein in rice plants as a response to environmental stresses

Abstract The SALT protein is a 14.5 kDa mannose-binding lectin originally described as preferentially expressed in rice plant roots in response to NaCl stress. Here, we studied the expression of the SALT polypeptide in rice plants submitted to different stress cues, by immunodetection of SALT protein in plant tissue extracts and using a rabbit polyclonal antibody raised to recombinant SALT protein. High levels of expression of SALT protein were detected in sheath extracts from plants treated with 170 mM NaCl, 170 mM KCl, dehydration, wounding, heat (42xa0°C) or abscisic acid. Even in the absence of stressor added, SALT protein was detected in extracts from seeds collected at early stages of development. SALT protein expression was induced in different levels by salinity in sheaths of several rice cultivars. However, analysis of the damage caused in photochemical efficiency of photosynthesis under salinity conditions in these cultivars revealed no correlation between the levels of SALT protein expression and sensitivity to the stress. These data indicate that the expression of SALT protein is not restricted to responses to environmental stresses and that high levels of expression of SALT protein do not confer tolerance to salinity. It is suggested that the SALT protein participates in a global response/sensor mechanism.

Photochemical efficiency in bean plants (Phaseolus vulgaris L. and Vigna unguiculata L. Walp) during recovery from high temperature stress

Utilizaram-se plantas de feijao (Phaseolus vulgaris L. cv Carioca e Negro Huasteco) e caupi (Vigna unguiculata L. Walp, cv Epace 10) crescidas em câmara controlada com FFF de 200 mmol.m-2.s-1 e temperatura media do ar 25 ± 1 oC. Aos 12 ou 13 dias, as plantas foram submetidas aos tratamentos de temperatura (25, 30, 35, 40, 45 e 48 oC) por 1,5 h. A eficiencia fotoquimica do PSII foi monitorada, durante a recuperacao das plantas, por meio da fluorescencia da clorofila a, em seis periodos (0,5; 1, 2, 4, 24, e 48 h) apos a inducao do estresse. As variaveis da fluorescencia da clorofila a foram obtidas com um fluorimetro de luz modulada a 25 oC. A temperatura de 45 oC provocou um aumento em Ff, com um decrescimo a 48 oC para todas as cultivares. Houve uma queda no valor da Fmax a 48 oC para Carioca e Negro Huasteco, mas nao para Epace 10, mostrando uma possivel correlacao entre queda na Fmax e suscetibilidade dessas cultivares a alta temperatura. Os baixos valores de Fmax ocorridos a 48 oC, indicam perda da atividade do PSII e foi precedido pela morte das plantas. Com o aumento da temperatura nao houve alteracoes na razao Fv/Fmax para Epace 10 ao passo que Carioca e Negro Huasteco atingiram valores nulos a 48 oC, mostrando a discrepância das cultivares em relacao a alta temperatura.

Marcadores moleculares RAPD e descritores morfológicos na avaliação da diversidade genética de goiabeiras (Psidium guajava L.)

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.

Responses of 1-MCP applications in 'Golden' papaya fruits on differents maturation stages.

The study of factors that influence the process of ripening is critical for planning the marketing process, mainly in standard breathing climacteric and perishing fruits, as it is the case of papaya. In this work it was evaluated the effect of the application of 1-MCP (1- methylcyclopropene) in the pattern of fruit ripening of papaya at the maturation stages 0, 1 and 2. The 1-MCP delayed the production of ethylene (≈79%) and the respiratory rate (≈45%) mainly in fruit maturation stages 0. The use of the inhibitor of the ethylene action delayed the degreening of the fruits, especially in fruit maturation stages 0 and 1. With 1-MCP application there was a reduction in loss of flesh and fruit firmness in stages 1 and 2. However, in fruit maturation stage 0, the flesh firmness showed excessively high, which may decrease the acceptance for consumer of these fruits. The solid soluble content was not influenced by the application of the 1-MCP. The effect of 1-MCP in the reduction of the activity of the enzymes PME and PG was bigger in fruit maturation stages 0 and 1 than fruit maturation stage 2. The PME enzyme activity demonstrated an increasing over the shelf life; however, the PG enzyme activity remained low during the first five days of shelf life, increasing later. The results showed that the PME enzyme exerts significant influence on loss of flesh firmness, and the PG acting later. The 1-MCP was effective delaying the process of ripening of papaya fruits being more efficient when associated with initial maturation stages.

Teores de Ca e variáveis meteorológicas: relações com a incidência da mancha fisiológica do mamão no Norte Fluminense

In Brazil and other parts of the world, papaya fruit suffer with a physiological disruption, known as skin freckles (SF). There is very little information available concerning the causes of this disruption that seriously affects the commercialization of the papaya fruit. In an attempt to discover the possible cause of SF, experiments were carried out during 12 months in a commercial plantation located in Sao Franscisco do Itabapoana, North of Rio de Janeiro State, Brazil, to measure the effect of climate on SF, such as air temperature, air vapor pressure deficit, rainfall and incoming solar radiation, as well as levels of Ca in the plants [blade, petiole, pedicel, epicarp (peel) not-exposed to sunlight (part of the fruit facing the stem) and the part o the fruit exposed to direct sunlight, related to the incidence of SF. A high incidence of SF was observed during the month of September 2000, however during the month of January 2001 no SF was detected. Thermal temperature during the three months before September was the variable that was most closely correlated to the incidence of SF. In September the levels of Ca in all parts of the fruit (exposed and non-exposed epicarp and pedicel) were higher than during other periods of evaluation. During the period before September, the ratios of Ca:K and Ca:Mg were higher in the exposed and non-exposed epicarp. Also at this time the ratio of Ca:P were higher in the non-exposed epicarp and pedicel. The effect of thermal amplitude on the incidence of SF are discussed and the hypothesis that low levels of Ca in the fruit could destabilize the cell walls, facilitating leaking of latex, provoking the symptoms of SF, will be reevaluated.

Ecophysiological adaptation and metal accumulation in water hyacinth from two tropical rivers

The ecophysiological adaptations of water hyacinth (metal hyperaccumulator) under adverse environmental conditions are not yet clearly elucidated. This work evaluated photosynthetic pigments and chlorophyll a fluorescence in water hyacinth plants sampled in different regions (upper, middle and lower) of Paraiba do Sul river (PSR) and Imbe river, Brazil. Additionally Mn, Fe, Zn, Cu, Cr, Pb and Ni were quantified on the shoots and roots. Roots were the preferential site of metal accumulation. Cromium was not detected in the shoots. Iron and Mn were the elements detected in higher concentrations in all samples. Zinc and Cu were detected in higher concentrations in roots of plants from middle and upper PSR, sites of higher anthropogenic activity. The highest concentrations of almost all metals were verified in plants from middle PSR. Regarding photosynthetic adaptations, plants from middle and upper PSR showed the highest concentrations of photosynthetic pigments, as well as the highest values of Fv/Fm and Fv/F0. The photosynthetic performance of plants suggests that they are not under stress conditions, even in regions of higher anthropogenic activity. Positive correlation was observed among nonphotochemical quenching and carotenoids, suggesting dissipation of energy in the form of heat as an strategy to keep the stable photochemical photosynthesis functioning, confirmed by values of the Fv/Fm. It is possible that such adaptative strategy is efficient as a long term response to stress factors, once literature data suggest that this is not a preferential path for photosynthesis in stress circumstances under short time controlled conditions.

Determinação da maturidade fisiológica de frutos de maracujazeiro amarelo colhidos na região norte do estado do Rio de Janeiro, Brasil

O trabalho teve como objetivo determinar o ponto de maturidade fisiologica dos frutos de maracujazeiro amarelo produzidos na regiao Norte Fluminense, na tentativa de se antecipar o ponto de colheita dos frutos, visando a qualidade e o aumento da vida de prateleira dos mesmos. Os frutos foram colhidos em tres periodos diferentes. A colheita 1 foi realizada aos 45 dias apos a antese (daa); a colheita 2 aos 54 daa e a colheita 3 aos 63 daa. Apos cada colheita os frutos foram lavados, secos e divididos em dois lotes para avaliacao. O primeiro lote foi avaliado imediatamente apos a colheita, e o segundo foi armazenado em câmara (23 ± 3oC e 85 ± 8% UR). Os frutos foram analisados periodicamente a cada 3 dias, quanto aos seguintes atributos de qualidade: coloracao e espessura da casca, rendimento de suco e teores de solidos soluveis (SS) e acidez titulavel (AT). Os resultados indicaram que o tempo de desenvolvimento do fruto de maracujazeiro amarelo, dentro do periodo de 45 a 63 daa, influenciou na qualidade do fruto colhido na regiao. Para as condicoes deste trabalho, o ponto ideal de colheita foi aos 63 daa, podendo, tambem, ser colhido a partir do 54o daa, porem, com perda de cerca de 21,0 % no rendimento de suco. Verificou-se, tambem, que durante a fase de amadurecimento, a manutencao dos frutos na planta retarda a evolucao da coloracao, bem como, a reducao na espessura da casca do fruto, em comparacao ao colhido e armazenado.

Different planting spacings and fertilization levels on the activity of nitrate reductase in leaves of papaya hybrid UENF/CALIMAN-01

The objective of this work was to evaluate the effect of different planting spacings and levels of NPK manuring on the activity of the nitrate reductase (NR) in the leaves of the papaya hybrid UENF/ CALIMAN-01, aiming to suggest possible adjustment in the handling of nitrogen fertilization, in the sense of maximizing the efficiency of the use of the nitrogen. The experiment was driven in the Caliman Agricola S.A. farm, in the municipal district of Linhares- ES. A complete block design, factorial, with three planting spacings among plants (E1 = 1.8 m, E2 = 2.25 m and E3 = 2.7 m), five levels of NPK conventional manuring (A1 = 80% of the standard, A2 = 100% of the company standard, A3 = 120% of the standard, A4 = 140% of the standard and A5 = 160% of the standard) and five evaluation periods ( from March to July) was used. The standard of the company NPK manuring consists of 350, 105 and 660 Kg ha -1 year -1 of sulfate of am- monium (20% of N), simple superphosphate (18% of P) and potassium chloride (60% of K), respectively. The data obtained for the activity of NR were submitted to a variance analysis and average test. Among the tested treatments, A1 (80% of standard), independent of the spacing, could be indicated in the handling of the hybrid UENF/CALIMAN-01, because in all of them the activity of the nitrate reductase in, practically, all of the appraised periods, presented appropriate values, or even, superiors to the ones found in the literature for the papaya tree. The reduction of NPK fertilization could be justified, once that did not have difference in the productivity of the plants among the evaluated treatments. Index terms: papaya, spacing, fertilizer, reductase of the nitrate.

Levels of nutrients in the leaves of twelve genotypes of grape.

The objective of this study was to characterize the levels of mineral nutrients: N, P, K, Ca, Mg, S, Mn, Fe, Zn, Cu, Mo and B of twelve genotypes of grapevine: Italy, Ruby , Patricia, Isabel, Redglobe, Roberta, Kyoho, Roman, Rosalinda, Moscatel de Hamburgo’, Niagara Rosada and UVF 01 in the North of Rio de Janeiro State. The plants were pruinned and fertilized (organic and mineral). The leaf blades were analyzed in two periods of the reproductive cycle of the vine: in full bloom and the beginning of berry ripening (veraison). In this characterization, it was concluded that the leaves reflected the nutritional status of the vine genotypes. The genotypes did not show levels of N below normal, with most genotypes showing normal levels. Neither genotype showed below normal levels of K and P. All genotypes showed levels of Ca below the normal range for all seasons and Mg in the normal range. All genotypes showed normal levels of B.