Estimativa da área foliar do mamoeiro utilizando o comprimento da nervura central

ABSTRACTQuatro genótipos de mamoeiro (Carica papaya L.), sendo dois do grupo 'Solo' (Sunrise Solo e Improved Sunrise Solo 72/12) e dois do grupo 'Formosa' (Tainung 02 e Known-You 01) cultivados em Macaé, RJ, Brasil, (lat. 220 24' S, long. 410 42' W) foram utilizados neste estudo. Folhas maduras foram coletadas no quarto e quinto mês após o transplantio para determinar a relação entre o comprimento da nervura central foliar (NCF) e a área foliar (AF). A declividade e o intercepto das retas calculadas para os quatro genótipos não apresentaram diferença significativa na análise de covariância. Portanto, o modelo matemático (Log AF = 0,315 + 1,85 Log NCF, R2=0,898) foi ajustado para estimar a AF em função do comprimento da NCF. Um modelo único pode ser aplicado para estimar a AF dos quatro genótipos de mamoeiro utilizando os comprimentos da NCF compreendidos no intervalo de 25 e 60 cm, em plantas com 150 a 180 dias após o transplantio.Four genotypes of papaya (Carica papaya L.) two from the 'Solo' group (Sunrise Solo and Improved Sunrise Solo line 72/12) and two from the 'Formosa' group (Tainung 02 and Known-You 01), grown in Macaé, RJ, Brazil (lat. 220 24' S, long. 410 42' W), were used in this study. Twenty-five mature leaves from each genotype were sampled four and five months after seedling transplant to the field to determine the length of the leaf central vein (LLCV) and the leaf area (LA). According to covariance analyses there were no significant differences in the slope and intercept of the mathematical models calculated for each genotype. Thus, a single mathematical model (Log LA = 0.315 + 1.85 Log LLCV, R2=0.898) was adjusted to estimate the LA using the length of LLCV for the four genotypes. An unique model can be applied to estimate the LA for the four papaya genotypes using LLCV in the range from 0.25 to 0.60 m, and for papaya trees 150 to 180 days after transplanting

Influência da restrição da raiz sobre as trocas gasosas em quatro genótipos de mamão

ABSTRACTFour papaya genotypes, two from the Solo group (Sunrise Solo TJ and Improved Sunrise Solo line 72/12) and two from the Formosa group (Tainung 02 and Know You 01) grown in ultisol under field conditions in Macaé, RJ, Brazil, were used in this study. Two different effective depths (ED) were determined in the area using a penetrographer with average soil moisture of 11.2%. The area with ED of 0.35 m with a maximum pressure of 4.12 MPa for penetration was defined as an area with restriction (WR) to root growth, while, the area with minimum ED of 0.60 m and a pressure lower than 2.30 MPa as an area with no restriction (NR). The net CO2 assimilation rate (A), stomatal conductance (gs), leaf temperature (Tl), intercellular partial pressure of CO2 (ci) and intrinsic water use efficiency (IWUE) were evaluated for three consecutive days after irrigation. Mechanical root restriction affected gas exchange of the four papaya genotypes. All genotypes grown in the WR area had lower A, gs and ci and higher Tl than the same genotypes in the NR area. All genotypes grown in the WR area had high IWUE and Sunrise Solo TJ had the highest IWUE. _____________________________________________________________________________________ RESUMONeste estudo, quatro genótipos de mamão, dois pertencentes ao grupo 'Solo' (Sunrise Solo TJ e Sunrise Solo 72/12) e dois pertencentes ao grupo Formosa (Tainung 02 e Know-You 01), foram cultivados num Argissolo Amarelo, em condição de campo, no município de Macaé, RJ, Brasil. A área de cultivo foi dividida em duas sub-áreas com profundidades efetivas (PE) distintas, determinadas com auxílio de um penetrógrafo a uma umidade média de 11,2%. Área com restrição CR apresentou PE média de 0,35 m com esforço máximo de 4,12 MPa para penetração, enquanto área sem restrição (SR) apresentou PE mínima de 0,60 m com esforço menor que 2,30 MPa. A taxa fotossintética líquida (A), a condutância estomática (gs), a temperatura foliar (Tl), a concentração interna de CO2 no mesofilo foliar (ci) e a eficiência intrínseca no uso da água (IWUE) foram determinadas em três dias consecutivos após a irrigação. A restrição do crescimento do sistema radicular afetou as trocas gasosas dos quatro genótipos de mamoeiro. Na área CR, todos os genótipos apresentaram valores reduzidos de A, gs e ci e elevados de Tl, em relação aos genótipos crescidos na área SR. Todos os genótipos crescidos na área CR apresentaram elevados valores de IWUE e o genótipo Sunrise Solo TJ foi o que apresentou o maior valor de IWUE

Trocas gasosas em folhas de diferentes estádios de desenvolvimento em genótipos de mamoeiro (Carica Papaya L.)

ABSTRACTNeste trabalho, utilizaram-se quatro genótipos de mamoeiro, sendo três genótipos do grupo 'Solo' (Sunrise Solo TJ, Sunrise Solo 72/12 e Baixinho de Santa Amália) e um do grupo 'Formosa' (Know-You 01). As plantas foram cultivadas em potes plásticos, sob condição de casa de vegetação, num solo franco-argilo-arenoso, corrigido, adubado e submetidas a irrigações periódicas até a capacidade de campo. Em todos os genótipos, a taxa fotossintética líquida (A, mmol m-2 s-1), a condutância estomática (gs, mol m-2 s-1), a temperatura foliar (Tl, 0C), a concentração interna de CO2 (ci, mL L-1) no mesofilo foliar foram determinadas aos 73 dias após o plantio (DAP), na 4a, 5a, 6a, 7a, 8a e 9a folhas, contadas a partir do ápice, por meio de um analisador de gás no infravermelho modelo LI-6200. Entre as folhas amostradas e entre os genótipos estudados, não foram observadas diferenças significativas nos valores de A, gs, ci e Tl. Foi observado que elevados valores de gs proporcionaram valores elevados de A em todos os genótipos estudados. Contudo, para a característica Tl, as relações com gs foram inversas, evidenciando a fundamental função do processo transpiratório no resfriamento foliar. Os resultados indicaram que, em todos os genótipos estudados, as folhas avaliadas funcionaram como órgãos fontes.In this research, was used four papaya (Carica papaya L.) genotypes: three from the 'Solo ( Sunrise Solo TJ, Sunrise Solo 72/12 and Baixinho de Santa Amália) group and one from the 'Formosa' group (Know-You 01). They were grown in plastic pots containing a sandy-clay-loam soil subjected to pH correction and fertilization, under greenhouse conditions. Throughout the experimental period plants were subjected to periodic irrigation to maintain the soil humitidy around field capacity. The experiment was conducted 73 days after sowing. In all genotypes, leaf gas exchange characteristics were determined. The net photosynthetic rate (A, mmol m-2 s-1 ), stomatal conductance (gs mol m-2 s-1), leaf temperature (TI, 0C) and intercellular carbon dioxide concentration (ci, mL L-1) on the 4th, 5th, 6th, 7th, 8th and 9th leaves from the plant apex were determined. No significant differences were observed for A, gs, ci, or Tl either among the leaves sampled from any of the genotypes. A was positively correlated with gs and in the other hand TI and gs were negatively correlated. The results suggest that, for 73 DAP, all the sampled papaya leaves functioned as sources of organs

Seasonal variation of leaf gas exchange in papaya plants grown under field condition

Na região do cerrado baiano, que se caracteriza por apresentar duas estações definidas: estação das secas (maio a setembro) e estação chuvosa (outubro a março), foi efetuado um estudo em um plantio comercial de Carica papaya L. com plantas do grupo 'Solo' (Sunrise Solo) e do grupo 'Formosa' (Tainung 01). Foram realizadas em duas épocas, sendo uma considerada época seca (julho e setembro) e a outra época considerada chuvosa (novembro e janeiro), medidas da taxa fotossintética líquida (A), condutância estomática (gs) e transpiração instantânea (E) em folhas completamente expandidas e crescidas a pleno sol. Nestes horários, foi possível medir a densidade de fluxo de fótons fotossintéticos (DFFF) e a temperatura do ar dentro da câmara (Tar ). A partir dos valores de A e gs, obteve-se a eficiência intrínseca no uso da água (A/gs). Em julho e setembro, nos dois genótipos estudados, foi verificado que os altos valores de DPVar causaram redução de gs e conseqüentemente redução de A quando comparado à estação chuvosa. A redução em gs causou elevação na eficiência intrínseca no uso da água. A ação do DPVar nas trocas gasosas foi semelhante nos dois genótipos.This study was carried out in a commercial orchard of papaya in the Savanna region of Bahia state where there are two distinct seasons: dry season, from May to September and a rainy one from October to March. Two genotypes, one from 'Solo' group (Sunrise Solo) and another from 'Formosa' group (Tainung 01) were used. Net CO2 assimilation rate (A), stomatal conductance (gs), instantaneous transpiration (E), air temperature inside the chamber (Tar) and photosynthetic photon flux density (PPFD) were measured at one hour interval in a fully expanded sun-exposed leaves in two season, one characterized as dry season (July and September) and another one as rainy season (November and January). Intrinsic water use efficiency (IWUE) was calculated using A and gs (A/gs). In both genotypes, the reduced gs due to high VPD in July and September contributed to reduce A. The behavior was similar in the two studied genotypes. In the dry season, reduced gs triggered a higher IWUE

Medidor portátil de clorofila : determinação dos teores de pigmentos fotossintéticos, nitrogênio e possibilidades de uso nas interpretações do processo fotoquímico em Carica papaya L.

ABSTRACTThe techniques utilized to extract chlorophyll from plant materials are destructive and based on methods that use organic solvents. This study proposes the non-destructive quantification of chlorophyll and nitrogen concentration using a portable chlorophyll meter (SPAD-502). Further, was possible to establish relationships between chlorophyll fluorescence and SPAD-502 values. This methodology could save time, space and resources, and could be used for analysis of the photosynthetic processes. Papaya leaves (Solo and Formosa groups) of different ages were collected from 15-month-old plants cultivated in a commercial field in São Francisco de Itabapoana, Rio de Janeiro State (410:15W; 210:27S). Correlations were established between the chlorophyll content and carotenoids extracted in DMSO, nitrogen content, a chlorophyll a fluorescence (Ff, Fmax, Fn/Fmax, qN, qP, NPQ) with readings from SPAD-502 taken on papaya leaves of different ages. The results show that while the qp and the Fn/Fmax increased with SPAD-502 readings of up to 40, the qN and NPQ variables decreased. The Fmax presented a direct linear correlation with the SPAD-502 values while the Ff variable did not correlate with the SPAD-502 values. The portable chlorophyll meter was shown to be useful for nondestructive determination of photosynthetic pigments (chlorophyll and carotenoids) and can be used indirectly in advanced interpretation of the photochemical process in Carica papaya L. leaves.Os métodos utilizados para a extração de clorofila em materiais vegetais são destrutivas e baseiam-se em métodos que utilizam solventes orgânicos. Este trabalho propõe a quantificação não-destrutiva dos teores de clorofila e nitrogênio por meio do SPAD-502. Ainda, foi possível estabelecer uma relação entre a fluorescência e os valores obtidos pelo SPAD-502. Tal metodologia poderá proporcionar uma substancial economia de tempo, espaço e recursos contribuindo na melhoria das interpretações dos processos fotossintéticos. Para tanto, foram utilizadas folhas de mamoeiros (grupos 'Solo' e 'Formosa') de diferentes estádios de desenvolvimento, coletadas de plantas com 15 meses de idade, cultivadas em plantio comercial no município de São Francisco de Itabapoana/RJ. Foram estabelecidas correlações entre os teores de clorofila e carotenóides extraídos em DMSO, os teores de nitrogênio, a fluorescência da clorofila a (Ff, Fmax, Fn/Fmax, qN, qP, NPQ) e as leituras pelo SPAD 502 em folhas da espécie em estudo, dos grupos 'Solo' e 'Formosa'. Os resultados mostraram que enquanto a variável qP e a relação Fn/Fmax foram crescentes, até leituras do SPAD-502 próximas a 40, as variáveis qN e NPQ se mostraram decrescentes. Foi verificado que a variável Fmax apresentou uma correlação linear, direta, em relação aos valores do SPAD-502, enquanto que a variável Ff não apresentou nenhuma correlação com os valores do SPAD-502. De acordo com os resultados apresentados, concluiu-se que o determinador portátil de clorofila poderá ser utilizado na quantificação dos pigmentos fotossintéticos (clorofilas e carotenóides) e poderá indiretamente auxiliar nas interpretações avançadas do processo fotoquímico da fotossíntese em plantas da espécie Carica papaya L

Growth and yield of Syagrus schizophylla (Mart.) Glass. in response to light gradients

This research studied growth and yield of Syagrus schizophylla, an extinction-endangered ornamental palm, grown under five light gradients. The treatments were: G1 - PAR=1234.10 μmol photons m-2 s-1, G2 - PAR=913.16 μmol photons m-2 s-1, G3 - PAR=666.34 μmol photons m-2 s-1, G4 - PAR=419.56 μmol photons m-2 s-1 and G5 - PAR=534.77 μmol photons m-2s-1. Before the experiment and at three, five and seven months of treatment, growth (plant height, collar diameter, number of leaves, petiole length, leaf length and width), gas exchange, chlorophyll a, and leaf green color intensity were assessed. The highest net photosynthetic rates were observed in plants under G2, G3 and G4. Values of maximum quantum efficiency (Fv/Fm) over 0.75 were observed under G2. At seven months, estimated SPAD values were 36 in G2 plants and 32 in G1 plants. According to the Dickson quality index (DQI), presented the highest growth and development rates. We conclude that G2 suits plants to be transplanted into the field, whereas G3 would be best for plants grown under shade environments. Highlights: Syagrus schizophylla is an extinction endangered ornamental palm. One layer of Red Chromatinet® 50% should be recommended for the first year of growth of schizophylla plants to be later transplanted to the field. Two Red Chromatinet® 50% layers would be best for plants meant to grow under shade environments. The highest net photosynthetic rates were observed in plants under G2, G3 and G4.This research studied growth and yield of Syagrus schizophylla, an extinction-endangered ornamental palm, grown under five light gradients. The treatments were: G1 - PAR=1234.10 μmol photons m-2 s-1, G2 - PAR=913.16 μmol photons m-2 s-1, G3 - PAR=666.34 μmol photons m-2 s-1, G4 - PAR=419.56 μmol photons m-2 s-1 and G5 - PAR=534.77 μmol photons m-2s-1. Before the experiment and at three, five and seven months of treatment, growth (plant height, collar diameter, number of leaves, petiole length, leaf length and width), gas exchange, chlorophyll a, and leaf green color intensity were assessed. The highest net photosynthetic rates were observed in plants under G2, G3 and G4. Values of maximum quantum efficiency (Fv/Fm) over 0.75 were observed under G2. At seven months, estimated SPAD values were 36 in G2 plants and 32 in G1 plants. According to the Dickson quality index (DQI), presented the highest growth and development rates. We conclude that G2 suits plants to be transplanted into the field, whereas G3 would be best for plants grown under shade environments. Highlights: Syagrus schizophylla is an extinction endangered ornamental palm. One layer of Red Chromatinet® 50% should be recommended for the first year of growth of schizophylla plants to be later transplanted to the field. Two Red Chromatinet® 50% layers would be best for plants meant to grow under shade environments. The highest net photosynthetic rates were observed in plants under G2, G3 and G4

DIFERENÇAS FISIOLÓGICAS ENTRE GENÓTIPOS DE MILHO DOCE (su-1) E MILHO COMUM DURANTE O DESENVOLVIMENTO

This work aimed to verify the influence of physiological characteristics of sweet corn (H43IN) and maize (UENF 506-8), at development stages, in carbohydrate contents and productivity in this species. These studies were conducted under field conditions at Colégio Agrícola Antonio Sarlo, in Campos dos Goytacazes-RJ. The experiments were developed from September to January / 2004. The physiological characteristics were investigated in four periods: period III of plant growth, V and VII reproductive and IX plant senescence. The physiological characteristics (net photosynthesis rate, leaf to air vapor pressure deficit, and stomatal conductance), observed during the different phenological cycles showed significant differences between the two genotypes. The sugar and starch contents determinated at stages V and VII also showed differences, as we expected, and the productivity in maize was higher than in sweet corn.Com o objetivo de verificar a influência de parâmetros fisiológicos das plantas de milho doce (H43IN) e milho comum (UENF506-8), nos períodos de desenvolvimento, nos teores de carboidratos e na produtividade desta espécie, foram conduzidos experimentos sob condições de campo, no Colégio Agrícola Antonio Sarlo, em Campos dos Goytacazes-RJ. Os experimentos foram instalados nos meses de setembro a janeiro de 2004. Os parametros fisiológicos foram estudados em quatro períodos: período III de crescimento vegetativo, V e VII reprodutivo e IX senescência da planta. Os parâmetros fisiológicos (taxa fotossintética líquida, déficit de pressão de vapor entre a folha e o ar e condutância estomática), observados, nas diferentes fases fenológicas, demonstraram haver diferenças significativas entre os dois genótipos. Os teores de açúcares e amido determinados nos estádios V e VII também demonstram diferenças, como esperado e a produtividade demonstrou superioridade do milho comum em relação ao milho doce

Níveis tóxicos de ferro em lavouras de café conilon (Coffea canephora L.) em solos de tabuleiros costeiros

The crops conilon coffee in Espírito Santo concentrate on soils with high redox potential, in these soils predominates the Fe in reduced form and more soluble (Fe2+) which can cause interferences in development and productivity. The objective of this study was to evaluate the impacts of iron concentration in plant tissues and the productivity of crops conilon coffee (Coffea canephora) grown in soils of coastal tablelands in the State of Espírito Santo. The study was conducted in three producing properties conilon coffee located in the South of the Espírito Santo, three areas in lowland environment and three areas in the hillside environment, to compare the influence of local. We evaluated the physical and chemical composition of the soil, the concentration of nutrients in roots, stems, leaves, grains and fruit peel and productivity in two seasons. The results evidenced that the concentration of iron in all evaluated organs was higher in lowland crops and that productivity has been significantly higher in the hillside fields. We conclude that the high concentration of iron in the soil and plant organs evaluated the lowland crops may be negatively influence the productivity of crops.Os plantios de café conilon no estado do Espírito Santo concentram-se em solos com elevado potencial de oxirredução, nestes solos predomina o Fe na forma reduzida e mais solúvel (Fe2+), o que pode causar interferências no desenvolvimento e na produtividade. Objetivou-se, neste estudo, avaliar os impactos da concentração de ferro nos tecidos vegetais e a produtividade de lavouras de café conilon (Coffea canephora), cultivadas nos solos dos tabuleiros costeiros do Estado. O estudo foi realizado em três propriedades produtoras de café conilon, localizadas no Sul do Espírito Santo, sendo três áreas em ambiente de baixada e outras três em ambiente de encosta, para comparar a influência dos locais. Foram avaliadas a composição físico-química dos solos, a concentração dos nutrientes em raízes, caules, folhas, grãos e casca das plantas e a produtividade em duas safras. Os resultados sugerem que a concentração de ferro, em todos os órgãos avaliados, foi maior nas lavouras de baixada e que a produtividade foi significativamente maior nas lavouras de encosta. Conclui-se que a alta concentração de ferro no solo e nos órgãos vegetais avaliados das lavouras de baixada pode influenciar negativamente na produtividade das lavouras

Inoculation With Piriformospora indica Is More Efficient in Wild-Type Rice Than in Transgenic Rice Over-Expressing the Vacuolar H+-PPase

Achieving food security in a context of environmental sustainability is one of the main challenges of the XXI century. Two competing strategies to achieve this goal are the use of genetically modified plants and the use of plant growth promoting microorganisms (PGPMs). However, few studies assess the response of genetically modified plants to PGPMs. The aim of this study was to compare the response of over expressing the vacuolar H+-PPase (AVP) and wild-type rice types to the endophytic fungus; Piriformospora indica. Oryza sativa plants (WT and AVP) were inoculated with P. indica and 30 days later, morphological, ecophysiological and bioenergetic parameters, and nutrient content were assessed. AVP and WT plant heights were strongly influenced by inoculation with P. indica, which also promoted increases in fresh and dry matter of shoot in both genotypes. This may be related with the stimulatory effect of P. indica on ecophysiological parameters, especially photosynthetic rate, stomatal conductance, intrinsic water use efficiency and carboxylation efficiency. However, there were differences between the genotypes concerning the physiological mechanisms leading to biomass increment. In WT plants, inoculation with P. indica stimulated all H+ pumps. However, in inoculated AVP plants, H+-PPase was stimulated, but P- and V-ATPases were inhibited. Fungal inoculation enhanced nutrient uptake in both shoots and roots of WT and AVP plants, compared to uninoculated plants; but among inoculated genotypes, the nutrient uptake was lower in AVP than in WT plants. These results clearly demonstrate that the symbiosis between P. indica and AVP plants did not benefit those plants, which may be related to the inefficient colonization of this fungus on the transgenic plants, demonstrating an incompatibility of this symbiosis, which needs to be further studied.info:eu-repo/semantics/publishedVersio

Inoculation with the endophytic bacterium Herbaspirillum seropedicae promotes growth, nutrient uptake and photosynthetic efficiency in rice

Main conclusion: Higher vacuolar proton pump activity may increase plant energy and nutrient use efficiency and provide the nexus between plant inoculation with Herbaspirillum seropedicae and growth promotion. Abstract: Global change and growing human population are exhausting arable land and resources, including water and fertilizers. We present inoculation with the endophytic plant-growth promoting bacterium (PGPB) Herbaspirillum seropedicae as a strategy for promoting growth, nutrient uptake and photosynthetic efficiency in rice (Oryza sativa L.). Because plant nutrient acquisition is coordinated with photosynthesis and the plant carbon status, we hypothesize that inoculation with H. seropedicae will stimulate proton (H+) pumps, increasing plant growth nutrient uptake and photosynthetic efficiency at low nutrient levels. Plants were inoculated and grown in pots with sterile soil for 90 days. Herbaspirillum seropedicae endophytic colonization was successful and, as hypothesized, inoculation (1) stimulated root vacuolar H+ pumps (vacuolar H+-ATPase and vacuolar H+-PPase), and (2) increased plant growth, nutrient contents and photosynthetic efficiency. The results showed that inoculation with the endophytic bacterium H. seropedicae can promote plant growth, nutrient uptake and photosynthetic efficiency, which will likely result in a more efficient use of resources (nutrients and water) and higher production of nutrient-rich food at reduced economic and environmental costs.info:eu-repo/semantics/publishedVersio