José Augusto Teixeira do Amaral

Growth periodicity in trees of Coffea arabica L. in relation to nitrogen supply and nitrate reductase activity

Abstract Vegetative growth of branches and leaf area gain in field-grown Arabica coffee trees in Vicosa, southeastern Brazil, exhibited active and quiescent phases. Nitrogen supplementation during the cool season did not prevent growth decline, nor did it alter the overall pattern of the tree growth; however, it enabled the plants to grow faster following the quiescent growth phase. Growth was related poorly to both nitrate content and nitrate reductase activity in leaves. In roots, N-fertilization in addition to accounting for greater content of nitrate, amino acids and ammonium was also associated with the maintenance of the nitrate reductase activity, but nitrate reduction was apparently nil in leaves during most of the cool season.

Allometric model for estimating leaf area in clonal varieties of coffee (Coffea canephora)

The evaluation of leaf area is required in several agronomic studies given their importance to assess the plant growth. The objective of this study was to use statistical models to estimate leaf area of five clonal varieties of coffee (Coffea canephora) from linear dimensions (length and width maximum). Were used in the studies five varieties of Coffea canephora Pierre ex Froehner: Emcapa 8111, Emcapa 8121 Emcapa 8131, Emcapa 8141 and at Incaper 8142. The results obtained in this study allow us to conclude that the linear model expresses the best estimate of leaf area. Among the different independent variables adopted, the product of length and greatest width (L.W) was found to be the greatest significance and higher coefficients of determination (R2). The regression equation that best expresses the estimated leaf area for the five clonal varieties is Ŷi = 0.6723 + 0.6779 xi, where xi represents the product of the greatest length and the greatest width of the leaves.

Accelerated aging test to evaluate the quality of crambe (Crambe abyssinica Hochst - Brassicaceae) seed physiology

Este estudio tuvo como objetivo evaluar la eficacia de la prueba de envejecimiento acelerado, para determinar los efectos fisiologicos de semillas Crambe abyssinica Hochst, un monton de dos cosechas (2009 y 2010). Se evaluaron: contenido de agua, la germinacion y el vigor por el indice de velocidad de la germinacion, envejecimiento acelerado a 41, 43 y 45 °C durante periodos de 24, 48, 72 y 96 horas, el peso fresco y el peso seco. El experimento se llevo a cabo en el esquema factorial 2x3x5 (mucha x temperatura x tiempo de exposicion), en un diseno completamente al azar, con cuatro repeticiones de 25 semillas. El peso fresco y peso seco no son eficientes para diferenciar la calidad fisiologica de las semillas de Crambe abyssinica. Las influencias de envejecimiento acelerado, de manera similar, el porcentaje de germinacion y el vigor, con una mayor sensibilidad cuando las semillas son tratadas con temperaturas de 41 o 43 °C durante 72 h, lo que indica un papel prometedor para la estratificacion de la calidad fisiologica de la semilla crambe de lotes con germinacion similar.

PRODUÇÃO DE MUDAS DE TOMATEIRO POR ESTAQUIA: EFEITO DO SUBSTRATO E COMPRIMENTO DE ESTACAS

Objetivou-se avaliar a viabilidade da producao de mudas de tomateiro por estaquia em diferentes substratos. O experimento foi conduzido em casa-de-vegetacao no Centro de Ciencias Agrarias da UFES, em Alegre-ES. Para a producao de mudas do tomateiro comparou se os substratos: mistura de solo + areia lavada + esterco bovino, Plantmax® e areia lavada. Os substratos foram acondicionados em recipientes plasticos ( 8 cm de altura e 7 cm de diâmetro), com capacidade para 200 mL. Brotacoes foram retiradas de diferentes posicoes de plantas matrizes. Assim, as estacas foram padronizadas em tres alturas: 5, 8 e 11 cm . O experimento foi instalado em esquema fatorial 3 x 3 (substratos x estacas) com tres repeticoes e 30 mudas por parcela, totalizando 810 mudas. Foram detectados efeitos significativos para a interacao entre os tipos de substratos e alturas de estacas nas seguintes caracteristicas: comprimento do sistema radicular, diametro medio das raizes, relacao entre a massa seca da parte aerea e massa seca do sistema radicular, massa seca total e massa seca do sistema radicular. Estacas de 5 cm apresentaram menor relacao PA/SR independente do tipo de substrato e maior proporcao de massa seca alocada no sistema radicular (53,8%). A propagado vegetativa do tomateiro e viavel, contudo maiores estudos sobre substratos alternativos, condicoes de enraizamento e padrao do material vegetal utilizado devem ser realizados.

Tolerance of arabica coffee cultivars for aluminum in nutritive solution

This work aimed to evaluate the Coffea arabica cultivars for aluminum toxicity tolerance, in modified Hoagland solution. A completely randomized design with five repetitions in a factorial 4 x 4 (cultivar x combinations of aluminum) was used. After 44 days of the sowing, were transferred ten seedlings each cultivar germinated in the absence of Al3+ to solution without Al3+, and ten for solution with Al3+; ten seedlings each cultivar germinated in presence of Al3+ to solution without Al3+, and ten for solution with Al3+. In the treatment with aluminum, the element was added to the nutritive solution in the concentration of 0.83 mmol L-1 as Al2(SO4)3.16H2O. The cultivars Catuai Amarelo IAC 62 and Iapar 59 were tolerant to the aluminum; cultivar Oeiras presented intermediate tolerance, while cultivar Obata IAC 1669-20 was sensitive. The tolerance of the coffee cultivars to the aluminum during the initial development of the seedlings did not depend on the presence of aluminum in the germination phase.

EMERGÊNCIA E CRESCIMENTO INICIAL DE PLÂNTULAS DE TANGERINEIRA ‘CLEÓPATRA’ SUBMETIDAS A DIFERENTES NÍVEIS DE SOMBREAMENTO

Os conhecimentos sobre as respostas das plantas a luminosidade sao de grande importância para a producao de mudas, mas nem sempre estes dados estao disponiveis para muitas especies. O objetivo deste trabalho foi avaliar a emergencia e o crescimento inicial de mudas de tangerineira ‘Cleopatra’ (Citrus reshni Hort. ex Tan) submetidas a diferentes niveis de sombreamento. Os niveis de sombreamento avaliados foram: 0 (pleno sol), 30, 50, 80% de sombra. As sementes foram plantadas em quatro repeticoes com 25 sementes, totalizando o numero de 100 sementes para cada nivel de sombreamento, em tubetes contendo o substrato Plantmax® Florestal. As caracteristicas analisadas foram: indice de velocidade de emergencia (IVE); percentual de emergencia (PER); altura (ALT); numero de folhas (NF); area foliar (AF); massa da materia seca da parte aerea e da raiz (MSPA e MSR) e teores de clorofila a, b e total (CLO A; CLO B; CLO T) nas folhas. Por meio de analises de regressao observou-se resposta linear para altura das plantas em funcao do nivel sombreamento. Para as demais caracteristicas observou-se comportamento polinomial de 2° grau, com as caracteristicas IVE, AF, MSPA e MSR apresentando pontos de maximo. Comportamento diferente dos observados para as caracteristicas NF, CLO A, CLO B e CLO T cujas curvas passam por ponto de minimo. Portanto, ao se analisar o conjunto das caracteristicas avaliadas observa-se que o nivel de sombreamento de 50% proporcionou maior emergencia e crescimento das mudas de tangerineira ‘Cleopatra’.

Crescimento vegetativo e produtividade de cafeeiros Conilon propagados por estacas em tubetes

The objective of this work was to evaluate the vegetative growth and productivity of conilon coffee-tree (Coffea canephora Pierre ex Froehner), proceeding from seedlings produced of deep-rooted cuttings initially in plastic tubes with capacity of 50 cm3. The treatments were constituted of permanence period in plastic tube for 0; 15; 30; 45 and 60 days. After these periods the plants were transplanted for polyethylene bags filled with substrate (soil + sand + manure bovine and chemical fertilization) maintained on the greenhouse with environment under shading canvas (50%) and automatic micro aspersion during 150 days. After this time the plants were maintained during 30 days in acclimatization greenhouse management. Field experiment was set up in September of 1999, at experimental area CCA-UFES, in Alegre, south state of the Espirito Santo, Brasil. The following measurements were made: length of orthotropic and plagiotropic branches after first year and the first four productions. The results showed there were no differences either in vegetative growth and fruits production.

Effects of aluminum, nitrate and ammonium on the growth, potassium content and composition of amino acids in Stylosanthes

Se estudiaron en condiciones controladas los efectos de la interaccion entre el aluminio, nitrato y amonio, en solucion nutritiva. Se realizo un analisis sobre el crecimiento, las concentraciones de potasio y la composicion porcentual de N de los aminoacidos en Stylosanthes guianensis y S. macrocephala, sensibles y resistentes, respectivamente, tanto al aluminio y al amonio. El amonio redujo el crecimiento del S. guianensis drasticamente. La toxicidad de amonio, comprobada solo en el S. guianensis, estaba asociada con la estimulacion de la sintesis de las rutas metabolicas de la prolina y arginina, a partir del acido glutamico, en detrimento de la sintesis de glutamina. El aluminio alivia parcialmente la toxicidad de amonio en el S. guianensis, concomitante al aumento en la retencion de asparagina y reduccion en la composicion de arginina en el sistema de raices. En presencia de la fuente nitrica, el aluminio aumento las concentraciones de potasio solo en el S. macrocephala. En presencia de la fuente nitrica, la interconversion de N-aminico fue influenciada por el aluminio en ambas especies; sin embargo, la composicion porcentual de N-aminoacidos se modifico mas en el S. macrocephala.

IBA levels and substrates in the rooting of UENF/CALIMAN 02 hybrid papaya minicuttings in a semi-hydroponic system

Mini-cutting is a technique with large applications in various crops, mainly due to the increase in the percentage and quality of adventitious roots, reducing time for the formation of clonal seedlings. The aim of this study was to evaluate IBA levels and substrates on the rooting of UENF/CALIMAN 02 hybrid papaya mini-cuttings. To perform the experiment, papaya mini-cuttings were taken from mother plants grown in pots in greenhouse, induced to produce shoots through pruning and growth regulator applications. Mini-cuttings were fixed in vermiculite or coconut fiver substrates placed in alveolate trays with 4.5x4.5x5.0 cm cells, and styrofoam trays were placed in plastic trays where different IBA levels were added in a modified Hoagland solution. After 45 days, rooted buds were transplanted to plastic pots of 600 mL of volume with soil, sand, well-cured bovine fertilizer, in the proportion of 3:1:1, remaining for 45 days. When they were taken from pots, roots were carefully washed, and the length of shoots, length of the largest root, dried mass of shoots and radicular system and root percentage were measured. The experiment was set up in a randomized complete block 5 x 2 factorial design, with 5 IBA levels: 0; 2.5; 5.0; 7.5 and 10 mg L-1, two substrates: vermiculite and coconut fiber, three replicates, with six plants per replicate. IBA levels of 5.0 mg L-1 and substrate vermiculite are the most adequate for the rooting of ‘UENF/CALIMAN 02’ papaya mini-cuttings in semi-hydroponic system in alveolate styrofoam trays with 4.5x4.5x5.0 cm cells.

GERMINAÇÃO IN VITRO DE Crambe abyssinica HOCHST

A germinacao in vitro para Crambe abyssinica Hochst e importante tanto para a propagacao massal, quanto como ferramenta para aplicacao de outras tecnicas biotecnologicas. O objetivo deste trabalho foi avaliar os efeitos de diferentes meios de cultura, condicoes fisicas da semente e condicoes de luminosidade na germinacao in vitro de crambe. O experimento foi conduzido em esquema de parcelas sub-subdivididas, tendo nas parcelas as condicoes luminosas (presenca ou ausencia de luz), nas subparcelas os meios de cultura (MS, WPM e B5) e nas sub-subparcelas as condicoes fisicas da semente (presenca ou ausencia de pericarpo). A porcentagem de germinacao foi maior nos meios B5 e WPM, com medias de 99,37% e 97,50%, respectivamente, independente da luz e das condicoes fisicas da semente. Os maiores valores de IVG foram observados tambem nesses meios com media de 3,87 na ausencia de luz em sementes sem pericarpo. O comprimento da parte aerea foi influenciado pela composicao do meio de cultura e condicao luminosa, em que, os meios B5 e WPM apresentaram os maiores valores na ausencia de luz, 13,2 e 11,7 cm, respectivamente. Os comprimentos das raizes foram significativamente maiores nos meios MS e B5, com medias de 6,8 e 5,0 cm, respectivamente, em relacao ao meio WPM, cuja media foi de 3,5 cm. Para as variaveis avaliadas, as condicoes mais favoraveis a germinacao e desenvolvimento das plantas in vitro sao em meio B5 ou WPM, na presenca ou ausencia de pericarpo e na presenca de luz.