Resumo O presente trabalho teve por objetivo avaliar a atividade enzimática em sementes de Annona x atemoya submetidas a tratamentos com reguladores vegetais do grupo dasgiberelinas e citocininas para superação de dormência, durante o processo de germinação. Inicialmente, foi determinada a curva de aquisição de água das sementes, sendo determinados dois pontos da fase II (72 e 144 horas) para a determinação da atividade das enzimas: superóxido dismutase (SOD), peroxidase (POD) e catalase (CAT) em sementes de atemoia, após a aplicação dos reguladores vegetais. Os tratamentos com GA resultaram em maior atividade da enzima SOD, o que pode ter favorecido a maior porcentagem e a velocidade de germinação em comparação ao tratamento-controle. Nos casos em que a enzima SOD apresentou elevada, as demais enzimas apresentaram atividade reduzida, o que indica a produção predominantemente de superóxidos nesse período. A enzima POD também teve atividade em sementes tratadas com giberelina, o que sugere a interação das EROS com GA no processo de superação da dormência. Os tratamentos com citocinina e citocinina + giberelina resultaram em porcentagem de germinação semelhante ao controle e não foi observado um padrão na atividade das enzimas SOD, POD e CAT que pudesse ser correlacionado ao metabolismo germinativo.

Abstract The objective of this work was to validate the enzymatic activity in Annona x atemoyaseeds submitted to treatments with plant growth regulators belonging to the group of gibberellins and cytokinins for overcoming dormancy during the germination process. Initially, the water acquisition curve was determined, where two points of phase II (72 and 144 hours) were determined to evaluate the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes in atemoya seeds after the application of two plant growth regulators. Treatments with GA resulted in higher activity of SOD enzyme, which may be favored the higher germination percentage and speed in comparison to control treatment. In cases in which SOD enzyme presented high activity, other enzymes showed the opposite, which indicates the predominantly production of superoxides during this period. The POD enzyme also has activity in seeds treated with gibberellin, which suggests interaction of ROS with GA in the process of dormancy overcoming. Treatments with cytokinin and cytokinin + gibberellin resulted in germination percentage similar to control and no activity pattern of SOD, POD and CAT enzymes that could be correlated with germination metabolism was observed.

ABSTRACT In viticulture, training systems and rootstocks are crucial factors in the growth and development of plants, thus affecting the production and quality of grapes. Therefore, the present study aimed to determine the best combination of rootstock and training system for ‘Sauvignon Blanc’, in Jundiaí, state of São Paulo, Brazil. To assess the data, a randomized block design in a 2 × 2 factorial scheme was used, that is, two rootstocks (‘IAC 766 Campinas’ and ‘106-8 Mgt’) and two training systems (low and high espaliers), with four replications. The characteristics assessed were production, physicochemical analysis and concentration of bioactive compounds. With regard to the physicochemical composition of the grape must, the results indicated that the tested combinations are within the standard requirements for the winemaking industry; outcomes may change according to the rootstock used, i.e., an increase in production or an increase in the nutritional quality of the fruits. Nevertheless, ‘106-8 Mgt’ rootstock showed great yield in both training systems, that is, an increase of up to 80%. Finally, ‘Sauvignon Blanc’ must be grafted on to ‘IAC 766 Campinas’ rootstock through a low espalier system to achieve a high content of phenolic compounds and flavonoids, and high antioxidant activity.

Resumen El tomate es un fruto rico en compuestos antioxidantes y tiene gran importancia nutricional y económica; anualmente se promueve investigaciones relacionadas con las características nutricionales y productivas. El objetivo de este estudio fue evaluar si la aplicación foliar de productos comerciales a base de reguladores vegetales [auxina, citocinina y giberelina (Ax+CK+GA)], micronutrientes [cobalto y molibdeno (Mi)] y mezcla de macro y micronutrientes [nitrógeno, boro, cobre, molibdeno y zinc (Ma+Mi)], de forma individual y combinada, sobre el aumento de la productividad y mejora de la calidad poscosecha de los frutos de tomate (Predador F1). El diseño experimental consistió en bloques al azar, con siete tratamientos y cuatro repeticiones, siendo (T1) control; (T2) Ax+CK+GA; (T3) Ma + Mi; (T4) Mi; (T5) Ax+CK+GA + (Ma + Mi); (T6) Ax+CK+GA + Mi; (T7) Ax+CK+GA + Mi + (Ma+Mi). Se evaluaron las variables producción, precocidad, contenido de sólidos solubles (SS), acidez titulable (AT), relación SS/AT, pH, azúcares solubles totales, ácido ascórbico y pérdida de peso. La aplicación de Ax+CK+GA de forma individual o combinada con Ma+Mi promovió la precocidad, mientras el uso de Ax+CK+GA y Mi, de forma separada, mejoró la productividad del tomate. Los reguladores de crecimiento y los macro y micronutrientes, separados o combinados, proporcionaron un aumento en el contenido de ácido ascórbico en los frutos.

ABSTRACT The tomato fruit is rich in antioxidant compounds and has great nutritional and economic importance, annually promoting research on the nutritional and productive characteristics. The present study aimed to evaluate whether foliar application of commercial products based on growth regulators [auxin, cytokinin and gibberellin (Ax+CK+GA)], micronutrients [cobalt and molybdenum (Mi)] and mixtures of macro and micronutrients [nitrogen, boron, copper, molybdenum and zinc (Ma+Mi)], isolated and in combination, increase productivity and improve the post-harvest quality of tomato fruits (Predador F1). The experiment design used randomized blocks, with seven treatments and four repetitions, which were (T1) control; (T2) Ax+CK+GA; (T3) Ma + Mi; (T4) Mi; (T5) Ax+CK+GA + (Ma + Mi); (T6) Ax+CK+GA + Mi; and (T7) Ax+CK+GA + Mi + (Ma+Mi). The variables production, precocity, soluble solids content (SS), titrata-ble acidity (TA), ratio (SS/TA), pH, total soluble sugars, ascorbic acid and weight loss were evaluated. The Ax+CK+GA application, isolated or in combination with Ma+Mi, promoted the precocity, and the use of isolated Ax+CK+GA and Mi improved the tomato plant productivity. The growth regulators, macro and micronutrients, isolated or in combination, increased the ascorbic acid content in the fruits.

O mogno (Swietenia macrophylla King) possui importância econômica, mas encontra-se em risco de extinção em razão da sua exploração intensiva. Portanto, o cultivo e os estudos que mostrem o comportamento fisiológico dessa espécie tornam-se relevantes. Tendo em vista estes aspectos, foi realizada esta pesquisa com o objetivo de avaliar os efeitos do sombreamento na atividade da enzima nitrato redutase e no crescimento de mogno em casa de vegetação. O plano para as unidades experimentais foi o delineamento inteiramente casualizado com quatro tratamentos (diferentes níveis de sombreamento) e nove repetições. Os dados de fitomassa seca de caule e a atividade da enzima nitrato redutase não diferiram estatisticamente entre os tratamentos. Com relação às raízes e folhas, observou-se um maior acúmulo de fitomassa seca com 20 e 50% de sombreamento. O mogno apresenta menor acúmulo de fitomassa seca sobre 0% de sombreamento; no entanto, a atividade da enzima nitrato redutase não é influenciada pelo sombreamento.

This work aimed to evaluate the effect of light on nitrate reductase activity and growth of Mahogany in greenhouse. A randomized design with four shading treatments and nine replicates was used. Data on dry mass of roots and nitrate reductase activity did not differ statistically between any of the treatments. Stem and leaves presented higher growth, with 20 and 50% of shade, respectively. Mahogany showed lower growth on 100% of shade; however, nitrate reductase activity was not influenced by shading.