ABSTRACT. This study examined biochemical changes associated with chilling injury (CI) in sweet potato roots stored at low temperatures and reconditioned at ambient temperature. Sweet potato cultivars BRS Amélia and BRS Rubissol were stored at 6 or 13°C for 4 days at ambient temperature (“ambient reconditioning”: 21 ± 2°C). CI on the outer surface of the roots occurred earlier in BRS Amélia than in BRS Rubissol. The CI index on the inner surface of the BRS Amélia was higher when it was stored at 6°C for 40 + 4 days. BRS Amélia showed higher proline content and electrolyte leakage when stored at 6°C. Ascorbate peroxidase was induced by storage at 6°C for 30 + 4 days in BRS Amélia and from 40 + 4 days in BRS Rubissol. The malondialdehyde and phenolic compounds of BRS Rubissol increased during storage at 6°C. CI in both cultivars was associated with increased peroxidase and polyphenol oxidase activities. Storage of sweet potato cultivars at 6°C for 50 + 4 days caused severe damage to the roots. Cultivars BRS Amélia and BRS Rubissol showed similar symptoms of CI and can be characterized as being sensitive to low temperatures.

Resumen En muchos tejidos vegetales, se ha utilizado el acondicionamiento a baja temperatura (LTC) para inducir respuestas adaptativas poscosecha para superar las consecuencias del daño por frío (CI). Este estudio tuvo como objetivo investigar si el LTC es eficaz para reducir la incidencia de daño por frío (CI) en cultivares de batata. Las raíces de batata BRS Cuia y BRS Rubissol se sometieron a almacenamiento en frío (6 °C o 13 °C) y LTC (10 °C durante 7 días, seguido de un segundo almacenamiento a 6 °C). El LTC aumentó la tolerancia de las raíces de la batata al IC mediante la activación del sistema antioxidante, principalmente en el cv. BRS Rubissol, que se asoció notablemente con un mayor contenido de fenoles solubles totales y prolina, así como una mayor actividad de la fenilalanina amonio liasa. Además, no se observaron lesiones externas ni internas en las raíces de LTC, manteniendo la calidad para el procesamiento, lo que indica que el LTC es eficaz para mitigar el daño por frío en los cultivares brasileños de batata.

Abstract In many plant tissues, low-temperature conditioning (LTC) has been used to induce postharvest adaptive responses to overcome chilling injury (CI) consequences. This study aimed to investigate whether LTC is effective in reducing the incidence of chilling injury (CI) in sweet potato cultivars. Sweet potato roots BRS Cuia and BRS Rubissol were submitted to cold storage (6 °C or 13 °C) and LTC (10 °C for 7 d, followed by second storage at 6 °C). LTC increased the tolerance of sweet potato roots to CI via antioxidant system activation, mainly in cv. BRS Rubissol, which was markedly associated with higher content of both total soluble phenolics and proline, as well as increased activity of phenylalanine ammonium lyase. Moreover, no either external or internal injuries were observed in the LTC roots, maintaining the quality for processing, which indicates that the LTC is effective in mitigating chilling injury in Brazilian sweet potato cultivars.

ABSTRACT High incidence of sprouts and loss of quality of sweet potato is one of the negative aspects that compromises the commercialization most, and the methods of sprout control are still very limited. The appearance of sprouts promotes the wilting of sweet potato roots, reducing their commercialization period. The main objectives of this study were to evaluate sprout control and physiological and biochemical changes, in addition to the impact on the quality of postharvest chips in sweet potato roots cultivar BRS Cuia treated with methyl jasmonate (MeJa) and nonanoic acid (NA). Roots were fogged with 10 μmol·L–1 MeJa or 5 μmol·L–1 NA applied at first sprout initiation and control. Physiological and biochemical alterations such as fresh weight loss assessment, sprouting incidence and sprout length, total soluble sugars, reducing sugars, nonreducing sugars, enzymatic peroxidase and polyphenol oxidase, chips quality after frying were then assessed. Besides that, to determine the influence of treatments and storage periods, multivariate analysis was also performed using the main components. The MeJa reduced the incidence of sprouting and maintained the root quality during storage at room temperature. Notably, such events led to an increased both shelf life and potential of commercialization. Moreover, MeJa-treated chips displayed lighter color appearance after frying than control and NA-treated roots. Roots fogged with NA did not suppress the growth of sprouts, which consequently triggered a higher browning intensity in fried sweet potato chips.

RESUMEN El cajueiro presenta enorme relevancia económica para el Nordeste Brasileño. Para el establecimiento de huertos de esta espécie, la fase más importante es la formación de plántulas. Por esto, estudios para mejorar aspectos de crecimiento y calidad de plántulas son de gran importancia. En tal sentido, el objetivo del presente trabajo fue evaluar el crecimiento y calidad de plántulas de cajueiro en respuesta a métodos de rompimiento de dormancia, volumen de la matera y aplicación de biofertilizante bovino. Se utilizó el diseño experimental completamente al azar con arreglo factorial 2x2x5, seis repeticiones y la unidad experimental de cinco plántulas. Los tratamientos consistieron en dos métodos de rompimiento de dormancia (escarificación por lija e inmersión en agua), dos volúmenes de matera (1 y 2 kg) y cinco dosis de biofertilizante bovino (0; 2,5; 5,0; 7,5 y 10 mL). El método de rompimiento de dormancia con agua normal durante 24 horas fue el más adecuado para la formación de plántulas de cajueiro. Las dosis 7,5 y 10,0 mL de biofertilizante bovino proporcionaron mayor crecimiento y calidad de plántulas de cajueiro. El volumen 2 kg de sustrato fue el volumen más indicado para el cultivo de plántulas de cajueiro.

ABSTRACT The dwaf cashew tree presents enormous economic relevance for the Brazilian northeast. When establishing orchards of this species, the most important phase is the formation of the seedlings. Therefore, studies aiming to improve growth aspects and seedling qualities are extremely relevant. In this sense, the present study aimed to evaluate the growth and quality of dwarf cashew tree seedlings as a result of methods for breaking dormancy, container volume and application of bovine biofertilizer. The experiment design was completely randomized, with a 2x2x5 factorial scheme and six replicates; the experimental unit consisted of five seedlings. The treatments involved two methods of breaking dormancy (scarification with sandpaper and immersion in water), two container volumes (1 and 2 kg) and five doses of bovine biofertilizer (0, 2.5, 5.0, 7.5 and 10 mL). The method for breaking dormancy with normal water for 24 hours was the most adequate for the formation of dwarf cashew tree seedlings. The doses of 7.5 and 10 mL of bovine biofertilizer provided higher growth and quality in the dwarf cashew tree seedlings. The volume of 2 kg of substrate was the most suitable volume for growing dwarf cashew trees.

RESUMO Um dos obstáculos ao cultivo comercial de cajazeira (Spondias mombin L.) é a dificuldade em estabelecer um protocolo de propagação dessa espécie. Objetivou-se avaliar o efeito do tratamento da planta matriz com ethephon e aplicação de ácido indolbutírico (AIB), em estacas de cajazeira. Foi utilizado delineamento inteiramente casualizado, composto por nove tratamentos, com doses de ethephon (0 mg L-1; 14,5 mg L-1; 50 mg L-1; 85,5 mg L-1; 100 mg L-1) e de AIB (0 mg L-1; 872,35 mg L-1; 3.000 mg L-1; 5.127,65 mg L-1; 6.000 mg L-1), combinados de acordo com o composto central de box, com quatro repetições. Cada unidade experimental consistiu de 12 estacas. Os maiores percentuais de enraizamento de estacas de cajazeira foram observados sem a aplicação de ethephon (45.83 %) nas plantas matrizes e com o uso de 3.000 mg L-1 de AIB (31.94 %). Para o enraizamento de estacas de cajazeira, não recomenda-se o uso de ethephon para o tratamento de planta matriz antes da retirada das estacas. A dose de 3.000 mg L-1 de AIB proporciona o enraizamento máximo de estacas de cajazeira, sendo essa dose a mais recomendada para a propagação via estaquia.

ABSTRACT One of the obstacles in the commercial cultivation of yellow mombin (Spondias mombin L.) is the difficulty in establishing a propagation protocol for the species. This study aimed to assess the effect of treating mother plants with ethephon and applying indolebutyric acid (IBA) to yellow mombin cuttings. A completely randomized design was used, consisting of nine treatments, with ethephon (0 mg L-1; 14.5 mg L-1; 50 mg L-1; 85.5 mg L-1; 100 mg L-1) and IBA (0 mg L-1; 872.35 mg L-1; 3,000 mg L-1; 5,127.65 mg L-1; 6,000 mg L-1) doses, combined according to the central compound box, with four replications. Each experimental unit consisted of 12 cuttings. The highest rooting percentages of yellow mombin cuttings were observed without the application of ethephon (45.83 %) in the matrix plants and with the use of 3,000 mg L-1 of IBA (31.94 %). For the rooting of yellow mombin cuttings, it is not recommended to use ethephon for treating the matrix plant before the cuttings are removed. The dose of 3,000 mg L-1 of IBA provides the maximum rooting of yellow mombin cuttings, being this dose the most recommended for the propagation via cutting.