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.

RESUMO A alface é considerada uma cultura de clima ameno e sua produção em regiões de baixa altitude e latitude é prejudicada principalmente devido às elevadas temperaturas e à predominância de dias longos. Assim, objetivou-se avaliar o comportamento de cultivares de alface numa condição que apresentasse essas características. Para isto, conduziu-se um ensaio na Horta Didática da Universidade Federal do Ceará, Campus do Pici, em Fortaleza. Utilizaram-se nove cultivares de alface de três grupos comerciais, distribuídos no delineamento em blocos casualizados, com quatro repetições. Foram avaliadas as características qualitativas, idade de pendoamento, formação de cabeça, textura da folha, antocianina e, estado fitossanitários das plantas quanto a infestação por pragas e doenças. Em relação às características quantitativas avaliaram-se, altura das plantas, diâmetro das plantas, massa fresca comercializável (MFC) e não comercializável (MFNC), massa fresca total (MFT), massa seca comercializável (MSC) e não comercializável (MSNC), massa seca total (MST), clorofila a, clorofila b e, relação clorofila ab. Os dados foram submetidos a análises de variância e, posteriormente, realizado o teste de agrupamento. Nenhum dos cultivares apresentou formação de cabeça, mas todos pendoaram precocemente. Os cultivares não apresentaram diferença para MFC, porém, Babá de Verão produziu quase 72% a mais que Repolhuda Brasil, de seu mesmo grupo. Quanto à MFT, os cultivares mais produtivos foram Babá de Verão, Crespa para Verão, Americana Delícia, Crespa Repolhuda e Kaiser. Contudo, para MSC apenas Babá de Verão e Crespa se sobressaíram. Esses últimos, juntamente com Crespa Repolhuda, foram os que apresentaram também os maiores valores de MST.

ABSTRACT Lettuce is considered a crop of mild climate and its production in regions of low altitude and latitude is impaired due to the high temperatures and the predominance of long days. Therefore, the aim of this study was to evaluate the behavior of lettuce cultivars in such conditions. An experiment was conducted at the Horta Didática of the Federal University of Ceará, Campus do Pici, in Fortaleza. Nine lettuce cultivars from three commercial groups were used and distributed in a randomized block design, with four replications. The following qualitative traits were evaluated: bolting, head formation, leaf texture, anthocyanin and phytosanitary status for pest and disease infestation. Regarding the quantitative traits, plant height, plant diameter, fresh marketable weight (FMW), and non-marketable (FNMW) total fresh weight (TFW), dry marketable weight (DMW) and non-marketable (DNMW), total dry weight, chlorophyll a, chlorophyll b, chlorophyll a/b ratio. Data were submitted to analysis of variance and, later, grouping test was performed. None of the cultivars presented head formation but all presented early bolting. The cultivars showed no difference for FMW, however, Babá de Verão produced almost 72% more than Repolhuda Brasil from the same group. Regarding FMW, the most productive cultivars were Babá de Verão, Crespa para Verão, Americana Delícia, Crespa Repolhuda and Kaiser. However, Babá do Verão and Crespa stood out for DMW.

Dentre os fatores ambientais, a água pode ser considerada o de maior influência no processo germinativo. Neste trabalho, objetivou-se avaliar períodos de pré-embebição de sementes de melancia em água e seus efeitos em características de crescimento e desenvolvimento de plântulas. Os tratamentos constituíram-se de pré-embebição por: 0, 12, 24, 48 e 72 h. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições. Aos seis e 12 dias após a semeadura (DAS), cinco plantas por repetição foram coletadas, sendo avaliados: comprimento da raiz principal, parte aérea e total da planta; massas fresca e seca da raiz principal, da parte aérea e total da planta. A pré-embebição das sementes por 12 horas favoreceu o aumento na emergência aos 12 DAS. As plântulas obtidas a partir de sementes pré-embebidas por 48 e 72 h foram as que apresentaram maiores valores para as características de crescimento e desenvolvimento avaliadas.

Among the environmental factors the water can be considered the one with the highest influence in the germination process. The aim of this work was to evaluate the different periods of watermelon seeds pre-soaking and its effects on seedlings growth and development.. The treatments constituted of different periods of pre-soaking: 0, 12, 24, 48 and 72h. The experimental design was completely randomized with four replicates. At 6 and 12 days after sowing, 5 plants of each replicate were collected and evaluated: main root, shoot and total length; fresh and dry mass of the main root, shoot and total.. The pre-soaking of the seeds for 12h has helped to increase the % E. In general, the seedlings obtained from seed treatments pre-soaked for 48 and 72 hs, were the ones that showed higher values for the growth and development characteristics evaluated.