Quality of adzuki bean seeds desiccated with flumioxazin and subjected to storage / Qualidade de sementes de feijão azuki dessecadas com flumioxazin e submetidas ao armazenamento

Production and storage environments influence the physiological and sanitary quality of seeds. This study aimed to evaluate the effects of the herbicide flumioxazin applied as a preharvest desiccant and storage on the physiological and sanitary quality of adzuki bean seeds. A randomized block design was used in a split-plot scheme, with four replications. Plots consisted of five doses of the herbicide flumioxazin (20, 25, 30, 35, and 40 g ai·ha-1) and subplots consisted of two evaluation times (harvest and six months after harvest). Two controls, with no herbicide application, were tested for each evaluation time. The physiological seed quality was maintained with doses from 25 to 35 g·ha-1 of flumioxazin. Increasing herbicide doses reduced the electrical conductivity of seeds. The increased doses also reduced the percentage of normal seedlings in the first germination count after six months of storage and caused seedling vigor loss. The storage of adzuki bean for six months reduced its physiological quality, leading to losses in germination and seed vigor. Storage and increasing doses of the desiccant flumioxazin reduced the incidence of the pathogens Rhizopus, Cladosporium, and Fusarium in the seeds. The increased doses of this herbicide reduced Aspergillus incidence. Penicillium incidence was not affected by treatments.(AU)

A qualidade fisiológica e sanitária de sementes é influenciada pelo ambiente de produção e de armazenamento. Neste trabalho objetivou-se avaliar os efeitos do herbicida flumioxazin aplicado como dessecante em pré-colheita e do armazenamento sobre a qualidade fisiológica e sanitária de sementes de feijão azuki. Foi adotado o delineamento experimental em blocos ao acaso, em esquema de parcelas subdivididas. Nas parcelas foram alocadas as cinco doses do herbicida flumioxazin (20, 25, 30, 35 e 40 g i.a·ha-1) e nas subparcelas as duas épocas de avaliação (colheita e 6 meses após a colheita), com quatro repetições. Foram testados dois tratamentos sem aplicação do herbicida para cada época de avaliação. Nas doses entre 25 a 35 g·ha-1 de flumioxazin observou-se a manutenção da qualidade fisiológica das sementes. Em doses crescentes reduziu-se a condutividade elétrica das sementes. O aumento das doses reduziu a porcentagem de plântulas normais na primeira contagem da germinação, após seis meses de armazenamento, e causou perda no vigor das plântulas. O armazenamento de feijão azuki durante seis meses reduziu a qualidade fisiológica, causando perdas na germinação e vigor das sementes. O armazenamento e o aumento das doses do dessecante flumioxazin reduziram a incidência dos patógenos Rhizopus, Cladosporium e Fusarium nas sementes. O aumento das doses reduziu a incidência de Aspergillus. A incidência de Penicillium não foi afetada pelos tratamentos.(AU)

Lifespan Extending and Stress Resistant Properties of Vitexin from Vigna angularis in Caenorhabditis elegans

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.

Genistein from Vigna angularis Extends Lifespan in Caenorhabditis elegans

The seed of Vigna angularis has long been cultivated as a food or a folk medicine in East Asia. Genistein (4',5,7-trihydroxyisoflavone), a dietary phytoestrogen present in this plant, has been known to possess various biological properties. In this study, we investigated the possible lifespan-extending effects of genistein using Caenorhabditis elegans model system. We found that the lifespan of nematode was significantly prolonged in the presence of genistein under normal culture condition. In addition, genistein elevated the survival rate of nematode against stressful environment including heat and oxidative conditions. Further studies demonstrated that genistein-mediated increased stress tolerance of nematode could be attributed to enhanced expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). Moreover, we failed to find genistein-induced significant change in aging-related factors including reproduction, food intake, and growth, indicating genistein exerts longevity activity independent of affecting these factors. Genistein treatment also led to an up-regulation of locomotory ability of aged nematode, suggesting genistein affects healthspan as well as lifespan of nematode. Our results represent that genistein has beneficial effects on the lifespan of C. elegans under both of normal and stress condition via elevating expressions of stress resistance proteins.