The breakdown of dormancy and early sprouting is one of the main causes of losses of stored potatoes. Sprouting control becomes important especially when tubers are submitted to long-term storage for further processing by the potato industry. The objective of this work is to evaluate the effect of organic sprout inhibitors, eugenol and menthol essential oils, on the suppression of growth on non-dormant 'Asterix' tubers stored at 8 °C. Administration of eugenol and menthol essential oils reduced the number and the length of sprouts during cold storage up to fifty days. Nevertheless, the essential oils stimulated the break of bud apical dominance, stimulating auxiliary buds growth. The effect of the oils was restricted to inducing necrosis of superficial sprout cells without any apparent effect on the skin periderm structure. Repeated applications of oils are necessary to prolong the inhibitory effects of the essential oils on sprouts growth.

Selenium (Se) is considered a beneficial element in higher plants when provided at low concentrations. Recently, studies have unveiled the interactions between Se and ethylene metabolism throughout plant growth and development. However, despite the evidence that Se may provide longer shelf life in ethylene-sensitive flowers, its primary action on ethylene biosynthesis and cause-effect responses are still understated. In the present review, we discuss the likely action of Se on ethylene biosynthesis and its consequence on postharvest physiology of cut flowers. By combining Se chemical properties with a dissection of ethylene metabolism, we further highlighted both the potential use of Se solutions and their downstream responses. We believe that this report will provide the foundation for the hypothesis that Se plays a key role in the postharvest longevity of ethylene-sensitive flowers.

AGRONOMY (AGRONOMIA) ABSTRACT: 'Galia' melon is a climacteric fruit with reduced shelf life, thus the goal of this work was to evaluate the post-harvest quality of fruits stored under normal and modified atmosphere at different temperatures. Fruits from cultivar Solarnet were stored under normal atmosphere (control) and modified atmosphere at 3, 7 and 11 o C and relative humidity of 90 ± 5%. Fruit evaluations were performed at 14, 21, 28 and 35 days of storage for pulp firmness, mass loss, internal and external appearance, chilling injury, total soluble phenolics, soluble sugars and enzymes polyphenoloxidase, peroxidase and catalase. Storage at 11 o C had the lowest pulp firmness and bigger mass loss in both atmospheres. Storage at 3 o C under modified atmosphere had the best postharvest conservation, but induced chilling injury, with development of superficial brown spots. 'Galia' melons showed higher peroxidase activity under storage at 3 °C in both storage atmospheres.

The longevity of cut flowers is limited by their ephemeral nature and by multiple stresses. Impairment in water uptake, depletion of stored carbohydrates, increases in both respiratory activity and ethylene production are signatures of flower senescence. A wide range of techniques is available to extend flower preservation, including the use of flower preservative solutions, ethylene action inhibitors, growth regulators, and control of temperature and flower dehydration. The use of sucrose in pulsing solution, or as a component of vase solution, extends the vase life of flowers by either improving water balance and energy or delaying the senescence via reductions in ethylene biosynthesis. Inhibitors of ethylene production and action affect the longevity by extending the vase life of some ethylene-sensitive flowers. Flowers have intense respiratory activity, which may deplete the limited reserves of carbohydrates in the tissues. Lower temperatures markedly reduce both carbon dioxide concentration and ethylene production as well as its action. However, chilling-sensitive flowers, such as bird-of-paradise, heliconia, orchid, and ginger, cannot be stored below 10 to 13°C due to the intense development of tissue discoloration.

Several experiments reveal that distilled water varies among different laboratories and also does not have a standard composition. Water electrical conductivity (EC) of vase solution is one of the parameters that influence the water uptake by cut flowers. Therefore, the objective of this work was to evaluate the influence of electrical conductivity on water uptake and vase life in cut stems of gladiolus. The stems harvested and kept in distilled water (pH 6.6, EC <0.01dS m -1 ) and tap water (pH 7.0, EC 0.75 dS m -1 ) at room temperature. Flowers kept in tap water showed lower fresh weight loss after the second day and higher water uptake during vase life. In a second set of experiments, we verified the limit EC saturation supported by the flower. . Keywords: Gladiolus grandiflora Hort., cut flowers, distilled water, longevity, RESUMO Influência da condutividade elétrica na absorção de água e vida de vaso de flores de gladíolosDiversos experimentos revelam que a qualidade da água destilada varia entre os diferentes laboratórios. A condutividade elétrica (CE) da solução de vaso é um dos parâmetros que influenciam na absorção de água pelas flores de corte. Portanto, o objetivo deste trabalho foi avaliar a influência da condutividade elétrica na absorção de água e vida de vaso de hastes de gladíolos. As hastes foram colhidas e mantidas em água destilada (pH 6,6 ; CE <0.01 dS m -1 ) e água da torneira (pH 7,0 ; CE 0,75 dS m -1 ), sob condições de temperatura ambiente. As flores mantidas em água de torneira apresentaram menor perda de peso fresco após segundo dia e maior absorção de água durante a vida de vaso. Em segundo experimento, verificou-se o limite de saturação da CE suportada pela flor. Para isso, as flores foram colocadas em tubos de ensaio individuais contendo quatro diferentes soluções com distintas concentrações de íons. Solução 2 (CE 0,60 dS m -1 ) promoveu o aumento da vida de vaso e o consumo máximo de água pelas flores. Os resultados mostram que a condutividade elétrica da solução de vaso é um parâmetro importante a ser avaliado em experimentos com a pós-colheita de flores de gladíolos. A presença de íons na solução de vaso aumenta a longevidade e melhora a absorção de água das hastes, com CE favorável entre 0,60-0,87 dS m -1 .

The increased demand for potato by the Brazilian processing industry requires long term refrigerated storage, but after a few months, natural dormancy ends, and sprouts start to grow. Thus, sprout inhibitors are necessary to reduce the rate of growth and allow further storage. The purpose of research described here was to determine the effects clove and menthol essential oils have on the inhibition of sprout growth in non-dormant ‘Asterix’ tubers. Both eugenol and menthol treatments reduced the rate of sprout growth during storage at 8oC for up to 50 days. Eugenol and menthol essential oils diminished the rate of accumulation of reducing sugar, which are responsible for browning of French fries. Color after frying was within acceptable levels when the tubers were treated with eugenol or menthol essential oils.

No abstract

Dne of the major problems affecting potatoes quality on stored is the susceptibility to enzymatic browning, which occurs mainly after wounds during the harvest, at postharvest handling and by aging, leading to the development of dark color compounds. Enzymatic browning is associated with the action of polyphenoloxidases (PPD) and peroxidases (PDD), which use phenolic compounds and oxygen as substrates. The products of these enzymes cause undesirable changes of color and flavor of processed potato products. The present study aimed to evaluate some kinetic properties based to optimum pH and reaction temperature, and to determine changes on activity of potato tubers PPD and PDD treated with sprouting suppressors compounds menthol and eugenol. For each treatment, samples were collected in six different periods, before application (day 0) and 10, 20, 30, 40, and 50 days after the treatments to determine the influence of sprout inhibitors on the activity of PPD and PDD. Changes in pH and temperature affected drastically the activity of both enzymes. The use of eugenol and menthol as sprouting suppressors decreased enzymatic activity on the treated tubers compared to control with an inverse relationship between enzymes activity and content of phenolic compounds.