Physiological responses and production of mini-watermelon irrigated with reject brine in hydroponic cultivation with substrates.

The scarce availability of good quality water for irrigation in semi-arid regions leads to the reuse of waters, such as reject brine. Associated with this, the use of alternatives, such as hydroponic cultivation in substrates suitable for the development of profitable crops, such as watermelon, a species considered moderately sensitive to salinity, will allow new opportunities for communities assisted by desalination plants. An experiment was conducted in a plastic greenhouse to evaluate the growth, physiological responses, yield, and fruit quality of 'Sugar Baby' mini-watermelon cultivated in a hydroponic system with reject brine from desalination plants and different substrates. The experimental design was randomized blocks, with treatments arranged in a 5 × 4 factorial scheme, corresponding to five mixtures of reject brine (9.50 dS m-1) and tap water (0.54 dS m-1) applied to mini-watermelon plants, in an open hydroponic system, with four types of substrate and four replicates, with two plants per plot. Mini-watermelon plants grown in coconut fiber substrate showed the best growth and production. On the other hand, washed sand was the substrate that most hampered the development of plants in all mixtures. The use of reject brine to prepare the nutrient solution reduced the growth and production of mini-watermelon, mainly in mixtures with salinity above 4.00 dS m-1. The changes in gas exchange caused by salt stress in mini-watermelon were of stomatal nature. Mini-watermelon has high energy stability under conditions of salt stress.

Bioactive compounds and antioxidant potential fruit of Ximenia americana L.

The caatinga ecoregion in northeast Brazil presents a wide variety in plant species. However, the potential of these species as a source of energy, carbohydrates, vitamins, minerals and bioactive properties beneficial to health is still unknown. Among these species we can find the wild plum (Ximenia americana). Due to its various phytotherapeutic properties and absence of studies on the chemical composition of the fruit this article aimed to evaluate the bioactive compounds and antioxidant potential of the X. americana in different stages of maturation. The fruits of X. americana showed considerable amounts of bioactive compounds, as well as antioxidant activity and antioxidant enzymes. The fruits at green maturity stage showed higher content of yellow flavonoids (22.07 mg/100g), anthocyanins (1.92 mg/100 g), polyphenols (3051.62 mg/100 g), starch (4.22%), antioxidant activity (489.40 g fruit/g DPPH and 198.77 µmol Trolox/g) and activity of antioxidant enzymes; the antioxidant activity allocated to the fruit was shown to be related to the contents of extractable polyphenols, yellow flavonoids, total anthocyanins and antioxidant enzymes.

Qualidade pós-colheita da banana 'Prata Catarina' submetida a diferentes danos mecânicos e armazenamento refrigerado / Postharvest quality of 'Prata Catarina' banana submitted to different mechanical damages and refrigerated storage

Objetivou-se avaliar o efeito dos danos mecânicos provocados por impacto, corte e abrasão sobre a qualidade de banana 'Prata Catarina', submetida ao armazenamento refrigerado (14°C ±1ºC e 84% ±5% de UR durante 21 dias). Os frutos foram provenientes de um pomar comercial, localizado no município de Limoeiro do Norte-CE. O experimento foi instalado em delineamento inteiramente ao acaso, no esquema de parcelas subdivididas no tempo, tendo-se, nas parcelas, as amostragens ao longo do tempo e, nas subparcelas, os quatro tratamentos: testemunha ou ausência de dano mecânico (T1), impacto (T2), abrasão (T3) e corte (T4), com quatro repetições de dois frutos cada. Os danos por impacto e abrasão foram os que proporcionaram maior velocidade de amadurecimento, sendo que o dano por impacto proporcionou maior atividade da enzima polifenoloxidase. As bananas 'Prata Catarina' que não sofreram danos podem ser comercializadas por até 21 dias de armazenamento (14°C ± 1ºC e 84% ±5% UR), sem perda da qualidade.

The aim of this study was to evaluate the effect of mechanical damages caused by impact, cut and abrasion on the quality of 'Prata Catarina' banana subjected to cold storage (14°C±1°C and 84%±5% RH for 21 days). The fruits were from a commercial orchard in the city of Limoeiro do Norte-CE. The experiment was conducted in a completely randomized design in split plot in time, taking up the samples in portions over time and in the subplots the four treatments: control or absence of mechanical damage (T1), impact (T2), abrasion (T3) and cut (T4), with 4 replicates of 2 fruits. Damages by impact and abrasion were the ones which provided the highest speed of ripening, and the damage caused by impact provided greater polyphenoloxidase enzyme activity. 'Prata Catarina' bananas that suffered no damage can be marketed until 21 days of storage (14°C±1°C and RH 84%±5%), without loss of quality.