Danilo Aros

Volatile emissions of scented Alstroemeria genotypes are dominated by terpenes, and a myrcene synthase gene is highly expressed in scented Alstroemeria flowers

Native to South America, Alstroemeria flowers are known for their colourful tepals, and Alstroemeria hybrids are an important cut flower. However, in common with many commercial cut flowers, virtually all the commercial Alstroemeria hybrids are not scented. The cultivar ‘Sweet Laura’ is one of very few scented commercial Alstroemeria hybrids. Characterization of the volatile emission profile of these cut flowers revealed three major terpene compounds: (E)-caryophyllene, humulene (also known as α-caryophyllene), an ocimene-like compound, and several minor peaks, one of which was identified as myrcene. The profile is completely different from that of the parental scented species A. caryophyllaea. Volatile emission peaked at anthesis in both scented genotypes, coincident in cv. ‘Sweet Laura’ with the maximal expression of a putative terpene synthase gene AlstroTPS. This gene was preferentially expressed in floral tissues of both cv. ‘Sweet Laura’ and A. caryophyllaea. Characterization of the AlstroTPS gene structure from cv. ‘Sweet Laura’ placed it as a member of the class III terpene synthases, and the predicted 567 amino acid sequence placed it into the subfamily TPS-b. The conserved sequences R28(R)X8W and D321DXXD are the putative Mg2+-binding sites, and in vitro assay of AlstroTPS expressed in Escherichia coli revealed that the encoded enzyme possesses myrcene synthase activity, consistent with a role for AlstroTPS in scent production in Alstroemeria cv. ‘Sweet Laura’ flowers.

Postharvest Sensory and Phenolic Characterization of ’Elegant Lady’ and ’Carson’ Peaches

La demanda de fruta de alta calidad se ha incrementado junto con la necesidad de asegurar este atributo a los consumidores. En este sentido, el objetivo de este estudio fue caracterizar durazno (Prunus persica (L.) Batsch) de variedades de pulpa fundente (‘Elegant Lady’) y no fundente (‘Carson’), considerando su contribucion de compuestos bioactivos y su calidad sensorial en fruta madura a cosecha y luego de un periodo prolongado de almacenamiento refrigerado. Las variedades fueron evaluadas a la cosecha (F0) y luego de 30 d de almacenamiento refrigerado (F30), ademas de un periodo de maduracion a 20 oC en F0 y F30 (R0 y R30, respectivamente). Se registro el peso del fruto, firmeza de pulpa, contenido de solidos solubles (CSS), acidez titulable (TA), y color de fondo (Hue) en cada tratamiento. Ademas se cuantificaron los fenoles totales y se realizo una caracterizacion fenolica de ambas variedades a traves de un HPLC (High-Performance Liquid Chromatography) para detectar los principales compuestos fenolicos de bajo peso molecular presentes en el fruto. Finalmente un panel entrenado evaluo los principales parametros sensoriales en R0 y R30. El contenido de fenoles totales no vario significativamente como resultado del almacenamiento en frio, las diferencias observadas solo fueron atribuibles a los genotipos. Se detectaron 15 y 12 compuestos fenolicos de bajo peso molecular en ‘Elegant Lady’ y ‘Carson’, respectivamente, siendo catequina el principal compuesto encontrado en ambos cultivares, aunque en mayores concentraciones en ‘Elegant Lady’. En la caracterizacion fenolica, ‘Elegant Lady’ aparecio mas estrechamente relacionada con los flavonoides que ‘Carson’. Despues de 30 d de almacenamiento en frio, ‘Elegant Lady’ no fue aceptable para consumo debido a la aparicion de desordenes fisiologicos como harinosidad, mientras que ‘Carson’ mostro una puntuacion promedio dentro del rango de aceptabilidad.

Does the maturity at harvest affect quality and sensory attributes of peaches and nectarines

Abstract Fruit quality has been described as a property that depends on many factors. Harvest time is one such factor, described as negatively affecting the fruit quality of peaches and nectarines when carried out at early stages of maturity. In order to assess this, fruit from peach cultivars ‘2B40’, ‘Elegant Lady’ and ‘Sweet September’, and nectarine cultivars ‘Antares’ and ‘5A29’ were harvested at three maturity levels, based on ground skin colour (M1 = green-yellow, M2 = pale yellow and M3 = yellow), and evaluated at harvest and after a ripening period. Evaluations included instrumental characterization, sensorial analysis and e-nose. Flesh firmness was the parameter that best segregated the three maturity levels. Sensorial attributes and acceptability did not show differences between stages of maturity, while e-nose data clustered M1, M2 and M3 into different groups. These results suggest that the maturity level at harvest, within the range evaluated in this research, does not affect the sensory quality of the product, in spite of the aroma assessed with an e-nose revealing differences among them.

Modified atmosphere packaging as a method to extend postharvest life of tulip flowers

ABSTRACT Tulip is one of the most important cut flowers in the world market and abscission of the tepals is this species’ most common symptom during vase life. To prevent these symptoms and extend postharvest life, passive and active modified atmosphere packaging (MAP) was applied at 0°C. Respiratory rate (CO2 Kg−1h−1), ethylene production (µL kg−1h−1) and concentration of CO2 and O2 (%) inside the packaging were evaluated during storage, while fresh weight loss (FWL) (%) and vase life (days) were assessed. Flowers stored using MAP performed significantly better than conventional packaging. A lower FWL (only up to 0.3%) was observed on MAP while FWL was as high as 18 to 21% for conventional packaging after 20 and 31 days, respectively. Vase life was 5.7 and 6.0 days for active and passive MAP, respectively compared to 3.3 days for conventional packing. Thus, MAP successfully extended postharvest life of tulip flowers.

An efficient method for in vitro propagation of Alstroemeria pallida Graham rhizomes

CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 76(1) JANUARY-MARCH 2016 7 7 Alstroemeria is a genus native to South America and commercially has commonly been propagated vegetatively by rhizome division, with low efficiency, high time consumption and a high risk of virus dissemination. In vitro propagation has several advantages, particularly in terms of efficiency and has been applied to the micropropagation of alstroemeria. This study aims to describe an efficient method for the in vitro propagation of Alstroemeria pallida Graham, a Chilean native species of high ornamental value. Concentrations of agar (0.0, 3.5 and 7.0 g L) and 6-benzylaminopurine (BAP) (0.0, 0.5, 1.0 and 2.0 mg L) were supplemented with MS culture medium to evaluate explant weight (g), rhizome length (cm), shoot length (cm) and proliferation rate. The highest explant weight was observed in rhizomes grown in culture medium supplemented with 3.5 g·L agar (3.79 g), and treatments using 2.0 g L BAP showed the highest weight increase (3.33 g) after 8 wk. The proliferation rate rose with increasing concentrations of BAP, whereas low concentrations of BAP promoted longer shoots. An efficient method for in vitro propagation of A. pallida rhizomes was described, which could be useful for its conservation, domestication and further breeding.

Role of flower preservative solutions during postharvest of Hydrangea macrophylla cv. Bela

Hydrangea macrophylla (hydrangea) is widely used as an ornamental plant and cut flower due to its inflorescence, which is composed of colored bracts. As cut flowers, hydrangeas show a postharvest life of up to 1 month at 2 °C, but little is known about their postharvest life during air shipment. This study was aimed at evaluating the effect of Triton X-100 (surfactant) and ClO2 (biocide) during an air shipment simulation of hydrangea harvested at two floral stages of development: fresh and antique. Vase life, fresh weight loss (FWL) and solution uptake were evaluated after an air shipment simulation. Furthermore, bacterial counts and microscopic observation of the bracts were performed in order to understand the water relations of hydrangea during vase life. The longest vase life was observed in antique hydrangeas, and the control (deionized water) was the best treatment, reaching up to 32.7 days in this floral stage. FWL was faster when using Triton X-100 (3.83 days to lose 20% of FW) compared to deionized water (8.75 days). However, this flower preservative was efficient at promoting solution uptake (31.96 mL). Bacterial plugging did not appear to occur considering that the high presence of microorganisms counted did not affect solution uptake or vase life. The presence of stomata on the bracts seems to be crucial for the dehydration of the inflorescence, a problem that was not solved by the higher water uptake promoted by Triton X-100. Thus, deionized water was the best treatment, and the effect of flower preservatives in order to extend vase life of hydrangea cut flowers was insignificant. Hydrangea macrophylla (hortensia) es ampliamente utilizada como planta ornamental y flor de corte debido a su inflorescencia compuesta por bracteas coloreadas. Como flor de corte, las hortensias presentan una vida en postcosecha de hasta un mes a 2°C pero poco se conoce sobre su postcosecha durante un envio aereo. Este estudio tuvo como objetivo evaluar el efecto de Triton X-100 (surfactante) y ClO2 (biocida) durante una simulacion de envio aereo de hortensias cosechadas en dos estados de desarrollo floral: ‘fresh’ y ‘antique’. Durante esta simulacion aerea se evaluo vida en florero, perdida de peso fresco y captura de solucion. Ademas, se realizo un conteo de bacterias y observaciones microscopicas de las bracteas para entender las relaciones hidricas durante la vida en florero. La vida en florero mas prolongada se observo en hortensias ‘antique’ y el control (agua deionizada) fue el mejor tratamiento alcanzando hasta 32,7 dias en este estado floral. La perdida de peso fresco fue mas rapida cuando se utilizo Triton X-100 (3,83 dias para perder 20% of peso fresco) en comparacion con el agua deionizada (8,75 dias). Sin embargo, este preservante floral fue eficiente en promover la captura de solucion (31,96 mL). El taponamiento por bacteria no fue sugerido para esta especie considerando que la alta presencia de microorganismos contabilizados no afecto la captura de solucion y la vida en florero. La presencia de estomas en las bracteas parece ser crucial para la deshidratacion de la inflorescencia, problema que no fue resuelto por la mayor captura de solucion promovido por el Triton X-100. Agua deionizada fue el mejor tratamiento y el efecto de preservantes florales fue insignificante para extender la vida en florero de flores de hortensia.

Rol de las soluciones preservantes de flores durante la postcosecha de Hydrangea macrophylla cv. Bela

Hydrangea macrophylla (hydrangea) is widely used as an ornamental plant and cut flower due to its inflorescence, which is composed of colored bracts. As cut flowers, hydrangeas show a postharvest life of up to 1 month at 2 °C, but little is known about their postharvest life during air shipment. This study was aimed at evaluating the effect of Triton X-100 (surfactant) and ClO2 (biocide) during an air shipment simulation of hydrangea harvested at two floral stages of development: fresh and antique. Vase life, fresh weight loss (FWL) and solution uptake were evaluated after an air shipment simulation. Furthermore, bacterial counts and microscopic observation of the bracts were performed in order to understand the water relations of hydrangea during vase life. The longest vase life was observed in antique hydrangeas, and the control (deionized water) was the best treatment, reaching up to 32.7 days in this floral stage. FWL was faster when using Triton X-100 (3.83 days to lose 20% of FW) compared to deionized water (8.75 days). However, this flower preservative was efficient at promoting solution uptake (31.96 mL). Bacterial plugging did not appear to occur considering that the high presence of microorganisms counted did not affect solution uptake or vase life. The presence of stomata on the bracts seems to be crucial for the dehydration of the inflorescence, a problem that was not solved by the higher water uptake promoted by Triton X-100. Thus, deionized water was the best treatment, and the effect of flower preservatives in order to extend vase life of hydrangea cut flowers was insignificant. Hydrangea macrophylla (hortensia) es ampliamente utilizada como planta ornamental y flor de corte debido a su inflorescencia compuesta por bracteas coloreadas. Como flor de corte, las hortensias presentan una vida en postcosecha de hasta un mes a 2°C pero poco se conoce sobre su postcosecha durante un envio aereo. Este estudio tuvo como objetivo evaluar el efecto de Triton X-100 (surfactante) y ClO2 (biocida) durante una simulacion de envio aereo de hortensias cosechadas en dos estados de desarrollo floral: ‘fresh’ y ‘antique’. Durante esta simulacion aerea se evaluo vida en florero, perdida de peso fresco y captura de solucion. Ademas, se realizo un conteo de bacterias y observaciones microscopicas de las bracteas para entender las relaciones hidricas durante la vida en florero. La vida en florero mas prolongada se observo en hortensias ‘antique’ y el control (agua deionizada) fue el mejor tratamiento alcanzando hasta 32,7 dias en este estado floral. La perdida de peso fresco fue mas rapida cuando se utilizo Triton X-100 (3,83 dias para perder 20% of peso fresco) en comparacion con el agua deionizada (8,75 dias). Sin embargo, este preservante floral fue eficiente en promover la captura de solucion (31,96 mL). El taponamiento por bacteria no fue sugerido para esta especie considerando que la alta presencia de microorganismos contabilizados no afecto la captura de solucion y la vida en florero. La presencia de estomas en las bracteas parece ser crucial para la deshidratacion de la inflorescencia, problema que no fue resuelto por la mayor captura de solucion promovido por el Triton X-100. Agua deionizada fue el mejor tratamiento y el efecto de preservantes florales fue insignificante para extender la vida en florero de flores de hortensia.

Floral scent evaluation in alstroemeria through gas chromatography-mass spectrometry (GC-MS) and semiquantitative RT-PCR

Alstroemeria is a member of the Alstroemeriaceae family, originally from South America, and is an important cut flower in the European market. Breeding programmes have developed new Alstroemeria varieties focused on aesthetic characteristics and vase life longevity, but little is known about the scent trait. Two scented (A. ‘Sweet Laura’ and A. caryophyllea) and two unscented Alstroemeria (A. ‘Rebecca’ and A. ‘Samora’) cultivars were analysed. Stages of development and senescence were evaluated based on changes in morphology. Scent production was assessed during this development and the stage with maximal scent production was identified. GC-MS analysis was tested to establish whether it could be used as a reliable system to evaluate floral scent of Alstroemeria. Sesquiterpenes were the main group of volatile compounds found in A. ‘Sweet Laura’, while a monoterpene was the only compound identified in A. caryophyllea. A partial cDNA homologous to Quercus ilex mRNA for a putative chloroplast terpene synthase was identified from subtractive cDNA libraries (ALSTER) in the ‘Rebecca’ cultivar. Evaluation of vegetative and reproductive organs showed ALSTER expression as flower-specific for A. caryophyllea and florally enhanced in A. ‘Sweet Laura’. The possible role of this gene is discussed.