Effect of applications of 1-MCP and ethylene on the ripening and degreening process of banana fruits cv. Barranquillo

The banana cv. Barranquillo (Musa acuminata, AAA, 'Gros Michel') is a highly desired fruit because of its productive potential and organoleptic quality but various aspects of the ripening process are unknown. The objective of this research was to evaluate the effect of applications of 1-MCP and ethylene on the ripening and degreening process. Two experiments were carried out at room temperature with fruits harvested at commercial maturity. The first four treatments evaluated maturation: control, ethylene, 1-MCP, and 1-MCP + ethylene. In the second experiment, different concentrations of ethylene based on ethephon (0, 100, 500 and 1000 µL L-1) were evaluated. The fruits treated with 1-MCP decreased the ripening process, and 1-MCP was a good alternative for conserving the fruits; the ethylene had opposite results. The color index of the skin, weight loss, firmness, total soluble solids, and maturity ratio had changes associated with the presence of ethylene. In the second experiment, the ethylene applications between 100 and 500 µL L-1 sufficiently stimulated degreening but accelerated the ripening process.

El banano cv. Barranquillo (Musa acuminata, AAA, 'Gros Michel') es un fruto muy apetecido por su potencial productivo y calidad organoléptica, pero se desconocen varios aspectos del proceso de maduración. El objetivo de esta investigación fue evaluar el efecto de la aplicación de 1-MCP y etileno en la maduración y en el proceso de desverdizado. Se realizaron dos experimentos a temperatura ambiente y con frutos cosechados en madurez comercial; en el primero, se evaluaron cuatro tratamientos, para entender la regulación de la maduración, estos fueron: testigo, etileno, 1-MCP y 1-MCP+etileno. En el segundo experimento, se evaluaron diferentes concentraciones de etileno, a base de etefon (0, 100, 500 y 1000 µL L-1). Los frutos tratados con 1- MCP presentaron una disminución en el proceso de maduración, por tanto, el 1-MCP, se convierte en una buena alternativa de conservación, mientras que con etileno, el proceso fue opuesto. Se evidenció que el índice de color de la epidermis, la pérdida de peso, la firmeza, los sólidos solubles totales y la relación de madurez se consideran cambios asociados a la presencia de etileno. En el segundo experimento se encontró que, aplicaciones de etileno entre 100 y 500µL L-1, se consideran suficientes para estimular el desverdizado, pero aceleran el proceso de maduración.

Phenological and physicochemical changes during fruit development in two peach cultivars in the high tropics / Cambios fenológicos y fisicoquímicos durante el desarrollo del fruto en dos cultivares de duraznero en trópico alto

ABSTRACT Several aspects of the development of the peach fruit under tropical conditions are unknown, this information allows agronomic practices to be carried out with technical criteria. Therefore, the objective was to determine the different changes and phenological changes of peach fruit depending on the Growing Degree Days (GDD) in the varieties 'Dorado' and 'Rubidoux', grown in the Colombian high tropics. This study randomly selected 51 trees and 100 flowers per plant that were in full flowering for sampling every 15 days until harvest to determine physical variables such as firmness, color index of the epidermis and pulp, and chemical properties such as soluble solids, titratable acidity, and respiratory rate. From full bloom to harvest, the Dorado and Rubidoux varieties took 1081.8 GDD (153 days) and 1667.1 GDD (205 days) respectively. The firmness increased in the two cultivars during phase 1 of development, then decreased until harvest. The color index of the epidermis and pulp increased during ripening, indicating yellow tones in the two varieties. The soluble solids increased continuously, with final values of 15.9 ± 0.9 and 15.5 ± 0.3 °Brix. The acidity increased during phase 2 and then decreased during ripening. The respiratory rate decreased between phase 1 and 3, with an increase in phase 2, which is related to the lignification of the endocarp in the two cultivars. These results contribute to the understanding of the development of the two peach cultivars under tropical conditions.

RESUMEN Se desconocen varios aspectos del desarrollo del fruto de duraznero en condiciones tropicales, información que permite realizar labores agronómicas con criterio técnico, por tanto, el objetivo fue determinar los diferentes cambios fisicoquímicos y fenológicos del fruto de durazno, en función del tiempo térmico, de las variedades 'Dorado' y 'Rubidoux', cultivados en zonas de trópico alto colombiano. Se seleccionaron al azar 51 árboles y 100 flores/planta, en estado de plena floración. Cada 15 días y hasta la cosecha, se hicieron mediciones de la firmeza, el índice de color de epidermis y pulpa, los sólidos solubles, la acidez titulable y la tasa respiratoria. De plena floración a cosecha, las variedades Dorado y Rubidoux tardaron 1081,8 GDC (153 días) y 1667,1 GDC (205 días), respectivamente. La firmeza presentó un incremento en los dos cultivares durante la fase 1 de desarrollo, luego disminuyó hasta la cosecha. El índice de color de epidermis y pulpa aumentó durante la maduración, con tonalidades amarillas, en las dos variedades. Los sólidos solubles incrementaron de forma continua y en los dos cultivares, con valores finales de 15,9 ± 0,9 y 15,5 ± 0,3 °Brix. La acidez mostró un incremento durante la fase 2 y luego disminuyó durante la maduración. La tasa respiratoria decreció entre la fase 1 y 3, con un incremento en la fase 2, relacionado con la lignificación del endocarpio, en los dos cultivares. Estos resultados contribuyen al entendimiento del desarrollo de los dos cultivares de durazno, bajo condiciones tropicales.

Photosynthetic performance and leaf water potential of gulupa (Passiflora edulis Sims, Passifloraceae) in the reproductive phase in three locations in the colombian andes / Desempeño fotosintético y potencial hídrico foliar de gulupa (Passiflora edulis Sims, Passifloraceae) en estado reproductivo en tres localidades de los Andes colombianos

Gulupa, Passiflora edulis Sims (Passifloraceae), is an important fruit due to its organoleptic and nutritional characteristics and its demand in the international market; however, very few studies have been conducted for studying its Ecophysiology. Until now, this crop has spread throughout the country through empirical knowledge without data that indicate the zones that are more suitable for its cultivation. For this reason, gas exchange, chlorophyll fluorescence (photosystem II operating efficiency and maximum quantum efficiency of photosystem II photochemistry) and leaf water potential were measured in three different locations of Cundinamarca department (Chia [2610 m a.s.l., 14 °C], Granada [2230 m a.s.l., 15 °C] and Tena [2090 m a.s.l., 17 °C]), whose climatic conditions were monitored with meteorological stations to evaluate the physiologic performance in each location related to the environmental factors. The results indicate that, even though the photosynthetic capacity was similar and high in Granada and Tena, the water status of the plant, the stomatal control of water loss and recovery of photosystems during the night were more efficient in Granada (p < 0.05). In Tena, the small differences between day and night temperature, humidity, and vapor pressure deficit (VPD) would limited the night water recovery in the plants. Meanwhile, in Chia, the increase of VPD during the day and the low temperatures would decreased the water potential both during the day and during the night, as well as the recovery of photosystem II. Therefore, in conclusion the climatic conditions similar to Granada, which are 18/13 °C day/night, a VPD close to 0.5 KPa, and radiation that did not exceed 1000 μmol photons/m²s favored the good physiological performance of gulupa.

La gulupa, Passiflora edulis Sims (Passifloraceae) es un frutal importante debido a sus características organolépticas, nutricionales y su demanda en el mercado internacional; sin embargo, existen muy pocos estudios relacionados con su ecofisiología. Hasta el momento, el cultivo se ha extendido a través del país por medio de conocimiento empírico sin tener datos que sustenten las zonas más apropiadas para su cultivo. Por esta razón, en el presente estudio se midió el intercambio de gases, la fluorescencia de la clorofila (factor de eficiencia del fotosistema II y eficiencia cuántica fotoquímica máxima del fotosistema II) y el potencial hídrico foliar en tres localidades diferentes del departamento de Cundinamarca (Chía [2610 m s.n.m., 14 °C], Granada [2230 m s.n.m., 15 °C] y Tena [2090 m s.n.m., 17 °C]), cuyas condiciones climáticas fueron monitoreadas con estaciones meteorológicas para evaluar el desempeño fisiológico en cada localidad y relacionarlo con los factores ambientales. Los resultados indican que aunque la capacidad fotosintética fue alta y similar en Granada y Tena, el estado hídrico de la planta, el control estomático de la pérdida de agua y la recuperación de los fotosistemas durante la noche fueron más eficientes en Granada (p < 0,05). En Tena, la estrecha diferencia entre los valores día/noche de temperatura, humedad y déficit de presión de vapor (DPV) limitarían la recuperación hídrica de la planta, mientras que en Chía el aumento de DPV en el día, y las bajas temperaturas disminuirían el potencial hídrico, tanto durante el día como durante la noche, así como la recuperación del fotosistema II. Por tanto, en conclusión, condiciones climáticas cercanas a las de Granada; 18/13 °C día/noche, DPV de 0,5 KPa, y una radiación que no exceda los 1000 μmol fotones/ m²s favorecen el buen desempeño de la planta.

Características fisiológicas de feijoeiro em competição com plantas daninhas / Physiological characteristics of beans in competition with weed

A competição das plantas daninhas com as culturas reduz o fornecimento de alguns recursos para as espécies, ocasionando deficiências que culminam em alterações nas características fisiológicas relacionadas à fotossíntese, como a deficiência hídrica e nutricional e a baixa qualidade ou quantidade de luminosidade. Assim, objetivou-se com o presente trabalho avaliar o efeito da competição e do manejo de plantas daninhas nas características fisiológicas de plantas de feijoeiro. Utilizou-se delineamento em blocos ao acaso com quatro repetições. Os tratamentos foram: plantas de feijoeiro submetidas à aplicação da mistura de herbicidas fomesafen+fluazifop-p-butyl (Robust®), cultivadas isoladamente e em competição com capim-marmelada (Brachiaria plantaginea), caruru (Amaranthus hybridus) e picão-preto (Bidens pilosa). As plantas de picão-preto foram as que mais afetam as características fisiológicas do feijoeiro, influenciando negativamente o consumo de CO2, a transpiração, a condutância estomática e principalmente a taxa fotossintética. Estes resultados podem estar relacionados ao fato dessa espécie daninha ser altamente eficiente no uso da água. A mistura de herbicidas fomesafen+fluazifop-p-butyl reduziu a taxa fotossintética do feijoeiro.

The weed competition with crops leads to lower supply of some resources for the species, causing deficiencies that culminate in changes in physiological characteristics related to photosynthesis, such as water deficiency and low nutritional quality or quantity of light. So aim with this study was to evaluate the effect of weed competition and management on physiological characteristics of bean plants. The experimental design comprised randomized blocks with four replications. The treatments were: bean plants subjected to the application of the herbicide mixture fomesafen + fluazifop-p-butyl (Robust ®), grown in isolation, in competition with alexandergrass (Brachiaria plantaginea), pigweed (Amaranthus hybridus) and beggar-ticks (Bidens pilosa). The plants are beggartick that most affect the physiological characteristics of bean, negatively influencing the consumption of CO2, transpiration, stomatal conductance and photosynthetic rate mainly for these results may be related to this photo weed be highly efficient water use. The herbicides mixture fomesafen + fluazifop-p-butyl reduced the photosynthetic rate of the bean plants.

Enzyme expression in indica and japonica rice cultivars under saline stress - doi: 10.4025/actascibiolsci.v34i4.8535

The southern State of Rio Grande do Sul (RS) is the main rice producer in Brazil with a 60% participation of the national production and 86% participation of the region. Rice culture irrigation system is done by flooding, which leads to soil salinization, a major environmental constraint to production since it alters the plants metabolism exposed to this type of stress. The indica cultivar, widely used in RS, has a higher sensitivity to salinity when compared to that of the japonica cultivar in other physiological aspects. Current research analyzes enzymes expression involved in salt-subjected indica and japonica rice cultivars respiration. Oryza sativa L. spp. japonica S.Kato (BRS Bojuru, IAS 12-9 Formosa and Goyakuman) and Oryza sativa L. spp. indica S. Kato (BRS Taim-7, BRS Atalanta and BRS Querencia) were the cultivars employed. Seedlings were transferred to 15 L basins containing 50% Hoagland nutrient solution increased by 0, 25, 50, 75 and 100 mM NaCl, and collected at 14, 28 and 42 days after transfer (DAT). Plant tissues were macerated and placed in eppendorf tubes with Scandálios extractor solution. Electrophoresis was performed in 7% of the polyacrylamide gels in vertical vats. Bands were revealed for the following enzymes systems: esterase, alcohol dehydrogenase, phosphoglucoisomerase, malate dehydrogenase, malic enzyme and alpha amylase. The enzymes expression was

Chemical composition fluctuations in roots of Plumbago scandens L. in relation to floral development

Plumbago scandens L. is a Brazilian tropical/subtropical species that occurs along the coast. Chemically it is mainly represented by naphthoquinones, flavonoids, terpenoids and steroids. The aim of the present work is to study quantitative changes in the root metabolic production of Plumbago scandens during different physiologic developmental stages relative to floration. The results indicated the presence of four substances in the extracts: plumbagin, epi-isoshinanolone, palmitic acid and sitosterol, independent on developmental stage. The naphthoquinone plumbagin has always showed to be the major component of all extracts. Naphthoquinones exhibited their highest content during floration, while the content of the two others components decreased during this stage, revealing an inverse profile. The chemical composition changed depending on the plant requirements.

Plumbago scandens L. é uma espécie brasileira tropical/subtropical que ocorre ao longo da costa. Quimicamente, é principalmente representada por naftoquinonas, flavonóides, terpenóides e esteróides. objetivo do presente trabalho é estudar mudanças quantitativas da produção metabólica nas raízes de Plumbago scandens durante diferentes estágios de desenvolvimento fisiológico, relativos à floração. Os resultados indicaram a presença de quatro substâncias nos extratos: plumbagina, epi-isoshinanolona, ácido palmítico e sitosterol, independente do estágio de desenvolvimento. A naftoquinona plumbagina tem sempre mostrado ser o componente majoritário de todos os extratos. Naftoquinonas exibiram seus maiores conteúdos durante a floração, enquanto o conteúdo dos dois outros componentes decresceu durante este estágio, revelando um perfil inverso. A composição química modificou dependendo das necessidades da planta.

Desfolha em videiras americanas e viníferas na fase de pré-maturação dos frutos / Defoliation of american and vinifera grapevines in the pre ripening of fruits

Foram avaliadas possíveis interferências que a localização da folha removida mediante desfolha em videira apresenta sobre o rendimento e qualidade dos frutos. As cultivares 'Niagara Branca' e 'Concord', ambas Vitis labrusca, e 'Cabernet Sauvignon' e 'Merlot', ambas Vitis vinifera, foram utilizadas em sistema de condução em espaldeira, na safra 2006/2007. O experimento foi conduzido em delineamento de blocos casualizados, com quatro repetições e quatro plantas por parcela, sendo testados 4 tratamentos: T1 (testemunha - sem desfolha), T2 (retirada das folhas localizadas opostas aos cachos), T3 (retirada das folhas do sarmento localizadas abaixo dos cachos) e T4 (retirada das folhas do sarmento localizadas abaixo e opostas aos cachos). As cultivares da espécie Vitis labrusca receberam um tratamento adicional T5, constando na retirada das folhas acima dos cachos. A aplicação dos tratamentos foi realizada na fase de mudança de cor das bagas para as cultivares 'Concord', 'Merlot' e 'Cabernet Sauvignon' e início do amolecimento das bagas para a cultivar 'Niagara Branca'. Avaliaram-se, após a colheita, a produção por planta, a massa dos cachos, os teores de sólidos solúveis (SS), a acidez titulável, (AT) e o pH dos frutos. Observou-se que a desfolha até a altura do cacho não influenciou na quantidade e na qualidade dos frutos. Porém, quando a desfolha foi realizada acima dos cachos, ocorreu um atraso na maturação das uvas americanas. Essa condição implica não ser necessária a desfolha seletiva até a altura dos cachos nas videiras estudadas, quando realizada na fase início de amadurecimento dos frutos.

This study aimed to evaluate the interference that the location of the leaf removed by defolation in grapevine has on fruits quality and yield. Such experiment was performed using Niagara Branca and Concord, both Vitis labrusca, and Cabernet Sauvignon e Merlot, both Vitis vinifera, trained in a unilateral cordon system during the 2006/2007 harvesting. The experiment was disposed in a randomized block design, with four replications and four plants per plot. The following treatments were tested: T1 (no defoliation), T2 (removal of leaves located in the opposite side of the grapes), T3 (removal of leaves located under the grapes) and T4 (removal of leaves located under and in the opposite side of the grapes). The Vitis labrusca received an additional treatment (T5) consisting of leaves removed above the grapes. These treatments were applied during the change of berries color for Concord, Cabernet Sauvignon and Merlot grapes and in the beginning of berries softening for Niagara Branca grape. After the harvesting, the grapevine production, cluster weight, total soluble solids, total titratable acidity and pH were evaluated. It was observed that the defoliation until the grapes height did not influence the quantity and quality of grapes. However, when the defoliation was carried out above the clusters, there was a delay in the maturation of american grapes. This condition shows that is not necessary a selective desfolation until the clusters height on grapevines, when it is realized during the initial fruit ripening phase.