Effect of fruit ripening on content and chemical composition of oil from three oil palm cultivars (Elaeis guineensis Jacq.) grown in Colombia.

A series of physical and chemical changes occur as oil palm fruits ripen in the bunch. We evaluated changes in lipid content in the mesocarp and fruits, and the chemical composition of fatty acids (FA), triacylglycerol (TAG), tocols, and carotenes of the lipids extracted from fruits of three commercial tenera cultivars, namely, Deli×La Mé, Deli×Ekona, and Deli×Avros, planted in two different geographical regions in Colombia, during the ripening process 12, 14, 16, 18, 20, 22, and 24 weeks after anthesis (WAA). It was found that 12 WAA the mesocarp contained less than 6% of total lipids. Oil content increased rapidly after 16 WAA, reaching the maximum oil content of 55% in fresh mesocarp and 47% in fresh fruits at 22 WAA, which was found the optimal time for harvesting. Changes in FA and TAG showed that total polyunsaturated fatty acids (PUFA) and triunsaturated triacylglycerols (TUTAG) decreased, while total saturated fatty acids (SFA) and disaturated triacylglycerols (DSTAG) increased, over the ripening period. Changes in FA were mainly observed in palmitic, oleic, linoleic, and linolenic acids, and in POP, POO, POL, and OLL for the TAGs evaluated. Levels of tocols changed depending on whether they were tocopherols or tocotrienols. In the earliest stages tocopherols were predominant but decreased rapidly from 6600 mg kg(-1) of oil at 14 WAA to 93 mg kg(-1) of oil at 22 WAA. Tocotrienols appeared at the same time as oil synthesis started, and became the main source of total tocols, equivalent to 87% in total lipids extracted.

Diagnóstico de la mecanización del cultivo de la palma de aceite en Colombia / Diagnostic of the mechanization of oil palm crop in Colombia

Con el fin de avanzar en el programa de investigación en mecanización del cultivo de palma de aceite, se seleccionaron plantaciones en cada una de las zonas palmeras de Colombia (Oriental, Central, Occidental y Norte), las cuales debían cumplir con las siguientes características: plantación de tamaño grande (> 500 ha) y algún grado de mecanización en ciertas actividades del proceso productivo. Una vez seleccionadas, se realizaron visitas guiadas por los directores agronómicos o por sus asistentes en cada plantación, se tomó un registro fotográfico y se diligenció el instrumento o encuesta relacionada con las líneas de investigación definidas con anticipación; se hizo énfasis en los equipos utilizados, la frecuencia relativa de las tecnologías y los rendimientos de las labores mecanizadas. Este estudio concluye que existe gran dependencia de mano de obra y bajos rendimientos en las diferentes labores, lo cual afecta directamente los costos de producción.

To advance the research agenda in the mechanization of oil palm production, some plantations were selected in each of the palm growing regions of Colombia (East, Central, West and North). These plantations had to meet the following criteria: large plantation (> 500 ha) and with some degree of mechanization in certain activities of the productive process. Once selected, visits guided by agronomic managers, or their assistants, were conducted in each plantation; a photographic record was taken and a survey form related to previously defined research lines was filled out. Emphasis was placed on the equipment used, the relative frequency of the technologies and the performance of the mechanized operations. This study concludes that there is a heavy reliance on manual labor and poor labor performance, which directly affect production costs.

La mecanización del cultivo de palma de aceite / The mechanization of oil palm crop

El cultivo de palma de aceite ha presentado en los últimos años un notable crecimiento y hay estudios que sugieren la existencia de zonas sin restricciones o con restricciones moderadas donde podría seguir creciendo. Sin embargo, ello presenta, entre muchos otros, problemas de escasez de mano de obra, que en países como Malasia se han enfrentado con la mecanización. En Colombia, en cambio, es un área que apenas empieza a ser investigada. Este artículo presenta una revisión del estado del arte sobre algunos aspectos relacionados con la mecanización agrícola, especialmente en el cultivo de palma de aceite en labores que requieren alta mano de obra como son: transporte interno de racimos de fruta fresca, aplicación de fertilizantes, control de malezas y corte de racimos.

Oil palm crop has been consistently growing in the last years; and according to some studies there are regions without restrictions or with mild restrictions through which oil palm planted area could expand. However, crop expansion in these regions must face, among others, labor shortage issues. Mechanization is an alternative to face this problem in countries such as Malaysia. However, this is a filed in which oil palm research has just begun in Colombia. This paper shows a review over some aspects related to agricultural mechanization, especially on oil palm cultivation in activities that are labor-demanding such as internal fresh fruit bunch handling and transport, fertilizer application, weed control and harvest.

Presión estática ejercida al suelo por sistemas para transporte interno de racimos de fruta fresca en palma de aceite / Static pressure exerted on the ground by internal transport systems for oil palm fresh fruit bunches

La presión estática es uno de los factores que afectan en forma directa la degradación mecánica en suelos; cambian propiedades físicas como densidad aparente, resistencia a la penetración, porosidad e infiltración, entre otras. En este suceso intervienen diversas causas, como por ejemplo la formación de suelos, los cambios en contenido de humedad, la introducción de animales de tiro o cargue, la velocidad de tránsito y el peso de los equipos. En esta investigación se identificaron inicialmente las características técnicas de los sistemas, con el objeto de que las mismas contribuyeran a determinar el área de contacto neumático/suelo y pezuña/suelo, en sistemas mecanizados y tradicionales, respectivamente. Entre esas características se encuentran el peso de los sistemas, la capacidad máxima de carga de racimos de fruta fresca (rff) y la huella dejada por los animales de tiro. Se encontró que la presión estática ejercida por los animales es comparable con la de los sistemas mecanizados, y ambos fueron superados únicamente por un sistema que utiliza como fuente de potencia un tractor de 65 hp; además, se observaron los beneficios de utilizar neumáticos tipo avión en los sistemas mecanizados.

Static pressure is one of the factors directly affecting soil mechanical degradation. It changes physical properties such as apparent density, penetration resistance, porosity, and infiltration, among others. There are many causes and interactions involved in this degradation, some of the most important are soil genesis, humidity content changes, animal usage on throw and loading, transit speed, equipment weight, etc. In the present research, technical characteristics of the systems, important for tire contact area/soil and hoof/soil determination on traditional and mechanized systems were investigated. The results show that static pressure caused by animals is comparable to that of the mechanized systems. Only the static pressure of a 65 hp tractor was higher than that produced by animals. Also it was possible to see the advantages of the airplane-type tires on mechanized systems.

Efecto de sistemas de renovación en la producción de palma de aceite en la Zona Norte de Colombia / Effect of the renovation system on oil palm yield in the Northern Region of Colombia

Cerca del 11% del área sembrada en palma de aceite en Colombia tiene una edad superior a los 25 años y ha finalizado su ciclo económico, por lo cual debe ser renovada. La práctica de renovación es costosa y afecta el flujo de caja de las empresas, debido al período improductivo del cultivo joven en las primeras etapas. Con el fin de disminuir este impacto económico se han diseñado diferentes métodos de renovación que afectan de manera diferencial la fisiología del cultivo joven, especialmente por el sombreamiento causado por las palmas viejas. Este artículo presenta resultados del seguimiento, durante cinco años, de variables fisiológicas y de producción de palmas en siembras nuevas con diferentes grados de interferencia del cultivo viejo. Se evaluaron sistemas sin interferencia del cultivo viejo (remoción completa), con interferencia por estípites del cultivo viejo en el suelo (apilar), con diferentes grados de interferencia por sombreamiento causado por la permanencia de diversos porcentajes de palmas del cultivo viejo sin erradicar, y entre siembra de la siembra nueva (entre siembra con erradicación 50% a los 12 meses y 50% restante a los 18 ó 24 meses; entre siembra sin erradicación por 36 meses con uso de podas). Los registros de producción muestran que las palmas del cultivo viejo sin erradicar influyeron negativamente en el proceso productivo de las palmas de la siembra nueva; se presentaron reducciones hasta del 44,7% en la producción de rff respecto al tratamiento apilar. La producción de la siembra nueva en el tratamiento de apilar presentó diferencias estadísticas con los demás tratamientos, y fue la mejor para las variables área y peso seco foliar, altura y producción.

About 11% of the area planted to oil palm in Colombia is older than 25 years and has completed its economic cycle; therefore, it must be replanted. Replacing old trees and replanting is a costly undertaking and it affects the cash flow of the plantations because of the unproductive period of young palms in the early stages. To lessen this economic impact, different replanting methods have been designed that differentially affect the physiology of the young crop, especially by the shading caused by the old palms. This paper presents the results of a 5-year monitoring of physiological and production variables of new palm plantings, with different degrees of interference by the old crop. Various systems were evaluated: without interference from the old crop (complete removal), with interference by felled old trunks on the floor (stacked), with different degrees of interference by shading caused by various percentages of standing old palms, intercropping with old palms (intercropping with 50% removal at 12 months and the remaining 50% at 18 or 24 months, intercropping without removal for 36 months with use of pruning). Production records show that old palms not removed adversely affected the production process of the new planting. Reductions of up to 44.7% in FFB production were found, compared to the stacking treatment. The production of the new planting under stacking conditions showed statistically significant differences with other treatments, and was the best treatment in terms of leaf area and dry weight, height and production variables.

Investigations into the role of the plastidial peptide methionine sulfoxide reductase in response to oxidative stress in Arabidopsis.

Peptidyl Met residues are readily oxidized by reactive oxygen species to form Met sulfoxide. The enzyme peptide Met sulfoxide reductase (PMSR) catalyzes the reduction of Met sulfoxides back to Met. In doing so, PMSR is proposed to act as a last-chance antioxidant, repairing proteins damaged from oxidative stress. To assess the role of this enzyme in plants, we generated multiple transgenic lines with altered expression levels of the plastid form of PMSR (PMSR4). In transgenic plants, PMSR4 expression ranged from 95% to 40% (antisense) and more than 600% (overexpressing lines) of wild-type plants. Under optimal growing conditions, there is no effect of the transgene on the phenotype of the plants. When exposed to different oxidative stress conditions-methyl viologen, ozone, and high light-differences were observed in the rate of photosynthesis, the maximum quantum yield (Fv/Fm ratio), and the Met sulfoxide content of the isolated chloroplast. Plants that overexpressed PMSR4 were more resistant to oxidative damage localized in the chloroplast, and plants that underexpressed PMSR4 were more susceptible. The Met sulfoxide levels in proteins of the soluble fraction of chloroplasts were increased by methyl viologen and ozone, but not by high-light treatment. Under stress conditions, the overexpression of PMSR4 lowered the sulfoxide content and underexpression resulted in an overall increase in content.