Effect of Prosopis spp. as a nurse plant on nutrient content and productivity of Opuntia ellisiana Griffiths

Abstract

In arid conditions, the low quality of the forage and water shortage could be eased by the introduction of Opuntia species. The cladodes contain high soluble carbohydrate, calcium and carotene contents, while they are low on protein and fiber. Furthermore, the adaptation of Prosopis to herbivory is the main reason for its dominance in silvopastoral systems in arid and semiarid areas of America. A number of species grows well usually under Prosopis canopy, responding to a higher nutrient content in the soil, creating ?islands of fertility?. The hypothesis of this research was that the productivity and nutrient contents of the cactus planted under P. flexuosa will be higher than of those planted outside the canopy, and that these parameters will be influenced by the cactus position, north or south from the center of the tree. Furthermore, the frost damage to cactus will be higher outside the canopy. The experimental design was carried out in 12 plants under the canopy of Prosopis and 17 outside of it, located in CRICYT?s campus (32° 53? 45?? S 68° 52? 28?? 840 msnm). After one year, the totality of the cladodes was harvested, except the double cladodes planted at the beginning of the experience. The average cladode production per plant was 5.7 and 3.1 under and outside the canopy, respectively. The bromatological values were: moisture (91.9 and 89.1%), organic matter (89.8 and 76.9%), crude protein (8.0 and 4.4%), acid detergent fiber (18.3 and 13.8%), potassium (3.6 and 3.2%), phosphorus (0.11 and 0.07%), calcium (4.5 and 5.8 %) and sodium (0.02 and 0.04%), under and outside the canopy, respectively. Moisture, organic matter, crude protein, acid detergent fiber, potassium and phosphorus values were higher and statistically different under the canopy, whereas calcium and sodium values were higher outside the canopy (P<0.05). Dry matter/plant productivity (48.75g and 35.26g), neutral detergent fiber (31.6 and 29.0%) and magnesium (1.86 and 1.83%) values were not affected by the position under or outside the canopy respectively. The north or south orientation did not influence any of the analyzed parameters either. Frost damage was not observed outside the canopy.El consumo frecuente de antocianinas mejora la salud y previenen enfermedades, debido a su actividad antioxidante. La exposición de algunas plantas a concentraciones altas de metales pesados puede incrementar la concentración de antocianinas y mejorar su calidad funcional. Este estudio determinó el efecto de la aplicación foliar de Cu en varias dosis y número de aplicaciones sobre el contenido de antocianinas, características físico-químicas y rendimiento de cálices de jamaica (Hibiscus sabdariffa L.). Para este propósito se cultivó el genotipo Reina Roja que durante la etapa vegetativa, se asperjó al follaje con Cu en dos, cuatro y seis ocasiones con 150, 300 y 450 mg L-1. Los resultados indican que cuatro y seis aplicaciones de cobre redujeron el rendimiento de cálices secos para todas las dosis. Dos aplicaciones no modificaron el rendimiento de cálices. El Cu incrementó significativamente el contenido de antocianinas, acidez titulable y disminuyó el contenido de ácido ascórbico en los cálices. Los aumentos mayores de antocianinas (57 y 44%) fueron con seis aplicaciones de 300 y 450 mg de Cu L-1. Los datos sugieren que dos aplicaciones de 150 mg de Cu L-1 pueden mejorar la calidad nutracéutica de los extractos de jamaica sin afectar el rendimiento de cálices secos.