EVALUACIÓN DE DOS TÉCNICAS DE ACODAMIENTO PARA LA PROPAGACIÓN VEGETATIVA DEL ALGARROBO Prosopis chilensis (Mol) Stuntz

El objetivo general del ensayo fue evaluar el uso de dos métodos de propagación vegetativa en P. chilensis: (A) acodo aéreo y (B) en montículo. En (A) se emplearon árboles de 3,5 años de edad y se ensayaron en dos épocas (primavera-verano), con AIB 1 % y el control testigo. En (B) se usaron plantas de 8 meses de edad, anillado con alambre y diferentes tipos de sustratos: arena, turba y una mezcla de ambos. Se obtuvieron 42,5 % de acodos enraizados en primavera con AIB y un promedio de 14,5 raíces por acodo aéreo, sin diferencias con respecto al verano. En (B), el máximo porcentaje de enraizamiento fue del 75 % en el sustrato arena, con alambre y un promedio de 3,89 raíces por acodo. En (A) se concluye que AIB mejora el porcentaje de enraizamiento en ambas épocas; y en (B) el alambre favorece el enraizamiento de los acodos en montículo en presencia del sustrato arena.

Increase in the antioxidant content in biscuits by infusions or Prosopis chilensis pod flour

Nowadays there is an increasing demand for healthy biscuits. The reduction in sugar and fat level, as well as the addition of bioactive compounds, is positively associated with a healthy diet. In the present work, low-fat and low-sugar biscuits were prepared with infusions (mate, coffee, and tea) or with Prosopis chilensis pod flour (PPF). Biscuits were made with maize starch and wheat flour (gluten formulations) or with gluten-free ingredients (gluten-free). The colour, texture, and the antioxidant capacity were evaluated in dough and biscuits. Among the formulations prepared with infusions, the mate dough showed the lowest firmness (1.1 N (gluten)-24.3 N (gluten-free)). However, no significant differences were found in the fracture stress of the final products (P > 0.05). Mate gluten biscuits and PPF gluten-free biscuits showed the highest fracture strain (16.2 and 9.4%, respectively) and the lowest Young’s modulus (7.3 and 13.3 MPa, respectively) in their groups. The highest antioxidant activity was found in biscuits with mate (8.7 µmol FeSO4/g (gluten)-4.3 µmol FeSO4/g (gluten-free)). These values were three times higher than the ones found in the control biscuits (2.9 µmol FeSO4/g (gluten)-3.9 µmol FeSO4/g (gluten-free)). The present results showed that the antioxidant content in biscuits could be successfully increased with infusion addition.

Genetic variance distribution of SSR markers and economically important quantitative traits in a progeny trial of Prosopis chilensis (Leguminosae): implications for the ‘Algarrobo’ management programme

Prosopis chilensis (Molina) Stuntz (Leguminosae) is a valuable native species in Argentina included in the Prosopis Management Programme. Natural provenances show important height and shape differentiation throughout their distribution in the Monte Desert. The availability of progeny trials provides an opportunity to quantify genetic differentiation among provenances and test the relative importance of demographic vs adaptive processes on morphological variation. We quantified both genetic and quantitative differentiation of neutral markers and five economically important traits, respectively, among four provenances in a provenance-progeny trial. We aimed to quantify the genetic basis of variations in height, basal diameter, tree shape, spine length and biomass. Two hypotheses were tested: (1) economically important traits have significant heritability, and (2) the phenotypic variation among provenances is the result of local adaptation to particular environmental conditions. Our results indicate that most morphological variation was found among individuals within families (~95 per cent). The h2 estimates were heterogeneous among traits and ranged from low (0 for number of stems) to moderate (0.22 and 0.28 for spine length and biomass, respectively). Variance among families (~5 per cent) was evenly distributed within and among provenances. Morphological differentiation among provenances was low, but significant, and could be attributed mainly to individuals from Villa Unión. Based on molecular markers, genetic differentiation among provenances was low and significant (FST = 0.03; P = 5 × 10−4) but was able to differentiate the groups from Villa Unión, Fiambalá and Mogna-Chilecito. Neutrality tests were conducted using the FST–QST test and DJSOST and δGREGORIUS alternative coefficients of differentiation. Neutrality tests yielded no evidence of local adaptation and were rather consistent in showing a trend toward stabilizing selection, particularly for spine length. The selection strategy for breeding programmes should depend on the trait to be improved and should consider both provenance and familiar information. Considering an intra-familiar ranking is encouraged in order to maximize the genetic gain. Additionally, in order to recover germplasm provenance diversity, based on morphological and microsatellite results, our recommendation would be to include seeds from individuals from at least the Villa Unión, Fiambalá and Mogna-Chilecito areas.

Selective Laser Sintering (SLS) and Post-Processing of Prosopis Chilensis/Polyethersulfone Composite (PCPC)

The range of selective laser sintering (SLS) materials is currently limited, and the available materials are often of high cost. Moreover, the mechanical strength of wood–plastic SLS parts is low, which restricts the application of a SLS technology. A new composite material has been proposed to address these issues, while simultaneously valorizing agricultural and forestry waste. This composite presents several advantages, including reduced pollution associated with waste disposal and reduced CO2 emission with the SLS process in addition to good mechanical strength. In this article, a novel and low-cost Prosopis chilensis/polyethersulfone composite (PCPC) was used as a primary material for SLS. The formability of PCPC with various raw material ratios was investigated via single-layer experiments, while the mechanical properties and dimensional accuracy of the parts produced using the various PCPC ratios were evaluated. Further, the microstructure and particle distribution in the PCPC pieces were examined using scanning electron microscopy. The result showed that the SLS part produced via 10/90 (wt/wt) PCPC exhibited the best mechanical strength and forming quality compared to other ratios and pure polyethersulfone (PES), where bending and tensile strengths of 10.78 and 4.94 MPa were measured. To improve the mechanical strength, post-processing infiltration was used and the PCPC-waxed parts were enhanced to 12.38 MPa and 5.73 MPa for bending and tensile strength.

Ecophylogeography of the disjunct South American xerophytic tree species Prosopis chilensis (Fabaceae)

The intraspecific evolutionary history of South American xerophytic plant species has been poorly explored. The tree species Prosopis chilensis has a disjunct distribution in four South American regions: southern Peru, southern Bolivia, central–western Argentina and central Chile. Here, we combined phylogeographical (based on chloroplast and nuclear markers), morphological and climatic data to evaluate the relative contribution of historical demo-stochastic and adaptive processes in differentiating the disjunct areas of distribution. The results obtained with the two molecular markers revealed two closely related phylogroups (Northern and Southern, predominating in Bolivian Chaco and in Argentine Chaco/Monte, respectively), which would have diverged at ~5 Mya, probably associated with transgression of the Paranaense Sea. Bolivia and Argentina have a larger number of exclusive haplotypes/alleles and higher molecular diversity than Chile, suggesting a long-lasting in situ persistence in the former and a relatively recent colonization in the latter, from the Bolivian and Argentinian lineages. The two main lineages differ in morphology and climatic niche, revealing two significant, independent evolutionary units within P. chilensis promoted by local adaptation and geographical isolation.

EVALUACIÓN DE LA VARIABILIDAD MORFOLÓGICA DE PROSOPIS CHILENSIS EN LA REGIÓN DE TACNA Y SU RELACIÓN CON LOS FACTORES ECOLOGICOS DEL MEDIO DESÉRTICO

Los valles costeros de área desértica en Tacna (Perú) han sufrido un importante fenómeno de deforestación debido a la explotación agrícola, ya que estos valles constituyen una fuente de suelos fértiles de la zona costera central del gran desierto de Atacama. El fenómeno de deforestación incluye la desaparición de muchas especies vegetales en el sur del Perú. Una de estas especies es Prosopis chilensis, árbol nativo de los ecosistemas áridos y semiáridos de América del Sur. Sin embargo, este árbol es particularmente útil para los pobladores locales y es usado como combustible (leña y carbón), madera para construcción y sus frutos como forraje para el ganado vacuno. Por esta razón se justifica el establecimiento de un programa de conservación y reforestación de esta especie. El principal objetivo de la presente investigación ha sido analizar la variabilidad morfológica de Prosopis chilensis así como su adaptación del medio ambiente desértico con la finalidad de mejorar su utilización en los programas de reforestación. Sin embargo, la investigación realizada con bajo número de individuos actualmente creciendo en el departamento de Tacna no hizo posible establecer una significante correlación entre la variabilidad morfológica y las condiciones ecológicas. A pesar de esto, los árboles de Prosopis chilensis muestran una irrevocable adaptación a los particulares condiciones extremas de aridez o estrés hídrico; estos atributos genéticos pueden ser explotados en un vasto programa de reforestación en las zonas áridas del sur del Perú.