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- ItemHoney and nectar from Quillaja saponaria Mol. (Quillajaceae): botanical characterization, isolation, identification, and biological evaluation of secondary metabolites(2025) Nuñez Pizarro, Paula Alejandra; Montenegro Rizzardini, Gloria; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería ForestalHoney is a natural sweet food produced by bees, revered for its distinct flavor, nutritional value, and health benefits. Beekeeping in Chile offers a diverse range of honey varieties, many of them unique. Quillay (Quillaja saponaria Molina, soapbark tree) is an endemic tree that grows in the sclerophyllous forests and matorral of central Chile standing as one of the country’s most significant melliferous species due to its high appeal to bees as a nectar source. This study focuses on the characterization and biological evaluation of honey and floral nectaries from Quillaja saponaria Mol. (Quillajaceae). The main objective was to identify a reliable chemical quality indicator of monofloral quillay honey by studying its chemical composition and linking it to its biological properties, emphasizing the antioxidant and antibacterial capacities. The evaluation of its hepatoprotective effects in vitro was also accomplish. Chilean honey samples were analyzed, in an attempt to find quillay honey. The botanical origin of honey samples was determined through the melissopalynology method, and a DNA-based method was performed to identify quillay monofloral honey. Honey samples and quillay nectaries were chemically characterized to identify the phenolic acids and flavonoids through HPLC-DAD, including measuring of total phenolic and flavonoid contents in honey samples. Also, chromatographic methods were used to isolated and identify chemical compounds from quillay honey. Finally, an evaluation of the biological properties of samples, including antioxidant capacity through oxygen radical absorbance capacity (ORAC-FL) and ferric reducing antioxidant power (FRAP) assays, antibacterial activity against pathogenic bacteria, and hepatoprotective potential in HuH-7 liver cell models was carried out. The PCR amplification confirmed the qualitative presence of Quillaja saponaria DNA in samples classified as monofloral based on melissopalynology. Monofloral quillay honey exhibited a higher total phenolic content (TPC) and flavonoid content (TFC) than multifloral honey. Additionally, the Spearman correlation indicates a positive and moderate association between the percentage of quillay pollen and the concentration of TPC in honey samples (R = 0.667), suggesting that phenolic content from quillay tree could contribute to the overall antioxidant capacity of this monofloral honey. The exploration and comparison of phenolic compounds in quillay nectaries and honey samples via HPLC-DAD enable us to propose chrysin and syringic acid as quality indicators for quillay monofloral honey. All honey samples demonstrated effectiveness against S. pyogenes, with a not statistically significant positive Spearman correlation (R = 0.07) between the percentage of quillay pollen and the antibacterial activity observed. In vitro assays in HuH-7 cell cultures revealed hepatoprotective effects of quillay honey extracts, linked to their ability to reduce oxidative damage induced by peroxyl radicals.The findings highlight the unique chemical and biological properties of Quillaja saponaria honey, supporting its potential as a high-value product with therapeutic applications. The research underscores the importance of integrating chemical and botanical analyses for honey authentication and characterization. Future studies are recommended to validate these findings using larger sample sizes and diverse experimental models.
- ItemPrioritization of strategic areas for forest restoration in high-productivity agricultural landscapes in Central Chile(2024) Madrid Ayala, Victoria Paz; Arellano, Eduardo; Pontificia Universidad Católica de Chile. Facultad de Agronomía y Sistemas NaturalesAgricultural intensification in Central Chile threatens biodiversity and ecosystem services. This thesis aims to prioritize strategic areas for forest restoration in intensive agricultural landscapes, considering ecological connectivity, ecosystem services, and productive interests. Given high land-use competition and the economic importance of fruit production, it proposes regional-scale corridor planning and a local-scale optimization model that integrates the maximization of ecological objectives in the provision of ecosystem services and forest cover, and productive objectives through the minimization of opportunity costs.
- ItemThe role of agricultural growth in poverty reduction: an empirical study of selected Latin American countries(2024) Quiñonez Florentín, Fabrizio; Anríquez Nilson, Gustavo; Pontificia Universidad Católica de Chile. Facultad de Agronomía y Sistemas NaturalesAgriculture plays a critical role in poverty reduction, particularly in developing countries where it serves as one of the leading sources of income and employment. This study examines how agricultural growth impacts poverty alleviation, focusing on the specific conditions and mechanisms in some Latin American countries that have received limited empirical attention. Each chapter addresses a different aspect of the central question: What are the mechanisms through which agricultural growth reduces poverty? The thesis begins with a review of foundational literature and progresses to empirical findings, applying well-established methodologies. The first chapter focuses on the regional disparities within Peru, a country with distinct natural regions characterized by unique agroecological and socio-economic conditions. The coastal areas, with agrifood systems strongly integrated into international markets and focused on labor-intensive crops and food industries, contrast sharply with the Sierra and Selva regions, where traditional subsistence farming prevails. The second chapter analyzes how the composition of economic growth sectors influences poverty reduction in Paraguay and Peru. The final chapter examines the persistence of rural poverty using continuous household surveys and a Dynamic Random Effects Probit Model. The thesis explores how regional disparities, economic structure, and government policies shape the pro-poor effects of agricultural growth. This topic gains even greater relevance in countries that depend more heavily on agriculture and have limited diversification of other economic sectors, such as Paraguay, a landlocked country at the heart of South America, or in challenging geographical regions like the Peruvian Sierra, where agriculture is a pillar, but distances and lack of market integration represent barriers. The findings highlight the need for tailored policies that consider local agricultural characteristics, labor market dynamics, and the integration of the agrifood sector to enhance the poverty-reducing potential of agriculture.
- ItemBiocultural Approaches to Pluralized Bird Conservation in Globally Important Social-ecological Wetland Systems(2024) Araneda Cid, Paola; Ibarra Eliessetch, José Tomás; Pontificia Universidad Católica de Chile. Facultad de Agronomía y Sistemas NaturalesTo be pluralising and just, conservation science and practice must embrace diverse worldviews. Wetlands are intricate repositories of knowledge where biophysical, social, and spiritual dimensions are profoundly intertwined. Birds connect people to wetlands, foster a sense of rootedness, and emotionally link individuals to their places. This thesis examined how situated human-bird interactions -manifested in knowledges, practices, and beliefs- of local wetland inhabitants in the Río Cruces wetland, are composed and being transformed by social-ecological processes, and how we can use this to move towards more effective and just biocultural conservation. The Río Cruces wetland, in Chile's Valdivian Hotspot, is the country's first Ramsar site and has faced significant socio-environmental transfor-mations. Surveys were conducted in 2021 with 41 participants in 8 localities around the Río Cruces wetland. We used interview kits as cultural probes for individual mapping and “memory walks”. The first chapter highlighted the need for targeted research on biocultural approaches to wetland birds. Secondly, wetland birds in Río Cruces played a significant role in biocultural knowledge containment, highlighting the importance of wetlands in memory storage. Finally, I reaffirm the crucial role of sense of place and identity in foster-ing the engagement needed to achieve conservation objectives.
- ItemSweet Cherry dynamics in the absorption and mobility of Calcium and Boron under different boron soil conditions, applied at different times and organs(2024) Arredondo Reyes, Gerardo Alejandro; Bonomelli de Pinaga, Claudia María; Nario Mouat, María Adriana; Pontificia Universidad Católica de Chile. Facultad de Agronomía y Sistemas NaturalesIntensive agriculture is characterized by the extensive use of inputs, causing great pressure on the environment. Fertilizer consumption has exponentially increased worldwide, causing serious environmental problems. Fertilization can also affect the accumulation of heavy metals in the soil and plant systems. Calcium (Ca) and Boron (B) are essential nutrients for plants. Ca and B deficiencies reduce the quality and fruit set of sweet cherry trees. Several studies have shown the advantages of foliar and soil Ca and B applications in fruit trees; however, there is little information on the distribution of both elements in the plant, which is an important issue when nutritional corrections are needed. This study aimed to determine the effect of foliar Ca application on fruits using a commercial formula of Ca 30 after full bloom, and B absorption, mobility, and distribution in sweet cherry trees, using 10 B applied to the flowers and soil, at different times and under two levels of soil B availability. Three experiments were conducted using sweet cherry trees. In a commercial orchard of Bing, Sweetheart, and Regina cultivars (cv.) with Ca and the second and third in Regina cv. under open-air conditions in the experimental field. In the last experiment, in the previous two seasons, the plants were managed under two soil B availability conditions (deficient and adequate). The experiments consisted of the application of 10 B solution to the flowers and soil at different times and under both soil B conditions. Ca application showed differences between cultivars in terms of firmness in Sweetheart and Regina, but not in Bing. The Ca concentration in fruit tissues only showed an effect in Regina cv. Higher 10 B absorption was observed when 10 B was applied to the soil at full bloom than when it was applied before leaf senescence. Boron was mobilized to all the tissues, but mainly to the leaves. Nevertheless, the fruit presented no differences in 10 B excess for both application timings. Irrespective of soil B conditions, 10 B applied to the soil at full bloom was absorbed and mobilized to different tissues. In conclusion, Ca exhibited different responses in each cultivar. B was absorbed and mobilized regardless of time and organ application. However, the B applied in full bloom was absorbed in greater quantities than that applied before leaf fall.