Dpto. Ciencias del Medio Natural - Natura Ingurunearen Zientziak Saila

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Open Access
Ammonia and GHG emission from environmental techniques in livestock farms based on modelization
(2017) Aguilar Ramírez, Maite; Merino Pereda, Pilar; Calvet Sanz, Salvador; Aparicio Tejo, Pedro María; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Actualmente, los sistemas agro-ganaderos tienen que hacer frente a desafíos ambientales, técnicos y económicos para tratar de responder a las demandas de desarrollo sostenible de la sociedad, lo cual requiere de soluciones innovadoras. En este sentido, las explotaciones avícolas y porcinas de gran tamaño deben obtener una autorización ambiental basada en la implementación de las Mejores Técnicas Disponibles (MTD) de acuerdo a la Directiva de Emisiones Industriales IED 2010/75 / EU. Esta tesis aborda el desarrollo de un modelo (modelo BATFARM) para la selección de técnicas ambientales en granjas comerciales de ganado porcino, avícola y de vacuno leche. Su objetivo es identificar las etapas clave que contribuyen a la emisión de amoniaco y de gases de efecto invernadero (GEI) en las explotaciones ganaderas, así como la comparación de diferentes escenarios de implementación de MTD. Diseñado con rigor metodológico y como una herramienta fácil de usar, calcula la producción y composición de los estiércoles y purines, las emisiones, los consumos y la producción animal. El modelo combina diferentes metodologías incluyendo factores de emisión y ecuaciones, tanto empíricas como basadas en procesos. Las pruebas realizadas parecen indicar que tanto las interacciones como el efecto de los factores con un impacto relevante en las emisiones, son considerados por el modelo. Sin embargo, los resultados deben ser interpretados como indicativos de la reducción relativa lograda y no como valores absolutos de emisión. La disponibilidad de estudios de investigación aplicada en granjas para determinar factores de emisión es fundamental en la modelización. En el marco de esta tesis se ha llevado a cabo la evaluación de un lavador de aire húmedo en una explotación comercial de ganado porcino, cuyos resultados se han incorporado en el modelo. Los lavadores húmedos parecen ser, también en nuestras condiciones climáticas, muy eficaces en la reducción de amoniaco. Sin embargo, es una técnica costosa que además puede perder su eficacia si no se aplican medidas adicionales en las subsiguientes etapas. Precisamente, los modelos permiten realizar este tipo de evaluaciones a lo largo de todas las fases de producción ganadera, clave para la selección de las técnicas que permitan alcanzar los objetivos de reducción de emisión requeridos en cada caso de la forma más eficaz.
Open Access
Compost de FORM con restos de alimentos cárnicos como componente de sustratos de cultivo
(Sociedad Española de Ciencias Hortícolas, 2014) Storino, Francesco; Irigoyen Iriarte, Ignacio; Ollo Alcasena, María Arantzazu; Aparicio Tejo, Pedro María; Muro Erreguerena, Julio; Producción Agraria; Ciencias del Medio Natural; Nekazaritza Ekoizpena; Natura Ingurunearen Zientziak
La utilización de compost de FORM como fertilizante es una práctica inocua y segura ampliamente implantada en la unión europea y que presenta gran cantidad de ventajas desde un punto de vista agronómico y medioambiental. La utilización de este tipo de compost como materia prima para la elaboración de sustratos de cultivo genera ciertas dudas por sus características, especialmente cuando provienen de sistemas de compostaje descentralizado en los que se han compostado restos de alimentos entre los que se incluyen alimentos de origen animal (carne y/o pescado). El objetivo del este trabajo es evaluar compost domésticos como componente de sustratos para cultivo de ornamentales que incluyen distintas proporciones de restos de alimentos cárnicos. Para este fin se compararon 3 compost domésticos (uno vegetal y dos con 15% carne) y uno comercial. Los compost fueron caracterizados mediante análisis de su composición elemental, pH y CE. Cada compost fue mezclado al 25 y 75 % v/v con sustrato a base de turba (utilizado puro como control). Además las dos mezclas con mayor CE fueron sometidas a lavados sucesivos, monitorizando el descenso de salinidad tras cada lavado y la composición elemental del líquido drenado. Plantas de pensamientos fueron cultivadas en macetas de 2 L con cada uno de los 11 sustratos indicados. Durante seis semanas de cultivo se midió la biomasa vegetal, la altura y el número de tallos, el número de flores y el contenido en clorofila mediante índice colorimétrico SPAD. Las diferencias entre los distintos tratamientos fueron pequeñas. El lavado previo de los sustratos no modifico significativamente la respuesta del cultivo. Se concluyen que los sustratos con compost de FORM que contiene hasta un 15% de restos de alimentos de origen animal no afectan negativamente al cultivo de pensamientos bajo las condiciones del presente ensayo.
Open Access
Compostaje descentralizado de residuos orgánicos domiciliarios a pequeña escala: estudio del proceso y del producto obtenido
(2017) Storino, Francesco; Irigoyen Iriarte, Ignacio; Aparicio Tejo, Pedro María; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Las más recientes políticas europeas en materia de residuos contemplan un sistema jerárquico de opciones de gestión, en el cual las acciones de prevención constituyen la más alta prioridad. Desde los años noventa el compostaje "in situ" a escala doméstica o comunitaria (autocompostaje) se está afirmando como vía de reducción de la generación de residuos en origen, presentando claras ventajas en términos medioambientales, económicos y sociales. Sin embargo, la literatura científica sobre los aspectos operativos del compostaje a pequeña escala cuenta todavía con un número exiguo de publicaciones. El objetivo de la presente tesis doctoral es profundizar en el estudio de aspectos operativos de las técnicas del compostaje a pequeña escala para favorecer su sostenibilidad y difusión como instrumento de prevención de residuos. En la primera parte de la tesis se realizó un "estudio de potencialidades" para identificar los aspectos técnicos a investigar en la parte experimental. Este estudio ha sido desarrollado a través de una revisión bibliográfica de trabajos de investigación, reports de entidades públicas y memorias de proyectos, con especial atención a aspectos medioambientales y económicos, y mediante la posterior realización de un análisis SWOT (DAFO). En este último se identificaron, a través de opiniones de expertos, técnicos gestores, educadores ambientales y participantes en iniciativas de autocompostaje recogidas en conferencias encuestas y entrevistas, los principales elementos de Fortaleza, Debilidad y posibles Amenazas y Oportunidades. Los resultados obtenidos en este estudio han puesto de manifiesto una serie de elementos de incertidumbre, problemas de carácter técnico y dudas sobre el manejo del proceso a pequeña escala, que son objeto de los diferentes ensayos desarrollados en la parte experimental de la tesis. El primer aspecto técnico abordado en la parte experimental ha sido el de determinar en qué difiere el compostaje doméstico del compostaje a escala industrial. Para este fin, se realizaron 4 ensayos comparando el compostaje del mismo tipo de residuo a escala industrial en pilas(> 1300 t) y doméstico en composteras (320 L), en términos de desarrollo del proceso y características del compost obtenido. Los primeros dos ensayos fueron realizados, respectivamente, con residuos agroindustriales y fracción orgánica de residuos municipales (FORM), utilizando el mismo material estructurante y la misma frecuencia de volteo. Durante estos primeros ensayos se observó un limitado desarrollo del proceso de compostaje a escala doméstica, ya que el tamaño del estructurante utilizado era demasiado grueso y la frecuencia de volteo insuficiente para el compostaje en composteras. Posteriormente, se realizaron un tercer y un cuarto ensayo compostando FORM a ambas escalas, modificando, en la escala doméstica, el tamaño del estructurante empleado y la frecuencia de volteo adoptada. En estos 4 ensayos se ha observado una mayor intensidad del proceso en las primeras fases de compostaje en composteras domésticas, afectando positivamente a la evolución del compost, mientras las características químico-fisicas y la madurez de los compost obtenidos al final del proceso fueron similares en ambas escalas. Asimismo se observó una mayor dependencia de la temperatura externa del compostaje en composteras, respecto al proceso realizado en pilas de grandes dimensiones. Adecuando el calendario de volteo y el tamaño de estructurante a escala doméstica se pudieron conseguir prestaciones incluso superiores al compostaje industrial, en términos de desarrollo de temperatura, reducciones de peso y volumen, madurez y composición del compost final. Posteriormente, se han realizados ensayos específicos sobre el proceso de compostaje en composteras domésticas: Por un lado se han evaluado distintos regímenes de alimentación de las composteras, comparando distintas frecuencias con la que se realizan los aportes y distintas cantidades de material orgánico adicionado con cada aporte. Se ha observado un mayor desarrollo de la temperatura y una mayor actividad microbiana durante el compostaje con aportes de mayor tamaño. Por otro lado, se han estudiado los efectos de la aportación de alimentos cárnicos, comparando diferentes mezclas de restos orgánicos iniciales obtenidas combinando dos proporciones distintas de carne/vegetal con dos dosis diferentes de estructurante. La presencia de restos cárnicos ha aumentado la temperatura durante el proceso, mejorando la madurez y el grado de humificación del compost, sin afectar negativamente a su conductividad eléctrica, pH, contenido en metales pesados ni a su fitotoxicidad. Un adecuado manejo del proceso es efectivo para reducir el riesgo microbiológico. A su vez, en otro ensayo se han evaluado cuatro materiales (3 vegetales y 1 mineral) para su utilización como estructurante en composteras domésticas. Las propiedades de los diferentes materiales estructurantes influyeron sobre el desarrollo del proceso afectando a la evolución de las características del compost. Los restos de poda triturados, habitualmente empleados en la práctica del autocompostaje, han sido los que proporcionaron mejores prestaciones en términos de calidad del compost y desarrollo del proceso. Paralelamente, se ha evaluado la capacidad de control del proceso de compostaje a escala doméstica sobre la vitalidad de semillas, mediante dos experimentos. En el primer experimento, se colocaron en el interior de las composteras unos contenedores metálicos con semillas de distintas plantas que fueron retiradas al término del proceso de compostaje para ponerlas a germinar. En el segundo experimento, se incubó compost doméstico en condiciones óptimas para poder observar la eventual germinación de semillas. Se concluye que el proceso de compostaje en composteras, alcanzando temperaturas termófilas, ha sido capaz de controlar la germinación de semillas. No obstante, son necesarios volteos suficientes, que aseguren que todo el material compostado sea sometido a condiciones de proceso. Con el material obtenido en los anteriores experimentos de compostaje se han realizado ensayos de cultivo en macetas, evaluando diferentes compost domésticos como fertilizante (en lechuga y espinaca) y como ingrediente para sustrato de cultivo (en pensamiento). A la luz de los resultados obtenidos en ambos ensayos, es posible concluir que el compost producido a nivel doméstico puede ser utilizado con toda seguridad como fertilizante o en la formulación de sustratos de cultivos, incluso en dosis más elevadas con respecto a compost industriales. Además, se investigó si la trituración de restos de poda, empleados como estructurante, puede constituir una fuente de metales pesados presentes en el compost. Para ello, se ha analizado el material triturado con 15 biotrituradoras móviles (con distintos tamaños, sistemas de corte y alimentación) y se han calculado las posibles concentraciones finales en el compost obtenido. Los materiales triturados presentaron bajos contenidos de metales pesados y su utilización no constituye una fuente significativa de contaminantes para el compost producido a nivel doméstico o comunitario. Finalmente, se ha realizado el seguimiento de un proyecto piloto de compostaje comunitario asistido por gallinas realizado en Noáin (Navarra) en colaboración con el ayuntamiento y 30 familias de dicha localidad. A la luz de los resultados obtenidos en los primeros tres años de funcionamiento, ha sido posible concluir que el manejo del compostaje ha sido técnicamente válido, con un correcto desarrollo del proceso y una alta calidad del compost producido. El sistema propuesto ha conseguido reducir satisfactoriamente una cantidad considerable de residuos orgánicos municipales destinados a la recogida y tratamiento centralizado, proporcionando, además, beneficios económicos, medioambientales y sociales. El autocompostaje en composteras de pequeñas dimensiones se ha revelado como herramienta eficaz para la prevención de residuos orgánicos domiciliarios, presentando, desde un punto de vista técnico, un correcto desarrollo del proceso. El compost obtenido presentó características adecuadas para su utilización doméstica. No obstante, para avalar y potenciar su difusión, sería interesante abordar en futuros estudios también aspectos sociales, demográficos, políticos, económicos y medioambientales asociados a estas prácticas.
Open Access
Effect of feeding regime on composting in bins
(Taylor & Francis, 2017) Storino, Francesco; Menéndez Villanueva, Sergio; Muro Erreguerena, Julio; Aparicio Tejo, Pedro María; Irigoyen Iriarte, Ignacio; Natura Ingurunearen Zientziak; Nekazaritza Ekoizpena; Ciencias del Medio Natural; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Composting in bins is one of the most practical home composting methods. There is currently a need for greater information to improve the management of the composting process and to create home composting programs, which ensure sustainable production of high quality compost. This study investigates how two aspects of the bin feeding regime—the feeding frequency and the amount of waste applied at each feed—influence the process's evolution and the quality of the compost. Compost bins were assayed after introducing the same amount of kitchen and garden waste according to three different frequencies: in a single batch, weekly, or every 3 weeks. A fourth treatment was applied to calculate the potential waste reduction achieved by the composting process, filling the bins to the brim on a weekly basis. Temperature, mass, and volume changes; the microbial diversity (by Biolog); and gas emissions (CO2, CH4, N2O, and NH3) were all determined during the process. At the end of the experiment, all of the composts were weighed and characterized. Results show that the main differences were very dependent on the quantity of waste provided. Large amounts of waste were added increasing the compost's temperature and maturity during the process, while slightly affecting the salinity and phytotoxicity of the final compost but without any clear effects on microbial diversity and gas emission. Therefore, from a technical point of view, the shared use of compost bins among several households (community composting) is preferable to individual us
Open Access
Elevated CO2 improved the growth of a double nitrate reductase defective mutant of Arabidopsis thaliana: the importance of maintaining a high energy status
(Elsevier, 2017) Jáuregui Mosquera, Iván; Aparicio Tejo, Pedro María; Baroja Fernández, Edurne; Ávila, Concepción; Aranjuelo Michelena, Iker; Natura Ingurunearen Zientziak; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Impairments in leaf nitrogen (N) assimilation in C3 plants have been identified as processes conditioning photosynthesis under elevated [CO2], especially when N is supplied as nitrate. Leaf N status is usually improved under ammonium nutrition and elevated [CO2]. However, ammonium fertilization is usually accompanied by the appearance of oxidative stress symptoms, which constrains plant development. To understand how the limitations of direct fertilization with ammonium (growth reduction attributed to ammonium toxicity) can be overcome, the effects of elevated [CO2] (800 ppm) exposure were studied in the Arabidopsis thaliana double nitrate reductase defective mutant, nia1-1/chl3-5 (which preferentially assimilates ammonium as its nitrogen source). Analysis of the physiology, metabolites and gene expression was carried out in roots and shoot organs. Our study clearly showed that elevated [CO2] improved the inhibited phenotype of the nitrate reductase double mutant. Both the photosynthetic rates and the leaf N content of the NR mutant under elevated CO2 were similar to wild type plants. The growth of the nitrate reductase mutant was linked to its ability to overcome ammonium-associated photoinhibition processes at 800 ppm [CO2]. More specifically: (i) the capacity of NR mutants to equilibrate energy availability, as reflected by the electron transport equilibrium reached (photosynthesis, photorespiration and respiration), (ii) as well as by the upregulation of genes involved in stress tolerance were identified as the processes involved in the improved performance of NR mutants.
Open Access
Evaluación del efecto de los inhibidores de la nitrificación derivados de dimetilpirazol y la nutrición amoniacal sobre la fisiología de las plantas
(2018) Rodrigues dos Santos, Janaina Maria; Aparicio Tejo, Pedro María; González Murua, Carmen; Lasa Larrea, Berta; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Los inhibidores de la nitrificación (IN) pueden ser bien productos biológicos producidos por las plantas o de síntesis química, estos últimos son añadidos a los fertilizantes granulados, solubles o líquidos y del mismo modo que los biológicos, son capaces de inhibir el crecimiento de los microrganismos nitrificantes. Los inhibidores procedentes de la síntesis química se han venido utilizando desde hace décadas en la agricultura y han sido desarrollados para tratar de disminuir las pérdidas de N de los agrosistemas (lixiviado de nitrato y emisiones de óxidos de nitrógeno), aumentando la eficiencia del uso del N de los fertilizantes aplicados a los cultivos. Actualmente la diciandiamida (DCD) y el 3,4-dimetilpirazol fosfato (DMPP) son los IN comercializados más utilizados y estudiados. Un nuevo producto ha sido desarrollado recientemente, el ácido 2- (N-3,4-dimetil-1H-pirazol-1-il) succínico, y que pertenece al mismo grupo de los dimetilpirazoles. Aunque su eficiencia es similar al DMPP, hasta la fecha hay pocos estudios sobre esta nueva molécula y su modo de acción no está del todo resuelto. En este trabajo se ha estudiado el efecto de los IN derivados de dimetilpirazol, así como la nutrición amoniacal sobre la fisiología de las plantas, dado que el empleo de IN modifica la presencia de las formas de nitrógeno disponibles en el suelo a favor de una mayor presencia de amonio. En nuestro estudio hemos observado que ambos IN derivados de dimetilpirazol, DMPP y DMPSA pueden ser absorbidos y translocados de la raíz hacia la parte aérea, aunque únicamente se ha observado afectación de las plantas con el DMPP a dosis muy elevadas. Para intentar dilucidar el posible modo de acción del DMPP sobre los procesos fisiológicos y metabólicos de la planta, se realizó un estudio con las herramientas moleculares (transcriptómica y proteómica), apoyados con estudios fisiológicos para así tener un mejor conocimiento de los mecanismos y rutas fisiológicas de las plantas que pudieran estar afectadas por el inhibidor. Dado que los IN favorecen la presencia de amonio en el suelo durante mayor tiempo tras la aplicación de fertilizantes de base amoniacal hemos realizado un estudio del efecto de diferentes ratios de NO3- y NH4+ en plantas de guisante y espinaca representativas de especies tolerantes y sensibles a la nutrición amoniacal. Hemos constatado que el mantenimiento del nivel de amonio en los tejidos es un factor importante en la respuesta a su tolerancia a esta fuente nitrogenada en las plantas.
Open Access
From ground pollution to soil fertilization: an environmental assessment of soil amendments derived from organic wastes
(2015) Calleja Cervantes, María Eréndira; Aparicio Tejo, Pedro María; Irigoyen Iriarte, Ignacio; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
El crecimiento de la población y sus necesidades de alimentación en las últimas décadas han sido mayoritariamente sustentados por un modelo productivo lineal a escala global basado en consumir recursos y generar residuos. Este modelo en muchas ocasiones ha contribuido de manera crucial al deterioro de agrosistemas y al cambio climático global. Para mejorar la sostenibilidad de los agrosistemas y mitigar el cambio climático es fundamental potenciar modelos productivos circulares locales basados en aprovechar residuos del entorno como recursos que permitan mejorar la fertilidad y resiliencia de los agrosistemas y desarrollar una agricultura más sostenible. Es por esto, que esta tesis tiene por objetivo general el estudio del uso continuado de residuos orgánicos en suelos agrícolas como enmiendas. Esta investigación se ha desarrollado en dos ensayos de larga duración ubicados en Navarra (España) donde se realizan distintos manejos de fertilización con residuos orgánicos. El primero de ellos es una viña de DOC Rioja (Bargota) en la que desde 1998 se aplican anualmente 3 compost diferentes. El segundo ensayo es una rotación cerealista (Arazuri) que desde 1992 recibe anualmente lodos de EDAR a distintas dosis. Los resultados de estos ensayos muestran un claro efecto beneficioso de la aplicación de distintos residuos orgánicos como fertilizantes en ambos agrosistemas.
Open Access
Insights into the regulation of nitrogen fixation in pea nodules: lessons from drought, abscisic acid and increased photoassimilate availability
(EDP Sciences, 2001) González García, Esther; Gálvez, Loli; Royuela Hernando, Mercedes; Aparicio Tejo, Pedro María; Arrese-Igor Sánchez, César; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Nitrogen fixation in legume nodules has been shown to be very sensitive to drought and other environmental constraints. It has been widely assumed that this decline in nitrogen fixation was a consequence of an increase in the so-called oxygen diffusion barrier and a subsequent impairment to bacteroid respiration. However, it has been recently shown that nitrogen fixation is highly correlated with nodule sucrose synthase (SS) activity under drought and other environmental stresses. Whether this correlation reflects a causative relationship or not has not been proven yet. The evidence presented here suggests that SS controls nitrogen fixation under mild drought conditions. However, nitrogen fixation cannot be enhanced only by increasing glycolytic flux, as under these conditions nodules become oxygen limited. Abscisic acid also induces a decline in nitrogen fixation that is independent of SS. The overall results suggest the occurrence of a complex regulation of nodule nitrogen fixation involving, at least, both carbohydrate and oxygen fluxes within the nodule.
Open Access
Integration of a communal henhouse and community composter to increase motivation in recycling programs: overview of a three-year pilot experience in Noáin (Spain)
(MDPI, 2018) Storino, Francesco; Plana, Ramón; Aparicio Tejo, Pedro María; Muro Erreguerena, Julio; Irigoyen Iriarte, Ignacio; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Producción Agraria; Nekazaritza Ekoizpena
This paper presents a three-year pilot experience of a new municipal waste management system developed in Navarre, Spain that integrates composting and hens. The aim of this new system is to motivate the general public to participate more in waste prevention programs. The Composter-Henhouse (CH) is a compact facility comprised of a henhouse and three composters. This is shared by 30 families who provide the organic part of their kitchen waste to feed the hens. Hens help speed up the composting process by depositing their droppings and turning the organic residue into compost. This study assesses the CH in terms of treatment capacity, the technical adequacy of the composting process, the quality and safety of the compost obtained and some social aspects. Over three years, the CH has managed nearly 16.5 tons of organic waste and produced approximately 5600 kg of compost and more than 6000 high-quality fresh eggs. No problems or nuisances have been reported and the level of animal welfare has been very high. The follow up of the composting process (temperature, volume reduction and compost maturity) and a physicochemical and microbiological analysis of the compost have ensured the proper management of the process. The level of involvement and user satisfaction has been outstanding and the project has presented clear social benefits.
Open Access
Isotopic composition of maize as related to N-fertilization and irrigation in the Mediterranean region
(Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 2011) Lasa Larrea, Berta; Irañeta, Iosu; Muro Erreguerena, Julio; Irigoyen Iriarte, Ignacio; Aparicio Tejo, Pedro María; Natura Ingurunearen Zientziak; Nekazaritza Ekoizpena; Ciencias del Medio Natural; Producción Agraria; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua, 17/2004
Nitrate leaching as a result of excessive application of N-fertilizers and water use is a major problem of vulnerable regions. The farming of maize requires high N fertilization and water inputs in Spain. Isotopic techniques may provide information on the processes involved in the N and C cycles in farmed areas. The aim of this work was studying the impact of sprinkler and furrow irrigation and N input on maize (Zea mays L.) yields, and whether isotopic composition can be used as indicator of best farming practices. Trials were set up in Tudela (Spain) with three rates of N fertilization (0, 240 and 320 kg urea-N ha–1) and two irrigation systems (furrow and sprinkler). Yield, nitrogen content, irrigation parameters, N fate and C and N isotope composition were determined. The rate of N fertilization required to obtain the same yield is considerably higher under furrow irrigation, since the crop has less N at its disposal in furrow irrigation as a result of higher loss of nitrogen by NO3 –-N leaching and denitrification. A lower δ13C in plants under furrow irrigation was recorded.The δ15N value of plant increased with the application rate of N under furrow irrigation.
Open Access
Leaf δ15N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated CO2, temperature and low water availability
(Frontiers Media, 2015) Ariz Arnedo, Idoia; Cruz, Cristina; Neves, Tomé; Irigoyen, Juan J.; García Olaverri, Carmen; Nogués, Salvador; Aparicio Tejo, Pedro María; Aranjuelo Michelena, Iker; Estatistika eta Ikerketa Operatiboa; Natura Ingurunearen Zientziak; Estadística e Investigación Operativa; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua
The natural 15N/14N isotope composition (δ15N) of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ15N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L.) plants were subjected to distinct conditions of [CO2] (400 vs. 700 μmol mol−1), temperature (ambient vs. ambient +4°C) and water availability (fully watered vs. water deficiency—WD). As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ15N in leaves, stems, roots, and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP) contents detected at 700 μmol mol−1 [CO2] and WD conditions. In summary, leaf δ15N provides relevant information integrating parameters which condition plant responsiveness (e.g., photosynthesis, TSP, N demand, and water transpiration) to environmental conditions.
Open Access
Leaves play a central role in the adaptation of nitrogen and sulfur metabolism to ammonium nutrition in oilseed rape (Brassica napus)
(BioMed Central, 2017) Coleto, Inmaculada; Peña, Marlon de la; Rodríguez Escalante, Jon; Bejarano, Iraide; Glauser, Gaëtan; Aparicio Tejo, Pedro María; González Moro, María Begoña; Marino Bilbao, Daniel; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Background: The coordination between nitrogen (N) and sulfur (S) assimilation is required to suitably provide plants with organic compounds essential for their development and growth. The N source induces the adaptation of many metabolic processes in plants; however, there is scarce information about the influence that it may exert on the functioning of S metabolism. The aim of this work was to provide an overview of N and S metabolism in oilseed rape (Brassica napus) when exposed to different N sources. To do so, plants were grown in hydroponic conditions with nitrate or ammonium as N source at two concentrations (0.5 and 1 mM). Results: Metabolic changes mainly occurred in leaves, where ammonium caused the up-regulation of enzymes involved in the primary assimilation of N and a general increase in the concentration of N-compounds (NH4 +, amino acids and proteins). Similarly, the activity of key enzymes of primary S assimilation and the content of S-compounds (glutathione and glucosinolates) were also higher in leaves of ammonium-fed plants. Interestingly, sulfate level was lower in leaves of ammonium-fed plants, which was accompanied by the down-regulation of SULTR1 transporters gene expression. Conclusions: The results highlight the impact of the N source on different steps of N and S metabolism in oilseed rape, notably inducing N and S assimilation in leaves, and put forward the potential of N source management to modulate the synthesis of compounds with biotechnological interest, such as glucosinolates.
Open Access
Meat waste as feedstock for home composting: effects on the process and quality of compost
(Elsevier, 2016) Storino, Francesco; Sánchez Arizmendiarrieta, Joseba; Irigoyen Iriarte, Ignacio; Muro Erreguerena, Julio; Aparicio Tejo, Pedro María; Ciencias del Medio Natural; Natura Ingurunearen Zientziak; Producción Agraria; Nekazaritza Ekoizpena
Home composting is a powerful tool, which is spreading in different parts of the world, to reduce the generation of municipal waste. However, there is debate concerning the appropriateness, in terms of domestic hygiene and safety, of keeping a composter bin in the household deputed to kitchen waste of animal origin, such as meat or fish scraps and pet droppings. The purpose of our work was to study how the addition of meat scraps to household waste influences the composting process and the quality of the final compost obtained. We compared four raw material mixtures, characterized by a different combination of vegetable and meat waste and different ratios of woody bulking agent. Changes in temperature, mass and volume, phenotypic microbial diversity (by Biolog TM) and organic matter humification were determined during the process. At the end of the experiment, the four composts were weighed and characterized by physicochemical analysis. In addition, the presence of viable weed seeds was investigated and a germination bioassay was carried out to determine the level of phytotoxicity. Finally, the levels of pathogens (E. coli and Salmonella spp.) were also determined in the final compost. Here we show that the presence of meat waste as raw feedstock for composting in bins can improve the activity of the process, the physicochemical characteristics and maturity of the compost obtained, without significantly affecting its salinity, pH and phytotoxicity. Pathogen levels were low, showing that they can be controlled by an intensive management and proper handling of the composter bins.
Open Access
Nitrogen source as key factor conditioning responsiveness of Arabidopsis plants to elevated CO2 conditions
(2014) Jáuregui Mosquera, Iván; Aparicio Tejo, Pedro María; Aranjuelo Michelena, Iker; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
The amount of carbon dioxide (CO2) in Earth's atmosphere has exceeded 400 parts per million (ppm) during three continuous months of observations in 2014, which is an absolute record for the last 800,000 years. As a consequence, plants, as photosynthetic organisms, will inevitably be influenced by the changed growing conditions that result from the increased [CO2]. The effect of increased [CO2] on plants has been widely studied and goes far beyond favouring carboxylation of Rubisco and generating higher growth rates. The present thesis aims to highlight the relevance of different nitrogen sources in the response of Arabidopsis thaliana, a C3 model plant, to elevated [CO2]. For this purpose, this has been an integrated study of leaf and root organs combining techniques that range from plant physiology to molecular biology. Under nitrate nutrition and elevated [CO2] conditions, Arabidopsis thaliana plants increase their biomass and maximum photosynthetic rates; nevertheless, the total soluble protein, Rubisco content and leaf N content reveal a general decrease in leaf N availability (chapter I). Although the expression of nitrate transporters was substantially upregulated in roots, plants did not efficiently transport nitrate and other minerals from roots to leaves, which compromised leaf N and mineral status. Therefore, our results suggest that the diminution of transpiration rates causes a reduction in the xylem flux, which inexorably generates an imbalance in the transport of nitrate and mineral elements between organs under elevated [CO2]. Moreover, root nitrate assimilation (based on the amino acid content) is favoured in order to overcome N limitations due to the reduction in leaf nitrate assimilation. In chapter II plant performance under elevated [CO2] and ammonium nitrate conditions was characterized and it was found that biomass doubled due to substantially increased photosynthetic rates. Gas exchange characterization revealed that these plants overcame photosynthetic acclimation. Plants maintained Rubisco concentrations at control levels alongside enhanced energy efficiency. The increments found in leaf carbohydrates and organic acid content linked to enhanced respiration rates supported the fact that the plants under elevated [CO2] maintained their energy status. The transcriptomic analysis enabled the identification of photoassimilate allocation and remobilization as fundamental processes used by the plants to avoid photosynthetic acclimatization. Moreover, based on the relationship between plant carbon status and hormone functioning, the transcriptomic analyses provided an explanation of why phenology accelerates under elevated [CO2]. Finally, in chapter III the relevance of ammonium nutrition under elevated [CO2] was analysed; for this purpose a double nitrate reductase mutant (NR mutant, nia1-1/chl3-5 defective) was used. These results highlight that plants under elevated [CO2] which preferentially assimilate ammonium as their only N source maintain leaf growth and photosynthetic rates similar to plants receiving ammonium nitrate. However, under ambient [CO2] concentrations, ammonium toxicity symptoms emerge and development is extremely constrained. In elevated [CO2] conditions, an NR mutant maintained the energy supply for the Calvin cycle pathway and managed efficient photoassimilate transport between plant tissues. Furthermore, the data suggest active ammonium assimilation in leaves due to the exceptional conditions (C skeletons, ATP, adequate pH homeostasis and no photoinhibition) of these plants under elevated [CO2]. Hence, the results obtained in the present doctoral thesis aim towards the incorporation of the source of nitrogen as key in the response at the elevated [CO2] of Arabidopsis thaliana plants. Consequently, the present doctoral thesis aims to determine whether the incorporation of the correct source of nitrogen is the key component in how Arabidopsis thaliana plants respond to elevated [CO2].
Open Access
Overexpression of a pine Dof transcription factor in hybrid poplars: A comparative study in trees growing under controlled and natural conditions
(Public Library of Science, 2017) Rueda López, Marina; Pascual, María Belén; Pallero, Mercedes; Henao, Luisa María; Lasa Larrea, Berta; Jáuregui Mosquera, Iván; Aparicio Tejo, Pedro María; Cánovas, Francisco M.; Ávila, Concepción; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
In this work, the role of the pine transcriptional regulator Dof 5 in carbon and nitrogen metabolism has been examined in poplar trees. The overexpression of the gene and potential effects on growth and biomass production were compared between trees growing in a growth chamber under controlled conditions and trees growing in a field trial during two growth seasons. Ten-week-old transgenic poplars exhibited higher growth than untransformed controls and exhibited enhanced capacity for inorganic nitrogen uptake in the form of nitrate. Furthermore, the transgenic trees accumulated significantly more carbohydrates such as glucose, fructose, sucrose and starch. Lignin content increased in the basal part of the stem likely due to the thicker stem of the transformed plants. The enhanced levels of lignin were correlated with higher expression of the PAL1 and GS1.3 genes, which encode key enzymes involved in the phenylalanine deamination required for lignin biosynthesis. However, the results in the field trial experiment diverged from those observed in the chamber system. The lines overexpressing PpDof5 showed attenuated growth during the two growing seasons and no modification of carbon or nitrogen metabolism. These results were not associated with a decrease in the expression of the transgene, but they can be ascribed to the nitrogen available in the field soil compared to that available for growth under controlled conditions. This work highlights the paramount importance of testing transgenic lines in field trials.
Open Access
Pea plant responsiveness under elevated [CO2] is conditioned by the N source (N2 fixation versus NO3 fertilization)
(Elsevier, 2013) Aranjuelo Michelena, Iker; Cabrerizo Geijo, Pablo María; Arrese-Igor Sánchez, César; Aparicio Tejo, Pedro María; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
The main goal of this study was to test the effect of [CO2] on C and N management in 2different plant organs (shoots, roots and nodules) and its implication in the 3responsiveness of exclusively N2-fixing and NO3--fed plants. For this purpose, 4exclusively N2-fixingand NO3--fed (10 mM) pea (Pisum sativumL.) plants were 5exposed to elevated [CO2] (1000 mol mol-1versus360 mol mol-1CO2). Gas 6exchange analyses, together with carbohydrate, nitrogen, total soluble proteins and 7amino acids were determined in leaves, roots and nodules. The data obtained revealed 8that although exposure to elevated [CO2] increased total dry mass (DM)in both N 9treatments, photosynthetic activity was down-regulated in NO3--fed plants, whereas N2-10fixing plants were capable of maintaining enhanced photosynthetic rates under elevated 11[CO2]. In the case of N2-fixing plants, the enhanced C sink strength of nodules enabled 12the avoidance of harmful leaf carbohydrate build up. On the other hand, in NO3--fed 13plants, elevated [CO2] caused a large increase in sucrose and starch. The increase in root 14DM did not contribute to stimulation ofC sinks in these plants. Although N2fixation 15matched plant N requirementswith the consequent increase in photosynthetic rates, in 16NO3--fed plants, exposure to elevated [CO2] negatively affected N assimilationwith the 17consequent photosynthetic down-regulation.
Open Access
Quantitative proteomics reveals the importance of nitrogen source to control glucosinolate metabolism in Arabidopsis thaliana and Brassica oleracea
(Oxford University Press, 2016) Marino Bilbao, Daniel; Ariz Arnedo, Idoia; Lasa Larrea, Berta; Santamaría Martínez, Enrique; Aparicio Tejo, Pedro María; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
Accessing different nitrogen (N) sources involves a profound adaptation of plant metabolism. In this study, a quantitative proteomic approach was used to further understand how the model plant Arabidopsis thaliana adjusts to different N sources when grown exclusively under nitrate or ammonium nutrition. Proteome data evidenced that glucosinolate metabolism was differentially regulated by the N source and that both TGG1 and TGG2 myrosinases were more abundant under ammonium nutrition, which is generally considered to be a stressful situation. Moreover, Arabidopsis plants displayed glucosinolate accumulation and induced myrosinase activity under ammonium nutrition. Interestingly, these results were also confirmed in the economically important crop broccoli (Brassica oleracea var. italica). Moreover, these metabolic changes were correlated in Arabidopsis with the differential expression of genes from the aliphatic glucosinolate metabolic pathway. This study underlines the importance of nitrogen nutrition and the potential of using ammonium as the N source in order to stimulate glucosinolate metabolism, which may have important applications not only in terms of reducing pesticide use, but also for increasing plants’ nutritional value.
Open Access
Unravelling the mechanisms that improve photosynthetic performance of N₂-fixing pea plants exposed to elevated [CO₂]
(Elsevier, 2014) Aranjuelo Michelena, Iker; Cabrerizo Geijo, Pablo María; Aparicio Tejo, Pedro María; Arrese-Igor Sánchez, César; Natura Ingurunearen Zientziak; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Although the predicted enhanced photosynthetic rates of plants exposed to elevated [CO₂] are expected to increase carbohydrate and plant growth, recent findings have shown a complex regulation of these processes. The aim of this study was to determine the effect of elevated [CO₂] on pathways leading to the main forms of leaf C storage (starch) and export (sucrose) and the implications of this increased [CO₂] on photosynthetic performance of exclusively N2 fixing plants. For this purpose, exclusively N2-fixing pea plants were exposed to elevated [CO₂] (1000 mol mol−1 versus 360 mol mol−1 CO₂). The data obtained highlighted that plants exposed to elevated [CO₂] were capable of maintaining hexose levels (involved in Rubisco down regulation) at control levels with the consequent avoidance of photosynthetic acclimation. More specifically, in plants exposed to elevated [CO₂] there was an increase in the activity of pathways involved in the main forms of leaf C storage (starch) and export (sucrose). Furthermore, the study highlighted that although starch content increased by up to 40% under elevated [CO₂], there was also an increase in the proteins and compounds involved in starch degradation. Such a finding, together with an increase in the activity of proteins involved in sucrose synthesis revealed that these plants up-regulated the sucrose synthesis pathway in order to meet the large nodule photoassimilate requirements. As a consequence, the study highlighted the relevance of controlling the activity of pathways that determine leaf cellular carbohydrate availability and how this is linked with C-demanding organs such as nodules.
Open Access
Yield and quality of sugar snap pea in the Ebro Valley: sowing date and seed density
(Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, 2012) Azpilicueta Unanua, Miren; Irigoyen Iriarte, Ignacio; Lasa Larrea, Berta; Muro Erreguerena, Julio; Aparicio Tejo, Pedro María; Nekazaritza Ekoizpena; Natura Ingurunearen Zientziak; Producción Agraria; Ciencias del Medio Natural; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Sugar snap pea (Pisum sativum L. var. macrocarpon Ser.) is an edible-podded sweet pea that is being considered as a new totally mechanized crop to supply raw material to the agri-food industry of the Ebro Valley (Northern Spain). It is of great interest from an agronomic and commercial standpoint but neither its agronomic behaviour nor its adaptation to the area are known. The objective of this study was to determine the effect of sowing date and seed density on the growth and yield of the sugar snap pea at industrial scale. Six randomized blocks experiments with four replicates were conducted on irrigated land in Villafranca (Navarra, Spain) in 1998, 1999, and 2000. Three experiments for testing sowing dates (Mar., Apr., and May) and another three for seed densities (from 75 to 150 plants m–2) were performed. Phenological development, thermal integral and qualitative and quantitative yield controls were performed. Sugar snap pea required 960 ºC d–1 (Tb = 3 ºC) from sowing to harvest. The early sowings gave more biomass, but yield was similar. However, Harvest Index and crop morphology varied. The sowing densities had similar yields sowing that sugar snap pea has a bigger adaptation availability. Sugar snap peas can be satisfactorily cultivated at industrial scale in the zone with sowings between Mar. and May and with seeding densities between 75 and 150 plants m–2.

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