Selección de Pseudomonas sp., Bacillus sp. y actinomicetos productores de Ácido Indol Acético (AIA) aislados de “Biol” de elaboración artesanal provenientes de Lima y Huancayo

El “biol” es un abono líquido rico en fitohormonas, como las auxinas o mejor conocido como Ácido Indol Acético (AIA). Éste ácido estimula el desarrollo de las plantas y en general, la germinación de semillas. El uso del biol, en la agricultura peruana ha cobrado mucha importancia, pues asegura mayor rendimiento de la producción, incrementando a la vez la calidad de los cultivos y sobretodo ofreciendo alimentos libres de productos químicos. Para esta investigación se prepararon 22 muestras de biol artesanal con composiciones variables instalados en Lima y Huancayo. Se realizaron 10 muestreos durante un periodo de 150 días de biodigestión para seleccionar Pseudomonas sp., Bacillus sp. y actinomicetos productores de AIA, los cuales fueron identificados por sus características culturales y pruebas preliminares. Posteriormente con todas las cepas seleccionadas se realizó la prueba cualitativa y cuantitativa del AIA. El 20% de Pseudomonas sp., 17,07% de Bacillus sp. y 21,35% de actinomicetos aislados resultaron positivos a la prueba de AIA y fue posible cuantificar su producción. Asimismo, se realizó una prueba de efectividad del AIA producido por nueve bacterias para evaluar su efecto promotor de crecimiento sobre el hipocotilo y la radícula en semillas de Lactuca sativa L. (lechuga). El análisis estadístico de las pruebas señaló que los resultados son altamente significativos, mostrando los mejores resultados la cepa PSIV-1-L para el hipocótilo y la cepa PSII-7-L para la radícula. Se comprobó así la presencia de bacterias productoras de AIA en las muestras de biol de preparación artesanal y a la vez fue posible evidenciar un efecto positivo sobre la germinación in vitro de semillas de Lactuca sativa L. (lechuga).Tesi

Characterization of different Arundo donax L. Clones from the Mediterranean region

The present study assessed the behaviour of a tour ecotypes of Arundo donax L. (giant reed) as a perennial rhizomatous grass with an increasing interest due to its high biomass production and great s adaptability to stress conditions. In this study we perform a molecular, physiological and biomass characterization in greenhouse conditions on four mediterranean ecotypes. Not large significant differences were found in physiological and biomass parameters. However, it was possible to observe large differences in the chromosome count for the four ecotypes. In this way, we detected different number of chromosomes for each ecotype (98 to 122), but surprisingly, no correlation was observad between their chromosomes number and their physiological and biomass responses

Photosynthesis, resource acquisition and growth responses of two biomass crops subjected to water stress

This study compares photosynthesis, growth, 13C and 15N labelling patterns of two biomass crops (Arundo donax L. and Panicum virgatum L.) grown under water stress in greenhouse conditions. Plants were exposed to three water stress levels: control (C, 100% Pot Capacity), mild stress (MS, 50% PC) and severe stress (SS, 25% PC). Photosynthesis, fluorescence parameters and relative water content were measured at the beginning (Ti) and the end of the experiment (Tf). Biomass parameters were measured at Tf. Short-term double labelling with 13C and 15N stable isotopes was performed in both species. Isotopic analyses of total organic matter, total soluble sugars and the CO2 respired were undertaken at T0 (prelabelling), T1 (24h after labelling) and T2 (7 days after labelling). Immediately after the 13C and 15N labelling, stems and rhizomes seemed to be the main sinks for labelled carbon and nitrogen in both species. Moreover, not all of the labelled carbon and nitrogen substrate was used by plant metabolism after seven days. Decreases in photosynthesis parameters were observed as a consequence of the increase in water stress (WS) in both species, with a greater magnitude decline in giant reed than in switchgrass. A decrease in height, number of green leaves and total dry weight due to WS was observed in both species. Both species were more 13C-enriched and more 15N-depleted during the increases in WS due to lower stomatal conductance and transpiration. In general, WS accelerated plant phenology and, consequently, the accumulation of storage compounds in the rhizome occurred in response to stress. This effect was more clearly visible in switchgrass than in giant reed

Drought Impact on the Morpho‐Physiological Parameters of Perennial Rhizomatous Grasses in the Mediterranean Environment

The selection of non‐food crops for bioenergy production in limiting environments is a priority for energy security and climate change mitigation. Therefore, more studies are needed on the interactions between species and environmental factors in specific sites which allows their selection for biomass production. The objective of this work is to study the impact of drought on the morpho‐physiological parameters of perennial rhizomatous grasses Panicum virgatum L., Miscanthus × giganteus, and Arundo donax L. in the Mediterranean environment. Plants were grown on field and trials were carried out under support‐irrigation and rainfed conditions during two consecutive years. Morpho‐physiological parameters were measured in May, June and August, and dry biomass at the end of the experiment. Under rainfed conditions, A. donax presented the highest photosynthesis rate (25, 15 and 10 CO2 m−2 s−1), relative water content (85-90%), and dry biomass (~4500 g plant−1) compared with P. virgatum (20, 5 and 5 CO2 m−2 s−1, 65-85% RWC and ~1400 g plant−1) and Miscanthus (18, 4 and 0 CO2 m−2 s−1, 80-10% RWC and ~260 g plant−1). It is concluded that A. donax would be the best perennial rhizomatous grass to be used as bioenergy crop under Mediterranean conditions

Salinity and Water Stress Effects on Biomass Production in Different Arundo donax L. Clones

Perennial rhizomatous grasses are regarded as leading energy crops due to their environmental benefits and their suitability to regions with adverse conditions. In this paper, two different experiments were carried out in order to study the salinity (S) and water stress (WS) effects on biomass production in giant reed (Arundo donax L.). In Experiment 1, eight clones of giant reed were subjected to four salinity (S) and water stress (WS) treatments: (1) well watered with non-saline solution, (2) water stress with non-saline solution, (3) well watered with saline solution and 4) water stress with saline solution. In Experiment 2, five clones of giant reed were subjected to increasing S levels in two locations: University of Catania (UNICT-Italy) (1) well watered with non-saline solution and (2) well watered with mild saline solution; and University of Barcelona (UB-Spain) (3) well watered with non-saline solution and (4) well watered with severe saline solution. Photosynthetic and physiological parameters as well as biomass production were measured in these plants. According to our data, giant reed seems to be more tolerant to S than WS. Both stresses mainly affected stomatal closure to prevent dehydration of the plant, eventually decreasing the photosynthetic rate. The differential performance of the giant reed clones was ranked according to their tolerance to S and WS by using the Stress Susceptibility Index. 'Agrigento' was the most WS resistant clone and 'Martinensis' was the most S resistant. 'Martinensis' and 'Piccoplant' were found to be the most suitable clones for growing under both stress conditions. Moreover, 'Fondachello', 'Cefalú' and 'Licata' were the most resistant clones to increasing S levels

No preferential C-allocation to storage over growth in clipped birch and oak saplings

Herbivory is one of the most globally distributed disturbances affecting C-cycling in trees, yet our understanding of how it alters tree C-allocation to different functions like storage, growth or rhizodeposition is still limited. We performed continuous 13C-labelling coupled to a clipping experiment to quantify the effects of simulated browsing on the growth, leaf morphology and relative allocation of stored vs. recently assimilated C to the growth (bulk biomass) and non-structural carbohydrate (NSC) stores (soluble sugars and starch) of the different organs of two tree species with contrasting wood anatomy: diffuse-porous (Betula pubescens) and ring-porous (Quercus petraea). Transfers of C from plants to bulk and rhizosphere soil were also evaluated. Clipped birch and oak trees shifted their C-allocation patterns above-ground as a means to recover from defoliation. However, such increased allocation to current-year stems and leaves did not entail reductions in the allocation to the rhizosphere, which remained unchanged between clipped and control trees of both species. B. pubescens and Q. petraea showed differences in their vulnerability and recovery strategies to clipping, the ring-porous species being less affected in terms of growth and architecture to clipping than the diffuse-porous. These contrasting patterns could be partly explained by differences in their C cycling after clipping. Defoliated oaks showed a faster recovery of their canopy biomass, which was supported by increased allocation of recently fixed C, but associated with large decreases in the fine root biomass of clipped trees of this species. Following clipping, both species recovered NSC pools to a larger extent than growth, but the allocation of 13C-labelled photo-assimilates into storage compounds was not increased as compared to controls. Despite their different response to clipping, our results indicate no preventative allocation into storage occurred during the first year after clipping in any of the two studied tree species

Arundo donax L. como gramínea perenne para la producción de biomasa en ambiente Mediterráneo

[spa] En los últimos años, es evidente la preocupación mundial sobre las emisiones de gases del efecto invernadero, especialmente CO2. Una de las principales acciones contaminantes es la quema de combustibles fósiles. Paradójicamente la economía mundial depende (directa e indirectamente) en gran medida de la energía derivada de estos combustibles, principalmente petróleo, carbón y gas natural (en medida progresiva). Los combustibles fósiles son finitos, aunque aún tenemos un margen de algunos años para agotarlos. Según los expertos, estamos entrando a una nueva era, que deja de lado los combustibles fósiles y en cambio, usa otras fuentes de energía alternativa, como por ejemplo: la biomasa para la producción de biocombustibles (segunda generación), la energía proveniente del sol y la energía obtenida con la fuerza del aire. Estas fuentes deben usarse en conjunto, no son excluyentes. Una de las decisiones más importantes de la reunión de la COP 21 en París, fue el acuerdo de la disminución progresiva de combustibles fósiles, dado que contaminan altamente el ambiente al liberar grandes cantidades de CO2. Los países industrializados, ya cuentan con algunas investigaciones de años atrás para emplear estas fuentes alternativas. En Europa y EEUU, en cuatro años, se debe incrementar el uso los biocombustibles 10 al 20 %. Por tanto, hacer uso de biomasa para la producción de biocombustibles es de principal interés. En el presente estudio, se trabajó con Arundo donax L., como cultivo energético para evaluar su rendimiento bajo estrés hídrico, a nivel fisiológico, bioquímico y molecular. Los resultados nos indican que A. donax tuvo un buen rendimiento a nivel de producción de biomasa, los parámetros fisiológicos no se ven excesivamente afectados, además que tienen un buena eficiencia en el uso del agua. Los resultados moleculares no proporcionaron mucha información en cuanto a genes de tolerancia a la sequía, sin embargo son resultados valiosos para las futuras investigaciones. Por tanto se puede recomendar a A. donax como un buen candidato a cultivo energético en el ambiente Mediterráneo.[eng] In recent years, global concern about emissions of greenhouse gases, especially CO2, is evident. One of the main pollutants actions is the burning of fossil fuels. Paradoxically, the world economy depends (directly and indirectly) largely on the energy derived from these fuels, mainly oil, coal and natural gas (in progressive measure). Fossil fuels are finite, although we still have a margin of a few years to exhaust them. According to the experts, we are entering to a new era, leaving aside the fossil fuels and instead, uses other alternative energy sources, such as: biomass for the production of biofuels (second generation), energy from the sun and the energy obtained with the air force. These sources must be used together, they are not mutually exclusive. One of the most important decisions of the COP 21 meeting in Paris was the agreement of the progressive decrease in fossil fuels; because of highly pollute the environment by releasing large amounts of CO2. Industrialized countries have already some research done years ago to use these alternative sources. In Europe and the USA, in four years, the use of biofuels should be increased from 10 to 20%. Therefore, make use of biomass for the production of biofuels is a main interest. In the present study, we worked with Arundo donax L., as an energy crop to evaluate their performance under drought stress, physiological, biochemical and molecular level. The results indicate that A. donax is a good performance at the level of biomass production; the physiological parameters are not unduly affected; besides they have a good water use efficiency. The molecular results did not provide much information about genes of drought tolerance; however, results are valuable for future research. Therefore, A. donax can be recommended as a good candidate for energy crop in the Mediterranean environment