This thesis focuses on the issues of growing and the use of annual plants at the higher level of basic schools. It includes an elaborate list of annual plants suitable for growing at basic schools also with possibility of the didactic use. In addition this thesis contains an instructional film, a commentary on the film for teachers and a worksheet for students.

Positive frequency-dependent predation (FDP) has been proposed as a species coexistence mechanism and theoretical models have shown how it may function. In positive FDP a rare species receives a temporary reprieve from predation pressure allowing an increase to its population growth rate and a chance for it to recover from rarity. This study tests for frequency-dependent foraging by granivorous desert rodents on the seeds of three species of winter annual plants that grow in the Sonoran Desert. While the preference for one species is much higher than the other two, preferences for each species are higher when common than when rare showing an asymmetric form of positive FDP. This study is the first empirical test for positive FDP on winter annual plants and by granivorous desert rodents and one of few to use more than two prey species, native prey species, or asymmetrically preferred prey species.

Este trabajo presenta los resultados de la investigación sobre la preparación y caracterización de las metilcelulosas a partir de las plantas anuales.Las pastas del miscanthus, el cardo, y el eucalipto, se prepararon mediante el proceso IRSP (Impregnation Rapid Steam Pulping) y se blanquearon con las secuencias del TCF (Total Chloride Free), que usan peróxido de hidrógeno y hidróxido de sodio (NaOH). Con el aumento de la severidad del proceso de obtención de las pastas, la accesibilidad y la reactividad de las pastas aumentaron mientras que la viscosidad y el número de la kappa disminuyeron. Se desarrolló un nuevo y sencillo método de metilación para preparar las metilcelulosas a partir de la madera y las plantas anuales en el laboratorio. Cada metilcelulosa de las pastas blanqueadas con las secuencias del TCF se sintetizó en una mezcla de isopropanol con metano de yodo a 600C durante 22 horas después la pasta del TCF se mercerizó en una solución del hidróxido de sodio al 40% durante 1 hora. La mercerización y la metilación se repitieron para obtener un grado de sustitución (DS) más alto. Los resultados de la espectroscopía infrarroja de transformada de Fourier (FTIR) (Fourier Transform Infrared Spectroscopy) mostraron que los grupos del OH de la celulosa habían sido sustituidos parcialmente por grupos del metoxil. Los modelos de sustitución supramolecular de las metilcelulosas se determinaron mediante espectroscopía de resonancia magnética nuclear del carbono-13. La viscosidad intrínseca de las metilcelulosas se midió con agua destilada, una solución al 4% de NaOH, o DMSO. Las propiedades reológicas de las metilcelulosas se midieron con DMSO, una solución al 4% de NaOH o agua destilada. Las metilcelulosas sintetizadas tenían unas propiedades similares a las metilcelulosas comerciales. Los volúmenes hidrosolubles y alcalinosolubles de la metilcelulosas se determinaron mediante extracción con disolventes.Las metilcelulosas se prepararon a partir de pastas de lino, yute, cáñamo, sisal, y abacá mediante metilaciones heterogéneas y homogéneas. Estas pastas se blanquearonmediante el proceso ECF (Elemental Chlorine Free). La mutilación inhomogénea de las pastas blanqueadas mediante el proceso ECF se sintetizó en una mezcla de isopropanol con metano de yodo a 600C durante 22 horas después la pasta del ECF se mercerizó durante 1 hora en una solución de NaOH al 50%. La mutilación homogénea de la pasta blanqueada mediante ECF se realizó en DMSO con metano de yodo a 300C durante 48 horas. Para esta metilación homogénea se usó una metilcelulosa con un grado de sustitución más bajo, que se disolvió completamente en DMSO. La espectroscopía infrarroja de transformada de Fourier (FTIR) de las metilcelulosas mostró la existencia de grupos de metoxiles sobre las moléculas de metilcelulosa. Se utilizó la espectroscopia de resonancia magnética nuclear del carbono 13 para medir los grados de sustitución de las metilcelulosas. Los pesos moleculares de las metilcelulosas hidrosolubles se determinaron con la cromotagrafía de exclusión por tamaños (SEC). Las viscosidades intrínsecas se midieron en una solución de NaOH al 4%. Las metilcelulosas preparadas a partir de pastas de elevadas accesibilidades y reactividades tenían las mejores grados de sustitución, pesos moleculares, viscosidades y viscosidades intrínsecas.Se investigaron las accesibilidades y reactividades de las pastas del ECF. Los volúmenes de glucosa y de xilosa de estas pastas se determinaron mediante HPLC (High performance liquid chromatography) después de la hidrólisis. Las accesibilidades de adsorción de yodo de estas pastas eran bajas y sus fragmentos accesibles estaban entre el 1,31% y el 5,16%. En la región amorfa, sus fragmentos accesibles estaban entre el 5% y el 24%. Las imágenes del SEM (Scanning Electrón Microscopy) mostraron que sus fibrillas tenían distintas estructuras morfológicas. Los resultados de la espectroscopía infrarroja de transformada de Fourier (FTIR) mostraron que, después de los pretratamientos, habían disminuido tanto la media de la intensidad de los enlaces de hidrógeno como los índices de cristalinidad relativos. Sus reactividades aumentaron significativamente después de la mercerización preliminar. Las accesibilidades y reactividades de la pasta del abacá se mejoraron con los tratamientos de impregnación con agua, la mercerización a 15 bares de presión, la explosión de vapor y la mercerización preliminar. La desintegración, el incremento de los huecos, el debilitamiento de la intensidad de los enlaces de hidrógeno, la depolimerización, y la decristalización son esenciales para mejorar las accesibilidades y las reactividades, pero el factor decisivo es la especie de la planta.Hemos estudiado los factores que influyen en el peso molecular (Mw) de las metilcelulosas hidrosolubles preparadas a partir de plantas anuales. El tiempo y la temperatura de impregnación y las condiciones de cocción influyeron de manera diferente en el peso molecular (Mw) de metilcelulosas preparadas a partir de los cardos recogidos en primavera y en verano, el miscanthus y el eucalipto. Se compararon los efectos de los pretratamientos (la impregnación con agua, la mercerización preliminar, la mercerización con presión y la explosión de vapor) en la pasta del abacá. Cuando se pretrató la pasta del abacá, su metilcelulosa hidrosoluble consiguió un peso molecular más alto. De entre los pretratramientos analizados, la explosión de vapor resultó el más adecuado. Para conseguir metilcelulosas con un peso molecular más alto deben perfeccionarse las condiciones de la preparación de las pastas blanqueadas mediante ECF. La especie de las plantas es el factor decisivo para conseguir el peso molecular más alto de las metilcelulosas y para seleccionar los pretratamientos más adecuados.Los parámetros del proceso de obtención de pastas, las condiciones de la metilación, las especies de las plantas, los pretratamientos, y la estructura morfológicas de las pastas influyó en los grados de sustitución de las metilcelulosas preparadas a partir de plantas anuales. Una severidad de impregnación más alta, una temperatura del proceso de obtención de pastas más alta y un incremento del tiempo del mismo proceso consiguieron grados de sustitución más altos. Un aumento de reactivos de la metilación causó un aumento de grado de sustitución. Las pastas obtenidas de distintas especies produjeron grados de sustitución diferentes, trabajando con las mismas condiciones de metilación. Los pretratamientos aumentaron el grado de sustitución de las metilcelulosas.Esta investigación contribuye a encontrar las condiciones apropiadas para metilcelulosas diseñadas a medida, sintetizadas a partir de plantas anuales. Esta investigación demuestra que estas plantas tienen la capacidad de ser preparadas para conseguir metilcelulosas de alta calidad y de alto valor aptas para distintas aplicaciones, como la industria alimentaria, la de la construcción o la farmacéutica. La industria puede utilizar estas plantas anuales de crecimiento rápido para producir metilcelulosas, con lo que, además, se evitará el uso de madera.Palabras clave: abacá, accessibilidad, blanqueo mediante TCF, cáñamo, cardo, eucalipto, grado de sustitución, lino, metilación, metilcelulosa, miscanthus, peso molecular, plantas anuales, proceso de obtención de pasta IRSP, sisal, yute. / Preparation and characterization of methylcelluloses from some annual plantswere investigated.Miscanthus, cardoon, and eucalyptus pulps were produced by Impregnation Rapid Steam Pulping (IRSP) process and bleached by Total Chloride Free (TCF) sequences using hydrogen peroxide and sodium hydroxide. With an increase of pulping severities, accessibilities and reactivities of bleached pulps increased while viscosities and kappa numbers decreased. A novel facile methylation was developed in order to prepare methylcelluloses from wood and annual plants. Each methylcellulose of TCF bleached pulps was synthesized in isopropanol slurry with iodomethane at 600C for 22 hours after the TCF bleached pulp was mercerized in 40% NaOH solution for 1 hour. The mercerization and methylation were repeated in order to obtain a higher degree of substitution (DS). Fourier Transform Infrared (FTIR) spectra showed OH groups of cellulose were partially substituted by methoxyl groups. Supramolecular substitution patterns of methylcelluloses were determined by 13C nuclear magnetic resonance (NMR) spectroscopy. Intrinsic viscosities of methylcelluloses were measured in distilled water, 4% NaOH solution, or dimethyl sulphoxide (DMSO). Rheological properties of methylcelluloses were measured in DMSO, 4% NaOH solution or distilled water, in which the synthesized methylcelluloses had similar properties as commercial methylcelluloses. Watersoluble and alkali-soluble contents of methylcelluloses were determined by solventextraction.We used iodomethane to synthesize methylcelluloses from Elemental Chloride Free (ECF) bleached abaca, hemp, flax, jute, and sisal pulps via heterogeneous and homogeneous methylations. The heterogeneous methylation was carried out in isopropanol with iodomethane at 600C for 22h after a ECF bleached pulp was mercerized in excessive 50% NaOH solution for one hour at ambient temperature. The homogeneous methylation was carried out in dimethyl sulfoxide with iodomethane at 300C for 48h using a methylcellulose of low degree of substitution. Fourier Transform Infrared (FTIR) spectra of the synthesized methylcelluloses showed the existence of methoxyl groups on methylcellulose molecules. The degrees of substitution of the synthesized methylcelluloses were measured by 13C Nuclear Magnetic Resonance (NMR) spectroscopy. The molecular weights of the waterVI soluble methylcelluloses were determined by Size Exclusion Chromatography (SEC). Intrinsic viscosities of the synthesized methylcelluloses were measured in 4% NaOH solution. Methylcelluloses with better properties, such as greater degrees of substitution, molecular weights, viscosities, and intrinsic viscosities, were prepared from the pulps with higher accessibilities and reactivities. The factors influencing the preparation of methylcelluloses from these pulps were discussed.Pretreatments (water-soaking, pre-mercerization, mercerization under a pressure of 15 bars, and steam explosion) were used to improve the accessibilities and reactivities of celluloses of bleached flax, hemp, sisal, abaca, and jute pulps for the synthesis of methylcellulose. Glucose and xylose contents of these pulps were determined by High Performance Liquid Chromatograph (HPLC) after hydrolysis. Degrees of crystallinity of these pulps were determined by X-ray Diffraction (XRD) spectra. Figures of Scanning Electron Microscope (SEM) showed that their fibrils had different morphological structures. The iodine adsorption accessibilities of these pulps were low and accessible fractions ranged from 1.3% to 5.2%. Accessible fractions in amorphous cellulose were calculated in the 5% to 18% range. The accessibilities of these pulps were hemp pulp > flax pulp > sisal pulp > jute pulp > abaca pulp. Fourier Transform Infrared (FTIR) spectra showed that mean hydrogen bond strengths were weakened and relative crystallinity indexes were decreased by pretreatments. The accessibility and reactivity of the abaca pulp were improved by water soaking, mercerization under 15 bars pressure, steam explosion and preliminary mercerization, of which steam explosion and pre-mercerization were thebest treatments. Species was the main factor for the accessibility and reactivity.We studied the factors that influenced the molecular weights (Mw) of watersolublemethylcelluloses prepared from annual plants and juvenile eucalyptus. Miscanthus and cardoon stalks, and bleached pulps of abaca, jute, sisal, hemp, and flax were used as the annual plant materials. A higher concentration of NaOH solution during the impregnation led to a spring cardoon methylcellulose having a lower molecular weight. As the impregnation times increased, so did the molecular weights of the water-soluble methylcelluloses of spring cardoon. The impregnation conditions had less influence on the methylcelluloses of summer cardoon than on the methylcelluloses of spring cardoon. As the cooking times increased, so did the molecular weights of miscanthus methylcelluloses. A lower pulping severity increased the molecular weight of eucalyptus methylcellulose. The preliminary treatments (water soaking, pre-mercerization, mercerization under pressure andsteam explosion) improved the molecular weights of water-soluble abaca methylcelluloses. The steam explosion method was the best of the preliminary treatments for the abaca pulp. Different species led to different molecular weights for methylcelluloses synthesized from ECF bleached pulps, and these were further improved by preliminary mercerization. The molecular weight of -cellulose methylcellulose changed as the ratio of the methylation reagent was varied. In order to synthesize an optimum Mw of methylcellulose, the different raw materials can be chosen, the pulping parameters adjusted (including impregnation and cooking), the cellulose pretreated, and the methylcellulose conditions changed. The plant species is the decisive factor for the Mw of methylcellulose.The pulping parameters, the methylation conditions, the species, the pretreatments, and the morphological structures of pulps influenced the degrees of substitution of the methylcelluloses prepared from the annual plants. A higher impregnation severity, a higher pulping temperature, and a longer pulping time caused a higher degree of substitution. An increase of methylation reagents led to an increase of degree of substitution. Methylcelluloses of different degrees of substitution were synthesized from the pulps of different species when a same methylation condition was used. The pretreatments increased the degrees of substitution of methylcelluloses.This investigation contributes to find appropriate conditions for the production of methylcellulose from annual plants. The present investigation demonstrates these annual plants have the capacities to produce upgraded and high quality methylcelluloses for varied applications, such as additives of foods, construction, pharmaceutics, polymerization, paints, and detergents etc. The industry can utilize these annual fast-growth plants to produce methylcelluloses. Therefore, a lot of wood will be saved.Keywords: abaca, accessibility, annual plants, cardoon, degree of substitution, eucalyptus, flax, hemp, IRSP pulping, jute, methylation, methylcellulose, miscanthus, molecular weight, sisal, steam explosion, TCF bleaching.

San Joaquin wooly-threads (Monolopia congdonii; Asteraceae) is a federally-listed, endangered annual plant species from the desert areas of the San Joaquin Valley. Its limited range puts it at risk of extinction if the climate changes in such a way as to hinder its growth and reproduction. The primary aims of the study were to 1) determine how long-lived the seeds of the M. congdonii are, a key determinant of survival of desert annual plant populations through long droughts and 2) determine how severely hotter, drier conditions impact the ability of emerged plants to grow and reproduce. Secondarily, I aimed to test two hypotheses 1) is seed longevity within the genus Monolopia correlated with habitat aridity? 2) do species’ geographic range limits represent their climatic tolerances? In testing the viability of seeds of Monolopia species collected from herbarium specimens and old field collections, I did not find evidence for the predicted pattern of seed longevity. Though, idiosyncrasies in the data suggest possible issues with the longevity of M. congdonii seeds that are collected prematurely and warrant further investigation to develop best practices for seed collections of this species. To test the climatic tolerance of M. congdonii and the relationship between geographic range and climatic tolerance, I grew several desert annual species under three manipulated water treatments. And while, M. congdonii failed to germinate, the other species showed variable tolerance for the drought treatments but this variability was seemingly unrelated to the species’ geographic range. Importantly, Monolopia lanceolata, a close relative of M. congdonii did not show exceptional vulnerability to the drought-stress conditions relative to other co-occuring species. Taken together, the results of this study enable better informed population viability analyses with the end goal of allowing recovery efforts to succeed.

Species diversity and coexistence have long been central foci of ecology, but field studies are often limited to describing diversity patterns, while theory frequently ignores environmental variation. Scale transition theory is an ideal framework in which to study species diversity, as it explicitly accounts for this environmental variability and allows for the quantification of coexistence mechanisms. Each coexistence mechanism arises from specific types of biotic and abiotic interactions. Moreover, mechanism magnitudes provide information about how these interactions contribute to coexistence. By studying how the natural history of a community determines these biotic and abiotic interactions, insight can be gained into how that natural history influences coexistence. Environmental variation is a central hypothesis for the maintenance of diversity in both desert annual plants and streams. This dissertation is broadly interested in the way differences in the environmental responses of species interact with the structure of the environmental conditions to affect coexistence. I use scale transition theory to develop theoretical understanding of how life history and environmental structure in these communities influence coexistence mechanisms and diversity. In desert annual plants, the focus is on the environmental response itself: how germination depends on environmental conditions. I analyze how this life history interacts with variation in the environment to affect coexistence. The germination responses of desert annual plants to an unstudied type of environmental variation, duration of soil moisture after rainfall, generate species-specific but highly structured patterns of germination variation. Although this germination variation is one-dimensional, the nonlinearities that arise due to germination biology generate sufficient germination variation to promote coexistence by the temporal storage effect. In stream communities, I examine how the physical structure of stream environments affects coexistence given that species’ performance is environmentally dependent. This dissertation demonstrates that patterns of diversity along the stream are related to the strength of coexistence. The downstream drift of organisms has relatively minor effects on coexistence despite asymmetric shifts in the distribution of organism in the stream. This study identifies conditions that eliminate the effects of the branched structure of stream networks on coexistence. Branching has no effect on community dynamics if (a) tributaries have identical environmental conditions, (b) habitat size increases additively at confluences, and (c) demographic stochasticity is unimportant. Any effects of branching on coexistence caused by violating the environmental condition are asymptotically eliminated as streams increase in size. These studies provide a theoretical, mechanistic foundation for the study of stream communities that addresses environmental and life history factors long recognized as important by empirical stream ecologists.