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Limited nutrient diffusion in three-dimensional (3D) constructs is a major concern in tissue engineering. Therefore, monitoring nutrient availability and diffusion within a scaffold is an important asset. Since nutrients come in various forms, we have investigated the diffusion of the oxygen, luciferin and dextran molecules within tissue-engineered constructs using optical imaging technologies. First, oxygen availability and diffusion were investigated, using transgenic cell lines in which a hypoxia-responsive element drives expression of the green fluorescent protein gene. Using confocal imaging, we observed oxygen limitation, starting at around 200 ?m from the periphery in the context of agarose gel with 1 million CHO cells. Diffusion of luciferin was monitored real-time in agarose gels using a cell line in which the luciferase gene was driven by a constitutively active CMV promoter. Gel concentration affected the diffusion rate of luciferin. Furthermore, we assessed the diffusion rates of fluorescent dextran molecules of different molecular weights in biomaterials by fluorescence recovery after photobleaching (FRAP) and observed that diffusion depended on both molecular size and gel concentration. In conclusion, we have validated a set of efficient tools to investigate molecular diffusion of a range of molecules and to optimize biomaterials design in order to improve nutrient delivery.

My thesis provides insights into the composition of aquatic and soil-dwelling animal assemblages in flooded paddy fields and their potential role in nutrient cycling processes. Decomposition is an essential ecosystem service which provides natural supply of nutrients for plant growth and decreases the need for applying artificial fertilizers. In flooded rice ecosystems invertebrates are of particular importance for an efficient decay of organic matter as microbial decomposition is considerably decelerated under anaerobic conditions. The experiments presented in this thesis substantiate the value of invertebrate detritivores for an effective breakdown of crop residues and therefore, for a sufficient nutrient availability in paddy soils. Further, my experiments revealed that the role of invertebrates in decomposition processes has to be seen in the context of field management. Thus, the development of sustainable management practices in rice agro-ecosystems should also be based on the knowledge about the mediating effects of different cultivation methods on decomposition as an ecologically and economically relevant ecosystem function. Continued efforts to reveal the link between the assemblage of animals in rice fields and their role in decomposition processes are crucial to extend our understanding of the mechanisms behind nutrient utilization promoted by rice straw decomposition. Exploiting the full fertilization potential of rice straw residuals will help to establish sustainable methods for productive rice agriculture., Für eine nachhaltige und natürliche Steigerung der Bodenfruchtbarkeit ist Reisstroh die potenziell wichtigste Nährstoffquelle in Reisfeldern. Um den Stickstoff im Stroh effektiv freisetzen zu können, ist eine funktionierende Gemeinschaft von Bodenorganismen unerlässlich. Unter den anaeroben Bedingungen der Reisfeldböden, die während der Anbauphase permanent gefluteten sind, spielen Invertebraten für die Zersetzung von organischem Material eine besonders wichtige Rolle. Das generelle Ziel unserer Experimente war daher, die Zusammensetzung der Fauna-Gemeinschaft in Reisfeldern im Zusammenhang mit ihrem Beitrag zum Abbau von Reisstroh zu untersuchen. Um den mikrobiellen Abbau von dem der Zersetzer-Fauna zu differenzieren, wurden Streubeutel mit zwei verschiedenen Maschenweiten (20 µm und 5 mm) verwendet und entweder auf die Bodenoberfläche der Reisfelder gelegt oder in die oberste Bodenschicht eingebracht. Bodenkern-Proben wurden zur Bestimmung der Bodenfauna verwendet und Wasserkescher-Proben zur Erfassung der aquatischen Fauna. Die Ergebnisse unserer ersten Studie zeigen deutlich, dass Invertebraten einen großen Einfluss auf die Zersetzung von Reisstroh haben und damit die Bodenfruchtbarkeit positiv beeinflussen können. Einige Zersetzer-Arten leben nur als Larven im Wasser bzw. den gefluteten Böden und benötigen als Adulte eine ausreichende Strukturvielfalt in der Umgebung der Felder. Wir konnten zeigen, dass in Ufernähe die Abbauaktivität der Fauna am höchsten ist und Richtung Feldmitte stetig abnimmt. Anstatt ein großes Reisfeld anzulegen, könnte das Aufspalten der Fläche in mehrere kleine Felder die Nährstofffreisetzung durch den Abbau von Reisstroh fördern und zur Verbesserung des Pflanzenwachstums beitragen. Das Ziel unserer zweiten Studie war es, den Einfluss verschiedener Bewirtschaftungsformen, genauer, den unterschiedlichen Umgang mit Ernterückständen auf die Aktivität der Zersetzer-Invertebraten und die Abundanzen der Wasser- und Bodenfauna zu untersuchen. Im Gegensatz zur Düngung mit der Asche von verbranntem Stroh, konnten in den Feldern, in denen Reisstroh als natürlicher Dünger verwendet wurde, eine deutlich höhere Anzahl an wirbellosen Tieren erfasst werden. Auch die Menge an abgebautem Stroh war stark abhängig von der jeweiligen Form der Bewirtschaftung. Generell konnte kein Zusammenhang zwischen der Abundanz der Boden- und Wasserfauna und der Abbaugeschwindigkeit des Reisstrohs in unseren Streubeuteln festgestellt werden. Dennoch konnten wir nachweisen, dass das Einbringen von Reisstroh in Reisfelder sowohl einen signifikanten Einfluss auf die Abbaugeschwindigkeit durch die Zersetzer-Fauna hat, als auch die Abundanz diverser Faunagruppen deutlich erhöhen kann. Um einen genaueren Einblick in die Zersetzungsvorgänge und den jeweiligen Beitrag der Fauna und der Mikroorganismen in Reisökosystemen zu bekommen, sind Langzeitstudien über mehrere Anbauperioden nötig. In dieser Zeit könnte sich die Gemeinschaft der Bodenorganismen an die veränderten Bewirtschaftungspraktiken anpassen. Die Einführung einer Trockenanbau-Periode im Wechsel mit Nassreis kann dazu beitragen, den enormen Wasserverbrauch und die extrem hohen Mengen an Treibhausgasen, die der geflutete Reisanbau produziert, zu reduzieren. Solch ein Fruchtwechsel birgt natürlich auch Risiken, besonders für die Gemeinschaft der Bodenorganismen. Deshalb haben wir verschiedene Fruchtwechsel daraufhin untersucht, welchen Einfluss sie auf die Abundanz und Aktivität der Bodenfauna haben. Mikrobielle Abbauprozesse sind bekanntermaßen unter Sauerstoffmangel stark verlangsamt. Daher war der mikrobielle Abbau des Reisstrohs unter den aeroben Bedingungen der Trockenphase sehr stark erhöht. Obwohl wir eine sehr viel höhere Anzahl an Invertebraten im Boden der Trockenfelder nachweisen konnten, war der Beitrag der Bodenfauna zum Streuabbau in dieser Zeit vernachlässigbar. Nach dem Fruchtwechsel zu geflutetem Nassreis zeigte die Zersetzer-Fauna wieder eine sehr hohe Aktivität, während der mikrobielle Beitrag stark abnahm. Der Gesamtverlust an Stroh unterschied sich am Ende zwischen den Fruchtwechseln nicht. Das heißt, die Gemeinschaft der Bodentiere ist in der Lage den stark verlangsamten mikrobiellen Abbau im gefluteten Nassreis-Anbau zu komplementieren, was sie zu einem essentiellen Faktor für die nachhaltige Verbesserung der Bodenfruchtbarkeit macht. Generell ist die Zersetzer-Fauna ein entscheidender Faktor auf dem Weg hin zu mehr Nachhaltigkeit im bewässerten Reisanbau. Sie kompensiert den stark eingeschränkten mikrobiellen Abbau von organischem Material unter den vorherrschenden anaeroben Bedingungen und beeinflusst damit die Versorgung des Bodens mit wichtigen Nährstoffen. Eine stabile Gemeinschaft von Bodenorganismen ist ausschlaggebend für ein optimales Pflanzenwachstum und kann dazu beitragen, die Bodenfruchtbarkeit zu steigern und dadurch den Bedarf an künstlichen Düngemitteln zu reduzieren. Es sollte daher genau untersucht werden, welche Auswirkungen sowohl landwirtschaftliche Intensivierungsmaßnahmen und der damit einhergehende Verlust an Biodiversität als auch der Klima‐ und Landnutzungswandel auf die Gemeinschaft und Funktionalität der Bodenorganismen haben.

The study was carried out in order to compare the development of berries growing on fruiting cuttings and on vines from the field, and to evaIuate this experimentaI system for grapevine physiology studies. The results show that the main developmental characteristics of the berries are close to those of berries from the vineyard. Fruit set is good and berry growth follows a double sigmoid curve. Final size is smaller than usual, even if seed number is higher for fruiting cuttings. The evolution of organics acids, sugar and mineral content is classical. At maturity, the berries from fruiting cuttings reach the same sugar content, but are less acidic, because the components of acid equilibrium are slightly modified. At flowering polyamine content is higher in the cluster of fruiting cutting but the variations aIong cluster development is the same than in the vineyard. Finally the application of exogenous putrescin on fruiting cuttings at flowering time improves fruit set, as in the field. Our data allow to conclude that fruiting cuttings behave mostly as bigger vines and could be a usefull tool for grapevine physiology studies.

Veränderungen in der Gesellschaft, wie beispielsweise die steigende Anzahl an berufstätigen Frauen, haben zur Folge, dass an den Schulen in Baden-Württemberg vermehrt Ganztagsschulangebote bereitgestellt werden und sich die Anzahl der GanztagsschülerInnen in den letzten 10 Jahren mehr als verdreifacht hat (Landesinstitut für Schulentwicklung et al. 2011). 2008 wurde deswegen vom Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz in gemeinschaftlicher Finanzierung mit dem Ministerium für Ländlichen Raum und Verbraucherschutz in Baden-Württemberg die Vernetzungsstelle Schulverpflegung eingerichtet. Ziel dieser Studie ist es, die Methoden der Vernetzungsstelle Schulverpflegung Baden-Württemberg zur Optimierung der Ernährung in schulischen Einrichtungen zu evaluieren und weiterzuentwickeln. Hierfür werden zehn Schulen mit den dazugehörigen sieben Mensen und den 6000 SchülerInnen von Juni 2010 bis Oktober 2011 von der Vernetzungsstelle Schulverpflegung Baden-Württemberg betreut. Ziel dieser Begleitung ist, die Nährstoffaufnahme der SchülerInnen zu verbessern und dadurch die Anzahl der SchülerInnen zu erhöhen, die einen Body-Mass-Index (BMI) im Normbereich haben. Um dieses Ziel zu erreichen, sollen sowohl die Qualität und die Rahmenbedingungen (z. B. Vorbestellung) des Mittagessens an den Schulen verbessert als auch die Kundenzufriedenheit und die daraus resultierende wöchentliche Teilnahme am Mensaessen erhöht werden. Weiterhin sollen die SchülerInnen für eine bedarfsgerechte Ernährung sensibilisiert werden. Basis der Begleitung der Schulen durch die Vernetzungsstelle Schulverpflegung Baden-Württemberg bildet der „Runde Tisch“. An diesen regelmäßigen Treffen verschiedener Zielgruppen, wird die Optimierung der Schulmensa organisiert. Es werden für die Schulmensa individuell wichtige Optimierungs- und Werbestrategien durchgeführt. Bei den Optimierungsstrategien werden beispielsweise die Caterer und das Ausgabepersonal geschult. Die Werbestrategien umfassen verschiedene Aktionen zur Steigerung der Akzeptanz rund um die Schulmensa. Um die Veränderungen durch die Intervention messbar zu machen, wird zu Beginn und am Ende der Studie eine Analyse durchgeführt. Hierbei werden die Rahmenbedingungen mittels eines Experteninterviews mit dem Schulmensaverantwortlichen erhoben. Die Kundenzufriedenheit wird anhand eines schriftlichen Fragebogens ermittelt. Die Qualität des Mittagessens wird mit den Kriterien des DGE-Qualitätsstandards für die Schulverpflegung ausgewertet. Bei den SchülerInnen der sechsten und siebten Klassen werden zusätzlich anthropometrische Daten erhoben. Es werden Körpergröße und –gewicht gemessen. Weiterhin werden durch eine Bioelektrische Impedanzanalyse die Körperzusammensetzung und anhand eines Körpermaßbandes der Bauchumfang gemessen. Es werden zusätzlich zwei Ernährungsanamnesen, ein Food Frequency Questionnaire und ein 24h-Recall, durchgeführt. An der ersten (bzw. zweiten) schriftlichen Befragung beteiligen sich insgesamt 2991 (bzw. 2966) SchülerInnen, 1939 (bzw. 1785) Eltern und 143 (bzw. 114) LehrerInnen. Durch die Optimierungs- und Werbestrategien wird die Akzeptanz der Schulmensa bei den SchülerInnen, den LehrerInnen und den Eltern durch die Zusammenarbeit mit der Vernetzungsstelle Schulverpflegung Baden-Württemberg erhöht. Die Schulmensabenotung (Skala 1-5) wird bei den SchülerInnen und den Eltern von 2,8 auf 2,4 und bei den LehrerInnen von 2,5 auf 2,2 verbessert. Durch die Zusammenarbeit wird die Nährstoffzusammensetzung des Mensaessens nicht verbessert. Die SchülerInnen geben an, dass sie seltener in der Stadt essen und häufiger ein Vesper von daheim mitbringen bzw. zuhause essen. Allerdings wirken sich diese Änderungen im Essverhalten bzgl. der Mittagsverpflegung nicht auf die Gesamtnährstoffaufnahme der untersuchten SchülerInnen der sechsten und siebten Klassen (N Erste Erhebung=436, N Zweite Erhebung=413) aus. Somit werden auch die anthropometrischen Parameter und die Körperzusammensetzung der SchülerInnen nicht beeinflusst. Die Methoden der Vernetzungsstelle Schulverpflegung Baden-Württemberg können zur Akzeptanzsteigerung der Schulmensa erfolgreich eingesetzt werden. Gründe für die nicht eingetretenen Veränderungen in der Nährstoffaufnahme der SchülerInnen sind vielseitig zu diskutieren. Eine Erklärung ist, dass die Interventionsphase zu kurz ist, um einen messbaren Einfluss auf die Nährstoffaufnahme zu nehmen. Als Fazit aus der Zusammenarbeit kann gezogen werden, dass zur Verbesserung der Mittagsverpflegung die Schulmensa zunächst ins Schulleben integriert werden und eine Person an der Schule die Zuständigkeit übernehmen muss. Weiterhin müssen alle Beteiligten gemeinsam an der Optimierung arbeiten. Erst im zweiten Schritt sind Optimierungsstrategien, wie die Qualitätsverbesserung des Mensaessens, erfolgreich. Ist das Angebot für die SchülerInnen akzeptabel kann die Schulmensa im dritten Schritt gut beworben werden. Changes in society, such as growing number of employed women lead to a larger amount of schools in Baden-Württemberg that offer full time school programs. Due to this, the number of all day school pupils has more than tripled over the last 10 years (Landesinstitut für Schulentwicklung et al. 2011). As a result, in 2008, the Federal Ministry of Food, Agriculture and Consumer Protection set up the Vernetzungsstelle Schulverpflegung in Baden-Württemberg in joint financing with the Ministry of Rural Affairs and Consumer Protection. The Vernetzungsstelle Schulverpflegung Baden-Württemberg supports the schools in this new additional task of lunch catering and improves the quality and acceptance of the school meals in Baden-Württemberg. This study aims to evaluate and enhance the methods of the Vernetzungsstelle Schulverpflegung Baden-Württemberg to optimize the nutrition in educational institutions. For this purpose, ten schools with the corresponding seven canteens and 6000 pupils had been reviewed from June 2010 until October 2011 by the Vernetzungsstelle Schulverpflegung Baden-Württemberg. This supervision targets to improve the nutrition consumption of the pupils and thereby increase the amount of pupils with normal body-mass-index In order to reach this aim, both, the quality as well as the general requirements (e.g. menu, reservation) of the school lunch needs to be improved. Furthermore, the satisfaction of the customers as well as the resulting weekly participation in lunch at school canteens should be increased. Additionally, the pupils shall be sensitized for an appropriate diet. The “round table” is the fundament of the supervision of schools by the Vernetzungsstelle Schulverpflegung Baden-Württemberg. Several target groups come together to organize the improvement of the school canteen. For each school canteen, individual important optimizing and advertising strategies take place. Optimizing strategies include the training of caterers and canteen personal. Advertising strategies comprise several events, like pasta day or Santa Clause day, which help to raise the acceptance of the school canteen. To be able to measure the changes caused by intervention, an analyses takes place at the beginning and the end of the the study. For that, the surrounding conditions are evaluated by an expert interview with the responsible person of the school canteen. The satisfaction of the customers, such as pupils, teachers and parents is evaluated by written questionnaire. The quality of the lunch is analyzed by the criteria of the DGE quality standards of school feeding. Additionally, anthropometric data, like body height, body weight and abdominal girth, of six and seventh class pupils are measured. A bioelectric impedance analysis determines the body composition. Furthermore, a food frequency questionnaire and a 24h recall are conducted. Results of the study show, that during the time of intervention, on average 8 optimizing strategies and 15 advertising strategies are executed. 2991 (2966) pupils, 1939 (1785) parents and 143 (114) teachers take part at the first (second) survey. The cooperation of the schools with the Vernetzungsstelle Schulverpflegung Baden-Württemberg leads to an increased acceptance of the scool canteen by pupils, teachers and parents. Pupils and parents upgrade the school canteen judgment (scale 1-5) from 2,8 to 2,4 and teachers upgrade from 2,5 to 2,2. The cooperation doesn´t lead to an improvement of the nutrition composition of the canteen food. The pupils declare that they eat in the city more rarely, however rather bring food from home or eat at home. These changes in lunch habbits, though, do not have any impact on the total nutrition intake of the pupils from the sixth and seven grades (N first evaluation=436, N second evaluation=413). Therefore, neither the antropometroc parameters nor the body composition of the pupils are influenced. The methods of the Vernetzungsstelle Schulverpflegung Baden-Württemberg can be used successfully to raise the acceptance of the school canteen. Reasons, why there have been no changes in the nutrition intake of the pupils, can be discussed versatile. One explanation is that the intervention phase is too short in order to take measurable influence on the nutrition intake. As a result of the cooperation one can say that the school canteen initially needs to be integrated in every day school life, in order to improve the lunch catering. Moreover, the schools should make sure that one person takes responsibility for the catering. In addition to that, all involved parties have to work together on the optimization. Not until these points are settled, optimizing strategies, such as quality improvement of the canteen food, can´t be possible and successful. Finally, the food offer needs to be acceptable for the pupils, in order to be advertising in a good way.

The currently widespread abandoning of agricultural land use in Western Europe offers new opportunities for ecological restoration and nature conservation. This is illustrated for abandoned arable fields and for permanent grasslands cut for hay after the cessation of fertilizer application. Although initiated by a sudden reduction of nutrient input to the system, the changing nutrient supply from the soil is considered to be the main driving force of succession. The soil nutrient supply is affected by soil organisms, both directly (root symbionts and herbivores) and indirectly (nutrient mineralization from dead organic matter). It is argued that because of the close association of changes in species diversity with changes in the functioning of ecosystems, biodiversity has to be studied in an ecosystem ecology context.

The trophic transfer across phytoplankton-zooplankton interface is crucially important in aquatic food webs. The factors regulating the trophic transfer efficiency have been widely studied. There is an increasing awareness of food quality in terms of chemical composition of phytoplankton as the major control of the phytoplankton-zooplankton interaction via bottom-up processes. Nutrient availability has broad effects on chemical composition of phytoplankton. Other factors, e.g., dilution rate in continuous and semicontinuous cultures, can interact with nutrient supply and affect phytoplankton food quality, hence affecting the performance of zooplankton. This study aimed to investigate the effects of nitrogen (N):phosphorus (P) supply ratios and growth rates (dilution rates) on elemental and biochemical composition of marine phytoplankton, as well as the effects of food quantity and quality on the trophic transfer of essential chemicals and the performance of copepods. For this purpose, laboratory experiments were firstly conducted with three species of marine phytoplankton in semicontinuous cultures to test the interactive effect of five N:P supply ratios and four growth rates. Subsequent copepod experiments were performed with one species of marine copepods (Acartia tonsa) feeding on one phytoplankton species (Rhodomonas sp.), where the factors of food quantity and quality were crossed. The results in this thesis highlight the importance of simultaneous consideration of elemental and biochemical food quality for understanding the trophic transfer of energy and matter in food webs. Evaluating responses of this mutual regulation to multiple ambient factors is a necessary step towards the phytoplankton-zooplankton relationship in more realistic scenarios that will allow in the future the prediction of zooplankton’s performances in changing aquatic environments.

Sufficient nutrient and oxygen transport is a potent modulator of cell proliferation in in vitro tissue-engineered constructs. The lack of oxygen and culture medium can create a potentially lethal environment and limit cellular metabolic activity and growth. Diffusion through scaffold and multi-cellular tissue typically limits transport in vitro, leading to potential hypoxic regions and reduction in the viable tissue thickness. For the in vitro generation of clinically relevant tissue-engineered grafts, current nutrient diffusion limitations should be addressed. Major approaches to overcoming these include culture with bioreactors, scaffolds with artificial microvasculature, oxygen carriers and pre-vascularization of the engineered tissues. This study focuses on the development and utilization of a new perfusion culture system to provide adequate nutrient delivery to cells within large three-dimensional (3D) scaffolds. Perfusion of oxygenated culture medium through porous hollow fiber (HF) integrated within 3D free form fabricated (FFF) scaffolds is proposed. Mouse pre-myoblast (C2C12) cells cultured on scaffolds of poly(ethylene-oxide-terephthalate)–poly(butylene-terephthalate) block copolymer (300PEOT55PBT45) integrated with porous HF membranes of modified poly(ether-sulfone) (mPES, Gambro GmbH) is used as a model system. Various parameters such as fiber transport properties, fiber spacing within a scaffold and medium flow conditions are optimized. The results show that four HF membranes integrated with the scaffold significantly improve the cell density and cell distribution. This study provides a basis for the development of a new HF perfusion culture methodology to overcome the limitations of nutrient diffusion in the culture of large 3D tissue constructs.

The orchid family has about 30,000 species spread throughout most of the globe. Among the orchids, the group of Cattleya has great importance in the world flower market. One of the main forms of production of these plants is the in vitro assymbiotic seeding. Many have been the culture media used for sowing and growing orchids, however, these methods do not seem to fully supply the nutritional requirements of plants. There is, therefore, great interest in developing new culture media with nutritional composition that supplies properly the demand of the culture during the growing period promoting the production of tissues and the morphogenic response wanted. That was the aim of this work. To adjust the nutrient concentrations in the culture medium suitable for the growth of cattleya seedlings were considered the reference content in their tissues, the dry matter yield production, the volume of culture medium per vial and recovery rates of the nutrients by this culture. This medium was called the medium Supply (S). To compare this medium with others, Cattleya walkeriana protocorms were cultured for 51, 94, 139 and 190 d in MS medium, B5, B & G ( 3 g L-1 of fertilizer Orchidées B&G®), Peters (3 g L-1 of fertilizer Peters® 10-30-20) and S, and tested different concentrations of salts of the latter (0.55, 0.73, 1.00 and 1.45 as the concentration of salts). The medium S, proposed in this work, offered the optimum nutrient supply for the production of seedlings of Cattleya walkeriana when compared with other media. The concentration that provided maximum production of complete seedling was 1.125 time the original concentration of salts of the medium S. The media containing higher concentrations of N and lower P led to the rise in the levels of N and P (TN/TP) in tissue culture, which correlated positively with the ratio of dry matter yield of corn and total. High ratio TN/TP induced reduction in the production of roots. The relationship between the production of roots and leaves increased when the concentration of nutrients in the medium was reduced, because of the consumption of the culture or by reducing the concentration of salt in the medium S. A família orquidácea possui cerca de 30.000 espécies espalhadas por quase todo o globo terrestre. Dentre as orquídeas, o grupo das catléias tem grande importância no mercado mundial de flores. Uma das principais formas de produção dessas plantas é o semeio assimbiótico in vitro. Muitos têm sido os meios de cultura utilizados para o semeio e crescimento de orquídeas; no entanto, esses meios parecem não suprir totalmente as exigências nutricionais das plantas. Há, portanto, grande interesse em se desenvolverem novos meios de cultura com composição nutricional que supra adequadamente, durante o período de cultivo, a demanda da cultura, promovendo produção de tecidos e resposta morfogênica deseja. O que constituiu o objetivo deste trabalho. Para ajustar as concentrações dos nutrientes do meio de cultura adequado para o crescimento de plântulas de catléia foram considerados os teores de referência em seus tecidos, a produção de matéria seca, o volume de meio de cultura por frasco e as taxas de recuperação dos nutrientes por essa cultura. Este meio foi denominado de meio Suprimento (S). Para a comparação desse meio de cultura com outros, protocormos de Cattleya walkeriana foram cultivados, durante 51, 94, 139 e 190 d, nos meios MS, B5, B&G (3 g L-1 do fertilizante B&G Orchidées®), Peters (3 g L-1 do fertilizante Peters® 10-30-20) e S, sendo testadas diferentes concentrações dos sais deste último (0,55; 0,73; 1,00 e 1,45 vez a concentração dos sais). O meio S, proposto neste trabalho, ofereceu a melhor condição de suprimento nutricional para a produção de plântulas de Cattleya walkeriana quando comparado com os demais meios. A concentração que proporcionou a máxima produção de plântulas completas foi de 1,125 vez a concentração original de sais do meio S. Os meios contendo maiores concentrações de N e menores de P levaram ao aumento na relação entre os teores de N e P (TN/TP) nos tecidos da cultura, a qual apresentou elevada correlação positiva com a relação entre a produção de matéria seca de calo e total. Alta relação TN/TP induziu a redução na produção de raízes. A relação entre a produção de raízes e folhas aumentou quando a concentração dos nutrientes no meio foi reduzida, seja pelo consumo da cultura ou pela redução na concentração dos sais no meio S.

Establishment of nutrient management of citrus groves for high yield and superior crop quality is a need for efficient production. Limited phosphorus (P) availability of low fertility tropical soils in Brazil impairs citrus production since adequate P supply is important in the first years after field planting. Research has demonstrated that tree growth and fruit yield in response to P fertilization vary depending on rootstock varieties. Therefore, this study evaluated P uptake and redistribution by Pêra sweet orange on Rangpur lime or Cleopatra mandarin rootstocks initially grown in nutrient solution containing either deficient (0.005 mmol/L) or suficient(1.0 mmol/L) P levels. Each of these groups of plants was later half maintained in the deficient P whereas other half was changed to the suficient P solutions both labeled with 32P (14.8 MBq per 9.0 L pot). Plants were further grown for 50 days. Based on concentrations of P in plant parts derived from solution and P remobilized in plant, we observed that, despite variations on plant growth on different rootstocks, P taken up by those on Rangpur lime was superior confirming greater efficiency of nutrient uptake of this rootstock under a non mycorrhized condition. Estimates of P remobilized from plant reserve to young leaves suggested that the process was more marked for plants on Cleopatra mandarin irrespective to P treatments. These explained the fact that leaf visual symptoms of P deficiency are more frequent on trees on Cleopatra rootstock and presented the need to fine tune P fertilization recommendations.

Climatic conditions play an important role in agricultural production. It has a profound influence on the growth, development and yields of a crop, incidence of pests and diseases, water needs and fertilizer requirements in terms of differences in nutrient mobilization due to water stresses. Nowadays, we have to know the dark side of the weather events because it is causing more and more problems and significant hazards to many horticultural regions in Hungary. The aim of this study is to explore the problems of nutrient uptake following climatic anomalies and response. These problems are: (i) water supply problems (water-stress); (ii) drought and frost as temperature­ strees. Reviewing the effects and nutrient disorders caused by climatic anomalies, the following statements can be taken: Nutrient demand of trees can be supplied only under even worse conditions. The most effective weapon against damage of climatic anomalies is preventative action. When developing a fruit orchard, three factors should be taken into consideration: "Location, Location, Location". Moreover, proper choice of cultivars, species and cultivation should provide further possibilities to avoid and moderate the effects of climatic anomalies. Fruit growing technologies especially nutrition should be corrected and adjusted to the climatic events as modifier factors. Urgent task of the near future is to correct and adjust the tested technologies of fruit growing according to these climatic events as modifier factors. Optimal nutrient supply of trees decreases the sensitivity for unexpected climatic events. To solve these problems supplementary, foliar fertilization is recommended, which adjusted to phonological phases of trees. Another solving is groundcover of soil means a potential opportunity to temper or even avoid climatic anomalies.

Intervertebral disc (IVD) degeneration is characterized by alterations of the matrix structure and its biochemical composition, which may cause back pain. Reduction of nutrient supply (glucose), extracellular osmolarity and pH as well as variations of oxygen concentration are the principal alterations occurring in the microenvironment of IVD-cells during degeneration. In the present study, the effects of environmental alterations on gene expression of IVD-tissue proteins and matrix-degrading enzymes were analysed. Moreover, the influence of a varied microenvironment on IVD-cell responsivity to mechanical loading was investigated. IVD-cells were separately isolated from the annulus fibrosus (AF) and nucleus pulposus (NP) of bovine and human IVD-tissue. After cell expansion, NP-cells were seeded into alginate beads, while AF-cells were either cultured in monolayer or collagen-type-I-gels. In each experiment, a single environmental factor (osmolarity, glucose, oxygen, pH) was varied, whereas one condition reflected the average physiological value. All other factors remained normal. After 24 hours of incubation, IVD-cells were mechanically stimulated by their predominant physiological load (AF: cyclic strain, NP: cyclic hydrostatic pressure), while mechanically unloaded cell cultures of each respective condition served as controls. Directly after stimulation, gene expression was determined by quantitative RT-PCR, normalized to GAPDH and to the respective standard condition. Reduced pH and glucose supply significantly down-regulated gene expression of aggrecan, collagen-type-I and collagen-type-II by bovine NP-cells. Osmotic alterations influenced mainly aggrecan expression, whereas oxygen variations had minor effects. Mechanically induced effects on gene expression were modest. Under low glucose supply, mechanical loading tended to increase Sox-9, collagen-type-I and type-II, while matrix metalloproteinases were slightly down-regulated by exemplary human NP-cells. Under acidic pH, mechanical loading tended to reduce the down-regulation of matrix components in bovine NP-cells. These results suggest that degenerative alterations of the IVD-microenvironment may influence the degradation of the IVD-tissue by an imbalanced matrix turnover. Dynamic loading might have beneficial effects on IVD-matrix maintenance in individual donors.

Se estudió la capacidad de suplemento de N, P y K de 4 abonos orgánicos. Se utilizó 3 análisis: concentración total de nutrimentos, bioensayo microbiano, y extracción de nutrimentos en invernadero. Este último se realizó con los abonos puros y mezclados suelo: abono 4:1. Los materiales fueron 1 vermicomposte (estiércol de ganado vacuno) y 3 compostes (cachaza de caña de azúcar, broza de café y pulpa de naranja). Las concentraciones totales oscilaron entre 0,90-2,12% para N, 0,36-3,02% para P y 0,94- 2,21% para K. Con el bioensayo microbiano la disponibilidad a 3 meses plazo fue 12-30% para N, 6-23% para P y 5-9% para K. Se considera que esta metodología subestima la disponibilidad para este último elemento, aunque parece predecir adecuadamente la disponibilidad de N y P a corto plazo. Con la extracción de nutrimentos en invernadero con los abonos puros, la disponibilidad varió de 4-15% para N, 1-4% para P y 6-49% para K. Se encontró una alta correlación entre las metodologías de análisis de totales y el bioensayo microbiano y una buena correlación entre estos 2 métodos y el ensayo de extracción en invernadero, con los abonos orgánicos mezclados con suelo, pero no con materiales puros. Este trabajo aporta evidencia cuantitativa de la disponibilidad de N, P y K a partir de abonos orgánicos, que sin pretender ser definitiva, presenta valores que podrían ser utilizados como referencia para futuros trabajos.

3 páginas, 1 figura, 2 tablas., The objetive of this work was to study if the addition of nutrients to the irrigation water modified ‘Manzanilla de Sevilla’ olive pulp and pit growth. The experiment was carried out during the 2003 fruitgrowth period in an irrigated orchard near Seville, southern Spain. Fruit samples were taken in July and September, at 12 and 21 weeks after full bloom(AFB) respectively, in trees irrigated with (T1) or without (T0) the addition of nutrients (N–P–K). The nutrient availability of T1 fruits increased the fruit fresh and dry weight, longitudinal and equatorial diameters, and the pulp-to-pit ratio, characteristics particularly appreciated for table olives. The balance of growth between the fruit mesocarp (pulp) and endocarp (pit) was modified because those two tissues were affected differently. Mesocarp fresh weight was significantly higher at both 12 and 21 weeks AFB in the fertilized treatment, as was mesocarp dry weight at 12 weeks AFB. Neither the endocarp fresh and dry weight nor shape (the ratio of the equatorial and longitudinal diameters) was altered at either of the two studied dates. These results emphasize the importance of an appropriate fertilization management in irrigated olive orchards, particularly for table olives, and also confirm the olive endocarp as a strong sink tissue that competes with the mesocarp during early development., This work was supported by the Programa de Mejora de la Calidad de la Producción del Aceite de Oliva (Olive Oil Quality Improvement)-CAO 98-004.

Fire and herbivory are known to modify plant community structure. Many studies have suggested that fire ashes may increase soil nutrients in dystrophic soils. Herbivores may also change plant community structure through direct effects of herbivory and affecting nutrient cycling. Leaf-cutting ants were traditionally viewed as herbivores, although their role may be more complex, because their nests affect both chemical and physical soil properties, thus affecting plants indirectly. We investigated the effects of frequent burning and of leaf-cutting ants on the nutrient status of an herbaceous and a shrub species occurring in the Brazilian Cerrado, a habitat that is characterized by natural burnings. The proximity of ant nests resulted in an increase of nutrients in the leaves of both vegetation strata, whereas burning sometimes resulted in a decrease of nutrients. Our results do not lead to a possible positive effect of fire on plant nutrient content. On the other hand, ant nests may represent an important source of nutrients for plants on the nutrient-depleted Cerrado soils and may accelerate vegetation recovery after burning.

Personalised, genotype-based nutrition is a concept that links genotyping with specific nutritional advice in order to improve the prevention of nutrition-associated, chronic diseases. This review describes the current scientific basis of the concept and discusses its problems. There is convincing evidence that variant genes may indeed determine the biological response to nutrients. The effects of single-gene variants on risk or risk factor levels of a complex disease are, however, usually small and sometimes inconsistent. Thus, information on the effects of combinations of relevant gene variants appears to be required in order to improve the predictive precision of the genetic information. Furthermore, very few associations between genotype and response have been tested for causality in human intervention studies, and little is known about potential adverse effects of a genotype-derived intervention. These issues need to be addressed before genotyping can become an acceptable method to guide nutritional recommendations. © The Authors 2007.

International audience; Several studies on coupled physical-biogeochemical models have shown that major deficiencies in the biogeochemical fields arise from the deficiencies in the physical flow fields. This paper examines the improvement of the physics through data assimilation, and the subsequent impact on the ecosystem response in a coupled model of the North Atlantic. Sea surface temperature and sea surface height data are assimilated with a sequential method based on the SEEK filter adapted to the coupling needs. The model domain covers the Atlantic from 20°S to 70°N at eddy-permitting resolution. The biogeochemical model is a NPZD-DOM model based on the P3ZD formulation. The results of an annual assimilated simulation are compared with an annual free simulation. With assimilation, the representation of the mixed layer depth is significantly improved in mid latitudes, even though the mixed layer depth is generally overestimated compared to the observations. The representation of the mean and variance of the currents is also significantly improved. The nutrient input in the euphotic zone is used to assess the data assimilation impact on the ecosystem. Data assimilation results in a 50% reduction of the input due to vertical mixing in mid-latitudes, and in a four- to six-fold increase of the advective fluxes in mid-latitudes and subtropics. Averaged zonally, the net impact is a threefold increase for the subtropical gyre, and a moderate (20-30%) decrease at mid and high latitudes. Surface chlorophyll concentration increases along the subtropical gyre borders, but little changes are detected at mid and high latitudes. An increase of the primary production appears along the Gulf Stream path, but it represents only 12% on average for mid and high latitudes. In the subtropical gyre centre, primary production is augmented but stays underestimated (20% of observations). These experiments show the benefits of physical data assimilation in coupled physical-biogeochemical applications.

Pepper, despite being among the vegetables consumed in largest quantities, does not play an important role as a nitrate source due to the low nitrate accumulation capacity of the cultivars grown in Hungary. Iii the classification of the average nitrate levels or that of the detected hazardous levels it can be sorted into the very 'favorable' class not exceeding 200 and 500 mg/kg respectively. The different elements of the production technology, this way the N supply, do not influence significantly the amount of nitrate accumulated within pepper fruits.

Megállapítható, hogy a megfelelő dózisú kezelések hatására a hozamnövekedésből adódó árbevétel-növekedés többszöröse a kezelés költségének. A bokrosodáskor végzett kezelésekben az 1,0 kg/ha-os réz-szénhidrát komplexes kezelés volt a legeredményesebb. A virágzáskor szintén a magasabb hozamot adó dózisok hozták a legnagyobb hasznot, így a 0,5 kg/ha-os dózis alkalmazása célravezető. A kísérletek alkalmazásának másik pozitívuma, hogy a szénhidrát és réztartalmú hulladékok újrahasznosítása a környezetszennyezést is csökkenti. ---------------------------------------------------- It can be stated that extra income from increased yield following treatment with an appropriate dose exceeds several times the costs involved. At the shrubbing stage treatment at 1,0kg/ha cupper-carbonhydrate complex proved to be the most effective. At the time of flowering doses bringing higher yields turned out to be the most profitable therefore the application of a dose of 0,5kg/ha appear to be expedient. Another positive element of these experiments is that re-cycling of cupper and carbonhydrate wastes reduces environmental pollution.

Several studies on coupled physical–biogeochemical models have shown that major deficiencies in the biogeochemical fieldsarise from the deficiencies in the physical flow fields. This paper examines the improvement of the physics through dataassimilation, and the subsequent impact on the ecosystem response in a coupled model of the North Atlantic. Sea surfacetemperature and sea surface height data are assimilated with a sequential method based on the SEEK filter adapted to the couplingneeds. The model domain covers the Atlantic from 20°S to 70°N at eddy-permitting resolution. The biogeochemical model is aNPZD-DOM model based on the P3ZD formulation. The results of an annual assimilated simulation are compared with an annualfree simulation.With assimilation, the representation of the mixed layer depth is significantly improved in mid latitudes, even though the mixedlayer depth is generally overestimated compared to the observations. The representation of the mean and variance of the currents isalso significantly improved.The nutrient input in the euphotic zone is used to assess the data assimilation impact on the ecosystem. Data assimilation resultsin a 50% reduction of the input due to vertical mixing in mid-latitudes, and in a four- to six-fold increase of the advective fluxes inmid-latitudes and subtropics. Averaged zonally, the net impact is a threefold increase for the subtropical gyre, and a moderate (20–30%) decrease at mid and high latitudes.Surface chlorophyll concentration increases along the subtropical gyre borders, but little changes are detected at mid and highlatitudes. An increase of the primary production appears along the Gulf Stream path, but it represents only 12% on average for midand high latitudes. In the subtropical gyre centre, primary production is augmented but stays underestimated (20% of observations).These experiments show the benefits of physical data assimilation in coupled physical–biogeochemical applications.

A 5-year study of the reforestation of a semiarid Mediterranean ecosystem with Pinus halepensis is presented. Reforestation of Mediterranean semiarid ecosystems is challenging as a result of harsh environmental conditions and historical human exploitation leading to degradation. New techniques have to be developed in order to increase survivorship and growth that integrates nursery and field treatments. A total of 60 treatments resulting from 12 site × 5 plant preparation techniques were tested. Plant preparation consists of mycorrhizing in nursery, extra fertilizing in nursery, planting in containers in the nursery, planting in the field with a polypropylene tube, and control plants (bred in plastic bags). Soil preparation consists of hole, subsoiling without amendment, subsoiling with composted organic amendment added in the surface or in the furrow of plantation and subsoiling with fresh organic amendment added in the surface or in the furrow of plantation. Each one of these treatments was tested with a hydrophilic acrylic copolymer and without it. Survivorship was very high (0.91) given the prevailing environmental conditions. Subsoiling promoted higher survival than holes, and plants bred in containers had lower levels of survivorship than control ones. Protecting seedlings with polypropylene tubes had no effect on survivorship. The most effective treatment for promoting growth was organic amendment, the effect of which increased until the fourth year. Protection with tubes was very effective in increasing height, although only in the short-term. Subsoiling also promoted faster growth than holes, although the effect was less noticeable after 3 years and was, in any case, less effective than organic amendment. Other treatments promoting faster growth were the use of fresh organic waste as opposed to composted waste and its incorporation in the plantation furrow rather than as a layer on the surface. The addition of hydrophilic acrylic copolymer reduced growth during the first months of the reforestation. The fertilization of plants in the nursery and inoculation with spores of mycorhyzal fungi did not improve seedling growth. Plants bred in containers performed worse than control plants bred in individual plastic bags. The findings suggests the importance of nutrient supply in semiarid environments, an aspect that has been previously neglected in favor of water supply. Organic amendments reinforce both and can be recommended as long as adequate environmental controls are in place., This work was supported by the Spanish National Plan of RþD (Project AGF99- 1132).

As recomendações de adubação para a cultura da bananeira devem ser mais confiáveis do ponto de vista técnico e, principalmente, mais propensas a ajustes com bases científicas, em relação às tabelas. O objetivo deste trabalho foi desenvolver um sistema para estimar doses de nutrientes a serem recomendadas para a cultura da bananeira (FERTICALC®-Bananeira), por meio da modelagem do balanço nutricional. O balanço nutricional é obtido pela diferença entre o requerimento do nutriente pela cultura e seu suprimento pelo solo e resíduos vegetais. Se o requerimento for maior que o suprimento, recomenda-se a aplicação de fertilizante; se for inferior ou igual ao suprimento, não se recomenda a aplicação de fertilizante. Simulações mostraram que as doses de nutrientes a serem recomendadas pelo FERTICALC®-Bananeira aumentam continuamente com o aumento da produtividade esperada e com a diminuição dos teores desses nutrientes no solo, sendo maiores no primeiro ciclo e menores a partir do segundo ciclo. Considerando a lógica envolvida em sua constituição e as variáveis utilizadas na modelagem do FERTICALC®-Bananeira, este sistema constitui importante alternativa para recomendação de adubação para a cultura da bananeira. Fertilizer recommendations for banana plantations should be technically sound and, mainly, more adjustable on a scientific base than the usual recommendation tables. A system was developed to estimate recommendable nutrient doses for banana (FERTICALC®-Bananeira), by means of modeling nutrient balance. This nutrient balance is obtained by the difference between the crop nutrient demand and supply through soil and plant residues. When the demand is higher than the supply, fertilizer application is recommended; when it is lower or equal to the supply, fertilizer application is not recommended. Simulations showed that the recommendable nutrient doses by the FERTICALC®-Bananeira increase continuously with the expected productivity rise and the reduction of nutrient contents in the soil that are higher in the first cycle and lower from the second cycle on. The FERTICALC®-Bananeira represents an important alternative for the recommendation of fertilizers for banana plantations due to the underlying logic and variables.

Introduction. The effects of global and local changes are most prominent at the land-sea margins where presently population growth is greatest. For example, the population of coastal counties of the USA has roughly doubled since 1960 (Eos, 1992). This gives rise to increased pressure on natural resources and a large number of disturbances to coastal regions. Presently, eutrophication of coastal waters is probably the most important environmental effect (Gesamp, 1991). The effects of nutrient enrichment thoroughly change coastal ecosystems and occur virtually worldwide. Nutrients move across the land-sea margins at such high rates that coastal waters and estuaries are the most fertilized ecosystems on earth (Figure 9.1).

The effects of soil drying on the activity of nitrate reductase (NR; EC 1.6.6.6) were studied in Helianthus annuus L. and non-nodulated Lupinus albus L. plants growing under two nutrient supply regimes. NR activity was assessed in leaf and root extracts by measuring the activity of the unphosphorylated active form (NR act ), the maximal extractable activity (NR max ) and the activation state. To obtain an insight into potential signalling compounds, nitrate, free amino acids and soluble sugars were also quantified. In both species, foliar NR act and NR max were negatively affected by soil drying and a decreased supply of nutrients, the observed changes in NR activity being linearly correlated with the depletion of nitrate. Similar results were obtained in the roots of sunflower. Conversely, in white lupin roots, NR max was found to be independent of tissue nitrate concentration. Regardless of the species and organ, the activation state of the enzyme was unaffected by the nutrient supply regime. In well-watered sunflower roots, only about 50% of the existing NR was unphosphorylated, but the activation state increased significantly in response to drought. In contrast, lupin roots always exhibited NR activation state values close to 80%, or even higher. At the leaf level, the NR activation state was hardly changed in response to soil drying. The observed changes in the concentrations of soluble sugars and free amino acids are discussed in terms of their possible contribution to the variations in NR activity.

Free amino acids, polyphenols and caffeine are particularly important groups of compounds for taste and quality of green tea infusions. The influence of nutrient supply on their accumulation in tea plants was investigated under controlled conditions. Plants supplied with NO3- grew much slower than those receiving NH4+ or NH4++NO3-. Concentrations of free amino acids in young tea shoots were considerably larger in NH4+- than in NO3--fed plants, attributing to the larger absorption rate of NH4+ than NO3- and their compartmental assimilation. Biosynthesis of catechins was reduced by the highest N supply due to more carbon resources were allocated to N metabolism. With the highest N supply, relatively more absorbed N was allocated to synthesis of arginine and glutamine with low C : N ratios to improve carbon economy. Application of Cl reduced the concentrations of total free amino acid and theanine in young shoots but did not affect theanine in roots, NH4+ uptake rate and GS activity. It is suggested that Cl might influnce translocation of theanine from root to shoot and its further catabolism in the young shoots.

14 pages, 3 figures, 3 tables, The species composition of spring blooms varies over open marine regions, displaying both spatial and inter-annual differences. We used semi-continuous cultures to promote species-specific blooms and investigate associated microbial food-web dynamics and inorganic nutrient utilization. Beginning with high-nutrient, low-biomass water from 13 in depth, we compared the changes that took place over 9 d in 2 treatments: (1) NEW, a 'new-nutrient' treatment that simulated horizontal or vertical advection; every 2 d, both particles and dissolved organic matter were removed and ca. 25 % of the volume of the container was replaced with nutrient-rich seawater from 200 m depth. (2) REC, a recycling treatment simulating grazing and sinking losses without nutrient replacement, i.e. conditions mimicking sharply stratified water columns; in this treatment the same volume of water was removed, but was then returned to the container following filtration through a 2.0 μm filter. In the NEW treatment, diatoms consumed the added nutrients and dominated the production and biomass of the protist community. Total protist community production in the REC treatment was significantly lower than in the NEW treatment, with either a late or no diatom bloom and prymnesiophytes such as Phaeocystis spp. attaining higher proportional biomass. Total production rates for heterotrophic protists, bacteria and viruses did not differ significantly between treatments. Nutrient consumption by the ensuing communities differed between the 2 treatments, with a significantly greater proportion of total inorganic nutrients consumed in the NEW than in the REC treatment. The results demonstrate that the character of nutrient supply and loss influences protist community structure and subsequent bulk nutrient utilization, The Natural Sciences and Research Council of Canada (NSERC) and the Department of Fisheries and Oceans Canada funded the International North Water Polynya Study led by Dr. L. Fortier. NSERC and the fonds of FCAR Québec also provided support to GIROQ (Groupe Interuniversitaire de Recherches Océanographiques du Québec). C.L. was supported by NSERC postgraduate fellowships throughout the study

Minimisation of nutrient and water loss to the environment, prediction and planning of production and product quality, such that they meet the demands of customers, and increased financial return are some of the goals of current greenhouse horticulture. This requires an integrated system for monitoring and control of the nutrient solution, plant growth and product quality. This paper describes the components of such a system. Tomato was selected as example crop. Plant sensors for photosynthesis, radiation interception and fresh growth rate were developed and tested, and the combined plant-substrate model was validated against greenhouse experiments and commercial growth data. Techniques for auto-calibration of the crop model with sensor information were developed. Scenarios describing various fertigation regimes were defined, and a technique for the generation of set points for water and nutrient application on the basis of pre-defined optimisation goals was developed. These goals included drainage volume and nutrient concentration, nutrient application rate, fruit dry matter concentration, and fruit growth rate. The overall system was evaluated in a greenhouse experiment. In comparison with simulated ‘normal’ cultivation, optimisation of water and nutrient application indeed resulted in reduced application and drainage rates, increased fruit growth rate, and a dry matter concentration that met the optimisation goal. In conclusion, the monitoring and control system offers good prospects for efficient control of water and nutrient use, and control of crop growth in future control of greenhouse cropping systems.