Zugl.: Hohenheim, Univ., Habil.-Schr., 2000

Folienmanagement ist von wirtschaftlicher Bedeutung im Freiland-Gemüsebau im Frühjahr. Aber die Prognose des optimalen Zeitpunktes der Abnahme von Plastik-Abdeckungen vom Bestand ist mit den bereits verfügbaren Mitteln zu ungenau, um die heutigen Anforderungen an die Produktionssicherheit zu erfüllen. Der bislang verwendete empirische Ansatz benötigt aktuelle Referenzmessungen unter den Abdeckungen, welche kostspielig sind. Das Ziel dieser Arbeit war es, die Grundlagen eines mechanistischeren Modellansatzes zu entwickeln, welcher auf dem physikalischen und biologischen Verständnis von Energiehaushalt, Pflanzenwachstum und den Prozessen der Qualitätsentwicklung unter den Abdeckungen beruht, um die zukünftige Produktionssicherheit zu verbessern. Entsprechende Feldversuche wurden durchgeführt, um Daten zum Pflanzenwachstum und Mikroklima unter und über der Abdeckung zu erhalten und neue sowie etablierte Untermodelle zu parametrisieren. Weiterhin wurden Laborversuche zum Verständnis z.B. der optischen Eigenschaften der Abdeckungen, Blätter und des Bodens ausgeführt. Außerdem wurde eine neue Methode zur Bestimmung des Blattflächenindex bei Kopfsalat und Kohlrabi geprüft und für die effiziente Erhebung der Pflanzendaten etabliert (Sandmann et al. 2013). Im Ergebnis können nun verschiedene Prozesse der Gemüseproduktion unter Abdeckungen besser verstanden und mit hinreichender Genauigkeit mathematisch beschrieben werden, z.B. Strahlungshaushalt (Graefe & Sandmann 2014) und Blattflächenwachstum. Die meisten Ziele der Arbeit wurden erreicht. Weitere Arbeit ist vor allem notwendig für die Modellierung der Lufttemperatur unter der Abdeckung und die Entwicklung eines mechanistischen Ansatzes zur Beschreibung der Pflanzenqualität. Hier konnte die Pflanzenqualität wegen der subjektiv beeinflussten Daten nur über einen empirischen Ansatz modelliert werden. Die übliche Erfassung der Pflanzenqualität sollte überdacht werden, um zukünftig möglichst objektive Werte zu erhalten. / Plastic film management is economically of importance for vegetable growing in the field in early spring, but the prediction of the best moment of removal of plastics from the crops is currently too imprecise to fulfill contemporary requirements in production safety. The broadly used approach for prediction is of empirical nature and is depending on current reference data from below covers, which are expensive to gather. The aim of this thesis was to develop the scientific foundations for a more mechanistic model approach, based on the physical and biological understanding of the energy balance, plant growth and plant quality formation process below plastic covers in order to increase future production safety. Field trials at three sites, with two species and several cover materials and removal strategies were carried out to gain data from plants and microclimate beneath and above covers for parameterization of new and established submodels. Additionally, laboratory experiments were performed to understand e.g. the optical properties of plastics, leaves and soil. Furthermore, a new method for determining leaf area index in lettuce and kohlrabi was adopted and established for a more efficient plant data collection (Sandmann et al. 2013). As a result, several processes of vegetable production using plastic covers are now better understood and can be described mathematically and sufficiently precise, e.g. the short wave radiation budget (Graefe & Sandmann 2014) and leaf area growth. Most, but not all aims of the thesis could be achieved. Further work will be necessary according to modeling of air temperature below the covers, leaf gas exchange and the development of a mechanistic approach for plant quality formation. Here, plant quality could only be modelled via an empirical approach, due to subjectively influenced data. Common plant quality data acquisition should be reconsidered to yield as much as possible objective values in the future.

<p>U ovom radu su ispitani hemijski sastav i biolo&scaron;ka aktivnost vrsta&nbsp;<em> Brassica oleracea&nbsp; </em>i<em>&nbsp; Brassica rapa</em>&nbsp; poreklom iz organskog i konvencionalnog sistema proizvodnje. Ispitivanja hemijskog sastava su obuhvatila određivanje volatilnih komponenata primenom headspace GC-MS tehnike, kvalitativnu analizu sokova ispitivanih vrsta pomoću LC-DAD-MS/MS tehnike, kvantifikaciju odabranih fenolnih jedinjenja&nbsp;pomoću LC-MS/MS tehnike i spektrofotometrijsko određivanje sadržaja ukupnih glukozinolata, fenola i flavonoida i sadržaja ukupnih monomernih antocijana. Biolo&scaron;ka aktivnost povrća je ispitana određivanjem antioksidantnog potencijal, antimikrobne i antitumorske aktivnosti sokova. Dobijeni rezultati pokazuju da su glavne volatilne komponente ispitivanih vrsta degradacioni proizvodi masnih kiselina i organosumpornih jedinjenja od kojih neke od identifikovanih komponenata predstavljaju ključne mirisne komponente. Na osnovu njihove distribucije nije bilo moguće utvrditi uticaj sistema proizvodnje na miris i ukus ispitivanih vrsta. Pomoću LC-DAD-MS/MS i LC-MS/MS tehnike je utvrđeno prisustvo primarnih metabolita, slobodnih hidroksibenzoevih i hidroksicimetnih kiselina, derivate hinske kiseline&nbsp;sa hidroksicimetnim kiselinama, glikozida flavonola, biflavonoida, i kumarina u sokovima spitivanih vrsta. Pored toga u svim sokovima subili prisutni kondenzacioni proizvodi degradacionih proizvoda indolnih glukozinolata sa askorbinskom kiselinom-&nbsp; askorbigen i metoksiaskorbigen. U sokovima crvenog kupusa su bili prisutni antocijani. Najveći sadržaj ukupnih glukozinolata je određen u brokoliju, dok je crveni kupus sadržao najveći sadržaj ukupnih fenola ukupnih flavonoida kao i hinske kiseline. Crveni kupus je bio varijetet koji je ispoljio najvi&scaron;i antioksidantni kapacitet u svim primenjenim testovima, brokoli i karfiol su ispoljili najjaču antimikrobnu aktivnost, dok je kelj bio varijetet sa najjačim antitumorskim delovanjem. Na osnovu analize hemijskog sastava i biolo&scaron;ke aktivnosti vrsta <em>B</em>. <span id="cke_bm_177S" style="display: none;">&nbsp;</span><em>oleracea</em><span id="cke_bm_177E" style="display: none;">&nbsp;</span> i&nbsp;<em> B. rapa</em>&nbsp; može se <span id="cke_bm_178E" style="display: none;">&nbsp;</span>zaključiti da u zavisnosti od primenjenog tipa&nbsp;proizvodnje mogu biti pobolj&scaron;ane neke od karakteristika ispitivanih vrsta i da je uticaj sistema proizvodnje značajan za pojedine varijetete, a nikako za celu vrstu. U konačnom obliku može se zaključiti da bi potencijalna kombinacija sokova crvenog kupusa, brokolija, karfiola i kelja mogla ostvariti značajno hemopreventivno i hemoterapeutsko delovanje, ispoljavajući istovremeno antioksidantnu, antimikrobnu i antitumorsku aktivnost.</p> / <p>Chemical composition and biological activity of<em>&nbsp; Brassica oleracea</em>&nbsp; and&nbsp; <em>B. rapa&nbsp;</em> species were investigated in the present work. Investigation of chemical composition&nbsp; encompassed determination of volatile compounds by headspace GC-MS technique, qualitative analysis of juices of investigated vegetables by LC-DAD-MS/MS technique, quantification of selected phenolic compounds by LC-MS/MS technique and spectrophotometric determination of total content of glucosinolates, phenolic compounds and flavonoids and total content of monomeric anthocyanes. Biological activity of vegetables was investigated by determination of antioxidant capacity, antimicrobial and antitumorigenic effect of juices. Obtained results showed that main volatile compounds were degradation products of fatty acids and organo-sulphur compounds among which some of the identified components were the key aroma compounds. Based on their distribution it was not possible to evaluate influence of cropping system on aroma and taste of investigated species. By LC-DAD-MS/MS and LC-MS/MS techniques, it was determined the presence of primary metabolites, freehydroxybenzoic and hydroxycinnamic acids, derivatives of quinic acid and hidroxicinnamic acids, flavonol glucosides, biflavnoids&nbsp; and a cumarin in juices of the investigated species. Furthermore, condensation products of degradation products of indole glucosinolates with ascorbic acid-&nbsp; ascorbigen and metoxiascorbigen were present in all juices. Anthocyanes were present in juices of red cabbage. The highest total content of glucosinolates was determined in broccoli, while red cabbage had the highest total phenolic content, total flavonoid content, as well as content of qunic acid. Red cabbage was a variety that showed the highest antioxidant capacity measured by different assays. Broccoli and cauliflower expressed the highest antimicrobial potential, while Savoy cabbage was a variety with the highest antitumor effect. Investigation of chemical composition and biological activity showed that applied cropping conditions may be useful for improving some of the characteristics of investigated species and significance of cropping system only&nbsp; for particular varieties, but not for the whole species in general. As the conclusion, potential&nbsp; combination of juices of red cabbage, broccoli, cauliflower and Savoy cabbage could be potent chemopreventive and chemotherapeutic agent, expressing simultaneously antioxidant, antimicrobial and antitumor activity.</p>