In a global warming scenario, an increase temperature is expected in addition to the occurrence and intensity of extreme climate events. One example of extreme events is the marine heat waves, which are a major threat to marine macroalgae. Ulva fasciata is a cosmopolitan species that occur in the whole Brazilian coast. This study was performed in two regions of Rio de Janeiro State (RJ) coast. Both regions are tropical, however, Arraial do Cabo/RJ is naturally colder than Niterói/RJ due upwelling phenomenon. This study aimed to: (i) confirm that U. fasciata individuals from these two Brazilian coast regions are of the same species; and (ii), physiologically analyze individuals of U. fasciata in the field and under in-laboratory controlled temperature experiment. We hypothesized that U. fasciata populations grown at thermally different locations would present distinct ecophysiological responses. In the field, it was accessed maximum quantum yield (Fv/Fm) and pigment content, and in laboratory, it was also evaluated growth rate. The in-laboratory controlled experiment comprised three phases: (i) a temperature gradient; (ii) a 5-day heat wave (+ 5 oC); and (iii) a 5-day recovery (- 5 oC). The molecular data allow us to state that the two populations belong to the same species. No differences of the fluorescence-derived factors were observed between individuals from both populations in the field, suggesting acclimation. However, differences were detected along all three experimental phases. The analysis of pigment content field data evidenced that individuals from the population of Niterói (warmer site) had higher concentrations of chlorophyll a than individuals from Arraial do Cabo (colder site). However, individuals of population from Niterói when cultured at 21 oC showed the lowest values of pigment. The differences observed suggest ecotypes. In conclusion, as the planet becomes warmer and extreme weather events become more frequent, the likelihood that heat wave to occur is higher. Therefore, U. fasciata from Arraial do Cabo showed better physiological responses to the effects of heat wave, what could confer them higher competitiveness ability to overcome thermal stress / Num cenário de aquecimento global, um aumento da temperatura é esperado, assim como a ocorrência e intensidade de eventos climáticos extremos. Um exemplo de evento extremo são as ondas de calor marinhas, que são a principal ameaça a macroalgas marinhas. Ulva fasciata é uma espécie cosmopolita que ocorre em toda costa brasileira. Esse estudo foi realizado em duas regiões da costa do Estado do Rio de Janeiro (RJ). Ambas regiões são tropicais, mas Arraial do Cabo/RJ é naturalmente mais fria que Niterói/RJ devido ao fenômeno de ressurgência. Esse estudo objetivou: (i), confirmar que os indivíduos de U. fasciata dessas duas localidades da costa brasileira são da mesma espécie; e (ii) analisar fisiologicamente indivíduos de U. fasciata em campo e em experimentos de temperatura em condições controladas de laboratório. Nossa hipótese era de que populações de U. fasciata procedentes de localidades termicamente diferentes iriam apresentar respostas ecofisiológicas distintas. Em campo, foi acessado o rendimento quântico máximo (Fv/Fm) e o conteúdo pigmentar, e em laboratório, foi também avaliada a taxa de crescimento. O experimento em condições controladas de laboratório consistiu de três fases: (i) gradiente de temperatura; (ii) onda de calor (+5 oC) de 5 dias; e (iii) recuperação (- 4 oC) de 5 dias. Os dados moleculares permitiram afirmar que as duas populações pertencem à mesma espécie. Não foram detectadas diferenças nos fatores derivados da fluorescência entre os indivíduos das duas populações avaliadas em campo, sugerindo aclimatação. Contudo, foram detectadas diferenças ao longo das três fases experimentais. A análise do conteúdo pigmentar em campo evidenciou que os indivíduos da população de Niterói (região mais quente) tinham mais clorofila a do que os indivíduos de Arraial do Cabo (região mais fria). No entanto, indivíduos da população de Niterói, quando cultivados em 21 oC, mostraram valores menores de pigmentos. As diferenças observadas sugerem ecótipos. Em conclusão, conforme o planeta se torna mais quente e eventos extremos climáticos se tornam mais frequentes, a probabilidade de ocorrência de ondas de calor é maior. Dessa forma, U. fasciata de Arraial do Cabo mostro melhor resposta fisiológica aos efeitos da onda de calor, o que lhe pode conferir maior capacidade de competição para superar estresses térmicos

Fusarium-Infektionen sind ein ernstes Problem im Weizenanbau, da die ausgeschiedenen Mykotoxine gesundheitsschädlich sind. Die Krankheitssymptome sind durch bildanalytische Methoden im Vorfeld der Ernte detektierbar, so dass befallene Partien getrennt geerntet werden könnten. Künstlich mit Fusarium culmorum infizierte Weizenpflanzen wurden mittels Chlorophyllfluoreszenz- und hyperspektraler Bildanalyse in Zeitreihenversuchen analysiert. Bei den Chlorophyllfluoreszenz-Bildanalysen wurde die photosynthetische Effizienz (Fv/Fm) und deren räumliche Ungleichverteilung genutzt, um den Effekt des Krankheitsgrades auf die photosynthetische Aktivität zu ermitteln. Mit dieser Methode ist eine sehr frühzeitige Erkennung möglich, da eine Verringerung der photosynthetischen Effizienz bei den kranken Ähren zwischen dem 6. und 11. Tag nach Inokulation festgestellt wurde. Der Befallsgrad korreliert mit der photosynthetischen Effizienz. Die Berechnung des kumulativen Fv/Fm bei 0,3 führte zu einer sehr effektiven und genauen Erkennung der Partiellen Taubährigkeit ab einem Befallsgrad von mindestens 5% und einer Differenzierungsgenauigkeit von 10%. Die Chlorophyllfluoreszenz-Bildanalyse war unter Freilandbedingungen bei Einhaltung der Rahmenbedingungen zur Fusarium-Erkennung ebenfalls möglich, wenn auch mit schlechteren Erkennungsraten. Die Aufnahmen im Labor mit einem hyperspektralen Bildanalysesystem im Spektralbereich von 400-1000 nm zeigten Unterschiede in distinkten Wellenlängenbereichen und lassen die Erkennung kranker Ähren in einem Zeitfenster von BBCH 71 bis BBCH 85 zu. Die bildanalytische Klassifizierung mittels des „Spectral Angle Mapper“ liefert gute Ergebnisse, ist aber sehr zeitaufwändig. Alternativ dazu nutzt der neu erstellte head blight-Index (HBI) die spektralen Unterschiede im Bereich 665-675 nm und 550-560 nm und kann eine feldtaugliche Klassifizierungsmöglichkeit zur Erkennung von Partieller Taubährigkeit sein. / Fusarium infections are serious problems in wheat production. Mycotoxins, synthesised by the fungi, are toxic and harmful in both human and animal nutrition. The symptoms of this so-called head blight disease caused by Fusarium spp. are recognizable by various image analysis methods prior to harvest. Using this information, farmer could differently utilize affected cereals, if necessary. Healthy and artificially Fusarium culmorum-infected wheat plants were analyzed with a chlorophyll fluorescence and hyper-spectral imaging system in time series. With chlorophyll fluorescence imaging (CFA), the potential maximum photochemical efficiency (Fv/Fm) and its spatially variable distribution was analyzed to determine the interactions between the degree of disease and the photosynthetic activity. By means of this method, early recognition was reliably achieved by a decreased photochemical efficiency in diseased ears between 6th and 11th day after inoculation. The degree of disease correlated with photochemical efficiency. At a degree of Fusarium infection of 5% and higher, calculation of the cumulative Fv/Fm at 0.3 enabled a very effective and precise determination of Fusarium head blight with a differentiation accuracy of at least 10%. Though less effective, CFA successfully detected head blight under outdoor conditions, if some boundary conditions (e.g. no direct solar irradiation) were observed. In the laboratory, a hyperspectral imaging system (wave length range 400 to 1000 nm) indicated specific spectral differences between affected and unaffected wheat ears. These differences allowed head blight recognition during BBCH 71 to BBCH 85. Imaging classification with the “Spectral Angle Mapper” method achieved good results; it is, however, very time-consuming. Alternatively, the newly derived head blight index (HBI), using spectral differences in the wave length ranges of 665 to 675 nm and 550 to 560 nm, can be a suitable outdoor classification method to evaluate head blight.

The initiation, persistence, and termination of harmful algal blooms (HABs) can all be influenced by nutrient availability. Recent studies have highlighted the role of both organic and inorganic nitrogen sources in HAB dynamics. The pelagophyte Aureoumbra lagunensis causes ecosystem disruptive algal blooms and is responsible for the longest recorded harmful algal bloom (1989-1997). Because of Aureoumbra's small size and its inability to use nitrate, it has been hypothesized that its ability to use ammonium and organic nitrogen, especially at low concentrations, contributed to the unusual persistence of this bloom. This project aimed to assess the response of Aureoumbra to inorganic and organic nitrogen sources by examining the expression of genes responsible for nitrogen assimilation, with an eventual intent of developing expression assays that are indicative of nitrogen source use and/or sufficiency in Aureoumbra. Large volume batch cultures of Aureoumbra were grown with either ammonium or urea as a nitrogen source. Physiological characteristics (C:N, chlorophyll [alpha] cell⁻¹, and Fv/Fm) were monitored throughout the growth period, and the expression of the AMT-1, AMT-2 and UREC genes was assayed at early-, mid- and late-exponential phases. The results show that Aureoumbra can use both ammonium and urea, and that it is well adapted to low-nutrient environments. Only one gene, AMT-1, appeared to be transcriptionally regulated in response to changing nitrogen concentration, and only to ammonium. The results of this study contribute to our understanding of how algae in general cope with low nutrient availability and should ultimately help to define the dynamics of these HAB events. / text

<p>Concentrations of various metals are elevated above background levels in several intertidal areas along the Tanzanian coasts. However, there is little available information concerning the toxicity of these metals and how the uptake of these metals by bioindicators are influenced by external factors, such as heavy rains and increased coastal eutrophication, which tend to fluctuate.</p><p>The present study focused on the uptake and toxicity of Cu and Zn in two common macroalgal species,<i> Padina gymnospora</i> (Phaeophyta) and<i> Ulva</i> <i>reticulata</i> (Chlorophyta). Laboratory studies were performed where metal content, growth (DGR), maximal quantum yields (Fv/Fm) and protein expression patterns (in <i>Ulva</i>) were measured as a response to exposure to Cu and Zn. The levels of metals accumulated in algal tissues correlated well to exposure concentrations and the longer the exposure time, the greater the uptake. However, an increased nutrient load (tested on <i>Padina</i>) or dilution of the seawater (tested on<i> Ulva</i>) affected both uptake of metals and their toxic effects. Here, DGR was more affected than Fv/Fm, suggesting DGR to be the more sensitive indicator of Cu and Zn toxicity. As shown by 2-D gel electrophoresis, more than ten proteins were up-regulated in <i>U. reticulata</i> after being exposed to Cu (1μg/L), while at higher concentrations (10 and 100 μg/L) of Cu numerous proteins were down-regulated.</p><p><i>P. gymnospora </i>was also used as a bioindicator to monitor long-term (1994–2005) and seasonal in-year variations in heavy metal concentrations in the Zanzibar Channel. No clear overall trends were revealed, but analysis of the combined dataset clearly pinpointed the most contaminated sites. It was concluded that seasonal and long-term variations, as well as environmental conditions need to be taken into consideration when using macroalgae as bioindicators.</p>

Concentrations of various metals are elevated above background levels in several intertidal areas along the Tanzanian coasts. However, there is little available information concerning the toxicity of these metals and how the uptake of these metals by bioindicators are influenced by external factors, such as heavy rains and increased coastal eutrophication, which tend to fluctuate. The present study focused on the uptake and toxicity of Cu and Zn in two common macroalgal species, Padina gymnospora (Phaeophyta) and Ulva reticulata (Chlorophyta). Laboratory studies were performed where metal content, growth (DGR), maximal quantum yields (Fv/Fm) and protein expression patterns (in Ulva) were measured as a response to exposure to Cu and Zn. The levels of metals accumulated in algal tissues correlated well to exposure concentrations and the longer the exposure time, the greater the uptake. However, an increased nutrient load (tested on Padina) or dilution of the seawater (tested on Ulva) affected both uptake of metals and their toxic effects. Here, DGR was more affected than Fv/Fm, suggesting DGR to be the more sensitive indicator of Cu and Zn toxicity. As shown by 2-D gel electrophoresis, more than ten proteins were up-regulated in U. reticulata after being exposed to Cu (1μg/L), while at higher concentrations (10 and 100 μg/L) of Cu numerous proteins were down-regulated. P. gymnospora was also used as a bioindicator to monitor long-term (1994–2005) and seasonal in-year variations in heavy metal concentrations in the Zanzibar Channel. No clear overall trends were revealed, but analysis of the combined dataset clearly pinpointed the most contaminated sites. It was concluded that seasonal and long-term variations, as well as environmental conditions need to be taken into consideration when using macroalgae as bioindicators.

Tesis por compendio / [ES] En las últimas dos décadas, la producción de caqui en España ha aumentado exponencialmente y la superficie de cultivo se ha multiplicado casi por ocho. En la actualidad, la producción de caqui está centralizada en el cultivar 'Rojo Brillante', que es mundialmente apreciado. Sin embargo, esta centralización supone una importante limitación comercial. En la presente Tesis se abordan dos objetivos principales: 1) Optimización de la tecnología pre y postcosecha con el fin de garantizar la calidad del caqui 'Rojo Brillante' durante la frigoconservación y el transporte a mercados internacionales. 2) Evaluación del comportamiento bajo condiciones mediterráneas de variedades introducidas de otras regiones productoras con el fin de ampliar el rango varietal de caqui. El primer objetivo de esta Tesis se logró a través de los estudios presentados en los Capítulos I al V. El segundo objetivo se abordó en los Capítulos VI y VII. En el Capítulo I se esclarecieron las causas del pardeamiento interno del fruto en los envíos a los mercados internacionales. La temperatura a la que se expone la fruta inmediatamente tras la aplicación del tratamiento de desastringencia con altas concentraciones de CO2 se identificó como el principal factor implicado en esta alteración. Los resultados obtenidos mostraron que esta alteración se puede evitar mediante la implementación de un período de atemperado de 24 h después del tratamiento con CO2, antes de conservar las frutas a bajas temperaturas. En el Capítulo II se evaluó la eficacia de un tratamiento de desastringencia recientemente patentado basado en la aplicación de una nueva cera que contiene etanol en su formulación. Los resultados mostraron que esta cera podría ser una alternativa al tratamiento convencional de desastringencia con altas concentraciones de CO2 cuando la fruta se envía a mercados lejanos a bajas temperaturas. La aplicación de la nueva cera antes de conservación en frío provocó la pérdida de astringencia de la fruta tras 30 días a 0 °C, preservando la firmeza y la calidad interna. Los resultados del Capítulo III demostraron que la realización de dos aplicaciones de ácido giberélico (AG) en precosecha permite retrasar el proceso de maduración de la fruta en el árbol con respecto a una sola aplicación. La combinación de AG en precosecha y 1-metilciclopropeno (1-MCP) en postcosecha resultó en una mayor calidad del fruto durante la frigoconservación en comparación con la aplicación únicamente de 1-MCP. Además, la fruta tratada con múltiples aplicaciones de AG mostró una firmeza ligeramente mayor tras de conservación a baja temperatura. En el Capítulo IV se demostró que, paralelamente al retraso de la maduración, el tratamiento con AG también retrasa la senescencia del cáliz, incrementando la calidad externa del fruto. La senescencia del cáliz durante la maduración del fruto se relacionó con una disminución de los parámetros de fluorescencia de clorofila (Fo, Fm y Fv/Fm). En el Capítulo V se estudiaron las condiciones óptimas de almacenamiento del caqui producido bajo cultivo ecológico. Según los resultados, no se deben almacenar los frutos cosechados con firmeza inferior a 30 N. La calidad del fruto durante la conservación dependió de las condiciones de almacenamiento, momento de aplicación del tratamiento de deastringencia y estado de madurez inicial. Por último, en los Capítulos VI y VII se abordó la evaluación bajo condiciones mediterráneas de 14 variedades de caquis no-astringentes procedentes de otros países. Se identificaron las variedades tempranas y tardías que pueden ser potencialmente interesantes para ampliar el período de cosecha en nuestra región. Los estudios postcosecha mostraron que todas las variedades estudiadas presentan una buena aptitud para ser comercializadas en los mercados nacionales y europeos. Sin embargo, la sensibilidad a los daños por frío que presentaron algunas de las variedades estudiadas podría limitar su comercialización a países de ultramar. Además, se observó que la respuesta al tratamiento con 1-MCP, para el control de los daños por frío, dependió en gran medida de la variedad. / [CA] En les últimes dues dècades, la producció de caqui a Espanya ha augmentat exponencialment i la superfície de cultiu s'ha multiplicat quasi per huit vegades. En l'actualitat, la producció de caqui està centralitzada en el la cultivar 'Rojo Brillante', que és mundialment apreciat. Malgrat això, aquesta centralització suposa d'una banda una important limitació comercial, ja que la producció es concentra en un període de collita relativament curt i, d'altra banda implica un alt risc fitosanitari. En la present Tesi s'aborden dos objectius principals: 1) Optimització de la tecnologia pre i postcollita amb la finalitat de garantir la qualitat del caqui 'Rojo brillante' durant la frigoconservació i el transport a mercats internacionals. 2) Avaluació del comportament de varietats introduïdes d'altres regions productores sota condicions mediterrànies amb la finalitat d'ampliar el rang varietal de caqui. En el Capítol I es van esclarir les causes de l l'enfosquiment intern. La temperatura a la qual s'exposa la fruita immediatament després de l'aplicació del tractament de desastringència amb altes concentracions de CO¿ es va identificar com el principal factor implicat en aquesta alteració. Els resultats obtinguts van mostrar que aquesta alteració es pot evitar mitjançant la implementació d'un període de temperat de 24 h després del tractament amb CO¿, abans de transferir la fruita a baixes temperatures. En el Capítol II es va avaluar l'eficàcia d'un tractament de desastringència recentment patentat basat en l'aplicació d'una nova cera que conté etanol en la seua formulació en caquis 'Rojo Brillante' i 'Triumph'. Els resultats van mostrar que aquesta cera podria ser una alternativa al tractament convencional de desastringència amb altes concentracions de CO¿ quan la fruita s'envia a mercats llunyans a baixes temperatures. L'aplicació de la nova cera abans de conservació en fred va provocar la pèrdua d'astringència de la fruita després de 30 dies a 0 °C, preservant la fermesa i la qualitat interna. Els resultats del Capítol III van demostrar que l'aplicació de dos tractaments d'àcid giberèlic (AG) en precollita permet retardar el procés de maduració de la fruita en l'arbre respecte a una sola aplicació. La combinació de AG en precollita i 1-metilciclopropeno (1-MCP) en postcollita va incrementar la qualitat del fruit durant la frigoconservació en comparació amb l'aplicació únicament de 1-MCP. A més, la fruita tractada amb múltiples aplicacions de AG va mostrar una fermesa lleugerament major després de conservació a baixa temperatura; no obstant això, una sola aplicació de AG també va ser eficaç per a previndre la manifestació de danys per fred en la fruita. En el Capítol IV es va demostrar que, paral·lelament al retard de la maduració, el tractament amb AG també retarda la senescència del calze, incrementant la qualitat externa del fruit. La senescència del calze durant la maduració del fruit es va relacionar amb una disminució dels paràmetres de fluorescència de clorofil·la (Fo, Fm i Fv/Fm). En el Capítol V es van estudiar les condicions òptimes d'emmagatzematge del caqui produït baix cultiu ecològic. D'acord amb els resultats obtinguts, no s'han d'emmagatzemar els fruits collits amb fermesa inferior a 30 N. La conservació del fruit va dependre de les condicions d'emmagatzematge, moment d'aplicació del tractament de desastringència i estat de maduresa de la fruita. Finalment, en els Capítols VI i VII es va abordar l'avaluació de 14 varietats de caquis no-astringents. Es van identificar les varietats primerenques i tardanes que poden ser potencialment interessants per a ampliar el període de collita. D'altra banda, els estudis postcollita van mostrar que totes les varietats estudiades presenten una bona aptitud per a ser comercialitzades en els mercats nacionals i europeus. No obstant això, la sensibilitat als danys per fred que van presentar algunes de les varietats estudiades podria limitar la seua comercialització a països d'ultramar. A més, es va observar que la resposta al tractament amb 1-MCP, per al control dels danys per fred, va dependre en gran manera de la varietat. / [EN] In the last two decades, persimmon production in Spain has increased exponentially and the cultivation area has expanded almost eight-fold. The current production of persimmon is focused on the cultivar 'Rojo Brillante', which is appreciated worldwide due to the high quality of the fruit. Nevertheless, centralized production of this single cultivar implies a major commercial limitation as its high volume of production is concentrated in a relative short harvesting period. Furthermore, it also implies a high phytosanitary risk. In this context, this Thesis addresses two main objectives: 1) Optimization of pre- and postharvest technology in order to guarantee the quality of 'Rojo Brillante' persimmon after cold storage and transportation to overseas markets. 2) Evaluation of the behavior of foreign varieties of persimmon under Mediterranean conditions in order to extend the varietal range. The first objective of this Thesis was tackled through the studies presented in Chapters I to V. The second objective was covered in Chapters VI and VII. Chapter I dealt with the causes of internal browning disorder manifested after cold shipment of 'Rojo Brillante' persimmons to overseas markets. The temperature to which fruit is exposed immediately after CO2 deastringency treatment was identified as the main factor involved in this alteration. Our results showed that this disorder can be avoided by implementing an attemperation period of 24 h after the CO2 treatment, before transferring fruit to cold storage. In Chapter II, the effectiveness of a recently patented deastringency treatment based on applying a new wax containing ethanol was assayed in 'Rojo Brillante' and 'Triumph' persimmons. The use of this new ethanol-based wax could be a potential alternative to the conventional CO2 deastringency treatment when the fruit are sent to distant overseas markets at low temperatures. Application of the new wax before cold storage led to loss of fruit astringency after 30 days at 0 °C while preserving fruit firmness and internal quality. The results of Chapter III demonstrated that two applications of gibberellic acid (GA) made it possible to delay the fruit maturity process on the tree more than with just a single application. The combination of GA and 1-methylciclopropene (1-MCP) preserved the fruit quality better than with the application of 1-MCP alone during cold storage. Moreover, the fruit treated by multiple GA applications showed a slightly higher firmness after cold storage. However, a single GA application was also effective in preventing the manifestation of chilling injury (CI) in fruit. Chapter IV demonstrated that in parallel to delaying maturity, the GA treatment also delayed calyx senescence, which meant that the fruit preserved a good appearance. The calyx lobe senescence during fruit ripening was linked to a decrease in all Chlorophyll Fluorescence Imaging (CFI) parameters (Fo, Fm, and Fv/Fm). Chapter V addressed the optimization of storage conditions for organic persimmons. According to our results, fruit harvested with a firmness lower than 30 N must not be stored. Fruit harvested with a higher level of firmness could be stored for up to three weeks depending on the storage conditions, the moment of application of the CO2 deastringency treatment, and the stage of fruit maturity. The longest storage period (3 weeks) was achieved when fruit were harvested with a firmness of around 45 N, submitted to CO2 treatment and then stored at 15 °C. Finally, 14 foreign varieties grown under Mediterranean conditions were evaluated to identify early- and late-season varieties with potential to extend the harvesting period. This is presented in Chapters VI and VII. In general, all the evaluated varieties fulfilled the quality criteria to be commercialized in domestic and European markets. However, sensitivity to CI was variety dependent and response to 1-MCP treatment was also observed to depend on the variety. / This study has been supported by the Instituto Nacional de Tecnología Agraria y Alimentaria de España (INIA) and Fondo Europeo de Desarrollo Regional (FEDER) through the projects RTA 2013-00043-C02-01 and RTA2017-00045-C02-01. In addition, it has been supported by the Valencian Institute for Agricultural Research (Project N° 51910). This study has also been founded by the Consellería de Educación, Investigación, Cultura y Deporte de la Comunidad Valenciana (project GV/2016/183). Ayoub Fathi Najafabadi thanks the INIA for grant FPI-INIA #43 (CPD2015-0151). The authors thank Fomesa Fruitech S.L.U. and Natural Hand S. L. for their technical support, Cooperativa Agrícola Ntra Sra de Loreto for its technical support and for making the plots and fruit used in this study available and Plant Production Department (Instituto Valenciano de Investigaciones Agrarias) for providing the fruit weight data and the photographs of the different varieties. / Fathi Najafabadi, A. (2021). Optimization of postharvest Technology for "Rojo brillante" Persimmon and Introduction of New Varieties in the Mediterranean Area [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171252 / TESIS / Compendio