Photosynthetic performance of contrasting Jatropha curcas genotypes during the flowering and fruiting stages.

Made available in DSpace on 2018-02-22T00:38:31Z (GMT). No. of bitstreams: 1 237531251121PB.pdf: 693116 bytes, checksum: ec4c19c5d89f4985257036a4cf4095e9 (MD5) Previous issue date: 2018-02-21bitstream/item/172918/1/23753-125112-1-PB.pd

Soybean Architecture Plants: From Solar Radiation Interception to Crop Protection

The soybean plant architecture in relation to better solar radiation interception and production gain is an aspect that requires a better understanding, since soybean is an important crop worldwide. The genetic traits, management and environmental conditions are points that further extend the range of issues on crop productivity. The light quality is measured by the red/far‐red (R/FR) ratio (R ∼ 660 nm, FR ∼ 730 nm). This affects the plant growth and morphological developments in different ways. The plant leaves change their angle during the day to better intercept radiation. This heliotropic movement and some computational models together have been used to enhance some agricultural practices. Soybean plant is dependent on the interaction between genotype and environment. Thus, the enhanced understanding in relation to photosynthetic activity, grain yield by light interception efficiency and culture protection managements in soybean are covered

Effects of Fruit Temperature, Calcium, Crown and Sugar Metabolizing Enzymes on the Occurrence of Pineapple Fruit Translucency

The role of preharvest fruit temperature, calcium, crown and sugar metabolizing enzymes in the occurrence of pineapple fruit translucency was studied. In Hawai‘i, pineapple fruit translucency began to appear 4 to 2 weeks before commercial harvest. Pineapple fruit flesh became very susceptible to high temperature 6 to 4 weeks before harvest as flesh cell electrolyte leakage increased. High fruit temperature during the last stage of pineapple fruit development decreased titratable acidity and increased translucency. The calcium concentration in pineapple fruit flesh declined with fruit development, possibly due to a decrease in the proportion of water imported via the xylem compared to the phloem. Mature fruit flesh tissue had a significantly reduced ability to bind divalent cations. Spraying calcium during pineapple fruit development decreased translucency occurrence at harvest. Removing the crown either at an early or late stage of pineapple fruit development did not cause any significant effect on the fruit weight and translucency, suggesting that the crown did not play a significant role in pineapple fruit development and translucency occurrence. Defoliation conducted 4 or 3 weeks before harvest did not significantly reduce the pineapple fruit weight, but did significantly reduce the total soluble solids and fruit translucency, suggesting that the photoassimilate partitioning during the last stage of fruit development played an essential role in the occurrence of translucency. Sucrose began to accumulate rapidly in pineapple fruit flesh 6 weeks before harvest, while the activities of three invertases and sucrose synthase were low. The activity of celliv wall invertase (CWI) increased in the fruit flesh again 4 weeks before harvest, followed by the occurrence of translucency. There was a positive correlation between the CWI activity and translucency severity in pineapple fruit flesh, suggesting that the high CWI activity, that favored apoplastic phloem unloading, may be one of the causes inducing pineapple fruit translucency

STUDY OF NUTRIENT SOLUTION MANAGEMENT IN SOILLESS ROSE CULTIVATION THROUGH THE ANALYSIS OF PHYSIOLOGICAL PARAMETERS AND NUTRIENT ABSORPTION

La optimización de la nutrición de los cultivos esw vital para evitar estreses y obtener altos rendimientos y calidades de los productos hortícolas. Los sistemas de cultivo sin suelo son interesantes porque permiten el manejo de los diferentes factores que afectan a la nutrición vegetal, como la composición y concentración de la solución nutritiva o la temperatura de dicha solución. En esta tesis, se ha estudiado el manejo de algunos de estos factores con la finalidad de optimizar la nutrición de plantas de rosal cultivadas para la producción de flor cortada. Este objetivo general ha sido tratado en tres capítulos. En el Capítulo 3 se expone el estudio de los factores que afectan a la absorción diaria de agua y nutrientes por las plantas de rosal. Cinco modelos de absorción mineral (nitratos, fosfatos, potasio, calcio y magnesio) y uno de absorción hídrica fueron desarrollados. El interés de estos modelos reside en la posibilidad de su aplicación en condiciones reales de producción debido a que fueron desarrollados con datos de más de un año de cultivo, y porque incluyen algunas de las prácticas más comunes en la producción de rosas para flor cortada como la renovación de tallos arqueados, el uso de malla de sombreo o la sincronización del desarrollo de los tallos florales para su cosecha en determinadas fechas. Además, otras variables independientes incluidas en los modelos fueron la concentración de la solución nutritiva, el déficit de presión de vapor, la intgegral de la radiación dentro del invernadero, la temperatura del aire y de la solución, la producción de tallos florales o factores internos desconocidos. Los modelos de absorción mineral también integraron el efecto de la absorción hídrica. El Capítulo 4 tiene como objetivo evaluar la tolerancia o sensibilidad de las plantas de rosal a la baja temperatura de la solución nutritiva mediante el estudio de su efecto sobre parámetros fisiológicos.Gorbe Sánchez, E. (2010). STUDY OF NUTRIENT SOLUTION MANAGEMENT IN SOILLESS ROSE CULTIVATION THROUGH THE ANALYSIS OF PHYSIOLOGICAL PARAMETERS AND NUTRIENT ABSORPTION [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6921Palanci

Genetic diversity for drought tolerance in the native forage grass Trichloris crinita and possible morpho-physiological mechanisms involved

IntroductionThe use of drought tolerant genotypes is one of the main strategies proposed for coping with the negative effects of global warming in dry lands. Trichloris crinita is a native forage grass occupying extensive arid and semi-arid regions in the American continent, and used for range grazing and revegetation of degraded lands.MethodsTo identify drought-tolerant genotypes and possible underlying physiological mechanisms, this study investigated drought tolerance in 21 genetically diverse T. crinita genotypes under natural field conditions. The accessions were grown under irrigated (control) and drought conditions for 84 days after initiation of the drought treatment (DAIDT), which coincided with flowering initiation. Various morpho-physiological traits were monitored, including total-, foliage-, and root biomass yield, dry matter partitioning to individual plant organs (roots, leaves, stems, and panicles), total leaf area, chlorophyll content, photochemical efficiency of photosystem II, stomatal conductance, and number of panicles per plant.Results and discussionBroad and significant variation (p<0.001) was found among the accessions for all the traits. Three highly tolerant and three very sensitive accessions were identified as the most contrasting materials, and their responses to drought stress were confirmed over two years of experiments. Under prolonged drought conditions (84 DAIDT), the tolerant accessions were generally more productive than the rest for all the biomass yield components analyzed, and this was associated with a postponed and more attenuated decrease in variables related to the plant photosynthetic activity, such as stomatal conductance, chlorophyll content, and photochemical efficiency. In contrast to previous findings, our data indicate no direct relationship between drought tolerance and the level of aridity in the accessions natural habitats, but rather suggest genetic heterogeneity and ample variation for drought tolerance in T. crinita natural populations derived from a particular location or environment. Also, having low total and forageable biomass yield, or increased biomass allocation to the roots (i.e., lower foliage/root ratio), under optimal water availability, were not associated with greater drought tolerance. The drought-tolerant accessions identified are of value for future genetic research and breeding programs, and as forage for range grazing and revegetation in arid regions

Yield Components and Biomass Partition in Soybean: Climate Change Vision

Long-term climate change and inter-annual climate variability are events of concern to farmers and humanity. Global warming could affect agriculture in various ways and it is anticipated that agricultural systems will face great pressure from the variability of climate factors and their extreme events, which in most cases are difficult to predict, particularly extreme events of rainfall, higher dry season, hot and cold waves and their interactions. Global warming could also have some positive effects for plants such as increasing the temperature of current cold regions and increasing carbon dioxide with its positive effect on photosynthesis, growth rates, the use of water and production. Meanwhile, there are still many questions that remain about this possible future. This chapter, brings the response of plants to future conditions through specifics alterations in its components of yield on environmental conditions with enrichment of CO2 and elevated temperature, two climatic factors, which is understood to be the factors of climatic change of greater global extent. The study of the components of yield and their alterations, can guide diverse sectors of the sciences and decision makers, in order to structure strategies of resilience in the cultivation of soybean

Unravelling the molecular and physiological components that contribute to iron deficiency chlorosis

Iron (Fe) deficiency chlorosis (IDC) is a serious condition affecting plants which are grown under calcareous or water logged soils. Under such conditions,Fe forms insoluble oxides and becomes unavailable for plant uptake, leading to stunted growth and severe yield reduction, causing aggravated agricultural losses. In the past years,efforts have been made to increase plant Fe content(so-called plant biofortification), in order to reduce the incidence of iron deficiency anaemia (IDA) prevalent around the world. To this end, legume grains and cereals, due to their rich nutritional profile and high worldwide intake by the population,have gained an important role in biofortification studies, which depend on the available molecular and physiological data for their successful implementation. The aim of this thes is was to contribute to the understanding of the molecular, physiological and biochemical mechanisms associated to Fe uptake and transport in Fe-stressed plants and to test a new class of Fe chelates as an efficient tool to prevent IDC. With the purpose of understanding the transcriptomic response to Fe deficiency in a set of different legume species, a non-targeted analysis was performed using Illumina technology. Transcriptome analysis was performed in the roots of soybean (Glycine max), common bean (Phaseolus vulgaris) and barrel medic (Medicago truncatula) grown in Fe deficiency and Fe sufficiency, and 114,723 annotated genes were obtained for all samples. Four IDC-related gene families were up-regulated in common by the three species and can be considered key players involved in the IDC response, namely, metal ligands, transferases, zinc ion binding and metal ion binding genes. Also, amongst the most highly expressed genes were genes of theisoflavonoid pathway and, on the other hand, oxidoreductases were the most down-regulated genes.Still on the search for IDC molecular players, two targetedgenetic analyses were performed,one on G.maxand M. truncatula and another on rice (Oryza sativa). Both studies involved the growth of plants under Fe sufficiency and Fe deficiency in order to compare the regulation of IDC related genes. Soybean and barrel medicare strategy I-crops,which means that, before uptake, they need to reduce Fe(III) to Fe(II) via an enzyme encoded by the FRO2 gene and, afterwards, Fe(II) is transported to the roots via ametal transporter encoded by the IRT1 gene. The expression of these two genes was analysed and both behaved similarly between species, appearingto be co-regulated.Moreover, the Fe transportersYSL1 andVIT1and the main Fe storage protein-encoding gene –ferritin–were up-regulated in the presence of Fe. The NRAMP3 gene, responsible for Fe remobilization from the vacuoles, was up-regulated under Fe deficiency,as was theGCN2gene, indicating a putative role of the latterin Fe metabolism and homeostasis.The targeted study performed in rice, a strategy II cereal that releases phytosiderophores in order to chelate and absorb Fe, involved the analysis of two rice cultivars with distinct susceptibilities to IDC –cv. Nipponbare and cv. Bico Branco. This different susceptibility was confirmed by their contrasting leaf chlorosis development and tissue nutrient accumulation patterns. Thecv. Nipponbare, that showed lower IDC susceptibility, was able to induce higher levels of the key reduction enzyme activity(Fe reductase)and showed higher levels of expression of the strategy I-OsFRO2 gene in roots.In contrast, cv. Bico Branco induced more genes involved in strategy II, specially, the transcription factor OsIRO2 and the phytosiderophore precursor OsTOM1.The screening for tolerant genotypes to IDC is an important tool in plant breeding programs. The most common IDC indicator is the degree of chlorosis development, which is quantified using a numerical scale. Therefore, after gathering the molecular data, the physiological mechanisms triggered by IDC were studied. The model crop G. max was selected,as it comprises lines well characterized according to their IDC-susceptibilities. To this end, two studies were performed. In the first study we aimed at understanding if the ability to partition Fe could be related to Fe-efficiency. We concluded that IDC susceptible lines, when compared to efficient lines,have lower ability to translocate Fe to the shoots, having about two fold higher Fe content at the root level, and they have lower capacity to induce the ferric reductase enzyme, having about three fold lower enzyme activity. In the second study the regulation of the antioxidant and tetrapyrrole systems under Fe deficiency was analysedfor the first time and we inferred that higher levels of oxidative stress might induce the oxidation of the tetrapyrrole heme into hemin, which leads to the induction of the heme-containing catalase enzyme and the reduction of ferric reductase activity. Taken together, the previous results indicate that low ferric reductase activity and Fe accumulation in the root tissue could be added as new IDC-related physiological markers.The application of fertilizers and Fe chelating agentsis one of the most frequently used tools to manage IDC. However, most of them are ineffective,too expensive or recalcitrant in the environment. Hence, the search for new Fe chelates is of utmost importance. In the last step of this thesis, we investigated the potential of a tris(3-hydroxy-4-pyridinonate) Fe(III) complex(Fe(mpp)3, which has never be enutilized in agricultural context)as na Fe fertilizer. Soybean plants were grown hydroponically under Fe deficiency and with Fe(mpp)3or Fe EDDHA supplementation. Results of both physiological and molecular markers showed that the new Fe complex led to healthier plants with increased growthby 24%,42% higher SPAD units and lower Fe retention in the roots.In general, the results presented in this thesis have contributed to a better understanding of the IDC-associated mechanisms and elucidated the key factors to be considered when analysing Fe deficient plants and their defence responses.Aclorose por deficiência de ferro (Fe) é uma condição grave que afeta plantas em solos calcários ou alagados. Sob estas condições, o Fe forma óxidos insolúveis e torna-se indisponível para absorção pelas plantas, o que conduz a um crescimento diminuído e a uma redução severa na produção, resultando em perdas agronómicas agravadas. Nos últimos anos, têm sido desenvolvidos estudos no sentido de aumentar o conteúdo de Fe nos tecidos vegetais (biofortificação), de forma a reduzir a incidência da anemia por deficiência de Fe prevalente no mundo. Com este objetivo, as leguminosas e os cereais, dado o seu perfil nutricional rico e o seu alto consumo pela população mundial, têm ganho particular enfoque nos estudos de bio fortificação, cujos resultados dependem da informação molecular e fisiológica disponível. O objetivo do presente trabalho foi contribuir para a compreensão dos mecanismos moleculares, fisiológicos e bioquímicos associados à absorção e transporte de Fe, bem como o estudo do potencial de uma nova classe de quelantes de Fe como uma ferramenta eficaz na prevenção da clorose férrica.Com o objetivo de compreender a resposta transcritómica à deficiência de Fe num conjunto de diferentes espécies de leguminosas, foi realizada uma análise não-direcionada com recurso à tecnologia Illumina. A análise transcritómica foi realizada nas raízes de soja (Glycine max), feijão (Phaseolus vulgaris) e luzerna-cortada (Medicago truncatula), crescidas em deficiência ou suficiência de Fe. Deste estudo, identificaram-se114.723 genes para todas as amostras. Quatro famílias de genes, nomeadamente ligandos de metais, transferases, proteína quinase e genes de ligação a metais e iões de zinco, foram sobre-expressas pelas três espécies e podem ter um papel relevante na resposta à clorose férrica. Entre os genes específicos mais expressos em deficiência de Fe, identificaram-se também genes da via dos isoflavonóides. Por outro lado, entre os genes cuja expressão foi diminuída sob deficiência de Fe, identificaram-se genes codificantes de oxidoreductases. Realizaram-se também dois estudos direcionados, um em G. maxe M. truncatulae outro em arroz (Oryza sativa). Ambos os estudos implicaram o crescimento de plantas com e sem suplementação de Fe, por forma a comparar a regulação de genes relacionados com a clorose férrica. A soja e a luzerna-cortada são leguminosas que utilizam a estratégia I, o que significa que, antes da absorção pelas raízes, elas necessitam de reduzir o Fe (III) a Fe(II) utilizando uma enzima codificada pelo gene FRO2 e, depois deste passo, o Fe (II) é transportado por um transportador de metais codificado pelo gene IRT1. A expressão destes dois genes foi estudada e verificou-se que ambos comportaram-se de forma semelhante entre espécies, sugerindo que a sua expressão é co-regulada. Estudaram-se também os transportadores de Fe YSL1 e VIT1, e o gene codificante da principal proteína de armazenamento de Fe –a ferritina–tendo sido todos sobre-expressos na presença de Fe. O gene NRAMP3, responsável pela remobilização do Fe dos vacúolos, foi sobre-expresso na deficiência de Fe, tal como o gene GCN2, o que sugeriu um possível papel deste último no metabolismo e homeostasia do Fe. No estudo realizado com o arroz, um cereal que utiliza a estratégia IIe que liberta fitosideróforos para quelatar e absorver o Fe, analisaram-se duas cultivares de arroz com suscetibilidades distintas à clorose férrica–cv. Nipponbare e cv. Bico Branco. A suscetibilidade diferencial foi confirmada pelo padrão oposto obtido nos resultados do desenvolvimento da clorose férrica e da acumulação de nutrientes nos tecidos. A cv. Nipponbare, que demonstrou menor suscetibilidade à clorose férrica, induziu níveis mais altos da enzima reductase férrica nas raízes, responsável pela redução de Fe(III), assim como do gene correspondente, OsFRO2, típico da estratégia I. Pelo contrário, a cv. Bico Branco induziu maiores níveis dos genes envolvidos na estratégia II, em particular, o fator de transcrição OsIRO3 e o precursor de fitosideróforos OsTOM1.A seleção de cultivares tolerantes à deficiência de Fe é uma ferramenta importante para programas de melhoramento de plantas. O indicador de clorose férrica mais comum é o grau de desenvolvimento de clorose, que é quantificado com uma escala numérica. Assim, após reunir os dados moleculares, estudaram-se os mecanismos fisiológicos associados à clorose férrica. A soja foi selecionada como espécie-modelo pelo facto de incluir diversas linhas amplamente caracterizadas de acordo com a sua suscetibilidade à clorose férrica. Deste modo, este estudo foi dividido em duas análises principais. Na primeira análise,o objetivo foi compreender se a capacidade de partição de Fe podia ser relacionada com a eficiência de Fe. Concluiu-se que as linhas suscetíveis, em comparação com as linhas eficientes, tiveram uma capacidade menor de translocação do Fe para a parte aérea da planta, acumulando cerca do dobro do conteúdo de Fe nas raízes e, mais ainda, estas linhas tinham também níveis três vezes mais baixos de atividade da enzima reductase. Na segunda análise estudou-se, pela primeira vez, a regulação dos sistemas antioxidante e tetrapirrólico na deficiência de Fe e observou-se que níveis superiores de stress oxidativo podem induzir a oxidação da molécula heme em hemina, que resulta na indução da enzima catalase e na redução da atividade da enzima reductase, sendo que ambas possuem o grupo heme na sua estrutura. Em suma, os resultados anteriores indicam que uma atividade baixa da enzima reductase férrica e acumulação de Fe nas raízes podem ser novos indicadores fisiológicos para a clorose férrica. A aplicação de fertilizantes e de agentes quelantes de Fe é uma das estratégias mais utilizadas para tratar a clorose férrica. Porém, muitos destes produtos são ineficazes, dispendiosos ou recalcitrantes no ambiente. Como tal, o desenvolvimento de novos quelatos de Fe é de extrema importância. Na última parte desta tese investigou-se o potencial de um complexo do grupo tris (3-hydroxy-4-pyridinonate) Fe (III) (Fe (mpp)3, nunca utilizado em contexto agronómico)como um fertilizante novo de Fe. Plantas de soja foram crescidas em hidroponia sob deficiência de Fe ou suplementadas com Fe(mpp)3ou Fe EDDHA. Quer os resultados dos marcadores fisiológicos, quer dos moleculares demonstraram que, com o novo complexo de Fe, as plantas desenvolveram-se de forma mais saudável, obtendo um crescimento superior em 24%, 42% maior acumulação de clorofilas e menor retenção de Fe nas raízes. Em geral, os resultados apresentados nesta tese contribuíram para uma melhor compreensão dos mecanismos associados à clorose férrica e esclareceram alguns dos fatores chave a considerar na análise das respostas de defesa de plantas sob stress de ferro

Adi ceviz (Juglans regia L.) ağacı yapraklarının kimyasal bileşiklerinin ağaç yaşına bağlı değişimi

In this present study, we investigated the chemical compounds in the fresh leaves of ancient walnut trees (Juglans regia L.) aged 25, 75, 100, and over 400 year. Under similar environmental conditions, the fresh leaves of walnut trees were collected and analysed for chlorophyll molecules as chlorophyll a, chlorophyll b and carotenoids, enzymatic compounds (ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) activities) and non-enzymatic compounds (proline, total soluble protein, total phenolic compounds), flavonoid and reducing sugars (glucose, sucrose, total soluble sugar). In addition, the oxidative stress level was determined by measuring lipid peroxidation (MDAmalondialdehyde) and hydrogen peroxide (H2O2). Significant differences in the chemical composition of the fresh leaves were found between the 4 different tree age classes. In general, the results showed that mean chlorophyll pigments were increased with increasing the age. There was also a general trend that mean glucose and starch concentrations increased with the age, while mean sucrose concentration decreased, but no changes were noted for mean total soluble carbohydrate. On the other hand, mean SOD concentration decreased with increasing the age. Other chemical compounds (mean proline, total soluble protein, malondialdehyde, hydrogen peroxide, APX and CAT), however, did not show clear trends with the age. As a result, these pioneer study have provided valuable insight into the variation in the chemical constituents of walnut tree leaves in relation to the age, and it can be used to better understanding, managing and fighting against pathogens of walnut ecosystems in future studies.Bu çalışmada ortalama yaşı 25, 75, 100 ve 400 yaş üzeri Adi ceviz (Juglans regia L.) olan ağacı yeşil yapraklarının kimyasal bileşikleri araştırılmıştır. Aynı yetişme ortamındaki, adi ceviz ağaçlarından toplanan yeşil yaprak örneklerinin içerdiği fotosentetik pigmentler (klorofil a, klorofil b ve karotenoit, askorbat peroksidaz (APX), katalaz (CAT), süperoksit dismutaz (SOD) enzim aktiviteleri, prolin, toplam çözünür protein, toplam fenolik bileşikleri, flavonoid gibi enzimatik olmayan bileşikleri ve indirgenmiş şekerlerden, glikoz ve sukroz miktarı ile toplam çözünür şeker miktarları belirlenmiştir. Ek olarak, yeşil yapraklar oksidatif stres seviyesi ile lipit peroksidasyonu (malondialdehit-MDA) ve hidrojen peroksit (H2O2) konsantrasyonları için analiz edilmiştir. Bu kimyasal bileşiklerden bazıları, ağaç yaşına bağlı olarak istatistiksel farklılıklar göstermiştir. Genel olarak, fotosentetik pigmentler, ağaç yaşı arttıkça artış göstermiştir. Glikoz ve nişasta miktarı ağaç yaşı ile artma eğilimi gösterirken, sukroz miktarı azalmış, fakat toplam çözünür karbohidrat içeriği ağaçlar arasında önemli bir farklılık göstermemiştir. Bunun yanında, SOD aktivitesi yaş arttıkça azalmıştır. Çalışmada incelenen diğer kimyasal bileşiklerle (prolin, toplam çözünür protein, MDA, H2O2, APX ve CAT) ağaç yaşı arasında belirgin bir ilişki tespit edilmemiştir. Sonuç olarak, öncü niteliğindeki bu bulgular, ceviz ağacı yapraklarının yaşa bağlı olarak kimyasal yapılarındaki değişimi hakkında önemli bilgiler sağlamış olup, ceviz ekosistemlerinin daha iyi anlaşılması, yönetimi ve zararlarına karşı uygulanacak mücadele yöntemlerine karar vermede gelecekteki çalışmalarda kullanılabilecektir