No description available.

The overall efficiency of plants to remediate soils contaminated by metals depends on their growth ability especially on soils with low-fertility. For twelve weeks, the ability of Psoralea pinnata to grow well and remove chromium and iron from artificially contaminated soil was tested. The concentrations of chromium and iron in two soils obtained from different sources namely, University of South Africa premises (US) and commercial potting soil (PS) were 80 ppm, 130ppm, 180ppm, 230ppm, 280ppm, 330ppm, 380pp, 430ppm and 480ppm. Psoralea pinnata was transplanted into the contaminated soils and the experiments were watered daily to maintain 70% moisture at field capacity in a greenhouse. Shoot height and root length of Psoralea pinnata before and after planting were measured. Other parameters that were measured were number of leaves, wet shoot and dry weights, and wet root and dry weights. The growth of Psoralea pinnata, after 12 weeks of experimentation was noticeably affected by the concentrations of chromium and iron in the soil. The percentage increases in shoot height of Psoralea pinnata in the PS Soil (C-PS, 48cm from initial shoot height of 12.6cm) treatments were generally higher than the increases in the US Soil (C-US, 45.2cm from initial shoot height of 12.8cm) treatments. Psoralea pinnata in the (US) treatments accumulated Fe (50.02 ppm) from the soil more than Cr (32.38ppm). In the (PS) treatments, Psoralea pinnata also accumulated more Fe (60.57 ppm) than Cr (38.34 ppm). In the experiments containing both Fe and Cr, the US treatments with 40 ppm each of Cr and Fe, chromium was initially mostly accumulated by Psoralea pinnata (68%). At higher concentrations (320 ppm) of the combined metals (Cr and Fe) treatment, more Fe (55%) was accumulated in Psoralea pinnata. This study however showed that Psoralea pinnata may not be an efficient phytoextraction plant for hyperaccumulation. / Environmental Sciences / M. Sc. (Environmental Management)

M. Tech. Horticulture / Honeybush tea is the herbal tea made from the leaves, stems and flowers of Cyclopia spp., indigenous to the Eastern and Western Cape Provinces of South Africa. Due to the health benefits of honeybush, the demand for this tea has increased worldwide. To meet the demand, it is required to cultivate honeybush as a commercial crop. The shortage of plant material and variation in the quality of honeybush has prompted the need to propagate plants vegetatively through rooted cuttings in order to improve the planting material by achieving homogeneity, and to meet the demand and thus relieve pressure on wild populations. A study was conducted to evaluate the vegetative propagation of honeybush (Cyclopia subternata) from stem cuttings to optimize the adventitious rooting protocols.

Thesis (PhD (Plant biotechnology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: In soils, the concentration of available phosphate (P) for plants is normally very low (ca. 1 µM in the soil solution), because most of the P combines with iron, aluminium and calcium to form relatively insoluble compounds. Inorganic P (Pi)-deficiency is thought to be one of the limiting factors of nitrogen fixation due to the high energy requirement for nitrogenase function of plants taking part in nitrogen fixation. Pideficiency has important implications for the metabolic Pi and adenylate pools of plants, which influence respiration and nitrogen fixation. An alternative route of pyruvate supply during Pi stress has been proposed involving the combined activities of phosphoenolpyruvate carboxylase (PEPc), malate dehydrogenase (MDH) and NAD-malic enzyme (ME) supplying pyruvate to the mitochondrion during Pi stress. Previously, three isoforms of PEPc were isolated from lupin nodules and roots, with two forms being nodule specific. The aim of this project was to determine the effect of Pi stress on these PEPc isoforms in Lupinus luteus at transcript and protein expression level with a view to produce genetically modified crops for nutrient-poor soils. Cytosolic P levels were measured over a time course to give an indication of temporal development of P stress in nodules. The changes in enzyme activities of PEPc, MDH and PK (pyruvate kinase) under P stress were measured and the downstream effect on amino and organic acid pools were analysed. Two novel PEPc isoforms, LUP1 (AM235211) and LUP2 (AM237200) were isolated from nodules, followed by transcriptional and protein expression analyses. Nodules under P stress had lower amounts of metabolically available Pi and as P stressed developed, the amount of Pi decreased. This decline in Pi levels was associated with lower growth, but higher biological nitrogen fixation (BNF). A greater proportion of root-nodule respiration was devoted to nutrient acquisition than to new growth. A typical P-stress response is higher anaplerotic carbon fixation via PEPc. However, in this study, no significant differences were found for PEPc, MDH or PK in P-stressed plants compared to P-sufficient plants which would lead to an increase in organic acids. An increase in key amino acids was reported along with unchanged levels of organic acids. These levels of organic and amino acid are in congruence with the increases in BNF under P-starvation. No significant differences were found in expression of PEPC1 or PEPC2 at 12 and 20 days for both P-sufficient and P-stressed plants which further supported the lack of engagement of the PEPc-MDH-ME bypass. PEPc activity appeared not to be regulated by gene expression or phosphorylation indicating that other posttranslational modifications such as a decrease in protein degradation may be of importance. / AFRIKAANSE OPSOMMING: Die konsentrasie van fosfaat (P) beskikbaar vir opname deur plante vanuit die grond is gewoonlik baie laag (in die omgewing van 1 µM) aangesien die P onoplosbare komplekse vorm met katione soos yster, aluminium en kalsium. ‘n Tekort aan anorganiese P (Pi) word gereken as een van die beperkende faktore van stikstofbinding as gevolg van die hoë energie behoefte wat nitrogenase plaas op plante wat van gefikseerde stikstof gebruik maak. Hierdie P-tekort het ook belangrike betrekking op die metaboliese fosfaat- en adenilaatpoele wat weer op hul beurt respirasie en stikstofbinding beÏnvloed. ‘n Alternatiewe roete van pirovaatvoorsiening aan mitochondria tydens fosfaatstres is voorgestel wat bestaan uit die aktiwiteite van fosfoenolpirovaat karboksilase (PEPc), malaat dehidrogenase en NAD-malaat ensiem. Vantevore is drie isovorme van PEPc uit Lupinus luteus wortelknoppies en wortels geïsoleer, met twee van die isovorme wat wortelknoppie-spesifiek was. The doel van hierdie projek was om die invloed van P-tekort op die transkripsie en proteien uitdrukkingsvlak van hierdie PEPc isovorme te bepaal met die doel van gemodifiseerde gewasse vir arm gronde ingedagte. Sitoplasmiese P konsentrasies is gemeet oor tyd om ‘n aanduiding te gee van die ontwikkeling van P-tekort oor tyd. Veranderinge in ensiemaktiwiteite van PEPc, MDH en pirovaatkinase (PK) is gemeet gedurende P-tekort as ook die moontlike effek van hierdie ensiemaktiwiteite op aminosuur en organiese suur poele. Twee nuwe PEPc isovorme, LUP1 (AM235211) en LUP2 (AM237200) is uit wortelknoppies geïsoleer en gekarakteriseer. Transkripsie en proteïenuitdrukking is geanaliseer. Wortelknoppies wat P-tekort behandeling ontvang het, het laer vlakke van metabolise beskikbare Pi gehad en soos die P-tekort ontwikkel het oor tyd, het die Pi vlakke gedaal. Hierdie afname in vlakke van Pi was geassosieer met laer groei, maar met ‘n toename in biologiese stikstofbinding. ‘n Groter proporsie van respirasie is toegestaan aan minerale opname as aan nuwe groei. ‘n Tipiese reaksie op P-tekort is hoër anaplerotiese koolstofbinding via PEPc. Alhoewel, in hierdie studie is geen gevind betekenisvolle verandering gevind in die aktiwiteite van PEPc, MDH en PK nie in plante wat P-tekort ervaar het nie. Verhoogde aktiwiteit van hierdie ensieme sou verhoogde organise suur konsentrasies tot gevolg hê. ‘n Toename in aminosuur konsentrasies is gevind tesame met onveranderde vlakke van organiese sure. Hierdie toename in aminosure word onderskryf deur die verhoogde biologiese stikstofbinding tydens P-tekort. Geen betekenisvolle verskille is gevind in die geenuitdrukking van pepc1 en pepc2 by beide 12 en 20 dae van P-tekort nie, wat verder die afwesigheid van die PEPc- MDH-ME alternatiewe roete beaam het. Dit blyk dat PEPc aktiwiteit nie deur geenuitdrukking of proteïenfosforilering beheer word nie, maar eerder dat ander posttranslasie modifikasies soos ‘n verlaagde afbraak van proteïen ‘n rol speel.

Thesis (PhD(Agric) (Plant Biotechnology))--University of Stellenbosch, 2010. / Includes bibliography. / ENGLISH ABSTRACT: Salinity is one of the major limiting abiotic stresses on legume plant yield, leading to early senescence of root nodules. This occurs because of accumulation of reactive oxygen species (ROS) in plant cells under salinity stress. Concurrent with the increase in cellular reactive oxygen species levels is the increase in cellular antioxidants and corresponding antioxidant enzymes. This feature is observed mostly in the shoots and roots of more tolerant genotypes compared to the susceptible genotypes. It is accepted that the mechanism of plant tolerance to stress is dependent upon the response of the antioxidant systems. Most studies carried out on shoot tissues suggest that scavenging of ROS by the plant antioxidant system is modulated by nitric oxide (NO). However, the pathways by which NO mediates such antioxidant responses are not fully understood. For legumes, salinity stress has adverse effects on yield and this is in part due to inhibition of nitrogen fixation in the root nodules of the legumes, which causes severe nitrogen starvation in nitrogen-deficient soils. Nodules are specialized organs comprising of both the rhizobia and the plant tissue, hence the physiological aspects may vary from the findings from the leaves. It was therefore deemed necessary to establish the role of NO on the nodule antioxidant system in the absence and presence of salinity stress. For the purposes of this study, the effect of both exogenously applied NO and endogenous NO on superoxide dismutase, glutathione peroxidase and glutathione content was determined. The studies involved the use of nitric oxide donors like sodium nitroprusside (SNP) and diethylenetriamine/nitric oxide adduct (DETA/NO), their respective fixed controls potassium ferricyanide and diethylenetriamine (DETA), plus a nitric oxide synthase inhibitor (to inhibit nitric oxide production by the enzyme nitric oxide synthase) on nodulated roots. The data obtained in this work points out specifically at roles played by nitric oxide in regulating superoxide dismutases, glutathione peroxidase and glutathione during salinity stress and proposes a link between nitric oxide-mediated changes in these antioxidant systems and salinity stress tolerance. Both the exogenously applied and endogenous nitric oxide increases the enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione reductase (GR). However, there is both time dependency and nitric oxide concentration dependency on the enzyme activities. The total SOD enzyme activity increases upon nitric oxide exposure and with time of exposure. The individual SOD isoforms identified and studied in the root nodules all contribute to this increase in SOD activity upon nitric oxide treatment except for MnSOD I. This increase in activity is regulated at transcriptional level as the RT-PCR results targeting the individual isoforms reveals an increase in transcript levels after 6 hours of nitric oxide treatment. However, the CuZn SOD I isoform transcripts are reduced upon nitric oxide treatment. A similar response was also observed in GPX enzyme activity in which nitric oxide increased the GPX activity above all the controls. The GR enzyme activity exhibits an opposite response because the activity decreases with time of exposure to NO and concentration of NO. In order to determine the effect of NO under saline conditions, an experiment was set up that involved incubation of nodulated roots in solutions containing 150 mM NaCl. The stressed nodules exhibited generally higher levels of enzyme activities than the non-stressed nodules. Furthermore, exposure to nitric oxide donor in combination with NaCl induced even higher activities of SOD and GPX than NaCl or nitric oxide donor alone. There were also higher levels of reduced glutathione and total glutathione recorded under stress compared to optimal conditions. Nitric oxide increased the concentration of these forms of glutathione, suggesting an improved redox status based on the GSH/GSSG ratios under salinity stress in the presence of nitric oxide. Attenuation of nitric oxide synthesis with L-Nω-Nitroarginine methyl ester (L-NAME) reverses all the recorded effects of nitric oxide on antioxidant enzymes and glutathione pool. This was observed in salinity stressed nodules and non-stressed nodules. This work further establishes that NO plays a pivotal role in modulating the enzymatic activities through a pathway that is mediated by guanosine 3,5-cyclic monophosphate (cGMP). The experiment involving the inhibition of soluble guanylyl cyclase (sCG) (an enzyme that catalyzes the biosynthesis of cGMP), cell-permeable cGMP anaologue and L-NAME revealed that GPx activity is modulated through a cGMP-dependent pathway and NO is positioned up-stream of cGMP in the pathway leading to improved GPX activity. Cyclic GMP also modulates the GPX activity in a concentration dependent manner. NO improves the redox status of the cell under both saline conditions and non-saline conditions and this effect is modulated through a cGMP-dependent pathway. It is thus rational to conclude that; in the root nodules of legumes, like in other plant tissues, the increased accumulation of antioxidants and the increased activity of their corresponding enzymes, as modulated through the cGMP-dependent pathway by nitric oxide, confer root nodule tolerance to salinity. This concept directly points out at an attractive strategy for developing legumes that are genetically improved for enhanced root nodule tolerance to salinity; via differential regulation of antioxidants and antioxidant enzyme genes in the root nodules under abiotic stress. Towards attaining the goal for such genetic improvement, experiments involving construction of an abiotic stress-responsive and nodule-specific chimeric promoter were carried out. By fusing the 5-untranslated (5-UTR) region of the LEA gene that contains an abiotic stress-responsive cis-acting element (from theGmPM9 promoter) to the nodulin N23 promoter bearing the highly functional cluster of motifs for nodule specificity, the candidate nodule specific promoter that is abiotic stress responsive (ASREF/NSP) was constructed. The construct harbouring this ASREF/NSP chimeric promoter was fused to the -glucuronidase (GUS) reporter gene so as to study the functionality of the promoter in Medigaco truncatula plants. The construct was delivered into the Medicago plants through Agrobacterium rhyzogenes mediated transformation to produce composite Medicago plants. The transgenic roots have been cultured for futher manipulation and to confirm the functionality of the promoter. Furthermore several strategies can be deployed via the use of this chimeric promoter so as to enhance the nodular antioxidant system. This would involve either gene regulator-chimeric promoter fusion or the use of a single gene approach. As part of this work, the MtNOA gene homologous to AtNOAs, has been cloned from Medicago trancatula and put as ASREF/NSP fusion in a binary vector pBINPLUS and delivered into Medicago trancatula for nodule-specific and abiotic stress-induced nitric oxide synthesis. Since there is no plant NOS identified to date, the possibility of the use of a regulatory gene in this aspect is still limited. There are other options involving the use of the chimeric promoter with the individual genes encoding the antioxidant enzyme genes such as genes encoding SOD, GPX and the glutathione synthatase to enhance the plant antioxidant system during abiotic stress. / AFRIKAANSE OPSOMMMING: Geen opsomming was ingedien met die tesis

Many plants are not commercially produced due to a lack of accessible information on their horticultural requirements and landscape potential. Members of the Legume Family (Leguminosae) are often conspicuous components of the vegetation of arid and semi-arid subtropical regions. Many of these plants are suitable for landscaping use in areas suited to their cultivation. Coursetia glandulosa, Erythrina flabelliformis, Eysenhardtia orthocarpa, Haematoxylon brasiletto, Lysiloma watsonii, Pithecellobium mexicanum, and Sophora arizonica are woody legumes native to the Sonoran Desert region which offer a variety of form, texture, color and function. All of these plants grow readily from scarified seed. E. flabelliformis and E. orthocarpa are easy to propagate from stem cuttings. Some irrigation is necessary for establishment and reasonable growth in the landscape. Maintenance and pests are minimal. Freezing temperatures are the primary limiting factor to several of the plants. S. arizonica is slow growing and is prone to rot in the nursery.

As hortaliças são alimentos amplamente consumidos na dieta dos brasileiros. Há alguns anos, estudos sobre compostos presentes em vegetais, como os carotenóides, vitaminas, fibras e compostos fenólicos vem sendo bastante explorados devido aos seus possíveis efeitos biológicos e benefícios à saúde humana. Os compostos fenólicos são produtos do metabolismo secundário das plantas e se destacam principalmente por seu poder antioxidante. O objetivo deste trabalho foi avaliar os compostos fenólicos e a atividade antioxidante em algumas hortaliças consumidas no Brasil. Os métodos utilizados foram o do radical livre DPPH e ABTS, auto-oxidação do sistema -caroteno/ácido linoléico, redução do ferro, estabilidade oxidativa em Rancimat e identificação química por meio da técnica de cromatografia gasosa acoplada a espectrômetro de massas. Extratos etanólicos foram utilizados em todas as análises. O teor de compostos fenólicos variou entre 1,2 a 16,9 mg/g, sendo que a cenoura apresentou a menor quantidade e a alface a maior. As hortaliças que apresentaram a maior atividade antioxidante foram a alface (54,9% e 0,45 µmol Fe2+/mg), nos métodos do DPPH e FRAP , respectivamente, o açafrão (111,8µM trolox/g e 92,8%), nos métodos ABTS+ e -caroteno, o agrião e o brócolis no método do Rancimat (fator de proteção 1,29). Além dessas, a alcachofra, espinafre, e aspargo também apresentaram atividade antioxidante considerável. Os compostos fenólicos mais frequentemente encontrados nas amostras pela técnica de CG-EM foram os ácidos ferúlico, caféico e p-cumárico. O ácido ascórbico presente também contribuiu para a atividade antioxidante de alguns vegetais. Desta forma, pode-se verificar boa atividade antioxidante de várias hortaliças, ressaltando assim a importância em uma dieta equilibrada destes vegetais. / Vegetables are widely consumed foods in the diet of Brazilians. A few years ago, studies on compounds present in vegetables such as carotenoids, vitamins, fibers and phenolic compounds have been conducted due to their biological effects and benefits to human health. Phenolic compounds are distinguished mainly by their antioxidant power. The aim of this study was to evaluate the phenolic compounds and antioxidant activity in some vegetables consumed in Brazil. The methods for evaluating the antioxidant activity used were the DPPH free radical and ABTS, -carotene bleaching, reduction of Fe3+, oxidative stability in Rancimat, while the chemical composition used the gas chromatography - mass spectrometry technique (GC-MS). Ethanol extracts were used in all analysis. The content of phenolic compounds ranged from 1.2 to 16.9 mg / g, with carrots presenting the lowest amount and lettuce the highest. The vegetables with the highest antioxidant activity were lettuce (54.9% and 0.45 mmol Fe2+/ mg), through DPPH and FRAP methods, respectively, saffron (111.8 mM trolox / g and 92.8%) through the ABTS+ and -carotene methods, watercress and broccoli through the Rancimat method (protective factor 1.29). Besides these, the artichoke, spinach, and asparagus also showed considerable antioxidant activity. Phenolic compounds most frequently found through the GCMS technique were ferulic acid, caffeic acid and p-coumaric acid. Ascorbic acid also contributed to the antioxidant activity of some vegetables. Generally, it is confirmed the good antioxidant activity of some vegetables, emphasizing its importance in a balanced diet.

Dentre as diversas famílias botânicas presentes na Mata Atlântica, as Fabaceae (leguminosas) apresentam grande importância, tanto pela sua abundância e ampla distribuição, como por desempenhar um papel importante no ciclo do nitrogênio (N). Levantamentos realizados em duas fisionomias florestais da Floresta Tropical Atlântica, situadas ao longo de um gradiente altitudinal (Floresta Ombrófila Densa de Terras Baixas e Florestas Ombrófila Densa Montana), mostraram uma maior disponibilidade de N nas Terras Baixas em relação à floresta Montana. Desta forma, o objetivo deste trabalho foi investigar o papel das leguminosas potencialmente fixadoras de N nessas duas fisionomias florestais. Para atingir esse objetivo, foram determinados os conteúdos de N e C, além da composição isotópica do N, nas folhas das leguminosas nodulantes (F+) ou não (F-), e nas folhas de não leguminosas (NF). As coletas foram feitas em uma parcela situada na floresta Montana e em duas parcelas na floresta de Terras Baixas. Analisaram-se 207 amostras foliares e considerando os dois gradientes altitudinais, a média do 15N foi menor nas F+ (0.4±1.2?) em relação a das NF (1.6±1.8?), mas não significativa quando comparada ao valor médio das F- (1.4±1.3?). O valor médio para a concentração de N nas F+ foi mais elevado do que nas NF e F-. Para as concentrações de P não houve diferença entre F+, F- e NF. A concentração de Ca foi mais elevada nas NF do que nas F+, sem diferença significativa em relação às F-. A razão C:N foi maior nas NF ao comparar-se com as F+ e F-, mas sem diferença significativa das NF em relação às F-. O valor médio da razão N:P foi mais elevado nas F+, sem diferir das F-. As Terras Baixas apresentaram maiores valores médios de 15N, P e Ca, e menores razões C:N e N:P. Ao considerar a interação entre altitude e capacidade de nodulação, o valor médio do 15NNF foi significativamente maior nas Terras Baixas, mas sem diferença para plantas F+ entre fisionomias. A concentração de N foi menor nas NF em relação às F+ nas duas altitudes, porém, entre as duas altitudes não houve diferença significativa entre as plantas. Para o PNF, as concentrações foram maiores nas Terras Baixas, mas sem diferença entre altitudes para o valor médio de PF+. O Ca foi mais elevado nas Terras Baixas, tanto para as NF quanto para F+. A razão C:NNF foi menor nas Terras Baixas, não demonstrando diferenças entre fisionomias nas plantas F+. N:P nas NF apresentou valor médio mais elevado nas Terras Baixas, mas sem diferença significativa para N:PF+. Foi possível confirmar que as leguminosas apresentam concentrações distintas de nutrientes em relação a outras espécies, as quais podem interferir na decomposição da matéria orgânica e na dinâmica do ciclo de N dessas fisionomias florestais da Mata Atlântica. Mas, não foi detectado que as leguminosas estavam ativamente fixando nitrogênio atmosférico. / Among several botanical families present in the coastal Atlantic Forest, the Fabaceae family has a significant ecological role not only due its abundance and wide distribution, but as well as for having an important role in the terrestrial nitrogen (N) cycle. Studies conducted by our group have shown that Atlantic tropical forest located in lower altitudes (Terras Baixas) has a more open nitrogen cycle, while, at higher altitudes (Montana Forest) has a more closed nitrogen cycle. Under this scenario the main objective of this project was to investigate the role of Fabaceae on the N and other nutrients cycles in two Atlantic forests, with distinct characteristics of the N cycle. One with an open nitrogen cycle located at 100 m of altitude and another with a closed nitrogen cycle located at 1000 m of altitude. A number of 207 leaf samples was analysed and considering the total sample within the two altitudinal gradients, 15N mean value was lower in F+ (0.4 ± 1.2 ?) relative to the NF (01.06 ± 01.08 ?) but not different when compared to average value of F- (1.4 ± 1.3 ?). The mean value for the concentration of the NF+ showed higher than the F- and NF. P concentrations did not differ between F+, F- and NF. Ca was higher than in NFF+, with no significant difference in relation to F-. C:N ratio was higher in NF when comparing with the F+ and F-, but did not differ to NFF-. Average value of N:P ratio was higher in F+, but did not show difference to F-. The Lowland had higher mean values of 15N, P and Ca, lower C:N and N:P ratios, but no significant difference in the concentration of N compared to Montana. When considering the interaction between altitude and nodulation, the average 15NNF was significantly higher in the Lowland, but no difference for F+ was observed between the sites. F- were not observed in the Lowland. The N concentration was lower in NF compared to F+ in the two altitudes, however, between these parameters and in different altitudes, there was no difference. PNF concentrations were higher in the Lowland, but no difference between altitudes for the average PF+ was observed. Ca was higher in Lowland for both NF and for F+. The C:NNF ratio was lower in the Lowland, showing no differences between the sites in F+ plants. N:P ratio in NF was higher in the Lowland, but there was no significant difference in N:PF+. With the data presented the paradox related to N richness in tropical forests and the absence of fixation in this environment continues. It can be conclude because it was the legumes are not fixing, even when comparing the different physical conditions and nutrient availability. However, it was confirmed that legumes have different concentrations of nutrients in their tissues over other species which may interfere with the decomposition of organic matter and in the N cycle of the ecosystem.

A família Fabaceae abundante nos trópicos, desperta grande interesse para o uso em recuperação de áreas degradas, já que em sua maioria, são lenhosas e perenes, se adaptam aos mais diversos ecossistemas brasileiros e são capazes de fazer associações simbiônticas com bactérias pertencentes ao gênero Rhizobium, que fixam nitrogênio atmosférico fornecendo-o para a planta em uma forma reativa. Dentro deste contexto, o presente estudo avaliou em um experimento em casa de vegetação como a fixação biológica de nitrogênio em três espécies pertencentes a família Fabaceae variou em função da adição de nitrogênio mineral em diferentes doses e através de tratamentos incluindo-se a inoculação com bactérias do gênero Rhizobium e fungos micorrízicos arbusculares (FMAs). Os resultados obtidos através da atividade da redução de acetileno indicaram que os nódulos se encontravam ativos no último mês de experimento nas três espécies fixadoras de N2. Houve uma grande variação na porcentagem de N na planta proveniente da fixação (NPPfix). Quando as plantas cresceram em meio onde a disponibilidade de N era baixa, sem a aplicação deste nutriente no solo, a FBN foi favorecida, variando de 34 a 84%. Pelo contrário, foi possível observar que a fixação foi inibida em vasos onde a adição de nitrogênio foi elevada. Devido ao uso do solo não esterilizado, os inoculantes aplicados (bactérias e fungos) parecem ter competido com a microbiota nativa do solo, assim sendo, diferenças entre os tratamentos inoculados e o controle (sem inoculação) não foram encontradas neste estudo / Legumes (Fabaceae) are abundant in the tropics and considered as of great interest as restorer of degraded areas, since most of them are woody and perennials, adapted to several Brazilian ecosystems and able to make associations with bacteria belonging to Rhizobium genus, which fix atmospheric nitrogen, and giving it to the plants in a reactive form. In this context, this study evaluated in a greenhouse experiment how nitrogen biological fixation (FBN) varied in three species of Fabaceae family according to the N-mineral addition in different doses and according to treatments including inoculation with bacteria of Rhizobium genus and arbuscular mycorrhizal fungi (AMF). The results obtained from the acetylene reduction activity indicate that the nodules were active in the last month of experiment in the three N2-fixing species. There was a wide variation in the plant N percentage derived from fixation (NPPfix). When plants grew in a soil where N availability was low, without application of this nutrient in the soil, the BNF was favored, ranging the NPPfix from 34 to 84%. On the contrary, it was possible to observe that FBN was inhibited in the pots where N additions were higher. Due to the use of unsterilized soil, the applied inoculants (bacteria and fungi) appear to have competed with the native soil microbiota, thus differences between inoculated and control (without inoculation) could not be established in this study

Introdução: O atual estilo de vida traz consequências negativas no que se refere aos padrões dietéticos, nível de atividade física (AF), uso de tabaco e estresse psicossocial, os quais predispõem ao aumento de doenças crônicas não-transmissíveis. Dieta rica em frutas, legumes e verduras (FLV) pode atenuar os efeitos sobre o risco cardiometabólico, havendo evidências consistentes de benefícios na prevenção da obesidade, dislipidemia e diabetes tipo 2. O consumo de FLV, fontes de vitaminas e minerais essenciais para a homeostase corporal está aquém do desejado. Estes alimentos contribuem para um perfil cardiometabólico favorável, atenuando o estresse oxidativo, inflamação e resistência à insulina. Objetivo: Este estudo analisou a associação entre o consumo FLV e de certos micronutrientes com marcadores do estado oxidativo, inflamatório e de resistência à insulina em indivíduos de risco cardiometabólico. Métodos:Nesta análise transversal foram incluídos 205 participantes (65 por cento mulheres; média de idade de 54,1 anos) do Estudo de Prevenção de Diabetes do CS-Escola da FSP-USP, com pré-diabetes ou de síndrome metabólica sem diabetes. Foram submetidos a questionários e coletas de sangue. Entre as dosagens, a superóxido dismutase (SOD) e a LDL oxidada (LDLox) serviram para indicar o estado anti/pró-oxidativo. O nível de AF foi medido pela versão longa do IPAQ. Três recordatórios alimentares de 24h foram empregados para cálculo da ingestão de micronutrientes e de FLV. Três categorias de consumo de FLV consumidas foram criadas considerando-se a recomendação internacional e a ingestão de micronutrientes estratificada segundo tercis de consumo, analisados por ANOVA. Coeficiente de Pearson e regressão linear múltipla foram também empregados. Resultados: Os participantes consumiram uma média de 1800 kcal/dia e 3,7 porções/1000 kcal de FLV. Ao longo das categorias de ingestão de FLV, os valores médios de circunferência da cintura (p=0,06) e pressão arterial diastólica (p=0,05) tenderam a diminuir e adiponectina (p=0,05) a aumentar. Indivíduos no tercil mais alto de ingestão de zinco apresentaram valores mais baixos de massa gorda e HOMA-IR, enquanto as concentrações de PCR foram marginalmente significantes (p=0,06). O HOMA-IR associou-se inversamente com ingestão de zinco e magnésio em todos os modelos. Associações diretas foram encontradas entre as concentrações de SOD com ingestão de FLV, bem como de magnésio em modelos ajustados. A concentração de LDLox se associou inversamente a ingestões de magnésio, vitaminas C e E em modelos ajustados. Resultados similares foram encontrados entre a concentração de LDLox e FLV, mas perdeu a significância após ajustes. Associação direta entre LDLox e ingestão de selênio manteve-se nos modelos ajustados. Conclusão: Nosso estudo sugere que a análise do consumo de FLV e/ou de certas vitaminas e minerais, ainda que estejam abaixo dos níveis recomendados, pode ser útil para identificar estresse oxidativo e resistência à insulina. / Introduction: Current lifestyle has deleterious consequences in dietary habits, physical activity, smoking and psychosocial stress, which have predisposed to non-communicable chronic diseases. A diet rich in fruits and vegetables can attenuate the effects on cardiometabolic risk, and there is consistent evidence of its benefit on the prevention of obesity, dyslipidemia and type 2 diabetes. Worldwide the consumption of fruits and vegetables, sources of vitamins and minerals, which are essential for body homeostasis, is low. These foods contribute to a favorable cardiometabolic profile, attenuating oxidative stress, inflammation and insulin resistance. Objective: Associations between the consumption of certain micronutrients and fruits and vegetables with markers of oxidative status, inflammation and insulin resistance were examined in individuals at cardiometabolic risk. Methods: This cross-sectional analysis included 205 participants (65 per cent women, mean age 54.1 years) with pre-diabetes or with metabolic syndrome without diabetes of the Diabetes Prevention Study of the FSP-USP Health Care Unit. They were submitted to questionaires blood collection. Superoxide dismutase (SOD) and oxidized LDL (oxLDL) were used to indicate the oxidative status. The physical activity level was measured by the long version of IPAQ. Three 24-hour dietary recalls were used to calculate intake of micronutrients and of fruits and vegetables. Three categories of fruits and vegetables consumption were created taking into consideration international recommendations, and micronutrient intake were grouped according tertiles of consumption, these categories analyzed by ANOVA. Pearsons correlation coefficient and multiple linear regression were used. Results: Participants consumed a mean of 1,800 kcal per day and 3.7/1000 kcal servings of fruit and vegetables. Mean values of waist circumference (p=0.06) and diastolic blood pressure (p=0.05) tended to decrease, and adiponectin (p=0.05) to increase across the categories of fruits and vegetables intake. Individuals in the highest tertile of zinc intake showed lower values of fat mass and HOMA-IR, while CRP concentrations were marginally significant (p=0.06). HOMA-IR was inversely associated with zinc and magnesium intakes in all the models. Direct associations were found between SOD concentrations and fruits and vegetables as well as magnesium intakes in adjusted models, while oxLDL concentration was inversely associated with magnesium, vitamin C and E intakes. Similar results were found between oxLDL concentration and fruits and vegetables intake but significance disappeared after adjustments. A direct association between oxLDL and selenium intake was detected after multiple adjustments. Conclusion: Our study suggest that fruits and vegetables and/or selected vitamins and minerals intakes albeit below recommended levels may be useful to identifying oxidative stress and insulin resistance.