15,056 research outputs found
Physiological mechanism of light-induced seminal root waving in rice seedlings
No full text光照是調控植物生長發育的重要環境訊息因子之一，本研究發現於水稻(Oryza sativa L.)種子發芽過程中，光照刺激會誘導秈型稻之台中在來1號(Taichung Native 1; TCN1)水稻種子根產生波動形態，而稉型稻之台農67號(Tainung 67; TNG67)則無此現象發生。幼苗局部照光之實驗結果指出，誘導根波動之光訊息主要是由根部組織直接接收及感應。由根部之切片觀察，發現光照會造成根部的中柱細胞兩側細胞產生不對稱生長，進而導致波動形態之發生。進一步觀察不同光質及光強度對TCN1水稻種子根之影響，結果發現不同光強度之紅光及白光處理下均會誘導TCN1水稻種子根產生捲曲及波動形態。另一方面，高光度之藍光(90 μmol m-2s-1)不會誘導根波動之現象發生，然而較低光度之藍光(30 μmol m-2s-1)則會誘導種子根波動；故不同藍光的光強度造成根部形態有明顯的差異。利用Aspirin抑制水稻內生茉莉酸之生合成，會降低TCN1水稻種子根於紅光(90 μmol m-2s-1)、低藍光(30 μmol m-2s-1)及白光(90 μmol m-2s-1)誘導下所產生的捲曲及波動百分比；進一步利用real-time RT-PCR分析TCN1水稻種子根中茉莉酸生合成及訊息傳導基因之表現，發現allene oxide synthase (OsAOS)家族基因、12-oxophytodienoic acid reductase 1 (OsOPR1)及root specific rice PR10 (RSOsPR10)均會受到紅光及白光處理而誘導其表現。N-1-naphthylphthalamic acid (NPA)會抑制生長素(Auxin)流出載體蛋白的功能，以破壞水稻之生長素極向運移，結果指出NPA會抑制白光誘導TCN1水稻種子根產生的波動形態且會影響根部之向地性反應。綜合以上實驗結果，推測茉莉酸生合成及生長素極向運移反應均為光照誘導TCN1水稻種子根產生捲曲及波動形態所必須之條件。Light is an important environmental factor controlling plant growth and development. In this study, it was observed that continuous white light can induce the wavy growth pattern of seminal roots in germinating rice (Oryza sativa L. cv. Taichung Native 1; TCN1) seeds. However, the phenotype of light-induced wavy root was genetic diverse among rice cultivars; for example, the light-induced wavy root could be presented in seedlings of indica type rice (such as TCN1), but could not be presented in that of japonica type cultivars (such as Tainung 67; TNG67). According to the experiment with plants partially exposed to light, it was suggested that the light signal for inducing the wavy roots were directly sensed by root tissues. Analysis of longitudinal sections of wavy seminal roots indicated that light-induced root waving was caused by the asymmetric cell growth on both side of vascular cylinder cells in the root tips. In addition to white light, red light (90 μmol m-2s-1) could also induce root curling phenotype on seminal roots. However; the blue light with high intensity (90 μmol m-2s-1) presented no effect on inducing root waving/curling. On the other hand, other results in our laboratory showed that low intensity (30 μmol m-2s-1) of blue light could induce root waving. Using Aspirin to inhibit endogenous jasmonic acid (JA) biosynthesis in TCN1 seedlings conducted the light-induced curling/wavy root phenotypes were absent. Furthermore, light effects on expressions of the genes involved in JA biosynthesis, i.e., allene oxide synthase (OsAOS) gene family and 12-oxophytodienoic acid reductase (OsOPR1), and a root specific JA-responsive gene, root specific rice PR10 (RSOsPR10) were observed. The data showed that transcript levels of most JA biosynthesis-related and JA-responsive genes were increased in white- and red-light conditions. Moreover, N-1-naphthylphthalamic acid (NPA), an inhibitor of auxin efflux carriers, was used to interrupt auxin polar transport in roots, and then the morphology of light-induced wavy root was eliminated. Thus, the results suggested that JA biosynthesis and auxin polar transport were essential for light-induced seminal root waving in seedlings of indica type rice
Emprego da tecnologia supercrítica para a valorização do resíduo de semente de chia (Salvia hispanica)
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Alimentos, Florianópolis, 2014.A chia (Salvia hispanica) é uma planta cultivada nas Américas do Sul e Central, cuja semente é fonte de antioxidantes naturais e ácidos graxos essenciais. O presente estudo avaliou a obtenção de extratos de torta de chia, subproduto proveniente da extração do óleo de chia. Foram aplicadas as técnicas a baixa pressão como extração em Soxhlet (SOX), ultrassom (US) e maceração (MAC) utilizando etanol (EtOH), hexano (Hex) e acetato de etila (EtOAc) como solventes, a fim de comparar com o processo de extração supercrítica (ESC). As operações de ESC foram realizadas com pressões de 150 bar a 300 bar e temperaturas de 40 °C e 50 °C empregando o CO2 como solvente. Também foi realizada a aplicação de EtOH e EtOAc como cossolventes no processo de ESC em concentrações de 2,5 até 7,5 %. O processo de extração supercrítica sequencial (ESC-S) foi estudado, o qual possui duas etapas de extração, com uma despressurização rápida do sistema entre a primeira e a segunda etapa. A construção da curva cinética e modelagem matemática de processos de ESC e ESC-S foram executadas, além da estimativa de custos de manufatura da instalação de uma unidade industrial de ESC. Todos os extratos obtidos foram submetidos a análises de atividade antioxidante (método ABTS), teor de fenólicos totais (TFT), perfil de ácidos graxos e atividade antimicrobiana. Nas extrações a baixa pressão, os maiores rendimentos foram obtidos utilizando SOX com EtOH (15,4 ± 0,4 %). Nas ESC com CO2 puro, a pressão de 300 bar permitiu alcançar rendimentos de até 10,6 ± 0,2 %, na maior temperatura estudada. A utilização de cossolvente causou aumento no rendimento de extração (11,3 ± 0,1% utilizando EtOH a 7,5%). Os extratos obtidos em extrações a baixa pressão com EtOH e EtOAc obtiveram os melhores valores de TFT e atividade antioxidante. A utilização de cossolvente afetou positivamente os resultados de TFT e atividade antioxidante dos extratos de ESC. O perfil de ácidos graxos dos extratos confirmou altos teores de ácido linoleico e a-linolênico em todos os extratos testados. Extratos obtidos pelas diferentes técnicas mostraram atividade antimicrobiana contra B. cereus. A ESC-S com despressurização rápida teve efeito positivo com relação ao rendimento, onde foi atingido rendimento de 8,7 ± 0,2%, estatisticamente igual ao rendimento obtido em ESC na mesma condição, porém reduzindo o tempo de extração pela metade. A realização da segunda etapa de ESC-S utilizando EtOH 7,5% ocasionou um aumento no TFT dos extratos obtidos. O modelo que melhor se ajustou as curvas experimentais foi o modelo de Martínez et al. (2003). Segundo o modelo de Sovová (1994), para os processos de ESC e primeira etapa de ESC-S, o mecanismo de convecção foi mais representativo. Na segunda etapa de ESC-S o mecanismo de difusão também mostrou representatividade. A ESC-S quando realizada até a etapa de despressurização (ESC-Desp) mostrou ser um processo economicamente viável e lucrativo para aplicação em escala industrial, com valores de extrato competitivos com os valores de mercado, gerando extratos de alta qualidade em um menor tempo de processo.Abstract : Chia (Salvia hispanica) is a plant cultivated in South and Central America, whose the seed is a source of natural antioxidants and essential fatty acids. The present study evaluated the extracts attainment from chia seed cake, which is a byproduct from chia seed oil extraction process. It were applied low-pressure techniques, like Soxhlet extraction (SOX), ultrasound assisted extraction (US) and maceration (MAC) using ethanol (EtOH), hexane (Hex) and ethyl acetate (EtOAc) and as solvents with the objective of comparing with the high pressure process, performed by supercritical fluid extraction (SFE). SFE were performed at pressures from 150 to 300 bar and temperatures of 40 °C and 50 °C, using CO2 as solvent. It was also performed an application of EtOH and EtOAc as cosolvents on SFE process, using concentrations from 2.5 to 7.5%. A sequential supercritical fluid extraction (S-SFE) process was studied, wich includes two steps of extraction, with a fast depressurization of the system between the first and the second step of extraction. The kinetic extraction curves of SFE and S-SFE processes were built and mathematical models adjusted the experimental data. It were also performed an estimative of manufacturing costs from installing a supercritical fluid extraction industrial unit. All extracts was submitted to antioxidant analysis (ABTS method), total phenolics content (TPC), fatty acids profile and antimicrobial analysis. Among low-pressure extraction, the highest yield was achieved using SOX with EtOH (15.4 ± 0.4 %). Among the SFE assays using pure CO2, the pressure of 300 bar allowed to achieve yields up to 10.6 ± 0.2 %, in the highest tested temperature. The use of a cosolvent caused increase in yield (11.3 ± 0.1% using EtOH 7,5%). Extracts obtained by lowpressure techniques using EtOH and EtOAc showed the best values of TPC and antioxidant activity. The using of a cosolvent affected in a positive way the results of TPC and antioxidant activity of SFE extracts. The fatty acids profile of the extracts confirmed the high content of linoleic and a-linolenic acids in all tested extracts. Extracts obtained by different techniques showed antimicrobial activity against B. cereus. SSFE process with fast depressurization caused a positive effect in yield, achieving a yield of 8.7 ± 0.2%, statiscally equal to the yield obtained by SFE using the same condition, but reducing the extraction time by half. The performance of the S-SFE second step using EtOH 7.5% caused an increase in the TPC of the obtained extracts. Martínez et al (2003) was the model which best-adjusted experimental data. According to Sovová s model (1994), in S-SFE first step and SFE processes, the convection mechanism was more representative. In the S-SFE second step, the diffusion mechanism showed to be representative. S-SFE process, when realized until the depressurization step (SFE-Desp), showed to be an economically viable and profitable process on an industrial scale application, with values of extract competitive with market values, generating high quality extracts in a shorter process time
Chia-Chen Hu Piano Recital Program Notes
No full textThese are the program notes of Ms. Hu, Chia Chen piano recital, held on May 20th, 2020, in the Fine Arts building FA4028 of the National Sun Yat-Sen University. The program of the piano recital includes Granados\ue2s Ochos Valses Poeticos, Beethoven\ue2s 32 Variations in C Minor, WoO. 80, and Chopin\ue2s Piano Sonata No.3 in B Minor, Op.58. These program notes will introduce how these three composers with different historical backgrounds compose piano pieces with their own characteristics
Micromechanical Modeling of Creep Behavior in Particle-Reinforced Silicone-Rubber Composites
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