RESUMO A tamareira acumula ampla variedade de metabolitos secundários com alto valor nutricional e terapêutico. No presente estudo, calos de tamareira (Phoenix dactylifera L., cv. Shaishi) induzidos a partir de ápices caulinares foram utilizados para estabelecer culturas de suspensão celular em meio líquido Murashige e Skoog (MS) contendo 1,5 mg L-1 de 2-isopenteniladenina (2iP) e 10 mg L-1 de ácido naftaleno acético (ANA). Para estudar a cinética de crescimento, as culturas foram mantidas por 12 semanas e medições semanais foram realizadas para determinar a acumulação de biomassa com base no volume de células empacotadas, peso fresco e peso seco. Além disso, a determinação dos polifenóis (catequina, ácido cafeico, kaempferol e apigenina) foi realizada semanalmente usando cromatografia líquida de alta performance (HPLC). A cultura de 11 semanas foi encontrada mais alta na produção de biomassa (62,9 g L-1 de peso fresco e 7,6 g L-1 de peso seco) e polifenóis (155,9 µg L-1 de catequina, 162,7 µg L-1 de ácido cafeico, 89,7 µg L-1 de kaempferol e 242,7 µg L-1 de apigenina) das culturas de suspensão celular. Este é o primeiro relato sobre a produção de polifenóis em suspensão celular de tamareira. Este estudo facilita a produção em larga escala de polifenóis e o uso de biorreatores.

ABSTRACT Date palm accumulates a wide range of secondary metabolites high in nutritional and therapeutic value. In the present study, date palm (Phoenix dactylifera L., cv. Shaishi) shoot-tip-induced callus was used to establish cell suspension cultures in Murashige and Skoog (MS) liquid medium containing 1.5 mg L-1 2-isopentenyladenine (2iP) and 10 mg L-1 naphthaleneacetic acid (NAA). To study the growth kinetics, cultures were maintained for 12 weeks during which weekly measurements were carried out to determine the biomass accumulation based on packed cell volume (%), fresh weight and dry weight (g). In addition, weekly determination of polyphenols (catechin, caffeic acid, kaempferol, and apigenin) was carried out using high performance liquid chromatography (HPLC). The 11-week-old culture was found highest in the production of biomass (62.9 g L-1 fresh weight and 7.6 g L-1 dry weight) and polyphenols (catechin-155.9 µg L-1, caffeic acid-162.7 µg L-1, kaempferol-89.7 µg L-1, and apigenin-242.7 µg L-1) from the cell suspension cultures. This is the first report on the production of polyphenols from the cell suspension culture of date palm. This study facilitates further development of large-scale production of polyphenols and the utilization of bioreactors.

RESUMO A tamareira (Phoenix dactylifera L.) é uma arvore frutífera adaptada à condições climáticas adversas predominantemente em regiões áridas do Oriente Médio e Norte Africano. As tâmaras possuem vários componentes químicos com alto valor medicinal e nutricional. A propagação tradicional por estacas não é suficiente para satisfazer a demanda por mudas e assim, a micropropagação apresenta-se como uma alternativa eficiente para a produção de mudas em larga escala. Embriogênese somática e organogênese, tanto direta quanto indireta via calos, tem sido usada para obter a regeneração in vitro de tamareira. O inicio do cultivo in vitro normalmente utiliza meristemas excisados de brotações jovens. Recentemente, inflorescências imaturas de árvores adultas são usadas como fonte alternativa de explantes não destrutiva. Além da origem do explante, o sucesso da regenerção depende do cultivar, da composição do meio de cultura e de condições físicas. Desafios na micropropagação de tamareira incluem um longo ciclo in vitro, contaminação, escurecimento do tecido, variação somaclonal além do enraizamento e aclimatização ex vitro. Diversos estudos investigando esses fatores tem conduzido à otimização de protocolos de micropropagação de inúmeros cultivares comerciais proporcionando o estabelecimento de vários laboratórios de cultura de tecidos de plantas. A caracterização molecular permite uma segura conformidade genética do material regenerado, considerado uma característica chave na produção comercial. Essa revisão descreve protocolos de micropropagação de tamareira e aborda as mais recentes conquistas relacionadas à variação somaclonal, marcadores moleculatres, criopreservação e perspectivas futuras.

ABSTRACT Date palm (Phoenix dactylifera L.) is a fruit tree resilient to adverse climatic conditions predominating in hot arid regions of the Middle East and North Africa. The date fruit contains numerous chemical components that possess high nutritional and medicinal values. Traditional propagation by offshoots is inefficient to satisfy current demands for date palm trees. Alternatively, micropropagation provides an efficient means for large-scale propagation of date palm cultivars. Both somatic embryogenesis and organogenesis, either directly or indirectly though the callus phase, have been demonstrated in date palm in vitro regeneration. Culture initiation commonly utilizes shoot-tip explants isolated from young offshoots. Recently, the immature inflorescences of adult trees were utilized as an alternative nondestructive source of explants. In addition to the nature of the explant used, successful plant regeneration depends on the cultivar, composition of the culture medium and physical status. Challenges of date palm micropropagation include long in vitro cycle, latent contamination, browning, somaclonal variation as well as ex vitro acclimatization and transplanting. A remarkable amount of research investigating these factors has led to optimized protocols for the micropropagation of numerous commercially important cultivars. This has encouraged the development of several international commercial tissue culture laboratories. Molecular characterization provides an assurance of genetic conformity of regenerated plantlets, a key feature for commercial production. This article describes date palm micropropagation protocols and also discusses recent achievements with respect to somaclonal variation, molecular markers, cryopreservation and future prospects.

Pounding of neighbouring construction of structures due to seismic excitation increases the damage of structural components or even causes collapse of structures. Among the possible building damages, earthquake induced pounding has been commonly observed in several earthquakes. Therefore it is imperative to consider pounding effect for structures. This study aims to understand the response behaviour of adjacent buildings with dissimilar heights under earthquake induced pounding. Effects of different separation distances between structures are also investigated. Nonlinear finite element analysis in time domain has been carried out for pounding of neighbouring structures having varying heights. To show the importance of avoiding pounding in structures the results obtained were compared with model having no pounding phenomena. The results were obtained in the form of storey shear, pounding force, storey drift, point displacement and acceleration. The acceleration at pounding level significantly increases during collision of building. The generated extra pounding force may cause severe damage to structural members of structures. Pounding produces shear at various story levels, which are greater than those obtained from no pounding case. Building with more height suffers greater damage than shorter building when pounding occurs. Increasing gap distance tends to reduce story shear in consistent manner. The results also show that the conventional modelling of building considering only beams and columns underestimates pounding effects. More realistic modelling such as beams, columns and slabs shall be adopted to accurately understand the pounding phenomenon.