986 resultados para Soilless cultivation


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This investigation was conducted at UNESP, Jaboticabal campus, São Paulo, Brazil, from March 8 to June 21, 1999, to evaluate net melon yield and fruit quality, using soilless culture. 'Bônus 2' and 'Mission' cultivars were grown in a substrate of ground quartz or thick sand, in a randomized block experimental design. Leaf and stem dry matter production, leaf size and soluble solids content of the fruit, of 'Bônus 2' were superior to 'Mission'. There was a significant interaction for the evaluated characteristics of fruit dry mass production and yield. The largest accumulation of fruit dry mass and yield of the 'Bônus 2' cultivar (61,325 kg/ha) was observed when a substrate of ground quartz was used, while the yield for the 'Mission' cultivar was higher in a substrate of thick sand (42,125 kg/ha).

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Este trabalho foi desenvolvido em Ribeirão Preto-SP, de 06/02 a 07/04 de 2006. O objetivo foi avaliar o desempenho de cinco cultivares de alface (Pira Roxa, Belíssima, Locarno, Crespona Gigante e Verônica) em dois ambientes de cultivo (casa de vegetação climatizada e não climatizada) em sistema hidropônico NFT. O delineamento experimental foi em blocos casualizados para cada ambiente com três repetições sendo cinco cultivares. Os ambientes foram comparados por meio de análise conjunta. Avaliaram-se a massa fresca e seca da parte aérea, massas fresca e seca do caule, massa fresca e seca da raiz, número de folhas maiores que 10 cm e número total de folhas. Não houve efeito significativo da interação cultivares e ambientes, demonstrando que as cultivares tiveram comportamento similar em ambos os ambientes.

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Avaliou-se o desempenho de substratos compostos por areia, bagaço de cana-de-açúcar e casca de amendoim no cultivo do tomateiro do grupo cereja. O delineamento experimental adotado foi em blocos casualizados, com sete substratos e quatro repetições. Os substratos resultaram da combinação de proporções volumétricas de areia (A), bagaço de cana-de-açúcar (BC) e casca de amendoim (CA): S1 = A; S2 = 2/3 A + 1/3 BC; S3 = 2/3 A + 1/3 CA; S4 = 2/3 A + 1/6 BC + 1/6 CA; S5 = 1/2 A + 1/2 BC; S6 = 1/2 A + 1/2 CA e S7 = 1/3 A + 1/3 BC + 1/3 CA. As variáveis avaliadas foram submetidas à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Os valores de densidade (D), espaço de aeração (EA) e água facilmente disponível (AFD) dos substratos foram estatisticamente diferentes. Os substratos apresentaram valores de D entre 790 e 1604 kg m-3, EA entre 2 e 21% e AFD entre 14 e 25%. A produtividade do tomateiro cultivado nos diferentes substratos foi estatisticamente igual, variando entre 8,5 e 10,7 kg m-2. O bagaço de cana-de-açúcar e a casca de amendoim podem ser utilizados na composição de substratos à base de areia, para o cultivo do tomateiro do grupo cereja, cultivar Sindy, em casa de vegetação.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Growth effects of cultivation on soil, sand and commercial substrate, on summer and winter time, of 'Bonus #2', 'Don Carlo's and 'Hy Mark' were assessed. The experiments were conducted in a greenhouse of FCAV-UNESP, in Jaboticabal- SP, Brazil, 21° 15' 22 S, 48° 18'58 W, and an altitude of 595 m, comprising the period from November '99 to April 2000 (Summer), and from July to November 2000 (Winter). On soil cultivation, chemical nutrients were used, and the plants received drip irrigation. On sand, fertigation with recirculation of the nutrient solution were used, and slabs and fertigation with non circulating nutrient solution was used with commercial substrate. 'Bonus #2', grown on sand and in the summer season had improved plant height, internodes length, stem diameter, leaf area and dry matter of shoots and roots. 'Hy Mark', when cultivated on commercial substrate had lower growth. During winter season, the growth was slower.

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Articular cartilage exhibits limited intrinsic regenerative capacity and focal tissue defects can lead to the development of osteoarthritis (OA), a painful and debilitating loss of cartilage tissue. In Australia, 1.4 million people are affected by OA and its prevalence is increasing in line with current demographics. As treatment options are limited, new therapeutic approaches are being investigated including biological resurfacing of joints with tissue-engineered cartilage. Despite some progress in the field, major challenges remain to be addressed for large scale clinical success. For example, large numbers of chondrogenic cells are required for cartilage formation, but chondrocytes lose their chondrogenic phenotype (dedifferentiate) during in vitro propagation. Additionally, the zonal organization of articular cartilage is critical for normal cartilage function, but development of zonal structure has been largely neglected in cartilage repair strategies. Therefore, we hypothesised that culture conditions for freshly isolated human articular chondrocytes from non-OA and OA sources can be improved by employing microcarrier cultures and a reduced oxygen environment and that oxygen is a critical factor in the maintenance of the zonal chondrocyte phenotype. Microcarriers have successfully been used to cultivate bovine chondrocytes, and offer a potential alternative for clinical expansion of human chondrocytes. We hypothesised that improved yields can be achieved by propagating human chondrocytes on microcarriers. We found that cells on microcarriers acquired a flattened, polygonal morphology and initially proliferated faster than monolayercultivated cells. However, microcarrier cultivation over four weeks did not improve growth rates or the chondrogenic potential of non-OA and OA human articular chondrocytes over conventional monolayer cultivation. Based on these observations, we aimed to optimise culture conditions by modifying oxygen tension, to more closely reflect the in vivo environment. We found that propagation at 5% oxygen tension (moderate hypoxia) did not improve proliferation or redifferentiation capacity of human osteoarthritic chondrocytes. Moderate hypoxia increased the expression of chondrogenic markers during redifferentiation. However, osteoarthritic chondrocytes cultivated on microcarriers exhibited lower expression levels of chondrogenic surface marker proteins and had at best equivalent redifferentiation capacities compared to monolayer-cultured cells. This suggests that monolayer culture with multiple passaging potentially selects for a subpopulation of cells with higher differentiation capacity, which are otherwise rare in osteoarthritic, aged cartilage. However, fibroblastic proteins were found to be highly expressed in all cultures of human osteoarthritic chondrocytes indicating the presence of a high proportion of dedifferentiated, senescent cells with a chondrocytic phenotype that was not rescued by moderate hypoxia. The different zones of cartilage support chondrocyte subpopulations, which exhibit characteristic protein expression and experience varying oxygen tensions. We, therefore, hypothesised that oxygen tension affects the zonal marker expression of human articular chondrocytes isolated from the different cartilage layers. We found that zonal chondrocytes maintained these phenotypic differences during in vitro cultivation. Low oxygen environments favoured the expression of the zonal marker proteoglycan 4 in superficial cells, most likely through the promotion of chondrogenesis. The putative zonal markers clusterin and cartilage intermediate layer protein were found to be expressed by all subpopulations of human osteoarthritic chondrocytes ex vivo and, thus, may not be reliable predictors of in vitro stratification using these clinically relevant cells. The findings in this thesis underline the importance of considering low oxygen conditions and zonal stratification when creating native-like cartilaginous constructs. We have not yet found the right cues to successfully cultivate clinically-relevant human osteoarthritic chondrocytes in vitro. A more thorough understanding of chondrocyte biology and the processes of chondrogenesis are required to ensure the clinical success of cartilage tissue engineering.

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This chapter explores the role of the built environment in the creation, cultivation and acquisition of a knowledge base by people populating the urban landscape. It examines McDonald’s restaurants as a way to comprehend the relevance of the physical design in the diffusion of codified and tacit knowledge at an everyday level. Through an examination of space at a localised level, this chapter describes the synergies of space and the significance of this relationship in navigating the global landscape.

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We have presently evaluated membranes prepared from Bombyx mori silk fibroin (BMSF), for their potential use as a prosthetic Bruch’s membrane and carrier substrate for human retinal pigment epithelial (RPE) cell transplantation. Porous BMSF membranes measuring 3 μm in thickness were prepared from aqueous solutions (3% w/v) containing poly(ethylene oxide) (0.09%). The permeability coefficient for membranes was between 3 and 9 × 10-5 cm/s by using Allura red or 70 kDa FITC-dextran respectively. Average pore size (± sd) was 4.9 ± 2.3 µm and 2.9 ± 1.5 µm for upper and lower membrane surfaces respectively. Optimal attachment of ARPE-19 cells to BMSF membrane was achieved by pre-coating with vitronectin (1 µg/mL). ARPE-19 cultures maintained in low serum on BMSF membranes for approximately 8 weeks, developed a cobble-stoned morphology accompanied by a cortical distribution of F-actin and ZO-1. Similar results were obtained using primary cultures of human RPE cells, but cultures took noticeably longer to establish on BMSF compared with tissue culture plastic. These findings encourage further studies of BMSF as a substrate for RPE cell transplantation.

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This paper presents a hybrid framework of Swedish cultural practices and Australian grounded theory for organizational development and suggests practical strategies for 'working smarter' in 21st Century libraries. Toward that end, reflective evidence-based practices are offered to incrementally build organizational capacity for asking good questions, selecting authoritative sources, evaluating multiple perspectives, organizing emerging insights, and communicating them to inform, educate, and influence. In addition, to ensure the robust information exchange necessary to collective workplace learning, leadership traits are proposed for ensuring inclusive communication, decision making, and planning processes. These findings emerge from action research projects conducted from 2003 to 2008 in two North American libraries.

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Purpose: The silk protein fibroin provides a potential substrate for use in ocular tissue reconstruction. We have previously demonstrated that transparent membranes produced from fibroin support cultivation of human limbal epithelial cells (Tissue Eng A. 14(2008)1203-11). We presently extend this body of work to studies of human limbal stromal cell (HLS) growth on fibroin in the presence and absence of serum. Methods: Primary cultures of HLS cells were established in DMEM/F12 medium supplemented with either 10% fetal bovine serum (FBS) or 2% B27 supplement. Defined keratinocyte serum-free medium (DK-SFM, Invitrogen) was also tested. The resulting cultures were analysed by flow cytometry for expression of CD34, CD90, CD45, and CD141. Cultures grown under each condition were subsequently passaged either onto transparent fibroin membranes prepared from purified fibroin or within 3D scaffolds prepared from partially-solubilised fibroin. Results: HLS cultures were successfully established under each condition, but grew more slowly and passaged poorly in the absence of serum. Cultures grown in 10% FBS were <0.5% CD34+ (keratocytes) and >97% CD90+ (fibroblasts). Cultures established in 2% B27 formed floating spheres and contained >8% CD34+ cells and reduced CD90 expression. Cultures established in DK-SFM displayed traces of epithelial cell growth (CD141), but mostly consisted of CD90+ cells with <1% CD34+ cells. Cells of bone marrow lineage (CD45) were rarely observed under any conditions. Cultures grown in 10% FBS were able to adhere to and proliferate on silk fibroin 3-D scaffolds and transparent films while those grown serum-free could not. Adhesion of HLS cells to fibroin was initially poorer than that displayed on tissue culture plastic. Conclusions: HLS cultures containing cells of predominantly fibroblast lineage can be grown on fibroin-based materials, but this process is dependent upon additional ECM factors such as those provided by serum.

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Filamentous fungi are important organisms for basic discovery, industry, and human health. Their natural growth environments are extremely variable, a fact reflected by the numerous methods developed for their isolation and cultivation. Fungal culture in the laboratory is usually carried out on agar plates, shake flasks, and bench top fermenters starting with an inoculum that typically features fungal spores. Here we discuss the most popular methods for the isolation and cultivation of filamentous fungi for various purposes with the emphasis on enzyme production and molecular microbiology.

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The interest in potentially economically valuable plants (for food, timber, dyes, fabric, and drugs) was part of the concerted effort given by colonial governments towards providing botanic gardens in new colonies. While convicts and guards laboured in Brisbane Town from 1825 until 1849, botanists such as Alan Cunningham were discovering the delights of native plants in their numerous excursions. Their observations and collections of seeds were sent south (to the local botanic gardens at Melbourne and Sydney) and onward to the Royal Botanic Gardens in Britain (at Kew and Edinburgh). This set the local pattern for future exchanges among the global British Imperial botanic garden network...