Arabinogalactan-protein and pectin epitopes in relation to an extracellular matrix surface network and somatic embryogenesis and callogenesis in Trifolium nigrescens Viv

The formation of an extracellular matrix surface network (ECMSN), and associated changes in the distribution of arabinogalactan-protein and pectin epitopes, have been studied during somatic embryogenesis (SE) and callogenesis of Trifolium nigrescens Viv. Scanning electron microscopy observations revealed the occurrence of an ECMSN on the surface of cotyledonary-staged somatic embryos as well as on the peripheral, non-regenerating callus cells. The occurrence of six AGP (JIM4, JIM8, JIM13, JIM16, LM2, MAC207) and four pectin (JIM5, JIM7, LM5, LM6) epitopes was analysed during early stages of SE, in cotyledonary-staged somatic embryos and in non-embryogenic callus using monoclonal antibodies. The JIM5 low methyl-esterified homogalacturonan (HG) epitope localized to ECMSN on the callus surface but none of the epitopes studied were found to localize to ECMSN over mature somatic embryos. The LM2 AGP epitope was detected during the development of somatic embryos and was also observed in the cell walls of meristematic cells from which SE was initiated. The pectic epitopes JIM5, JIM7, LM5 and LM6 were temporally regulated during SE. The LM6 arabinan epitope, carried by side chains of rhamnogalacturonan-I (RG-I), was detected predominantly in cells of embryogenic swellings, whilst the LM5 galactan epitope of RG-I was uniformly distributed throughout the ground tissue of cotyledonary-staged embryoids but not detected at the early stages of SE. Differences in the distribution patterns of low and high methyl-esterified HG were detected: low ester HG (JIM5 epitope) was most abundant during the early steps of embryo formation and highly methyl-esterified form of HG (JIM7 epitope) became prevalent during embryoid maturation

Avaliação da maturação dos frutos de linhagens das cultivares Catuaí Amarelo e Catuaí Vermelho(Coffea arabica L.) plantadas individualmente e em combinações Fruit ripening evaluations of Catuai Amarelo and Vermelho (Coffea arabica L.) lineages of coffee cultivar, planted isolated and in combinations

Instalou-se este experimento na Fazenda Experimental da EPAMIG em São Sebastião do Paraíso, MG, com o objetivo de avaliar as percentagens de frutos chochos e maturação de linhagens das cultivares Catuaí Vermelho (IAC 44, IAC 81 e IAC 99) e Catuaí Amarelo (IAC 47, IAC 62 e IAC 86), no período de 1994 a 1999, plantadas isoladas e em diferentes combinações. O experimento foi instalado obedecendo ao delineamento experimental de blocos ao acaso, com três repetições, parcelas constituídas de seis covas, com uma planta em cada uma adotando o sistema de manejo usualmente empregado na região, no espaçamento de 3,50 m entre linhas x 1,00 m entre covas. As linhagens foram agrupadas por cultivar plantadas isoladas e em multilinhas nas proporções de 33% e 50%. As análises estatísticas foram realizadas considerando seis características avaliadas individualmente, em parcelas subdivididas no tempo. Na análise estatística utilizou-se o teste de Duncan para comparação de médias. Pelos resultados, verificou-se que não houve diferenças significativas dos sistemas de plantio, isolado ou em combinações, sobre os diferentes estádios de maturação dos frutos.<br>The experiment conducted in EPAMIG’s experimental station at São Sebastião do Paraíso, MG, to evaluate percentage of empty fruits and fruit ripening, of Catuaí Vermelho (IAC 44, IAC 81, and IAC 99) and Catuai Amarelo (IAC 47, IAC 62, and IAC 86), all Catuai lineages, from 1994 to 1999, planted isolated and in different combinations. A randomized block design was used, with 3 replications and 14 lineages combination as treatment, each plot with six plants, spaced 3.5 by 1.0 m, respectively among interrows and lines. Lineages cultivars were grouped and planted isolated and in multi-lines at proposition of 33% and 50%. Six characteristics were evaluated, and averages compared by Duncan test. There were no differences in planting systems over the fruit maturation stages and empty fruits