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Percorrer por autor "Rodrigues, M. H."

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  • Bougainvillea post-production: NAA and STS control of bract abscission is subject to exogenous ethylene
    Publication . Gago, Custódia; Monteiro, José; Rodrigues, M. H.
    The effect of NAA (500 mg.L-1 sprayed once at end-of-production), STS (0.4 mM sprayed every 15 days after bracts started to be apparent) and STS+NAA on plants exposed or not to exogenous ethylene (from ethephon), were tested using two completely randomized experiments. At the end-of-production plants were placed for three days under simulated transport conditions (17 +/-1 degreesC, no light) and then, placed under interior conditions (21 +/-1 degreesC and 11 mu mol.m(-2)s(-1) of cool white fluorescent light 12 hr a day). Twice a week, during postproduction (PP) the number of developing (D) bracts as well as the number of completely developed (CD) bracts remaining in the plants were assessed. Among the treatments tested, NAA was enough to reduce CD bract abscission during post-production, abscising at day 32 PP, a maximum of 50% of the bracts, provided that no exogenous ethylene was present. If plants were exposed to exogenous ethylene, then the treatment STS + NAA was needed to reduce bract abscission, abscising at 32 PP a maximum of 58% of CD bracts. At this time, plants treated only with STS had abscised all CD bracts if exposed to ethylene or at least 97% of CD bracts if not exposed to ethylene.
    2001Documento de conferência Acesso restrito Ver mais
  • Efficiency of triple emitter source (TES) for irrigation experiments of horticultural crops
    Publication . Beltrão, José; Jesus, S. B.; Silva, V.; Sousa, P. B.; Carvalho, Isabel Saraiva de; Trindade, D.; Rodrigues, M. H.; Machado, A.
    Triple emitter source TES experimental irrigation was designed. Three trickle laterals were connected together in order to form a triple joint lateral. Two of them and their emitters are connected to two tanks of stock solutions. The third lateral contains only fresh water. The emitters of the two solution lines have different and varying discharges to obtain several mixings of the two stock solutions. The third line is necessary to obtain constant water application rates for each trickling point along the lateral. This method was tested for several experiments involving the study of the combined effects of salinity and fertilizers on the yield function of horticultural crops, namely lettuce and cabbage. As concluding remarks, it was shown the high uniformity of the factor to be evaluated, through the use of Christiansen coefficient of uniformity distribution CUC, which value was always larger than 90%. Main advantage of this experimental design is its smaller experimental plots (reducing pollution and research costs).
    2002Documento de conferência Acesso restrito Ver mais