Indicadores precoces de longevidade em buganvília envasada

Gago, Custódia

http://hdl.handle.net/10400.1/739

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Authors

Gago, Custódia

Advisor(s)

Monteiro, José A.

Abstract(s)

The aims of this work were to study bract and flower abscission in Bougainvillea spectabilis ?Killie Campbell? plants, under post-production conditions. The effect of spraying with Silver Thiosulphate (STS) and with Naphtalene Acetic Acid (NAA, at high concentration: 500 mg.l-1), separately or together, was tested on plants exposed or not to exogenous ethylene. Quantification of non-structural carbohydrates in the bracts, leaves and stems, as well as the respiratory rates of these plant organs were assessed. In another stage, the photosynthetic rates of leaves and bracts were determined and the anthesis of the flowers, existing in the interior of each group of bracts, was monitored. In the absence of exogenous ethylene, NAA was enough to reduce CD bract abscission during post-production. If plants were exposed to exogenous ethylene, then the treatment STS+NAA was needed to reduce bract abscission. Pooling together the four post-production treatments, bract abscission was positively correlated with bract+flower dark respiration, and with bract+flower total non-structural carbohydrates. Similary to what was previous found for other plant organs bract+flower respiration seems to be a good early indicator of bract longevity. Plants that presented greater bract longevity (i. e., NAA and STS+NAA treatments) were the ones that had a reduced percentage of opening flowers and whose flowers had shorter period of anthesis. Flower and bract longevity in potted bougainvillea are distinct events although they abscise together.