Use of Plant Hormones on Postharvest Physiology of Bird of Paradise

Bird of Paradise (Strelitzia reginae Banks) has great market potential due to its intrinsic beauty and
longer vase life. However, storage and transportation conditions are not always adequate and may
lead to negative consequences on postharvest physiology and the quality of these flowers. Thus, this
study determined the effect of pulsing treatment containing methyl jasmonate (MeJA) or salicylic acid
(SA) in association with sucrose on the postharvest physiology of Bird of Paradise. Two
independent experiments were carried out. In the first one, floral stems were treated with 100, 250
and 400 μmol L-1 of MeJA plus 200 g L-1 of sucrose for 24 h. In the second experiment, the treatments
consisted of 2, 4 and 6 mmol L-1 of SA in association with 200 g L-1 sucrose for 24 h. After the pulsing
treatment, the floral stems of both experiments were kept in containers with water at room
temperature. The analyses were performed on days 0 and 7 and the assessment comprised: Water
uptake rate, transpiration rate, fresh mass loss, electrolyte leakage, peroxidase activity (POD) and
phenolic compounds of the bracts and sepals. MeJA and SA reduced the water uptake rate by the
stems. SA reduced transpiration rate, loss of fresh mass and phenolic compounds of sepals on day 0.
On day 7, MeJA treatment reduced electrolyte leakage and increased POD activity. Otherwise, SA
had no effect on electrolyte leakage and reduced POD activity. These results suggest that MeJA and
AS act antagonistically on the electrolyte leakage and POD activity which might promote different
effects on the postharvest physiology of Bird of Paradise stems, such as adverse patterns of the
transpiration rate.