Gibberellic acid and sugar improve the quality and extend the longevity of cut costus flowers (Costus sp.)

T. Maithong, C. Wongs-Aree, M. Buanong
Costus flower is often characterized and distinguished from relatives such as Zingiber (true ginger) by its spiraling stems. However, the main senescence symptom of costus flowers accompanies visible changes which include loss of chlorophyll in the stem within 4 days after harvest and wilting bract. To ensure the best quality of flowers, treatments for extending the vase life of cut costus flowers are needed to maintain after harvest. Gibberellic acid (GA3) is considered to be a senescence-delaying plant growth regulator. An exogenous sugar supply also is added in the vase solution as the most efficient means to delay senescence. Therefore, the objective of this experiment was to determine the effect of gibberellic acid and sugar on improving the quality and extending the longevity of cut costus flowers (Costus sp.). Costus flowers were held in deionized water (DI) as a control, 1% sucrose (SU), 0.5 µM gibberellic acid (GA3), and GA3 + SU in an observation room (21±2°C, 60-70% RH under cool-white fluorescence lights for 12 h d-1) throughout the experimental period. To all treatments 50 ppm sodium dichloroisocyanurate (DICA) was added to prevent microbial growth in the solution. It was revealed that treatments of GA3 + SU gave the best results in delaying the yellowing stem of cut costus for 6.5 d, while the control had more than 50% of yellowing stem within 4.0 d, which was closely related to the content of total chlorophyll. Treatments of GA3 alone and GA3 + SU had significantly higher total chlorophyll content in the stem than that of SU and DI which continuously decreased throughout the vase period. However, adding sugar in the vase solution induced higher accumulation of anthocyanin and total sugar contents in the bract compared to treatments of DI (control) and GA3 alone.
Maithong, T., Wongs-Aree, C. and Buanong, M. (2018). Gibberellic acid and sugar improve the quality and extend the longevity of cut costus flowers (Costus sp.). Acta Hortic. 1210, 131-138
DOI: 10.17660/ActaHortic.2018.1210.18
costus, gibberellic acid, sucrose, vase life

Acta Horticulturae