THE EFFECT OF ALUMINIUM SULPHATE, SODIUM HYPOCHLORITE PLUS CITRIC ACID AND SILVER THIOSULPHATE ON WATER RELATIONS AND VASE LIFE OF HARVESTED EUSTOMA GRANDIFLORUM FLOWERS
Eustoma (Eustoma grandiflorum), one of the top ten cut flowers in the international markets, is sensitive to many postharvest handling biocides. The objective of this study was to investigate the effects of various postharvest handling chemicals for cut Eustoma flowers. The rationale was to identify effective postharvest handling solutions. Deionised water was used as a control. The experiments were laid out in a Randomized Complete Block Design (RCBD) and the entire experiment was repeated. Transpiration, water uptake, water balance, chlorophyll content, floret opening and wilting, were assessed. Silver thiosulphate (STS) prolonged vase life and improved the maintenance of chlorophyll by 116% and 138%, respectively, relative to the deionised water control. The cumulative water balance trend of sodium hypochlorite + pH adjustment to 3.5 (citric acid) treated cut Eustoma flowers was the most impressive; sustaining a steady rise to a peak on day 13 of holding, followed by a gradual decline, within the 19 days of experimental duration. Sodium hypochlorite + pH adjustment to 3.5 (citric acid) significantly improved the maintenance of turgor and delayed wilting of the florets relative to the deionised water control. Silver thiosulphate is a powerful anti-ethylene cut Eustoma pre-treatment, however, it is a potent environmental hazard owing to its silver content; and therefore, needs to be phased out. Sodium hypochlorite plus citric acid was demonstrated to be a potent postharvest handling solution for Eustoma flowers, boosting water balance and vase life. This treatment is therefore recommended for use in the entire postharvest handling system, from the grower to the retailer and the consumer.
Musembi, N.N., Hutchinson, M.J. and Waithaka , K. (2015). THE EFFECT OF ALUMINIUM SULPHATE, SODIUM HYPOCHLORITE PLUS CITRIC ACID AND SILVER THIOSULPHATE ON WATER RELATIONS AND VASE LIFE OF HARVESTED EUSTOMA GRANDIFLORUM FLOWERS. Acta Hortic. 1077, 57-63
biocide, anti-ethylene, preservative solution, postharvest handling, water balance, bent-neck, chlorophyll