Physiological effects of silver thiosulfate, (aminooxy)acetic acid, and malonate pulse treatments on the inhibition of ethylene biosynthesis and mode of action in carnations

Data concerned with the inhibition of ethylene (C[subscript]2H[subscript]4) biosynthesis and mode of action by pulsing carnations with silver thiosulfate (STS), (aminooxy)acetic acid (AOA), and malonate (MA) are presented. (Aminooxy)acetic acid at 12 [mu]mole/flower extended vase life to 15.1 days, STS at 1 [mu]mole/flower extended vase life to 15.3 days, and MA at 1 [mu]mole/flower shortened vase life to 8.8 days compared with 10.3 days for the water control. (Aminooxy)acetic acid and STS inhibited the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, and this resulted in a low ACC content and a low activity of the constitutive ethylene-forming-enzyme (EFE). The ultimate result of these metabolic events was that C[subscript]2H[subscript]4 biosynthesis was inhibited. Moreover, both AOA and STS decreased the respiratory rate as measured by CO[subscript]2 production. Malonate increased ACC synthase activity, and this increased the ACC content. Also, malonate increased respiration, which was unexpected. However, MA in combination with either AOA or STS reduced both C[subscript]2H[subscript]4 biosynthesis and respiration;Little ACC synthase activity existed in the upper portion of the petals, while the basal portion of the petals contained a higher ACC synthase activity. At the beginning of the vase-life cycle, ACC synthase activity was low. This was followed by a burst of activity at the climacteric, and this was followed by a decline before the death of the flowers. Ethylene-forming-enzyme activity was assayed by determining the maximum rate of C[subscript]2H[subscript]4 production. Flowers pulsed with AOA or STS showed low EFE activity related to C[subscript]2H[subscript]4 production, while the MA pulse treatment showed an increase of EFE activity at the climacteric;These results indicate that the inhibition of C[subscript]2H[subscript]4 biosynthesis and mode of action was caused by AOA and STS. Malonate pulse treatments need to be mixed with C[subscript]2H[subscript]4 biosynthesis inhibitors to inhibit C[subscript]2H[subscript]4 production and to preserve carbohydrates in the preservative solution. These results provided background information on the use of the preservatives for both inhibition of C[subscript]2H[subscript]4 biosynthesis and reduced use of carbohydrates