Wire coils increase sugar content of tomato juice

A method called ‘basal wire coiling’ has been effective in increasing the sugar concentration of tomato juice. Researches from Tokyo University of Agriculture say the finding could improve the marketability of tomato juice.

“We investigated whether coiling wire around the lower part of the plant stems to reduce the capacity of xylem to transport water to the shoot would result in low shoot moisture conditions and increase the sugar concentration of fruit like salt and water stresses,” the authors said. They noted that basal wire coiling is less complex than other treatments, such as subjecting tomato plants to salt or water stress, which can require special equipment and techniques.

The study was published in the February 2014 issue of HortTechnology.

Researchers Ken Takahata and Hiroyuki Miura coiled bonsai wire around the stems of tomato seedlings between the cotyledon node and the first leaf node. These seedlings had markedly larger stem diameters, less elongated stems and fewer nodes compared with control plants.

Several months after this treatment, the fruit harvested from the plants treated with the wire was weighed and juiced. The treated plants’ fruit had sucrose, fructose and glucose concentrations far higher than that of the control plants.

The results suggest that the effects of the wire decreased moisture content, decreased photosynthate production, activated sugar translocation and reduced competition for photosynthates, resulting in increased sugar concentrations in tomato juice.

Takahata and Miura recommended further studies to determine the practical application of basal wire coiling for tomato production; specifically to identify the appropriate location and time for coiling plants with wire, the optimum width of the wire coil, optimal methods for nutrient and water management and to calculate the economic impacts for producers and consumers.

The complete study and abstract are available here