Researchers from the Tokyo University of Agriculture have found an effective method of increasing the sugar concentration in tomato fruit juice through the use of a new prototypic method known as "basal wire coiling".
Traditional methods have usually involved subjecting plants to salt and water stresses, however basal wire coiling appears to be a more simpler and effective method of increasing sugar concentration in tomato juice, thus increasing its marketability, Science Daily reports.
The researchers, Ken Takahata and Hiroyuki Miura, coiled bonsai wire around the stems of tomato seedlings between the cotyledon node and the first leaf node. According to Takahata and Miura, the use of basal wire coiling appeared to be less complex than other traditional methods of increasing sugar concentration.
"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.
"Eleven days after treatment, the stem diameters immediately above the wire coils were markedly greater in treated plants compared with the corresponding stem regions of control plants."
The researchers noted that the stems of treated plants were less elongated and developed fewer nodes at 39 and 51 days after treatment than the control plants did.
Several months after the treatment, the researchers found that fruit harvested from the treated plants were between 49 to 89 percent the weight of the fruit from the control plants. They also noted that sucrose, fructose and glucose concentrations were far higher than the control plants.
"Since basal wire coiling in this experiment markedly suppressed root growth, presumably by impeding photosynthate translocation through the phloem to the roots, we assume that water absorption was also decreased by this treatment," Takahata and Miura wrote.
"Furthermore, impeding water transport through the xylem to the upper parts of the plant by this treatment should accelerate a reduction in the moisture content of the shoot."
The study, Increasing the Sugar Concentration in Tomato Fruit Juice by Coiling Wire Around Plant Stems, was published in the American Society for Horticultural Science.