The Effect of Sucrose and Silicon on the Quantitative and Qualitative Characteristics of Cherry Tomatoes

The cherry tomato is one of the most important cultivars of greenhouse tomato (Solanum lycopersicom) that has been welcomed and paid much attention in recent years. Like other cultivars, cherry tomatoes are sensitive to low light intensity, because of this; in the northern regions of Iran where natural sunlight is limited during autumn and winter, light conditions are not appropriate for indoor tomato cultivation. To alleviate this problem, an experiment was designed to evaluate the effect of two factors consisting of silicon (at two levels: 0 and 1 millimolar) and carbohydrate nutrition (at five levels: control, sucrose 2%, sucrose + potassium nitrate 5 g L-1, sucrose + magnesium nitrate 5 g L-1, sucrose + boric acid 0.5 g L-1) on the quantitative and qualitative traits of cherry tomatoes in greenhouse conditions. The results showed that the lowest flower fall was obtained in the treatment of silicon with sucrose + potassium, but it was not significantly different with the treatment of sucrose + boron. The sucrose + boron treatment which produced a high number of flowers, also increased fruit set, and the highest number of fruit per plant belonged to this treatment. The highest leaf silicon concentration was observed in plants treated by silicon treatment combined with sucrose + boron. In this experiment, sucrose + boron exhibited the lowest leaf sugar content, which was not significantly different from sucrose + potassium and silicon treatments. Since sucrose + potassium treatment had the highest amount of stem and root sugar, it is obvious that leaf carbohydrate depletion in this treatment was done toward the stem and root. The highest percentage of soluble carbohydrates was recorded in the sucrose + boron treatment, which clearly showed that in this treatment, soluble carbohydrates moved from the leaf source to the fruits. Overall, the results showed that silicon treatment in the absence of sucrose foliar application caused the depletion of sugars from the leaves and the movement of carbohydrates to fruits, but reduced the export of carbohydrates to the roots. It seems that the transfer of carbohydrates to the fruit occurred after the foliar application of silicon; because of this, silicon could reduce flowering fall and increase plant yield.