Determination of Frequencies and Amplitudes in Flowers of Tomato Varieties for Vibrational Pollination

Abstract

　In this study, we investigated the differences in efficient vibrational pollination related to flower characteristics among 10 commercially available Japanese tomato cultivars, focusing on their shapes, weights, and natural frequencies. Although the acceleration thresholds for pollen dispersion varied depending on the excitation frequency and tomato cultivar, they were significantly higher at 100 Hz compared to 15, 30, and 50 Hz. For cherry tomato cultivars, the acceleration thresholds were lower at 50 Hz, while for large and medium tomato cultivars, those were lower at 15–50 Hz than those at 100Hz. No correlation was found between the acceleration threshold for pollen dispersal and the amount of pollen per flower. The natural frequencies of the flowers were examined by applying vibrations ranging from 5 to 100 Hz to the flowers using a non-contact shaker and measuring the displacement with a high-speed camera. Although the natural frequencies varied among individual flowers, differences were also observed among different varieties. Furthermore, the optimal period for vibrational pollination of ‘Momotaro Hope’ was determined to be from 1 day before to 4 days after flowering, in terms of the acceleration threshold for pollen dispersion, which closely aligns the optimal period identified in previous studies.