Abstract
For cultivation of cucumber (Cucumis sativus L.) under greenhouse, the “wire-suspended cultivation system with intact growing runners” which requires routine exercises for successive repositioning of growing tips of the runners or secondary vines throughout the cultivation period, is now widely employed by the horticultural growers in Japan. During the growth of young vines of cucumber plants under the forcing-culture conditions, repositioning of vines is frequently required due to the spatial limitation or for the ease of fruit harvesting. As the vines are actively self-fixed on the wires by tendril-based networking, the vine repositioning exercise requires cutting or removal of multiple tendrils without severely damaging the vines or growing tips. The present study documented the tendril tensile resisting against the mechanical vine repositioning exercises. The mean tensile strength for single tendril support was shown to be ca. 6.12 N (1.07 N/mm2 or 1.07 MPa at the base of tendrils). The force required for tendril removal per single vine would be 5.20 N and 15.78 N for exercises performed at 2 day-interval and a week interval, respectively. Based on these figures, we propose here a simplified mechanical procedure for tendril cutting and repositioning of vines, which could be readily automated through the future efforts.
