Abstract
The effect of difference (DIF) between day temperature (DT) and night temperature (NT) and photoperiod on stem elongation of Verbena bonariensis L. plant was investigated. The combination of treatments was -10, 0 and +10 DIF and photoperiod of 8, 12 and 16 hours. Stem elongation was measured and analyzed with a non-contact method by a computer vision based system. Daily elongation markedly increased as DIF increased in all photoperiod treatments of 8, 12 and 16 hours. Longer photoperiod enhanced daily elongation at positive DIF (DT>NT) and zero DIF (DT=NT). DIF significantly affected elongation during the light period (EL) comparing to that during the dark period (ED). The magnitude of EL increased with increasing DIF and photoperiod.
