2013 ASHS Annual Conference

Application of low concentrations of thidiazuron (N-phenyl-N’-1,2,3-thiadiazol-5-ylurea, TDZ) has been shown to be a very effective means of delaying leaf yellowing and improving the postharvest performance of cut flowers and potted plants.  We studied the effects of TDZ applications on the growth and development of potted Tulipa gesneriana ‘Christmas Dream’. Plants were treated with foliar sprays of a range of concentrations of TDZ (deionized water, 10 μM, 100 μM) at two developmental stages - four days prior to flower opening (stage 1) and the day flowers were just fully-opened (stage 2). Spray treatments with 10 to 100 μM TDZ at both stages resulted in a considerable delay in leaf yellowing compared to the controls (0 μM). The TDZ-treated tulip leaves tended to maintain higher chlorophyll contents through the lifecycle. Treatments with TDZ at 10 and 100 μM at both stages significantly increased the display life of potted tulip flowers, up to 10 days from 6 days in controls. In addition, TDZ-treated plants produced considerably larger (at least 2-fold) ovaries. Our results indicate significant potential for TDZ as a tool to improve the postharvest life of potted tulip plants.