A THIDIAZURON PULSE TREATMENT DELAYS LEAF AND FLOWER SENESCENCE IN IRIS

Thidiazuron (N-phenyl-N’-1,2,3-thiadiazol-5-ylurea, TDZ), a non-metabolized phenyl urea compound with cytokinin-like activity, is a potent inhibitor of leaf senescence in cut flowers.
In the present study, we determined the potential for TDZ to delay both leaf and flower senescence on cut iris ‘Discovery’ stems.
We found that a postharvest pulse with 200, 500 or 1000 µM TDZ for 6, 12 or 24 hours at 20°C prevented leaf yellowing and extended flower life by 0.6-1.5 days (12-34%) relative to control (0 µM TDZ) stems.
Treatment with TDZ also increased the length of shoots on which flowers develop by 0.7-2.5 cm (8-30%) over control stems.
The benefits of TDZ treatment were maintained even when flowers were held dry for 3 days at 0°C after pulsing.
Treating flowers with 500 µM TDZ in combination with 350 mg/L GA₃ further increased floral shoot growth and led to more complete flower opening.
The extension in flower life may be a direct effect of TDZ treatment in delaying floral senescence or a reflection of improved carbohydrate supply from leaf tissues.
Our findings highlight the potential use for TDZ as a postharvest pulse treatment to improve the opening and longevity of iris flowers.

VI International Postharvest Symposium

A.J. Macnish, M.S. Reid, C.-Z. Jiang

cytokinin, gibberellic acid, flower opening, floral shoots, leaf yellowing, postharvest

https://doi.org/10.17660/ActaHortic.2010.877.244