IMPROVING WATER BALANCE AND VASE LIFE OF CUT FOLIAGE BRANCHES OF DODONAEA 'DANA' BY POSTHARVEST TREATMENTS

Dodonaea viscosa hybrid cv. 'Dana' is one of the new foliage branches selected and cultivated in Israel. It has a high export potential as decorative foliage, but has a limited vase life due to leaf wilting. The wilting problem of cut Dodonaea 'Dana' branches results from improper water conductance, which may be caused by xylem vessel occlusions, air embolism, or increased transpiration. Therefore, our research was focused on studying the anatomical properties of Dodonaea 'Dana', as well as on examining the effect of various postharvest treatments on water balance parameters to extend branch longevity. Anatomical analysis revealed that the Dodonaea 'Dana' stems are of diffuse-porous type and are enriched with fibers. In the xylem of the leaf petioles some unidentified depositions were observed, which increased during vase life. Dipping the branches in a commercial antitranspirant solution (Folicote) reduced transpiration but did not improve vase life, suggesting that leaf wilting may result from vessel blockage rather than from increased transpiration. Pulsing Dodonaea 'Dana' branches for 24 h with a solution composed of aluminum sulfate (TOG-10), organic chlorine (TOG-6) and the ethylene action inhibitor, silver thiosulfate (STS), improved longevity, due to a positive effect on branch fresh weight (FW), leaf water potential and water uptake. Holding Dodonaea 'Dana' branches in warm (40°C) water for 30 min improved their water uptake. These treatments probably overcome the problems of vessel occlusions and air embolism. Storage of the branches for 24 h at 6°C to simulate air transportation caused leaf abscission and reduced the branch FW during vase life, suggesting that they should be transported at temperatures higher than 6°C. Our results suggest that treatments which affect the water balance status of Dodonaea 'Dana' cut branches can significantly improve their quality and prolong their shelf life.