Physiological changes during postharvest life of cut sunflowers

The vase life of sunflowers (Helianthus annuus) is limited by early wilting of leaves and ray flowers. Vase life was positively correlated with stem length (5 days in 50 cm stems, 9 days in 70 cm stems). We also studied the vase life after a 24 h pulse treatment with a number of chemicals. It was significantly increased by treatment with 150 mg L-1 citric acid. Treatment with 10μl L-1 ethylene reduced vase life and induced both flower bending and abscission of ray flowers. In contrast, 2 mM amino-oxyacetic acid (AOA), an ethylene inhibitor, reduced ethylene production but did not increase vase life. 8-Hydroxyquinoline (8-HQS) at 150 mg L-1 did not lengthen vase life. Vase life was reduced by treatment with 2% sucrose combined with either 150 mg L-1 citric or with 150 mg L-1 8-HQS