PHYSIOLOGICAL CHANGES IN CARNATION PETALS AS AFFECTED BY STORAGE AND TRANSPORT

In this study we attempted to elucidate the physiological background for the deterioration of carnation flowers quality during storage and transport. Several changes in physiological processes are characteristic to aging carnation petals: decrease in membrane fluidity and in membrane phospholipid content; decrease in petals capacity for uptake of ¹⁴C-sucrose; and decrease in petal ATPase activity. None of these changes occurred in petals of cold stored flowers.

Flowers exposed to short-term water stress, fully recovered their water saturation deficit (WSD) upon transfer to water at 80% R.H., but their subsequent longevity was shortened. No rise in ethylene production was observed during stress. Pretreatment with amino-oxyacetic acid (AOA), an inhibitor of ethylene production, only partially reduced the rise in WSD and the effect of stress on longevity.

The rise in ethylene production was at the same time for fresh flowers and for pre-stored flowers, but the time lag between the peak of ethylene production and wilting was reduced in stored flowers, indicating increased sensitivity to endogenous ethylene. Storage also increased the sensitivity of flowers to external ethylene.

These results indicate that the deleterious effects of cold storage and water stress on longevity of carnation flowers does not stem from a slow rate of senescence processes in storage, nor from promotion of ethylene biosynthesis, but from enhancing processes increasing the sensitivity of the tissue to ethylene.