Transient Water Stress in Carnation Flowers: Effect of Amino-oxyacetic Acid

Abstract

A short and temporary water stress imposed on cut carnation flowers (Dianthus caryophyllus L., cv. White Sim) flowers advanced senescence symptoms, including ethylene production and wilting. Pretreatment with amino-oxyacetic acid (AOA) resulted in an increase of the resistance of the flowers to water stress: water loss during stress was reduced, recovery was more rapid and wilting was delayed. Water stress accelerated the decrease in level of membrane phospholipids, but pretreatment with AOA counteracted this effect. Since the content of membrane sterols was not affected by the treatments, the mole ratio of sterol to phospholipid increased in water-stressed flower petals but not in stressed flowers pretreated with AOA. Membrane permeability and fluidity were also adversely affected by water stress and AOA: water stress alone resulted in an increase in permeability and a decrease in fluidity, but in AOA-pretreated stressed flower petals these parameters were similar to those of nonstressed control flower petals. On the basis of these results two main conclusions can be drawn: (a) Water stress induces alterations in the physical and compositional properties of carnation petal membranes, (b) Pretreatment of the flowers with AOA influences petal membrane traits, most probably via modifications in phospholipid turnover, in a way which counteracts the effects of water stress.