Cold storage of rose flowers: Effects of cold storage and water loss on opening and vase life of ‘Mercedes’ roses

Abstract

The effects of storing ‘Mercedes’ rose flowers ( Rosa hybrida L.) without water at 2°C and 95% RH on flower opening and on vase life were studied. Flowers were held without water (“dry”) or with their stem bases in deionised water (“wet”). Dry storage for 10 days did not significantly reduce the water content of the petals, but did reduce the subsequent vase life at 22°C compared with freshly cut flowers. Dry storage also reduced the maximum flower diameter and the number of reflexed petals after transfer to 22°C. Flowers stored wet had higher petal water content but shorter vase life than dry-stored flowers. The effects of water loss induced at 22°C were studied and compared with the effects of cold storage. Flowers were held at 22°C and 65% RH without water for 24 or 36 h and then placed in water. Only when petal fresh weight loss reached 19% was the flower vase life reduced. Water loss also caused a reduction in maximum flower diameter, petal area and the amount of petal reflexing. The effects of water loss on petal life could be nullified by detaching petals from the flowers and placing them in water. This indicated that in intact flowers, water loss induced an obstruction to subsequent water uptake and rehydration of the petals. In contrast, detachment of petals did not alleviate the effect of cold storage on vase life. It was concluded that water loss during dry cold storage is not the cause of the reduced vase life of cold-stored rose flowers.