Respiration: Even more dramatic are the effects of temperature on respiration. Respiration is the process whereby food and oxygen is converted to energy, heat, water and carbon dioxide. Every living entity respites or it dies.

As respiration rates increase in plants, food reserves are used up and flower and/or plant life shortened. The following table demonstrates the effect of temperature on respiration rates.

Relative respiration rates (heat production)of carnations and roses at different temperatures *

Temperature		Relative rate of respiration
ºC	ºF	Carnation	Rose
0	32	1.0	1.0
20	68	24.6	28.3

Respiration rates affect flower quality even more than transpiration rates. In this example, the relative rate of respiration-and hence heat production-of carnations and roses gives a realistic picture of what happens to flower quality when the temperature is too high. For example, flowers which should be held in the low 30s often will be held at or near 68 degrees Fahrenheit. Both roses and carnations respire about 25 times faster at 68 degrees than at 32 degrees. You could postulate from these data that every hour at 68 degrees is equivalent to 24 hours at 32 degrees. Hence, if a flower such as a rose can be successfully stored at 32 degrees for 10 days, holding these flowers at 68 degrees for only five hours prior to 32 degree storage could effectively cut the total possible storage time at 32 degrees in half.

Other research shows that carnations stored at 41 degrees Fahrenheit (five degrees centigrade) for 14 days had their subsequent vase life reduced by over 65 percent, compared to carnations stored for 14 days at 32 degrees. Yet, many people in the flower industry are happy with flowers held at 41 degrees Fahrenheit. Most would also be happy if carnations and roses arrived at 41 degrees. Perhaps these perspectives should be reconsidered.

* Adapted from Maxie, et al, 1973.

Information reprinted from SAF Flower and Plant Care Manual, (Society of American Florists: Alexandria, VA, 1994), pp. 145-146.