The New Student's Reference Work/Autumn Coloration

Autumn Coloration (in plants). This phenomenon is associated with the deciduous habit, and is displayed by shrubs and trees throughout the temperate regions. The vivid colors have attracted a great deal of attention, but as yet no adequate explanation has been offered. The two types of color which appear, the reds and the yellows, seem to be due to different causes. The yellow is a post-mortem change of the green, an example of which may be observed in a poorly blanched stalk of celery, where the transition from green to white is seen to be through yellow. The red color is a product of the living substance of the leaves, manufactured at a time when the work of the leaf is beginning to flag. It has been suggested that the red color is of incidental advantage to the plant in that it raises the temperature of the leaves slightly and in this way protects the living substance from chill while it is retreating into the permanent parts of the plant previous to the fall of the leaves.