VOLUME LXXI NUMBER 2 
PH. 
DOTANICAT (4 87e Tre 
FEBRUARY 1927 
A CHEMICAL AND PHYSIOLOGICAL STUDY OF 
MOTTLING OF LEAVES 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 277 
F. M. ScHERTZ 
(WITH SIX FIGURES) 
Introduction 
During the year 1917 SAMPSON (43) used Coleus Blumei (var. 
Golden Bedder) for studying the chemistry and physiology of 
leaf fall. He noticed that when the leaves were ready to drop 
they had completely or almost completely lost their chlorophyll, 
and that in general they were inclined to lose their chlorophyll or 
to mottle. It was thought that this accentuated material might 
be excellent for the study of the factors involved in mottling of 
leaves in general. 
Loss of chlorophyll from plant organs is a very general phe- 
homenon. It is thought of as an orderly and natural thing in autum- 
nal coloration, but is considered a diseased condition when it occurs 
during the growing season. In the latter case it is spoken of as 
mottling or chlorosis. It is not at all improbable that a study 
which throws new light on mottling will also illuminate autumnal 
coloration. Indeed, this work indicates that the two have many 
things in common. 
Borescu (6) found that algae growing for some time on nutrient 
solutions gradually changed from a dark green to gold or red brown. 
If nitrate solution was added to these cultures, the algae regained 
81 
