PLANT Coors IN Maize 21 
plants developed less rapidly at both excessively high and excessively 
low temperatures than at more moderate temperatures, and that color 
shows less during the early stages of development than during later stages. 
It may be safely concluded, therefore, that color development in maize 
is not notably influenced, except perhaps indirectly, by diverse temper- 
atures. 
SOIL FERTILITY AND COLOR DEVELOPMENT 
There is still another way in which it was thought the excess of water 
might indireetly affect the development of color in maize plants in flooded 
fields. Not only may nutrient salts be removed in part by an excess of 
water, but certain of these salts — nitrates — are not formed normaily 
in very wet soils. Tests were made, therefore, of the relation of soil 
fertility to color development. 
Rich compared with poor soil 
The same plant-color types as were employed in the soil-moisture and 
temperature tests were included in these soil-fertility tests. In fact, for one 
of the tests the same plants were used as in the moisture and temperature 
studies. One lot of plants was grown in rich soil and a duplicate lot in 
poor soil. Field soil furnished the basis of both soils. To one lot was 
added about 50 per cent by measure of thoroly decayed stable manure, 
and to the other about 50 per cent of clean sand. 
The effect of soil fertility on color development of certain color types 
was strikingly apparent from the time the seedlings were two or three 
weeks old. At this age and for some time later, there was no appreciable 
difference in color between purples, sun reds, dilute purples, and dilute 
sun reds. In the rich soil all these color types had very little red color. 
There was some color in the coleoptile and the lower leaf sheath, but none 
in the leaf blades except for a slight amount in their margins. The same 
color types in poor soil had considerable color in the leaf blades and much 
color in the leaf sheaths. The plants in rich soil grew rapidly and were 
dark green, even the lower leaves remaining healthy. The plants in poor 
soil, on the contrary, grew less rapidly and were lighter green, and their 
lower leaves soon became yellow and died. In all cases the leaf blades 
became brilliantly red before they died. This is in strong contrast with 
the condition of the lower leaves of plants in dry, rich soil. When the 
