1965 Volume 33 Issue 4 Pages 301-308
For the purpose of estimating the deepness of green color and chlorophyll content per leaf area in intact leaves of crop plants, a type of chlorophyllo-meter was constructed, basing on the principle of a difference attenuance which corresponds the difference between the attenuance at 670 mμ attributable to chlorophyll contained in leaves and that at 750 mμ showing the basic absorption. From the photoelectric characters of chlorophyllo-meter, it was suggested that the reading (-log T) of the meter might be directly proportional to the quantity of chlorophyll present within the light path, provided that the leaf tissue is homogeneous and the chlorophyll content is less than a certain limit. The experimental results may clear the following points: (1) High correlations exist between the order of reading and that of deepness of green color judged by naked eye in rice leaves, particularly in case where the reading difference was greater than 10 per cent (Table 1). (2) Relation between the reading and chlorophyll content per leaf area was studied in several crop plants including rice, wheat, Italian rye grass and sweet potato. As the result, very high positive correlations were obtained within respective plant kind when the leaf parts determined were relatively homogeneous exclusive of the midrib or veins (Figs. 5 and 8B), while some lowering in the correlation was noticed when the midrib was placed in the center of light path in graminaceous plants (Figs. 2, 3, 4, 6, 7 and 8A). (3) Regression coefficient of chlorophyll content per leaf area to the reading differs widely according to the kind of plants. There was not, however, much difference in coefficient among the plants which are included in the same family (Fig. 9). It was concluded that the chlorophyllo-meter may be used for determining the deepness of green color and estimating the chlorophyll content per area in intact plant leaves.
