The authors worked previously on the relative contents of chlorophylls by means of paper chromatography. Further the changes of chlorophyll a and b contents as well as the ratio a/b were studied by electrospectrophotometer on different materials under various environments.
1. The change of chlorophyll contents was not found generally among the individuals of the same strain in sweet potato and rice. This result is considered to be due to the high homozygositic characters in these strains or lines.
2. The change of chlorophyll contents was observed corresponding to the developmental stages of leaves in sweet potato. In the growth of ordinally cultivated plants, the chlorophyll contents reached the maximum in some stages (the 7th8th leaves from the top of the stem), and then decreased (toward the stem basis). However, the contents of chlorophyll a and b were considered to change in parallel causing no difference in the ratio a/b.
3. The differences of the chlorophyll contents due to the strains and lines were small in sweet potato but large in those of rice; the content differences in the latter case seem to be attributed to the degree of differentiations in the strains or lines.
4. Concerning the differences of the influence by various fertilizers on the test plants (sweet potato and rice), nitrogen and potassium seem to be considerably favorable to increase the chlorophyll a and b contents. Especially the nitrogen-rich fertilizer increased the chlorophyll contents and the nitrogenless one decreased them. However, the ratio a/b in the both test plants was scarcely affected by these fertilizers.
5. The influence of environmental factors on the sweet potato brought different values on the chlorophyll a and b contents and on the ratio a/b. Especially the influences on the chlorophyll contents were remarkable at the test plants in dry moisture plot or in the fill water plot.
6. The effect of chemicals on the chlorophyll contents was tested on
Lagenaria. Growth promoting substances seem to increase the chlorophyll contents, but weed killers seem to decrease the contents.
7. The change of chlorophyll contents comprises the change of absolute amount and the increase or decrease of chlorophyll a or b content. The relationship between the chlorophyll contents and the photosynthesis should be elucidated in future researches.
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