植物体に於ける加里の生理的関與の研究

植物体各部の加里濃度分布と葉齡に伴う葉内加里濃度変化とに及ぼす加里供給量の影響

抄録

Helianthus tuberosus and Ipomosa edulis grown under the various amount of potassium supply were used.
The potassium content in the lamina, petiole, root, tuber, upper and lower parts of stem was determined, and its values were given by mg. per 1cm³ powder volume of the tissues, because it has been proved by R. Kôketsu that the physiological concentration of substance in the plant can be more reasonably expressed by this“powder method”than by the amount per unit fresh weight, dry weight, or unit area of the leaf.
And the distribution of potassium in the guard-cells, palisade and spongy parenchyma and epidermis of the leaf was studied by microchemical method, too.
In the present paper were discussed also the relationship between the potassium content of plant organs and the pH value, refractive index, and electric conductivity of the tissue fluids, which had been studied in author′s previous researches.
The important points be summarized as follows:
1) There were significant direct proportional relations between the amount of supplied potassium and potassium content, pH value and electric conductivity, and inverse proportional relation between potassium content and refractive index in every plant organs.
2) Though the potassium content of the every organs varied according to the amount of supplied potassium, the content of the leaf was always higher than that of other organs, and that of the tuber was always the lowest.
3) The ratio of potassium content of the leaf to other organ became greater and greater as the supplied amount of potassium increased.
4) It was shown that potassium may move from the leaf to another organ, especialy to the reserve organ, on account of the concentration gradient between them.
5) The potassium content of leaves reduced notably with age, and the decrease was more remarkable in the low potassium than in the high-potassium cultures.
6) Potassium was more concentrated in palisade parenchyma than spongy parenchyma, more in the upper cell-layer of the palisade parenchyma than lower layer of the same parenchyma; and these differences in potass um content between these tissues were emphasized by potassium deficiency; i. e., there was a tendency that greatest concentration of potassium occurred in the tissue exposed to sunlight most intensively. From these facts it is suggested that potassium may participate in photosynthesis.